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you 've probably heard that carbon dioxide is warming the earth , but how does it work ? is it like the glass of a greenhouse or like an insulating blanket ? well , not entirely . the answer involves a bit of quantum mechanics , but do n't worry , we 'll start with a rainbow . if you look closely at sunlight separated through a prism , you 'll see dark gaps where bands of color went missing . where did they go ? before reaching our eyes , different gases absorbed those specific parts of the spectrum . for example , oxygen gas snatched up some of the dark red light , and sodium grabbed two bands of yellow . but why do these gases absorb specific colors of light ? this is where we enter the quantum realm . every atom and molecule has a set number of possible energy levels for its electrons . to shift its electrons from the ground state to a higher level , a molecule needs to gain a certain amount of energy . no more , no less . it gets that energy from light , which comes in more energy levels than you could count . light consists of tiny particles called photons and the amount of energy in each photon corresponds to its color . red light has lower energy and longer wavelengths . purple light has higher energy and shorter wavelengths . sunlight offers all the photons of the rainbow , so a gas molecule can choose the photons that carry the exact amount of energy needed to shift the molecule to its next energy level . when this match is made , the photon disappers as the molecule gains its energy , and we get a small gap in our rainbow . if a photon carries too much or too little energy , the molecule has no choice but to let it fly past . this is why glass is transparent . the atoms in glass do not pair well with any of the energy levels in visible light , so the photons pass through . so , which photons does carbon dioxide prefer ? where is the black line in our rainbow that explains global warming ? well , it 's not there . carbon dioxide does n't absorb light directly from the sun . it absorbs light from a totally different celestial body . one that does n't appear to be emitting light at all : earth . if you 're wondering why our planet does n't seem to be glowing , it 's because the earth does n't emit visible light . it emits infared light . the light that our eyes can see , including all of the colors of the rainbow , is just a small part of the larger spectrum of electromagnetic radiation , which includes radio waves , microwaves , infrared , ultraviolet , x-rays , and gamma rays . it may seem strange to think of these things as light , but there is no fundamental difference between visible light and other electromagnetic radiation . it 's the same energy , but at a higher or lower level . in fact , it 's a bit presumptuous to define the term visible light by our own limitations . after all , infrared light is visible to snakes , and ultraviolet light is visible to birds . if our eyes were adapted to see light of 1900 megahertz , then a mobile phone would be a flashlight , and a cell phone tower would look like a huge lantern . earth emits infrared radiation because every object with a temperature above absolute zero will emit light . this is called thermal radiation . the hotter an object gets , the higher frequency the light it emits . when you heat a piece of iron , it will emit more and more frequencies of infrared light , and then , at a temperature of around 450 degrees celsius , its light will reach the visible spectrum . at first , it will look red hot . and with even more heat , it will glow white with all of the frequencies of visible light . this is how traditional light bulbs were designed to work and why they 're so wasteful . 95 % of the light they emit is invisible to our eyes . it 's wasted as heat . earth 's infrared radiation would escape to space if there were n't greenhouse gas molecules in our atmophere . just as oxygen gas prefers the dark red photons , carbon dioxide and other greenhouse gases match with infrared photons . they provide the right amount of energy to shift the gas molecules into their higher energy level . shortly after a carbon dioxide molecule absorbs an infrared photon , it will fall back to its previous energy level , and spit a photon back out in a random direction . some of that energy then returns to earth 's surface , causing warming . the more carbon dioxide in the atmosphere , the more likely that infrared photons will land back on earth and change our climate .
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if our eyes were adapted to see light of 1900 megahertz , then a mobile phone would be a flashlight , and a cell phone tower would look like a huge lantern . earth emits infrared radiation because every object with a temperature above absolute zero will emit light . this is called thermal radiation .
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explain the relationship between thermal radiation and every object with a temperature above absolute zero .
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technetium is the first element in the periodic table which is naturally radioactive , so it is the lightest radioactive element and so for a long time very little was known about it . now people are beginning to study it in suitably strong surroundings of ů to contain the radioactivity and they have discovered that the chemistry of technetium is in many ways quite similar to that of rhenium or manganese . and there are a number of medical treatments now which use the radioactivity of technetium in order to trace through the body and look at their emissions to find out about different diseases . and so the chemistry of technetium is becoming more important in the medical role , how to make a compound that you can get into the body safely and quickly so that it can be used for medical purposes .
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technetium is the first element in the periodic table which is naturally radioactive , so it is the lightest radioactive element and so for a long time very little was known about it . now people are beginning to study it in suitably strong surroundings of ů to contain the radioactivity and they have discovered that the chemistry of technetium is in many ways quite similar to that of rhenium or manganese .
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technetium is the lightest radioactive element in the periodic table . how do we use this property ?
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one of the most striking properties about life is that it has color . to understand the phenomenon of color , it helps to think about light as a wave . but , before we get to that , let 's talk a little bit about waves in general . imagine you 're sitting on a boat on the ocean watching a cork bob up and down in the water . the first thing you notice about the motion is that it repeats itself . the cork traces the same path over and over again ... up and down , up and down . this repetitive or periodic motion is characteristic of waves . then you notice something else ... using a stopwatch , you measure the time it takes for the piece of cork to go over its highest position down to its lowest and then back up again . suppose this takes two seconds . to use the physics jargon , you 've measured the period of the waves that cork is bobbing on . that is , how long it takes a wave to go through its full range of motion once . the same information can be expressed in a different way by calculating the wave 's frequency . frequency , as the name suggest , tells you how frequent the waves are . that is , how many of them go by in one second . if you know how many seconds one full wave takes , then it 's easy to work out how many waves go by in one second . in this case , since each wave takes 2 seconds , the frequency is 0.5 waves per second . so enough about bobbing corks ... what about light and color ? if light is a wave , then it must have a frequency . right ? well ... yes , it does . and it turns out that we already have a name for the frequency of the light that our eyes detect . it 's called color . that 's right . color is nothing more than a measure of how quickly the light waves are waving . if our eyes were quick enough , we might be able to observe this periodic motion directly , like we can with the cork and the ocean . but the frequency of the light we see is so high , it waves up and down about 400 million million times a second , that we ca n't possibly see it as a wave . but we can tell , by looking at its color , what its frequency is . the lowest frequency light that we can see is red and the highest frequency is purple . in between all the other frequencies form a continous band of color , called the visible spectrum . so , what if you had a yellow pencil sitting on your desk ? well , the sun emits all colors of light , so light of all colors is hitting your pencil . the pencil looks yellow because it reflects yellow light more than it reflects the other colors . what happens to the blue , purple and red light ? they get absorbed and the energy they are carrying is turned into heat . it is similar with objects of other colors . blue things reflect blue light , red things reflect red light and so on . white objects reflect all colors of light , while black things do exactly the opposite and absorb at all frequencies . this - by the way - is why it 's uncomfortable to wear your favorite metallica t-shirt on a sunny day .
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the cork traces the same path over and over again ... up and down , up and down . this repetitive or periodic motion is characteristic of waves . then you notice something else ... using a stopwatch , you measure the time it takes for the piece of cork to go over its highest position down to its lowest and then back up again .
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what do you call the repetitive motion of a wave ( such as the way a cork may bob up and down in the ocean ) ?
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so , i think all good tornado talks need to start with an awesome tornado shot . and this is not that awesome tornado shot . that was the first tornado i ever saw , it was really cool , really scary , and i 'm showing it to you guys because that 's why i got into the field in the first place . so even though it 's a bad photograph , it was really cool to be out there the first time . but now i 'm taking real tornado footage . fast forward a few years . this is a few years ago , during a field project called vortex2 , where myself and a bunch of other scientists were out there , surrounding tornadoes with different types of instrumentation and trying to figure out how tornadoes form . it 's a big question we 're trying to answer . it sounds like a very basic one , but it 's something we 're still trying to figure out . we 're also still trying to figure out what the winds are like near the surface . we know what the winds are like above building level , but we really do n't know what they 're like at the surface and how that relates to what we 're seeing above building level . most tornadoes form from what we call supercell thunderstorms . supercell thunderstorms are what you commonly think of as tornado-raising storms . they 're big , rotating thunderstorms that happen a lot of times in the midsection of the united states . but the problem is that even though they 're rotating up above , it does n't mean they 're rotating at the surface . and when we look at these storms and at these pictures and at the data we have , they all kind of look the same . and it 's really problematic if we 're trying to make tornado forecasts or warnings , because we only want to warn or forecast about the storms that are going to actually make a tornado . one of the big , critical distinguishing features , we think , between these storms , is something about the rear-flank downdraft . so these big rotating thunderstorms have this downdraft that wraps around the rear edge of it , hence the `` rear-flank '' downdraft . but we think how warm that is , how buoyant that air is , and then also how strong the updraft it 's wrapping into , makes a big difference on whether or not it 's going to make a tornado . there 's a lot more that goes into it -- i 'll tell you about that in a second . once you actually get a tornado , again , the problem that we have is getting measurements near the surface . it 's really hard to get measurements near the surface -- most people do n't want to drive into tornadoes . there are a few exceptions ; you might have seen them on tv shows . but most people do n't want to do that . even getting instrumentation in the path of the tornado is pretty tricky , too . because , again , you do n't want to be that close to a tornado because sometimes the winds around the tornado are strong as well . so getting information , that critical location , is key for us because , again , we do n't know if the winds that we 're seeing above ground level , way above building level , actually map to the surface , if they 're stronger , weaker , or about the same as what we 're seeing above buildings . the way we get at answering a lot of these questions -- and i 'm an observationalist ; i love to get out in the field , and collect data on tornadoes -- we compile a lot of observations . i work with this group who operates mobile radars , and they 're exactly what they say -- basically , a radar on the back of a big blue truck , and we drive up really close to tornadoes to map out the winds . we map out the precipitation . we map out all these different things that are going on in order to better understand the processes in these storms . and that bottom there , that 's what a tornado looks like when you 're looking at it with a mobile radar , and really close . also , what we do is a lot of modeling , so we do a lot of computer models and simulations , because the atmosphere is governed by the laws of physics . so we can model the laws of physics and see where the tornado might go , where the storm might go , how strong the winds are near the surface and not actually have to go out in the field . but of course , we want to have both observations and modeling to move forward with the science . so , i showed you that video earlier that went real quick , too . this is what it looks like , looking at it with a radar . so you saw it visually , but this is what i get really excited about when i see now in the field , stuff that looks like this . the really exciting thing about looking at stuff like this is that we caught this storm from when it did n't make a tornado to when it made a tornado and intensified and when it dissipated . this is the one of the rare data sets that we have out there that were able to study the entire life cycle of a tornado . i talked about how we think that rear-flank downdraft is important because it tilts , there 's a lot of spin in the atmosphere , but the problem with all this spin in the atmosphere is it needs to be oriented vertically , because that 's what tornadoes are doing , and it needs to orientated vertically near the ground . so we think this rear-flank downdraft just pulses . and these pulses in this rear-flank downdraft , we think , are very important for converging that rotation , but also getting that rotation into the right place . other things we 've learned is that we have gotten a bunch of fortuitous measurements in the path of the tornadoes and very near the surface . and we found out that the winds near the surface are actually pretty comparable to what we 're seeing 30 , 40 meters above ground level . so there 's not a big reduction in what we 're seeing above the surface to what we 're seeing at house level . and that was a pretty surprising finding for us , because we kind of assumed that the winds decrease pretty substantially near the surface . i 'm going to end with this real quick . and this is not my last tornado i ever saw , but i really like this image , because this was taken with one of those mobile radars i was talking about . this is a tornado , not a hurricane , and this is what it looks like when you 're really close to it . and i find this amazing , that we can actually take technology this close to these types of storms and see these inner workings . and for those of you who look at tornado images often , you can see there 's a lot going on -- there 's rain spiraling , and you can actually see the debris cloud associated with this tornado . i look forward to the future and future technologies and being able to learn a lot more about these storms , as the world advances , as you guys contribute to the science and we 're able to really learn more about how tornadoes form . thank you . ( applause )
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so , i think all good tornado talks need to start with an awesome tornado shot . and this is not that awesome tornado shot .
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the enhanced fujita scale ________ .
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some superheroes can grow to the size of a building at will . that 's very intimidating ! but a scientist must ask where the extra material is coming from . the law of conservation of mass implies that mass can neither be created nor destroyed , which means that our hero 's mass will not change just because his size changes . for instance , when we bake a fluffy sponge cake , even though the resulting delicious treat is much bigger in size than the cake batter that went into the oven , the weight of the cake batter should still equal the weight of the cake plus the moisture that has evaporated . in a chemical equation , molecules rearrange to make new compounds , but all the components should still be accounted for . when our hero expands from 6 feet tall to 18 feet tall , his height triples . galileo 's square cube law says his weight will be 27 - 3 times 3 times 3 equals 27 - times his regular weight since he has to expand in all three dimensions . so , when our superhero transforms into a giant , we are dealing with two possibilities . our hero towering at 18 feet still only weighs 200 pounds , the original weight in this human form . now , option two , our hero weighs 5,400 pounds - 200 pounds times 27 equals 5,400 pounds - when he is 18 feet tall , which means he also weighs 5,400 pounds when he is 6 feet tall . nobody can get in the same elevator with him without the alarm going off . now , option two seems a little more scientifically plausible , but it begs the question , how does he ever walk through the park without sinking into the ground since the pressure he is exerting on the soil is calculated by his mass divided by the area of the bottom of his feet ? and what kind of super socks and super shoes is he putting on his feet to withstand all the friction that results from dragging his 5,400 pound body against the road when he runs ? and can he even run ? and i wo n't even ask how he finds pants flexible enough to withstand the expansion . now , let 's explore the density of the two options mentioned above . density is defined as mass divided by volume . the human body is made out of bones and flesh , which has a relatively set density . in option one , if the hero weighs 200 pounds all the time , then he would be bones and flesh at normal size . when he expands to a bigger size while still weighing 200 pounds , he essentially turns himself into a giant , fluffy teddy bear . in option two , if the hero weighs 5,400 pounds all the time , then he would be bones and flesh at 18 feet with 5,400 pounds of weight supported by two legs . the weight would be exerted on the leg bones at different angles as he moves . bones , while hard , are not malleable , meaning they do not bend , so they break easily . the tendons would also be at risk of tearing . tall buildings stay standing because they have steel frames and do not run and jump around in the jungle . our hero , on the other hand , one landing at a bad angle and he 's down . assuming his bodily function is the same as any mammal 's , his heart would need to pump a large amount of blood throughout his body to provide enough oxygen for him to move 5,400 pounds of body weight around . this would take tremendous energy , which he would need to provide by consuming 27 times 3,000 calories of food every day . now , that is roughly 150 big macs . 27 times 3,000 calculated equals 81,000 calculated slash 550 calories equals 147 . he would n't have time to fight crime because he would be eating all the time and working a 9-to-5 job in order to afford all the food he eats . and what about superheroes who can turn their bodies into rocks or sand ? well , everything on earth is made out of elements . and what defines each element is the number of protons in the nucleus . that is how our periodic table is organized . hydrogen has one proton , helium , two protons , lithium , three protons , and so on . the primary component of the most common form of sand is silicon dioxide . meanwhile , the human body consists of 65 % oxygen , 18 % carbon , 10 % hydrogen , and 7 % of various other elements including 0.002 % of silicon . in a chemical reaction , the elements recombine to make new compounds . so , where is he getting all this silicon necessary to make the sand ? sure , we can alter elements by nuclear fusion or nuclear fission . however , nuclear fusion requires so much heat , the only natural occurrence of this process is in stars . in order to utilize fusion in a short amount of time , the temperature of the area needs to be hotter than the sun . every innocent bystander will be burned to a crisp . rapid nuclear fission is not any better since it often results in many radioactive particles . our hero would become a walking , talking nuclear power plant , ultimately harming every person he tries to save . and do you really want the heat of the sun or a radioactive nuclear plant inside of your body ? now , which superpower physics lesson will you explore next ? shifting body size and content , super speed , flight , super strength , immortality , and invisibility .
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the law of conservation of mass implies that mass can neither be created nor destroyed , which means that our hero 's mass will not change just because his size changes . for instance , when we bake a fluffy sponge cake , even though the resulting delicious treat is much bigger in size than the cake batter that went into the oven , the weight of the cake batter should still equal the weight of the cake plus the moisture that has evaporated . in a chemical equation , molecules rearrange to make new compounds , but all the components should still be accounted for .
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if a baker is putting an even layer of frosting on the surface of all the cakes , would a smaller cake or a bigger cake have the higher frosting to cake ratio ? please use the square-cube law to justify your answer .
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translator : nadja nathan reviewer : denise rq hello . i 'm chetan bhatt and when i give my name , i 'm often asked , `` where are you from ? '' i normally say , `` london . '' ( laughter ) and then i 'm asked , `` where are you originally from ? '' and if i happen to be particularly cheeky that day , i say , `` well , originally , i am from my mummy 's warm and cosy tummy . '' as we all are . obviously not my mum 's , but our own mothers . ( laughter ) but of course , i know what they 're really asking , so i say something like : `` well , my grandparents and my mum were born in india . my dad and i were born in kenya . and i was brought up in london . '' then they got me mapped : `` ah , you 're a kenyan asian . i have worked with one of those . '' and from my name they probably assume that i 'm a hindu . and this sort of fixes me for them . but what about the christians , and the muslims , and the atheists that i grew up with ? or the socialists , and the liberals , even the occasional tory , indeed all kinds of women and men , vegetable sellers , factory workers , cooks , car mechanics , living in my working class area . in some profoundly important way , they 're also a part of me , and are here with me . maybe that 's why i find it hard to respond to questions about identity and about origin . and it 's not just a sort of teenager refusal to be labelled . that 's not where i am coming from . it 's about our own most identities , the ones we put our hands up to , the ones that we cheer for , the ones that we fight for , the ones that we love or hate . it 's about how we apprehend ourselves as well as others . it is about identities we just assume that we have without thinking too much about them . but our responses to questions of identity and origin have substantial social and political importance . we see the wars , the rages of identity , going on all around us . we see violent religious , national , and ethnic disputes , and often the conflict is based on old stories of identity , and belonging , and origins . and these identities are based on myths , typically about ancient primordial origins . and these could be about adam and eve , or about the supremacy of a caste or gender , or about the vitality of a supposed race , or about the past glories of an empire or civilization , or about a piece of land that some imagined deity has gifted . people say that origin stories and identity myths make us feel secure . what 's wrong with that ? they give us a sense of belonging . identity is your cultural clothing , and it can make you feel warm and fuzzy inside . but does it really ? do we really need identity myths to feel safe ? because i see , religious , national , ethnic disputes adding to human misery . can i dare you to refuse every origin myth that claims you ? if you consider yourself to be human - and i 'm assuming that everybody here does – then humanity is your mirror . how then are you going to be at ease with the complexity of humanity that faces you ? what 's your feeling towards the person that others consider to be your enemy in the world ? what if we reject every single primordial origin myth and develop a deeper sense of personhood , one responsible to humanity as a whole rather than to a particular tribe ? or a radically different idea of humanity that exposes how origin myths mystify , disguise global power , rapacious exploitation , poverty , the worldwide oppression of women and girls , and of course massive , accelerating inequalities . origin myths are closely linked to tradition . the word 'tradition ' points to something old and permanent , almost natural . and people assume tradition is just history , simply the past condensed into a nice story . but let 's not confuse tradition with history , the two are often in severe conflict . origin stories are usually recently created fictions of ancient belonging , and they are absurd given the complexity of humanity and our vastly interconnected even if very unequal world . and today , we see claims to tradition that claim to be ancient changing rapidly in front of our eyes . i was brought up in the 1970s , near wembley , with asian , english , caribbean , irish families living in our streets . and the neo-nazi national front was massive then , with regular marches and attacks on us , and a permanent threat , and often a frequent reality of violence against us , on the streets , in our homes ; typically by neo-nazis and other racists . and i remember during a general election , a leaflet came through our letterbox with a picture of the national front candidate for our area . and the picture was of our next door neighbour . he threatened to shoot me once , when i played in the garden as a kid . and many weekends , shaven headed national front activists arrived at his house and emerged with scores of placards screaming that they wanted us to `` go back home '' . but today , he 's one of my mum 's best mates , he is a very lovely , gentle , and kind man . and at some point in his political journey out of fascism , he embraced a broader idea of humanity . there was a hindu family that we got to know well , and you have to understand that life in our street was a little bit like a setting for an asian soap opera , everyone knew everyone else 's business , even if they did not want it to be known by anyone at all . you really had no choice in this matter . but in this family there was a quiet little boy who went to the same school as i did . and after i left school , i did n't hear much more about him except that he 'd gone off to india . around 2000 , i remember seeing this short book . the book was unusual because it was written by a british supporter of al qaeda . and in it , the author calls for attacks in britain . this is in 1999 . so , 9/11 and the invasion of iraq was still in the future . and he helped scout new york bombing targets . he taught others how to make a dirty bomb to use on the london underground . and he plotted a massive bombing campaign in london shopping areas . he 's a very high risk security prisoner in the uk , and one of the most important al qaeda figures to be arrested in britain . the author of that book was that very same quiet little boy who went to my school . so a hindu boy from britain became an al qaeda fighter and a most wanted international terrorist . and he rejected what people would call his hindu , or indian , or british identity . and he became someone else . he refused to be who he was . he recreated himself . and this kind of journey is very common for young men and women who become involved in al qaeda , or islamic state , or other transnational armed groups . al qaeda 's media spokesman is a white american from a jewish and catholic mixed background . neither he nor the boy from my school were from muslim backgrounds . there is no point asking them where they are from . a more important question is , `` where are they going ? '' and i would also put it to you that exactly the same journey occurs for those young men and women who were brought up in muslim family backgrounds . most of those who join al qaeda , and other salafi-jihadi groups from europe , asia , north america , even in many cases the middle east are those who have comprehensively rejected their backgrounds to become , in essence , new people . they spend an enormous amount of time attacking their parents ' backgrounds as profane , impure , blasphemous , the wrong type of islam . and their vision instead is a fantastical view of cosmic apocalypse . it 's a born again vision . discard your past , your society , your family , and friends since they are all impure . instead , become someone else , your true self . your authentic self . this is n't about a return to the past , it is about using a forgery of the past to envision an appalling future which begins today , at year zero . this is why over an 80 % of the victims of al qaeda and the islamic state are people from muslim backgrounds . the first act by salafi-jihadi groups when they take over an area is to destroy existing muslim institutions , including mosques , shrines , preachers , practices . their main purpose is to control and punish people internally , to dictate the spaces that women may go , their clothing , family relations , beliefs , even the minute detail of how one prays . and you get the impression in the news that 'they ' are after 'us ' in the west , but they are actually mainly after people from other muslim backgrounds . in their view , no other muslim can ever be pure enough . so , ordinary beliefs and practices that have existed for centuries are attacked as impure by teenagers from birmingham or london who know nothing about the histories that they so joyously obliterate . here , their claim to tradition is at war with history but they 're nevertheless , very certain about their purity and about the impurity of others . purity , certainty , the return to authentic tradition ; the quest for these can lead to lethal visions of perfect societies and perfected people . this is what the main hindu fundamentalist organization in india looks like today at its mass rally . maybe it reminds you of the 1930s in italy or germany . and this movement 's roots are indeed in fascism . it was a member of this same hindu fundamentalist movement who shot dead mahatma gandhi . hindu fundamentalists today view this murderer as a national hero , and they want to put up statues of him throughout india . they have been involved for decades in large scale mass violence against minorities . they ban books , art , films , they attack romantic couples on valentine 's day , christians on christmas day . they do n't like others talking critically about what they see as their ancient culture or using its images , or caricaturing it , or drawing cartoons about it . but the people making the strongest possible claims about ancient timeless hindu religion are dressed in brown shorts and white shirts , while claiming , oddly , to be the original aryan race , just like the violent salafi-jihadis who make their claims , about their primordial religion , while dressed in black military uniforms and wearing balaclavas . these people are manufacturing pure , pristine identities of conviction , and of certainty . fundamentalists see religion and culture as their sole property , their property . but religions and cultures are processes , they are not things . they are impermanent , they are messy , they are impure . look at any religion and you will see disputes and arguments going all the way down . any criticism of religion , in any form , has to therefore be part of the expansive sense of humanity we should aspire to . i respect your right to have and to express your religion , or your culture , or your opinion , but i do n't necessarily have to respect the content . i might like some of it , and i like how an old church looks for example , but this is n't the same thing . similarly , i have a human right to say something that you may find offensive , but you do not have a human right not to be offended . in a genuine democracy we are constantly offended since people express different views all the time . they also change their views , so their views are impermanent . you can not fix someone 's political views based on their religious , or national , or cultural background . these points about religious purity also apply to nationalism and to racism . i 'm always puzzled to have pride in your national or ethnic identity . pride in the accident of birth from a woman 's cosy womb ? belief in your superiority because of the accident of birth ? these people have very firm ideas about what belongs and what does n't belong inside the cosy national cultures that they imagine . and i 'm going to caricature a bit here , but only a little bit . i want you to imagine the supporter of some little englander or british nationalist political party , and he 's sitting at home . and he is screaming about foreigners invading his country , while watching fox news , an american cable channel owned by an australian , on his south korean television set which was bought by his spanish credit card , which is paid off monthly by his high street british bank which has its headquarters in hong kong . he supports a british football team owned by a russian . his favourite brand of fish and chips is owned by a swedish venture capitalist firm . the church he sometimes goes to has its creed decided in meetings in ghana . his union jack underpants were made in india . ( laughter ) ( applause ) thank you . and they 're laundered regularly by a very nice polish lady . there is no pure ethnicity , nation , or culture . and the ethical choices we have today are far wider than being forced to choose between racist right and religious right visions ; dismal visions of culture . culture is n't just about language , food , clothing , and music , but gender relations , ancient monuments , a heritage of sacred texts . but culture can also be what 's been decided to be culture by those who have a political stake in pounding culture into the shape of a prison . big political identity claims are elite bids for power . they 're not answers to social or economic or political injustices , they often obscure them . what about the large number of people across the globe who ca n't point to a monument from their past who do n't possess a sacred written text , who ca n't hark back to the past glories of a civilization or empire ? are these people lesser parts of humanity ? what about you now listening to this ? what about you and your identity ? because you stitch your experiences and your thoughts into a continuous person moving forward in time . and this is what you are when you say 'i am ' or 'me ' . but this also includes all of your hopes and dreams all of the 'yous ' that you could have been , and it includes all the other people and the things that are in the biography of who you are . they , the others , are also a part of you , moving forward with you . your authentic self , if such a thing exists , is a complex , messy , and uncertain self . and that is a very good thing . why not value those impurities and uncertainties ? maybe clinging to pure identities is a sign of immaturity , and ethnic , nationalist , and religious traditions are bad for you . why not be skeptical about every primordial origin claim made on your behalf ? why not reject the identity myths that call on you to belong , that politicians and community leaders , so-called community leaders , place on you ? if we do n't need origin stories and fixed identities , we can challenge ourselves to think creatively about each other and our future . and here culture always takes care of itself . i 'm not worried about culture . cultures are creative , dynamic processes , not imposed laws and boundaries . i 'd be the first to admit that some cultural innovations can seem , a little [ haggis curry ] ( laughter ) a little bit unusual . but so what if they are ? because the same dynamism of cultures can bring us unexpected gifts . i want to end with the story of two muslims from two very different times . in the late 1980s , when the protests against salman rushdie book `` the satanic verses '' were emerging in britain , dr. ghayasuddin siddiqui was at the absolute heart of the muslim fundamentalist movement in britain and internationally . he went as part of a group from britain - a delegation - to persuade ayatollah khomeini , in iran , to denounce rushdie 's book as a blasphemy and khomeini , of course , as we know , said that rushdie had to be put to death . at the very same time , i was involved in a tiny little group that was defending rushdie 's right to free expression . now , a few years later , dr. siddiqui was with some other fundamentalist activists and they had heard news about a young girl in pakistan and she had been raped , and then she had been killed for adultery . and his friends around him said the killing was unfortunate , but then again , she 's only a girl . and dr. siddiqui told me , many years later , that at that moment , something shattered in his heart . he decided to refuse to be who he was . like my former national front neighbour , his was a flight away from these ideas of primordial purity , he instead became a tireless , deeply courageous fighter for women and children 's rights , and human rights , and against religious fundamentalism of all kinds , and racism , and extreme nationalism . he staunchly opposed the fundamentalists he previously worked with and he worked with youngsters to pull them away , wean them away from salafi-jihadi ideas and he continues this work to this day aged 75 . and part of his inspiration and his energy comes from this man , in whose name dr. siddiqui initiated an annual lecture . this is abu walid muhammad ibn rushd , a very senior muslim judge and thinker in cordoba in the 12th century . and his writings were considered deeply blasphemous , heretical , and evil . long after he died , followers of his work were ruthlessly hunted down , banished , and killed over several centuries by the most powerful religious institution of the medieval period . that institution was the roman catholic church . why ? because ibn rushd said that something true in religion may conflict with something that your reason finds to be true on earth . but the latter is still true . there are two distinct worlds of truth , one based on our reason and evidence , and one that is divine . and the state , political power , social law are in the realm of reason . religious life is a different realm . they should be kept separated . social and political life should be governed by our reason not by religion . and you can see why the church was upset by his writings as indeed were some muslims during his lifetime , because he gives us a strong statement of secularism of a kind which is normal in europe today . history plays many tricks on us . it undermines our fixed truths and what we believe to be 'our culture ' and 'their culture ' . ibn rushd , someone who happens to be a muslim is considered one of the key influences in the introduction and spread of secularism in europe . so against religious nationalist and racial purists of all kinds , can you make his story a part of your own ? not because he happened to be a muslim , not because he happened to be an arab , but because he was a human being with some very good ideas that shook his world and ours . thank you . ( applause )
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in some profoundly important way , they 're also a part of me , and are here with me . maybe that 's why i find it hard to respond to questions about identity and about origin . and it 's not just a sort of teenager refusal to be labelled .
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why does bhatt find it hard to respond to questions about identity and about origin ?
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what do these animals have in common ? more than you might think . along with over 5,000 other species , they 're mammals , or members of class mammalia . all mammals are vertebrates , meaning they have backbones . but mammals are distinguished from other vertebrates by a number of shared features . that includes warm blood , body hair or fur , the ability to breathe using lungs , and nourishing their young with milk . but despite these similarities , these creatures also have many biological differences , and one of the most remarkable is how they give birth . let 's start with the most familiar , placental mammals . this group includes humans , cats , dogs , giraffes , and even the blue whale , the biggest animal on earth . its placenta , a solid disk of blood-rich tissue , attaches to the wall of the uterus to support the developing embryo . the placenta is what keeps the calf alive during pregnancy . directly connected to the mother 's blood supply , it funnels nutrients and oxygen straight into the calf 's body via the umbilical cord , and also exports its waste . placental mammals can spend far longer inside the womb than other mammals . baby blue whales , for instance , spend almost a full year inside their mother . the placenta keeps the calf alive right up until its birth , when the umbilical cord breaks and the newborn 's own respiratory , circulatory , and waste disposal systems take over . measuring about 23 feet , a newborn calf is already able to swim . it will spend the next six months drinking 225 liters of its mothers thick , fatty milk per day . meanwhile , in australia , you can find a second type of mammal - marsupials . marsupial babies are so tiny and delicate when they 're born that they must continue developing in the mother 's pouch . take the quoll , one of the world 's smallest marsupials , which weighs only 18 milligrams at birth , the equivalent of about 30 sugar grains . the kangaroo , another marsupial , gives birth to a single jelly bean-sized baby at a time . the baby crawls down the middle of the mother 's three vaginas , then must climb up to the pouch , where she spends the next 6-11 months suckling . even after the baby kangaroo leaves this warm haven , she 'll return to suckle milk . sometimes , she 's just one of three babies her mother is caring for . a female kangaroo can often simultaneously support one inside her uterus and another in her pouch . in unfavorable conditions , female kangaroos can pause their pregnancies . when that happens , she 's able to produce two different kinds of milk , one for her newborn , and one for her older joey . the word mammalia means of the breast , which is a bit of a misnomer because while kangaroos do produce milk from nipples in their pouches , they do n't actually have breasts . nor do monotremes , the third and arguably strangest example of mammalian birth . there were once hundreds of monotreme species , but there are only five left : four species of echidnas and the duck-billed platypus . the name monotreme means one hole referring to the single orifice they use for reproduction , excretion , and egg-laying . like birds , reptiles , fish , dinosaurs , and others , these species lay eggs instead of giving birth to live young . their eggs are soft-shelled , and when their babies hatch , they suckle milk from pores on their mother 's body until they 're large enough to feed themselves . despite laying eggs and other adaptations that we associate more with non-mammals , like the duck-bill platypus 's webbed feet , bill , and the venomous spur males have on their feet , they are , in fact , mammals . that 's because they share the defining characteristics of mammalia and are evolutionarily linked to the rest of the class . whether placental , marsupial , or monotreme , each of these creatures and its unique birthing methods , however bizarre , have succeeded for many millennia in bringing new life and diversity into the mammal kingdom .
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directly connected to the mother 's blood supply , it funnels nutrients and oxygen straight into the calf 's body via the umbilical cord , and also exports its waste . placental mammals can spend far longer inside the womb than other mammals . baby blue whales , for instance , spend almost a full year inside their mother .
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most of the mammals that exist on earth today are placental mammals . name three placental mammals from three different continents that were not mentioned in the video .
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how does your smartphone know exactly where you are ? the answer lies 12,000 miles over your head in an orbiting satellite that keeps time to the beat of an atomic clock powered by quantum mechanics . phew . let 's break that down . first of all , why is it so important to know what time it is on a satellite when location is what we 're concerned about ? the first thing your phone needs to determine is how far it is from a satellite . each satellite constantly broadcasts radio signals that travel from space to your phone at the speed of light . your phone records the signal arrival time and uses it to calculate the distance to the satellite using the simple formula , distance = c x time , where c is the speed of light and time is how long the signal traveled . but there 's a problem . light is incredibly fast . if we were only able to calculate time to the nearest second , every location on earth , and far beyond , would seem to be the same distance from the satellite . so in order to calculate that distance to within a few dozen feet , we need the best clock ever invented . enter atomic clocks , some of which are so precise that they would not gain or lose a second even if they ran for the next 300 million years . atomic clocks work because of quantum physics . all clocks must have a constant frequency . in other words , a clock must carry out some repetitive action to mark off equivalent increments of time . just as a grandfather clock relies on the constant swinging back and forth of a pendulum under gravity , the tick tock of an atomic clock is maintained by the transition between two energy levels of an atom . this is where quantum physics comes into play . quantum mechanics says that atoms carry energy , but they ca n't take on just any arbitrary amount . instead , atomic energy is constrained to a precise set of levels . we call these quanta . as a simple analogy , think about driving a car onto a freeway . as you increase your speed , you would normally continuously go from , say , 20 miles/hour up to 70 miles/hour . now , if you had a quantum atomic car , you would n't accelerate in a linear fashion . instead , you would instantaneously jump , or transition , from one speed to the next . for an atom , when a transition occurs from one energy level to another , quantum mechanics says that the energy difference is equal to a characteristic frequency , multiplied by a constant , where the change in energy is equal to a number , called planck 's constant , times the frequency . that characteristic frequency is what we need to make our clock . gps satellites rely on cesium and rubidium atoms as frequency standards . in the case of cesium 133 , the characteristic clock frequency is 9,192,631,770 hz . that 's 9 billion cycles per second . that 's a really fast clock . no matter how skilled a clockmaker may be , every pendulum , wind-up mechanism and quartz crystal resonates at a slightly different frequency . however , every cesium 133 atom in the universe oscillates at the same exact frequency . so thanks to the atomic clock , we get a time reading accurate to within 1 billionth of a second , and a very precise measurement of the distance from that satellite . let 's ignore the fact that you 're almost definitely on earth . we now know that you 're at a fixed distance from the satellite . in other words , you 're somewhere on the surface of a sphere centered around the satellite . measure your distance from a second satellite and you get another overlapping sphere . keep doing that , and with just four measurements , and a little correction using einstein 's theory of relativity , you can pinpoint your location to exactly one point in space . so that 's all it takes : a multibillion-dollar network of satellites , oscillating cesium atoms , quantum mechanics , relativity , a smartphone , and you . no problem .
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that characteristic frequency is what we need to make our clock . gps satellites rely on cesium and rubidium atoms as frequency standards . in the case of cesium 133 , the characteristic clock frequency is 9,192,631,770 hz .
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about how far away are the orbiting gps satellites ?
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hendrix , cobain and page . they can all shred , but how exactly do the iconic contraptions in their hands produce notes , rhythm , melody and music . when you pluck a guitar string , you create a vibration called a standing wave . some points on the string , called nodes , do n't move at all , while other points , anti-nodes , oscillate back and forth . the vibration translates through the neck and bridge to the guitar 's body , where the thin and flexible wood vibrates , jostling the surrounding air molecules together and apart . these sequential compressions create sound waves , and the ones inside the guitar mostly escape through the hole . they eventually propagate to your ear , which translates them into electrical impulses that your brain interprets as sound . the pitch of that sound depends on the frequency of the compressions . a quickly vibrating string will cause a lot of compressions close together , making a high-pitched sound , and a slow vibration produces a low-pitched sound . four things affect the frequency of a vibrating string : the length , the tension , the density and the thickness . typical guitar strings are all the same length , and have similar tension , but vary in thickness and density . thicker strings vibrate more slowly , producing lower notes . each time you pluck a string , you actually create several standing waves . there 's the first fundamental wave , which determines the pitch of the note , but there are also waves called overtones , whose frequencies are multiples of the first one . all these standing waves combine to form a complex wave with a rich sound . changing the way you pluck the string affects which overtones you get . if you pluck it near the middle , you get mainly the fundamental and the odd multiple overtones , which have anti-nodes in the middle of the string . if you pluck it near the bridge , you get mainly even multiple overtones and a twangier sound . the familiar western scale is based on the overtone series of a vibrating string . when we hear one note played with another that has exactly twice its frequency , its first overtone , they sound so harmonious that we assign them the same letter , and define the difference between them as an octave . the rest of the scale is squeezed into that octave divided into twelve half steps whose frequency is each 2^ ( 1/12 ) higher than the one before . that factor determines the fret spacing . each fret divides the string 's remaining length by 2^ ( 1/12 ) , making the frequencies increase by half steps . fretless instruments , like violins , make it easier to produce the infinite frequencies between each note , but add to the challenge of playing intune . the number of strings and their tuning are custom tailored to the chords we like to play and the physiology of our hands . guitar shapes and materials can also vary , and both change the nature and sound of the vibrations . playing two or more strings at the same time allows you to create new wave patterns like chords and other sound effects . for example , when you play two notes whose frequencies are close together , they add together to create a sound wave whose amplitude rises and falls , producing a throbbing effect , which guitarists call the beats . and electric guitars give you even more to play with . the vibrations still start in the strings , but then they 're translated into electrical signals by pickups and transmitted to speakers that create the sound waves . between the pickups and speakers , it 's possible to process the wave in various ways , to create effects like distortion , overdrive , wah-wah , delay and flanger . and lest you think that the physics of music is only useful for entertainment , consider this . some physicists think that everything in the universe is created by the harmonic series of very tiny , very tense strings . so might our entire reality be the extended solo of some cosmic jimi hendrix ? clearly , there 's a lot more to strings than meets the ear .
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they can all shred , but how exactly do the iconic contraptions in their hands produce notes , rhythm , melody and music . when you pluck a guitar string , you create a vibration called a standing wave . some points on the string , called nodes , do n't move at all , while other points , anti-nodes , oscillate back and forth .
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on an electric guitar , pickups translate string vibrations into _____ .
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translator : tom carter reviewer : bedirhan cinar ( zombie sounds ) doctor 1 : so , how did it get to be this way ? doctor 2 : well , it 's my professional opinion that the large gaping bite mark on its shoulder might have something to do with it . d1 : thanks . i mean , what causes its behavioral abnormalities ? d2 : well , we know all behaviors are rooted in the brain , so i 'd expect that something 's gone terribly wrong probably in there . d1 : thanks again , doctor obvious . let me be more specific . what changes in the brain would have to occur in order to cause this kind of behavior ? d2 : hmm . well , let 's see . the first thing i notice is how it moves . stiff legged , with long , lumbering steps , very slow and awkward . almost like what you 'd see in parkinson 's disease . maybe something 's wrong with his basal ganglia ? those are a collection of deep brain regions that regulate movement , through a neurochemical called dopamine . although most people think of dopamine as the `` happy '' chemical of the brain , the dopamine-containing neurons in the basal ganglia die off in parkinson 's disease , that 's what causes it . makes it more and more difficult to initiate actions . d1 : what ? look again at how it moves . stiff legs , long stance , these are n't parkinsonian movements , parkinson 's patients take short , shuffling steps , and the posture 's all wrong . this looks to me like what happens when the cerebellum is damaged . the cerebellum 's a little cauliflower-shaped area in the back of your head , but do n't let its size fool you . that little guy contains almost half of the neurons in the entire brain . patients who suffer degeneration from this region , something called spino-cerebellar ataxia , show a lack of coordination that results in stiff legs , wide stance , and a lumbering walk . my money 's on the cerebellum . d2 : touché . ok . so we 've nailed its motor problems . now what about that whole groaning , lack of talking thing ? d1 : hmm . you know , it sounds kind of like expressive aphasia , or broca 's aphasia , which makes producing words difficult . this is caused by damage to the inferior frontal gyrus , or possibly the anterior insula , both regions behind your temple on the left side of your head . d2 : i think you 're only half right . zombies definitely ca n't communicate , that 's for sure . but they do n't seem to do a good job of understanding things either . watch this . hey , walker ! your father smelt of elderberries ! ( laughs ) see ? no reaction . either it 's not a monty python fan , or it ca n't understand me . i 'd say this is like spot-on fluent wernicke 's aphasia , damage to an area at the junction of two of the brain 's lobes , temporal and parietal , typically on the left side of the brain , is the culprit . this area is physically connected to broca 's area , that you mentioned , by a massive bundle of neurofibers called the arcuate fasciculus . i hypothesize that this massive bundle of connections is completely wiped out in a zombie . it would be like taking out the superhighway between two cities . one city that manufactures a product , and the other that ships it out to the rest of the world . without that highway , the product distribution just shuts down . d1 : so , basically it 's a moot point to reason with a zombie , since they ca n't understand you , let alone talk back . d2 : ( laughs ) i mean , you could try , man , but i 'm going to stay on this side of the glass .
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look again at how it moves . stiff legs , long stance , these are n't parkinsonian movements , parkinson 's patients take short , shuffling steps , and the posture 's all wrong . this looks to me like what happens when the cerebellum is damaged .
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how do reports on pervious neurological patients help us to deduce the nature of a brain injury in future patients ?
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a few years ago , i got one of those spam emails . and it managed to get through my spam filter . i 'm not quite sure how , but it turned up in my inbox , and it was from a guy called solomon odonkoh . ( laughter ) i know . ( laughter ) it went like this : it said , `` hello james veitch , i have an interesting business proposal i want to share with you , solomon . '' now , my hand was kind of hovering on the delete button , right ? i was looking at my phone . i thought , i could just delete this . or i could do what i think we 've all always wanted to do . ( laughter ) and i said , `` solomon , your email intrigues me . '' ( laughter ) ( applause ) and the game was afoot . he said , `` dear james veitch , we shall be shipping gold to you . '' ( laughter ) `` you will earn 10 % of any gold you distributes . '' ( laughter ) so i knew i was dealing with a professional . ( laughter ) i said , `` how much is it worth ? '' he said , `` we will start with smaller quantity , '' -- i was like , aww -- and then he said , `` of 25 kgs . ( laughter ) the worth should be about $ 2.5 million . '' i said , `` solomon , if we 're going to do it , let 's go big . ( applause ) i can handle it . how much gold do you have ? '' ( laughter ) he said , `` it is not a matter of how much gold i have , what matters is your capability of handling . we can start with 50 kgs as trial shipment . '' i said , `` 50 kgs ? there 's no point doing this at all unless you 're shipping at least a metric ton . '' ( laughter ) ( applause ) he said , `` what do you do for a living ? '' ( laughter ) i said , `` i 'm a hedge fund executive bank manager . '' ( laughter ) this is n't the first time i 've shipped bullion , my friend , no no no . then i started to panic . i was like , `` where are you based ? '' i do n't know about you , but i think if we 're going via the postal service , it ought to be signed for . that 's a lot of gold . '' he said , `` it will not be easy to convince my company to do larger quantity shipment . '' i said , `` solomon , i 'm completely with you on this one . i 'm putting together a visual for you to take into the board meeting . hold tight . '' ( laughter ) this is what i sent solomon . ( laughter ) ( applause ) i do n't know if we have any statisticians in the house , but there 's definitely something going on . ( laughter ) i said , `` solomon , attached to this email you 'll find a helpful chart . i 've had one of my assistants run the numbers . ( laughter ) we 're ready for shipping as much gold as possible . '' there 's always a moment where they try to tug your heartstrings , and this was it for solomon . he said , `` i will be so much happy if the deal goes well , because i 'm going to get a very good commission as well . '' and i said , `` that 's amazing , what are you going to spend your cut on ? '' and he said , `` on realestate , what about you ? '' i thought about it for a long time . and i said , `` one word ; hummus . '' ( laughter ) `` it 's going places . ( laughter ) i was in sainsbury 's the other day and there were like 30 different varieties . also you can cut up carrots , and you can dip them . have you ever done that , solomon ? '' ( laughter ) he said , `` i have to go bed now . '' ( laughter ) ( applause ) `` till morrow . have sweet dream . '' i did n't know what to say ! i said , `` bonsoir my golden nugget , bonsoir . '' ( laughter ) guys , you have to understand , this had been going for , like , weeks , albeit hitherto the greatest weeks of my life , but i had to knock it on the head . it was getting a bit out of hand . friends were saying , `` james , do you want to come for a drink ? '' i was like , `` i ca n't , i 'm expecting an email about some gold . '' so i figured i had to knock it on the head . i had to take it to a ridiculous conclusion . so i concocted a plan . i said , `` solomon , i 'm concerned about security . when we email each other , we need to use a code . '' and he agreed . ( laughter ) i said , `` solomon , i spent all night coming up with this code we need to use in all further correspondence : lawyer : gummy bear . bank : cream egg . legal : fizzy cola bottle . claim : peanut m & amp ; amp ; ms . documents : jelly beans . western union : a giant gummy lizard . '' ( laughter ) i knew these were all words they use , right ? i said , `` please call me kitkat in all further correspondence . '' ( laughter ) i did n't hear back . i thought , i 've gone too far . i 've gone too far . so i had to backpedal a little . i said , `` solomon , is the deal still on ? kitkat . '' ( laughter ) because you have to be consistent . then i did get an email back from him . he said , `` the business is on and i am trying to blah blah blah ... '' i said , `` dude , you have to use the code ! '' what followed is the greatest email i 've ever received . ( laughter ) i 'm not joking , this is what turned up in my inbox . this was a good day . `` the business is on . i am trying to raise the balance for the gummy bear -- ( laughter ) so he can submit all the needed fizzy cola bottle jelly beans to the creme egg , for the peanut m & amp ; amp ; ms process to start . ( laughter ) send 1,500 pounds via a giant gummy lizard . '' ( applause ) and that was so much fun , right , that it got me thinking : like , what would happen if i just spent as much time as could replying to as many scam emails as i could ? and that 's what i 've been doing for three years on your behalf . ( laughter ) ( applause ) crazy stuff happens when you start replying to scam emails . it 's really difficult , and i highly recommend we do it . i do n't think what i 'm doing is mean . there are a lot of people who do mean things to scammers . all i 'm doing is wasting their time . and i think any time they 're spending with me is time they 're not spending scamming vulnerable adults out of their savings , right ? and if you 're going to do this -- and i highly recommend you do -- get yourself a pseudonymous email address . do n't use your own email address . that 's what i was doing at the start and it was a nightmare . i 'd wake up in the morning and have a thousand emails about penis enlargements , only one of which was a legitimate response -- ( laughter ) to a medical question i had . but i 'll tell you what , though , guys , i 'll tell you what : any day is a good day , any day is a good day if you receive an email that begins like this : ( laughter ) `` i am winnie mandela , the second wife of nelson mandela the former south african president . '' i was like , oh ! -- that winnie mandela . ( laughter ) i know so many . `` i need to transfer 45 million dollars out of the country because of my husband nelson mandela 's health condition . '' let that sink in . she sent me this , which is hysterical . ( laughter ) and this . and this looks fairly legitimate , this is a letter of authorization . but to be honest , if there 's nothing written on it , it 's just a shape ! ( laughter ) i said , `` winnie , i 'm really sorry to hear of this . given that nelson died three months ago , i 'd describe his health condition as fairly serious . '' ( laughter ) that 's the worst health condition you can have , not being alive . she said , `` kindly comply with my bankers instructions . one love . '' ( laughter ) i said , `` of course . no woman , no cry . '' ( laughter ) ( applause ) she said , `` my banker will need transfer of 3000 dollars . one love . '' ( laughter ) i said , `` no problemo . i shot the sheriff . '' [ ( but i did not shoot the deputy ) ] ( laughter ) thank you . ( applause )
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a few years ago , i got one of those spam emails . and it managed to get through my spam filter . i 'm not quite sure how , but it turned up in my inbox , and it was from a guy called solomon odonkoh .
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what does veitch 's interactions with spam emails tell us about the purpose of spam ?
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we all know the scene : dorothy closes her eyes , and repeats the good witch 's mantra , `` no coordinates exist like one 's domicile , no coordinates exist like one 's domicile , no coordinates exist like one 's domicile . '' only dorothy does n't say that . she says five one-syllable words , `` there 's no place like home . '' each a word you probably learned in your first year of speaking , each perfectly concise . it 's not that l. frank baum did n't have a thesaurus , it 's that in most cases $ 10 words fail . would aerosmith have had a hit with `` ambulate this direction ? '' probably not . would patrick henry have ignited a revolution by saying , `` provide me with liberty or bestow upon me fatality ? '' unlikely . when it comes to words , bigger is n't always better . ten-dollar words are rendered worthless if they 're not understood . that 's not to say every piece of literature should be written at a fourth-grade reading level , but it is important to know your audience . if you 're a novelist , your audience is probably expecting 300 pages of vivid descriptors . at the very least , they 're expecting you wo n't use the same 50 words to fill those pages . but most of us do n't have the luxury of a captive audience . we 're competing against a whole world of distractions and we 're fighting for space in an attention span that continues to shrink across generations . so get to the point already . variety may be the spice of life , but brevity is its bread and butter . so when it comes to $ 10 words , save your money and buy a scrabble board .
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we all know the scene : dorothy closes her eyes , and repeats the good witch 's mantra , `` no coordinates exist like one 's domicile , no coordinates exist like one 's domicile , no coordinates exist like one 's domicile . '' only dorothy does n't say that .
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which of america ’ s founding fathers gets a nod in the video ?
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this episode of scishow might make you a little paranoid about computer viruses and internet security . but that ’ s probably a good thing . when we talk about a computer virus , we usually mean any kind of code that ’ s designed to do harm and spread itself to more computers . they ’ re created by malicious programmers who might want to use your computer to attack other targets , or make money by stealing your personal information . they could also just be trying to see how far their virus will spread . different viruses can affect windows , mac , and linux computers , and even the data servers that keep companies , and the internet itself , running . antivirus programs help , but they can have trouble dealing with threats they ’ ve never seen before . over the years , there have been thousands and thousands of viruses spread online , and they ’ ve caused billions of dollars of damage from lost productivity , wasted resources , and broken machines . a few dozen of those viruses stand out , some spread especially quickly , or affected a lot of people , or created a ton of damage all by themselves . some did all of the above . since a lot of viruses were very bad , in a lot of different ways , it ’ s hard to pick out which ones were objectively the worst . but with that in mind , here are 5 of those extra-destructive viruses . these are snippets of code that changed the way people thought about computer security , both the people designing the viruses , and the people trying to protect against them . say it ’ s may 1999 . you ’ re an unsuspecting computer user who ’ s never gotten a virus , let alone been trained to look for the signs that an email might be malicious . you get an email from someone you know , with a subject line that says it ’ s an important message . the message inside just says “ here 's that document you asked for ... do n't show anyone else , ” with a winking emoticon . the attachment is a word document labeled “ list. ” so you click on it , because you ’ re curious … and a list of porn sites pops up . at this point , you realize the email was probably some kind of virus . but it ’ s too late , the first 50 people in your address book have already gotten a copy of the exact same email , with a subject line saying that the message is from you . that was the melissa virus . it spread through microsoft ’ s outlook email program , and even though the attachment seemed like an innocent word document , it was able to infect computers because of something called a macro . a macro is a specific kind of computer program that ’ s used to create shortcuts . in word , they ’ re meant to make it easier to edit a document . instead of manually making a set of changes to the document one by one , a macro is a piece of code that will let you do it all with one click . the problem is , that functionality gives macros a lot of power over your computer . so a macro that ’ s actually a virus , like melissa , takes advantage of that power using malicious code . in just a few days , melissa spread to hundreds of thousands of computers . it didn ’ t do any damage to the computers themselves , but it did make email services slow way down , and cost companies about $ 80 million overall . eventually , it professionals and antivirus programs put safeguards in place to stop the virus , both by preventing the emails from sending , and by keeping them from reaching other people ’ s inboxes if they did send . the programmer behind the virus , david l. smith , was caught about a week after melissa was first released . he spent 20 months in prison and paid a $ 5000 fine . why melissa ? apparently that was the name of a stripper he met in florida . melissa spread very quickly because of social engineering : it was designed to make people curious enough to open the attachment . the iloveyou virus , which spread about a year later , in may of 2000 , was also successful because of social engineering . it reached around 45 million computers in just two days , and caused about $ 10 billion dollars in damage . the infected email had the subject line “ iloveyou ” , and came with an attachment titled “ love letter for you.txt ” . when you clicked on the attachment , the virus would go through your system ’ s files , looking for media like documents , images , and audio files . then it would overwrite them with copies of itself , so if you didn ’ t have your files backed up , you ’ d lose all your data . meanwhile , the virus would send itself to everyone in your address book . iloveyou was a type of virus called a worm , which means that it was a standalone program that didn ’ t use a host program to run , the way melissa used microsoft word . it looked like a text document , so opening it seemed relatively harmless , but the “ love letter for you ” file was actually a type of file called a visual basic script , which uses the file extension .vbs . users couldn ’ t see the vbs at the end of the filename , though , because the windows operating system they were using was hiding file extensions by default . visual basic scripts send your computer a list of instructions to execute . so if they ’ re meant to cause harm , they can be very dangerous , and do things like delete all of your files . like melissa , the iloveyou worm was mostly contained after a few days . it was filtered out of people ’ s inboxes and companies released fixes for machines that had been infected . but plenty of damage had already been done . the virus was attributed to two programmers in the philippines . but even though they were both arrested , they were released because at the time , there weren ’ t any laws against what they ’ d done . iloveyou showed just how easily , and quickly , a worm could spread , and how much damage it could do . on january 25 , 2003 , just before 6 am , the internet broke . south korea lost both internet and cell phone service . 300,000 people in portugal couldn ’ t connect to the internet . airlines couldn ’ t process tickets and had to cancel flights . bank atms went down . 911 in seattle had to start using paper to log calls . even for a lot of devices that were still connected to the internet , the connections had become suddenly very slow , even by 2003 standards . so what happened ? as you can probably guess by now , all of this chaos was caused by a virus . but it wasn ’ t the kind of virus that spreads through email , or infects the sort of computer most people have at home . slammer was a worm that targeted sql servers , which store databases using a piece of microsoft software called … microsoft sql server . it worked by taking advantage of a bug in the software : it sent the server a specially-formatted piece of code , one that looked like it was just an ordinary request for information , but actually reprogrammed the server to send out more copies of the same worm . the worm spread faster than any other virus ever had , infecting 75,000 servers in just 10 minutes . those servers were all sending requests to thousands of other servers , which couldn ’ t handle all the traffic . in all , millions of servers were affected , and the internet went kaput for a while . slammer is thought to have caused about $ 1.2 billion in damage before it was stopped , and the programmer behind it was never caught . the whole mess could have been prevented , though , six months earlier , microsoft released a fix for the bug that slammer exploited , but lots of people just hadn ’ t installed it yet . the 2007 storm worm was another worm that spread through email . but its purpose wasn ’ t to destroy your computer or information , it wanted to take over your computer instead . the original subject line read “ 230 dead as storm batters europe , ” which is where the virus gets its name . but instead of an attachment , the email contained a link to a website , which promptly downloaded the virus onto the user ’ s machine . and then … nothing happened . or at least , nothing the user could see . storm worm was designed to be as invisible as possible , so that you wouldn ’ t detect and destroy it . this way , it was able to use your computer to do all kinds of stuff in the background . the virus would connect your machine to what ’ s known as a bot-net , a collection of computers that form a network . a bot-net can do all kinds of things , from launching coordinated attacks that slow down or disable the web servers that keep a company going , to stealing passwords , banking , and identity information . but at first , the network didn ’ t actually do very much , it just grew . antivirus and it companies knew it was there , but it was hard to stop it . for one thing , different machines in the network had different jobs . only a small fraction of infected computers were in charge of spreading the virus . another small set of computers served as the command-and-control centers , which sent out instructions and helped control the rest of the bot-net . the rest just followed those instructions . so even if you shut down most of the computers spreading the virus , the network would still be out there , doing its thing . but it was hard to stop storm worm from spreading in the first place . sure , it started out as an email about a storm in europe , but soon there were emails with all kinds of different headlines . and since they were coming from someone in your address book , they seemed relatively innocent . to make matters worse , antivirus programs had trouble finding the virus on an infected machine . the code for storm worm was designed to change every half hour , so it always looked different . at its peak , the storm worm bot-net consisted of about 1.5 million machines . the programmers didn ’ t seem to be using it for anything nefarious , though , they just sold the network to other criminals and scammers . after a while , companies did figure out how to stop the virus from spreading . they removed it from infected machines , and by late 2008 , the bot-net was mostly gone . but , like with slammer , the people behind it were never caught . mebroot is also a virus that slowly started to spread in 2007 . and its main goal was also to hook you up to a bot-net , called torpig . both are especially sophisticated . mebroot usually gets into your computer via a drive-by download , where you visit a malicious web page and the program downloads in the background without you even knowing it . from there , it overwrites what ’ s known as the master boot record , the part of your computer ’ s hard drive that stores the instructions that tell your computer how to start up . being able to control the master boot record gives mebroot a lot of power , because it can tell your computer what to do right from the start . and what it tells your computer , is to connect to the torpig bot-net … which then steals all of your information . torpig uses a spying technique known as man-in-the-browser , which is as creepy as it sounds . it lurks in your browser , logging everything you do and any private information you happen to enter . it ’ ll also try to actively steal information , using fake websites that look and behave exactly like the originals , but send the data to the torpig servers instead . and all the while , you ’ d never know it was there . by late 2008 , torpig had stolen info connected to 500,000 bank accounts , and again , the people who created it haven ’ t been caught . by now , you might be wondering whether a worm will make the internet go down tomorrow , or whether your computer is secretly part of a bot-net . and i don ’ t really blame you . there are things you can do to avoid getting viruses : install an antivirus program . don ’ t click on suspicious links or emails from nigerian princes . keep your operating system and computer programs updated with the latest security patches . computers are amazing , but they just do what they ’ re told , and when viruses tell them to do bad things , it can create a lot of damage . thanks for watching this episode of scishow , brought to you by our patrons on patreon . if you want to help support the show , just go to patreon.com/scishow . and don ’ t forget to go to youtube.com/scishow and subscribe !
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the whole mess could have been prevented , though , six months earlier , microsoft released a fix for the bug that slammer exploited , but lots of people just hadn ’ t installed it yet . the 2007 storm worm was another worm that spread through email . but its purpose wasn ’ t to destroy your computer or information , it wanted to take over your computer instead .
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what is a `` worm '' virus ?
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you 've probably seen an email or an internet post about how weird and random english spelling seems to be . but what if i told you that it actually makes perfect sense ? in fact , that 's spelling 's job : making sense . think of spelling a word as peeling back the layers of an onion . the first layer is a word 's sense and meaning . often there are multiple layers of meaning . another layer is the word 's structure . think of the center of the onion as a word 's base element , its essential kernel of meaning . a free-base element , like o-n-e , or t-w-o , can stand on its own as a word , like one , or two . a bound base , like the r-u-p-t of `` erupt '' or `` rupture '' needs another element in order to surface in a word . two or more bases give us compounds , like `` twofold '' or `` someone '' or `` bankrupt . '' once we figure out a word 's meaningful elements , we can peel back its history to shed a little more light on why it 's spelled as it is . the word `` two , '' for example , needs its `` w '' in order to mark its connection to words like `` twice , '' `` twelve , '' `` twenty , '' `` twin '' and `` between . '' a word 's history is another layer of the onion . with that understanding , let 's investigate the word `` one . '' first we need to check in with what it means . unique , single , solitary . `` one 's '' historical layers include its relatives `` only , '' `` once , '' `` eleven , '' and even `` a , '' `` an '' and `` any . '' but it 's the morphological relatives - the ones that share the base o-n-e - that are really astonishing . there are the familiar ones , like `` anyone , '' and `` one-track '' and `` oneself '' - those are obvious . but let 's take a look at some unexpected derivations of the word `` one . '' the word `` alone '' is built from the prefix a-l plus the base o-n-e . it 's the same a-l prefix that we see in `` always , '' `` already , '' `` almighty '' and `` almost . '' it means `` all . '' the word `` alone '' means `` all one . '' it was misanalysed in the middle ages as having the prefix `` a , '' like in `` asleep '' and `` awake '' and `` around , '' and a new base was born : l-o-n-e , which then developed into its own family . in the word `` atone , '' we find the familiar preposition `` at '' compounded with the base o-n-e. see , when we atone for something we 've done wrong , we attempt to make things whole again , to fix what 's broken , to be at one again with whomever we hurt . but here 's perhaps the best one of all : the word `` onion , '' which is also frequently derided as irregular or crazy , for its spelling of `` uh '' with an o . but again , if we look into the word 's structure , and its history , it 's a mystery no more . when we look at the roots of an onion , we learn that it is written as o-n-e plus i-o-n , the same suffix we find in `` tension , '' `` action , '' `` union '' and thousands of other words in english . unlike the many cloves in a head of garlic , an onion has a single bulb . it is marked by the state or condition of oneness . like an onion , english is one - one single writing system shared across time and space . its structure and its history have many layers , and peeling them apart can really add flavor to our language and spice up our understanding . see , spelling is never just about spelling , but about how written words make sense . it 's almost enough to make you want to cry .
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the word `` two , '' for example , needs its `` w '' in order to mark its connection to words like `` twice , '' `` twelve , '' `` twenty , '' `` twin '' and `` between . '' a word 's history is another layer of the onion . with that understanding , let 's investigate the word `` one . ''
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the word onion
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as far as we know , medieval england was never invaded by ice zombies , or terrorized by dragons , but it was shaken by a power struggle between two noble families spanning generations and involving a massive cast of characters with complex motives and shifting loyalties . if that sounds familiar , it 's because the historical conflicts known as the wars of the roses served as the basis for much of the drama in game of thrones . the real-life seeds of war were sewn by the death of king edward iii in 1377 . edward 's oldest son had died before his father , but his ten-year-old son , richard ii , succeeded to the throne ahead of edward 's three surviving sons . this skipping of an entire generation left lingering claims to the throne among their various offspring , particularly the lancasters , descended from edward 's third son , and the yorks , descended from his fourth son . the name of the ensuing wars comes from the symbols associated with the two families , the white rose of york and the red rose of lancaster . the lancasters first gained the throne when richard ii was deposed by his cousin henry iv in 1399 . despite sporadic unrest , their reign remained secure until 1422 , when henry v 's death in a military campaign left an infant henry vi as king . weak-willed and dominated by advisors , henry was eventually convinced to marry margaret of anjou to gain french support . margaret was beautiful , ambitious , and ruthless in persecuting any threat to her power , and she distrusted richard of york , most of all . york had been the king 's close advisor and loyal general , but was increasingly sidelined by the queen , who promoted her favorite supporters , like the earls of suffolk and somerset . york 's criticism of their inept handling of the war against france led to his exclusion from court and transfer to ireland . meanwhile , mounting military failures , and corrupt rule by margaret and her allies caused widespread discontent , and in the midst of this chaos , richard of york returned with an army to arrest somerset and reform the court . initially unsuccessful , he soon got his chance when he was appointed protector of the realm after henry suffered a mental breakdown . however , less than a year later , henry suddendly recovered and the queen convinced him to reverse york 's reforms . york fled and raised an army once more . though he was unable to directly seize the throne , he managed to be reinstated as protector and have himself and his heirs designated to succeed henry . but instead of a crown , york 's head acquired a pike after he was killed in battle with the queen 's loyalists . his young son took up the claim and was crowned edward iv . edward enjoyed great military success against the lancasters . henry was captured , while margaret fled into exile with their reportedly cruel son , edward of westminster . but the newly crowned king made a tragic political mistake by backing out of his arranged marriage with a french princess to secretly marry the widow of a minor noble . this alienated his most powerful ally , the earl of warwick . warwick allied with the lancasters , turned edward 's jealous younger brother , george , against him , and even briefly managed to restore henry as king , but it did n't last . edward recaptured the throne , the lancaster prince was killed in battle , and henry himself died in captivity not long after . the rest of edward iv 's reign was peaceful , but upon his death in 1483 , the bloodshed resumed . though his twelve-year-old son was due to succeed him , edward 's younger brother richard iii declared his nephews illegitimate due to their father 's secret marriage . he assumed the regency himself and threw the boys in prison . though no one knows what ultimately became of them , after a while , the princes disappeared and richard 's power seemed secure . but his downfall would come only two years later from across the narrow sea of the english channel . henry tudor was a direct descendant of the first duke of lancaster , raised in exile after his father 's death in a previous rebellion . with richard iii 's power grab causing a split in the york faction , henry won support for his royal claim . raising an army in france , he crossed the channel in 1485 and quickly defeated richard 's forces . and by marrying elizabeth of york , elder sister of the disappeared princes , the newly crowned henry vii joined the two roses , finally ending nearly a century of war . we often think of historical wars as decisive conflicts with clearly defined winners and losers . but the wars of the roses , like the fiction they inspired , show us that victories can be uncertain , alliances unstable , and even the power of kings as fleeting as the seasons .
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and by marrying elizabeth of york , elder sister of the disappeared princes , the newly crowned henry vii joined the two roses , finally ending nearly a century of war . we often think of historical wars as decisive conflicts with clearly defined winners and losers . but the wars of the roses , like the fiction they inspired , show us that victories can be uncertain , alliances unstable , and even the power of kings as fleeting as the seasons .
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why were they called the wars of the roses ?
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commas are tricky things , especially when subordinates and conjunctions are involved . if you can remember a few basic rules , a simple law of physics , and some common scenarios , you will be able to use commas correctly . i like to think of the different parts of our sentence as characters . let 's meet a few of them : the tiny conjunctions , the mighty subordinates , and the clever comma . conjunctions are small and nimble . they are words that connect clauses , words , and phrases . you can easily remember the conjunctions by remembering the acronym fanboys . the conjunctions are for , and , nor , but , or , yet , so . because they 're so small , more often than not , they require the help of a comma but not always . subordinates , on the other hand , are the wwe heavyweight champions of sentences . they are words that connect two unequal things , dependent and independent clauses . subordinates make it very clear what is being prioritized in a sentence . commonly used subordinates are although , because , before , however , unless , and even though . because subordinates are all about power , they can do a lot of heavy lifting by themselves . but , of course , sometimes even the strongest among us needs some help from our clever friends . because our clever comma is so nice , she often roams her neighborhood looking for some community service to do . today , as soon as she leaves her house , she sees a subordinate lifting the weight of two complete sentences , one on each arm . bartheleme loves engaging in political debate even though he usually loses . the comma asks the subordinate if he needs help . well , we know that subordinates are the wwe heavyweight champions of sentences . they can easily hold the weight of these two complete sentences because they are distributed evenly on both arms . so , when the comma asks if it can help , the subordinate is appalled at the idea of needing assistance . no thanks , maybe next time ! so , the comma continues on . soon , she seems a couple of subordinates attempting to lift the weight of sentences directly in front of themselves . even though bartheleme loves to sing , he never sings in front of others . the comma asks the subordinates if they need help . they might not want to admit it , but this time the subordinates do need help . complete sentences weigh quite a bit . simple physics tells us that it 's easier to balance heavy objects if the weight is evenly distributed . so , while the subordinates are quite capable of balancing two complete sentences when carrying the weight on both sides , they 're having trouble picking just one up . the comma rushes over to help the struggling subordinates , but how will she help ? when subordinates begin sentences , the comma will place herself directly after the first thought or complete sentence . after helping the subordinates , our comma heroine continues on and spots a conjunction holding the weight of two complete sentences . bartheleme was accepted into the university of chicago , and he is on the waitlist for stanford university . the comma asks the conjunction if he needs help . of course he does ! hurry ! the comma rushes and places itself before the conjunction . fanboys are n't as militant as subordinates . for this reason , the commas do n't have to fall in line behind the fanboys . fanboys are courteous creatures . they allow the comma to go ahead of them . helping others is hard work ! on her way home , our comma sees a conjunction holding up the weight of a complete sentence and a fragment sentence . bartheleme is going to major in molecular biology or interpretive dance . the now-exhausted comma asks the conjunction if he needs help lifting the items . this is one of the rare occassions where a conjunction does n't need the help of a comma . the conjunction assures the comma that help is n't needed , which is good for the comma because by now , all it wants to do is go home and rest up for another day of vigilant sentence constructing .
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today , as soon as she leaves her house , she sees a subordinate lifting the weight of two complete sentences , one on each arm . bartheleme loves engaging in political debate even though he usually loses . the comma asks the subordinate if he needs help .
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even though people don ’ t think i am shy i am .
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for most of history , humans had no idea what purpose the heart served . in fact , the organ so confused leonardo da vinci , that he gave up studying it . although everyone could feel their own heart beating , it was n't always clear what each thump was achieving . now we know that the heart pumps blood . but that fact was n't always obvious , because if a heart was exposed or taken out , the body would perish quickly . it 's also impossible to see through the blood vessels , and even if that were possible , the blood itself is opaque , making it difficult to see the heart valves working . even in the 21st century , only a few people in surgery teams have actually seen a working heart . internet searches for heart function , point to crude models , diagrams or animations that do n't really show how it works . it 's as if there has been a centuries old conspiracy amongst teachers and students to accept that heart function can not be demonstrated . meaning that the next best thing is simply to cut it open and label the parts . that way students might not fully grasp the way it works , but can superficially understand it , learning such concepts as the heart is a four-chambered organ , or potentially misleading statements like , mammals have a dual-circulation : one with blood going to the lungs and back , and another to the body and back . in reality , mammals have a figure-eight circulation . blood goes from one heart pump to the lungs , back to the second heart pump , which sends it to the body , and then back to the first pump . that 's an important difference because it marks two completely different morphologies . this confusion makes many students wary of the heart in biology lessons , thinking it signals an intimidating subject full of complicated names and diagrams . only those who end up studying medicine compeltely understand how it all actually works . that 's when its functions become apparent as medics get to observe the motion of the heart 's valves . so , let 's imagine you 're a medic for a day . what you 'll need to get started is a whole fresh heart , like one from a sheep or pig . immerse this heart in water and you 'll see that it does n't pump when squeezed by hand . that 's because water does n't enter the heart cleanly enough for the pumping mechanism to work . we can solve this problem in an extraordinarly simple way . simply identify the two atria and cut them off , trimming them down to the tops of the ventricles . this makes the heart look less complicated because the atria have several incoming veins attached . so without them there , the only vessels remaining are the two major heart arteries : the aorta and pulmonary artery , which rise like white columns from between the ventricles . it looks -- and really is -- very simple . if you run water into the right ventricle from a tap ( the left also works , but less spectacularly ) , you 'll see that the ventricular valve tries to close against the incoming stream . and then ventricle inflates with water . squeeze the ventricle and a stream of water squirts out of the pulmonary artery . the ventricular valves , called the tricuspid in the right ventricle and the mitral in the left , can be seen through the clear water opening and closing like parachutes as the ventricle is rhythmically squeezed . this flow of water mimics the flow of blood in life . the valves are completely efficient . you 'll notice they do n't leak at all when the ventricles are squeezed . over time , they also close against each other with very little wear and tear , which explains how this mechanism continues to work seamlessly for more than 2 billion beats a heart gives in its lifetime . now , anyone studying the heart can hold one in their hands , make it pump for real and watch the action unfold . so place your hand above your own and feel its rhymic beat . understanding how this dependable inner pump works gives new resonance to the feeling you get when you run a race , drink too much caffeine or catch the eye of the one you love .
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although everyone could feel their own heart beating , it was n't always clear what each thump was achieving . now we know that the heart pumps blood . but that fact was n't always obvious , because if a heart was exposed or taken out , the body would perish quickly .
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the left ventricle pumps blood through the aorta to the body . the right ventricle pumps blood through the pulmonary artery to ________ .
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on october 4 , 1957 , the world watched in awe and fear as the soviet union launched sputnik , the world 's first man-made satellite , into space . this little metal ball , smaller than two feet in diameter , launched a space race between the u.s. and u.s.s.r. that would last for eighteen years and change the world as we know it . sputnik was actually not the first piece of human technology to enter space . that superlative goes to the v-2 rocket used by germany in missile attacks against allied cities as a last-ditch effort in the final years of world war ii . it was n't very effective , but , at the end of the war , both the u.s. and u.s.s.r. had captured the technology and the scientists that had developed it and began using them for their own projects . and by august 1957 , the soviet 's successfully tested the first intercontinental ballistic missile , the r-7 , the same rocket that would be used to launch sputnik two months later . so , the scary thing about sputnik was not the orbiting ball itself , but the fact that the same technology could be used to launch a nuclear warhead at any city . not wanting to fall too far behind , president eisenhower ordered the navy to speed up its own project and launch a satellite as soon as possible . so , on december 6 , 1957 , excited people across the nation tuned in to watch the live broadcast as the vanguard tv3 satellite took off and crashed to the ground two seconds later . the vanguard failure was a huge embarassment for the united states . newspapers printed headlines like , `` flopnik '' and `` kaputnik . '' and a soviet delegate at the u.n. mockingly suggested that the u.s. should receive foreign aid for developing nations . fortunately , the army had been working on their own parallel project , the explorer , which was successfully launched in january 1958 , but the u.s. had barely managed to catch up before they were surpassed again as yuri gargarin became the first man in space in april 1961 . almost a year passed and several more soviet astronauts completed their missions before project mercury succeeded in making john glenn the first american in orbit in february 1962 . by this time , president kennedy had realized that simply catching up to each soviet advance a few months later was n't going to cut it . the u.s. had to do something first , and in may 1961 , a month after gargarin 's flight , he announced the goal of putting a man on the moon by the end of the 1960s . they succeeded in this through the apollo program with neil armstrong taking his famous step on july 20 , 1969 . with both countries ' next turning their attention to orbital space stations , there 's no telling how much longer the space race could have gone on . but because of improving relations negotiated by soviet premier leonid breshnev and u.s. president nixon , the u.s.s.r. and u.s. moved toward cooperation rather than competition . the successful joint mission , known as apollo-soyuz , in which an american apollo spacecraft docked with a soviet soyuz craft and the two crews met , shook hands , and exchanged gifts , marked the end of the space race in 1975 . so , in the end , what was the point of this whole space race ? was it just a massive waste of time ? two major superpowers trying to outdo each other by pursuing symbolic projects that were both dangerous and expensive , using resources that could have been better spent elsewhere ? well , sure , sort of , but the biggest benefits of the space program had nothing to do with one country beating another . during the space race , funding for research and education , in general , increased dramatically , leading to many advances that may not have otherwise been made . many nasa technologies developed for space are now widely used in civilian life , from memory foam in mattresses to freeze-dried food , to leds in cancer treatment . and , of course , the satellites that we rely on for our gps and mobile phone signals would not have been there without the space program . all of which goes to show that the rewards of scientific research and advancement are often far more vast than even the people pursuing them can imagine .
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so , on december 6 , 1957 , excited people across the nation tuned in to watch the live broadcast as the vanguard tv3 satellite took off and crashed to the ground two seconds later . the vanguard failure was a huge embarassment for the united states . newspapers printed headlines like , `` flopnik '' and `` kaputnik . ''
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who was the president of the united states during the sputnik launch ?
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4,000 years ago , the ancient sumerians made a surprising discovery . if they scraped the bark off a particular kind of tree and ate it , their pain disappeared . little did they know that why they 'd found was destined to influence the future course of medicine . what the sumerians had discovered was a precursor to the medicine known today as aspirin . aspirin 's active ingredient is found commonly in willow trees and other wild plants , which is how it came to infuse the medical traditions of sumer , ancient egypt , ancient greece , and other cultures . around 400 bc , hippocrates , thought of as the father of modern medicine , first recommended chewing willow bark for pain relief and making willow leaf tea to ease the pain of childbirth . but it took over 2,000 years for us to comprehensively investigate its potential . in the mid-18th century , an englishman named edward stone ran five years of experiments , showing that willow bark crushed into a powder and eaten could cure a fever . it took nearly another 70 years for a german pharmacist , johann buchner , to finally identify and purify the substance that made all this possible , a compound called salicin . by then , doctors were routinely using willow bark and other salicin-rich plants , like the herb meadowsweet , to ease pain , fever , and inflammation . but identifying the exact compound suddenly opened up the possibility of manipulating its form . in 1853 , a french chemist managed to chemically synthesize the compound , creating a substance called acetylsalicylic acid . then in 1897 , the pharmaceutical company bayer found a new method and began marketing the compound as a pain reliever called aspirin . this was widely recognized as one of the first synthetic pharmaceutical drugs . originally , aspirin was just bayer 's brand name : a for acetyl , and spir for meadowsweet , whose botanical name is spiraea ulmaria . soon , aspirin became synonymous with acetylsalicylic acid . as its influence grew , aspirin was found to ease not just pain , but also many inflammation-related problems , like rheumatoid arthritis , pericarditis , which enflames the fluid-filled sack around the heart , and kawasaki disease , where blood vessels become inflamed . yet , despite aspirin 's medical value , at this point , scientists still did n't actually know how it worked . in the 1960s and 70s , swedish and british scientists changed that . they showed that the drug interrupts the production of certain chemicals called prostaglandins , which control the transmission of pain sensations and inflammation . in 1982 , that discovery won the researchers a nobel prize in medicine . over time , research has also uncovered aspirin 's risks . overconsumption can cause bleeding in the intestines and the brain . it can also trigger reye 's syndrome , a rare but often fatal illness that affects the brain and liver in children with an infection . and in the late 20th century , aspirin 's success had been overshadowed by newer pain killers with fewer side effects , like acetaminophen and ibuprofen . but in the 1980s , further discoveries about aspirin 's benefits revived interest in it . in fact , the 1982 nobel prize winners also demonstrated that aspirin slows production of thromboxanes , chemicals that cause clumping of platelets , which in turn form blood clots . a landmark clinical trial showed that aspirin reduced heart attack risk by 44 % in participants who took the drug . today , we prescribe it to people at risk of heart attack or stroke because it cuts the likelihood of clots forming in the arteries that supply the heart and brain . even more intriguingly , there 's a growing body of research that suggests aspirin reduces the risk of getting and dying from cancer , especially colorectal cancer . this might be due to aspirin 's anti-platelet effects . by reducing platelet activity , aspirin may decrease the levels of a certain protein that helps cancer cells spread . these discoveries have transformed aspirin from a mere pain reliever to a potentially life-saving treatment . today , we consume about 100 billion aspirin tablets each year , and researchers continue searching for new applications . already , aspirin 's versatility has transformed modern medicine , which is astounding considering its humble beginnings in a scraping of willow bark .
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and in the late 20th century , aspirin 's success had been overshadowed by newer pain killers with fewer side effects , like acetaminophen and ibuprofen . but in the 1980s , further discoveries about aspirin 's benefits revived interest in it . in fact , the 1982 nobel prize winners also demonstrated that aspirin slows production of thromboxanes , chemicals that cause clumping of platelets , which in turn form blood clots .
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aspirin has benefits in the following conditions except which one ?
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tellurium is , is quite a nice element here . i shall pick it up carefully . tellurium . you ’ ve never had anything to do with this ? nothing to do with it in my life . so this is a new one for me . this is tellurium powder . so let ’ s see what ’ s inside the vial . so as we open it and tap out the glass vial . this one is going to be stubborn . this bell shape here is a sample of tellurium . the reason…shall i hold it for you ? … so , a sample of tellurium . i ’ m slightly cagey about touching this because as i think i explained with selenium that , if you ingest tellurium into the body it can get into your sweat and make you smell enough to really drive people mad . and these crystals like this one can be cut up and mounted into a piece of apparatus like this . so a chemist won ’ t deal with all the elements on the periodic table in his career normally . no , no , very few chemists will deal with more than perhaps a handful of different elements . so this is the tellurium and this is , again , this is very high standard material . 3 grams of the tellurium material and you can see it ’ s a very dark powder at the bottom of the vial . it was used in this piece of apparatus to shine in an infrared laser that ’ s like a heat ray at one frequency and it came out as twice the frequency . so you can use it to change the effect of the lasers . unfortunately the guy doing it didn ’ t make a very good job of it and you can see he ’ s completely burnt the surface of this piece of tellurium . so the main use of tellurium is as components like this for laser optics and it ’ s not widely used in the chemical industry or similar areas .
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i shall pick it up carefully . tellurium . you ’ ve never had anything to do with this ?
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similar to its predecessor on the periodic table , selenium , what would be the problem if we were to touch a sample of tellurium with our hands ?
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one day the universe will die . but why ? and how ? and will the universe be dead forever ? and how do we know that ? first of all , the universe is expanding . and not only that , the rate of its expansion is accelerating . the reason : dark energy . dark energy is a strange phenomenon that scientists believe permeates the universe . until 1998 we thought that the universe must work a bit like a ball that you throw into the sky . the ball moves up , but at some point it has to come down again . but the expansion of the universe is actually speeding up . that ’ s like throwing a ball up and watching it fly away faster and faster and faster . where is this acceleration coming from ? well , we don ’ t know , but we call it “ dark energy ” . einstein thought of it first and then decided it was stupid . now , astrophysicists have decided it is plausible . trouble is , this is all very theoretical , and we don ’ t actually know what the properties of dark energy are . but there are various theories and they lead us to three scenarios for the end of the universe . one : the big rip . since its birth , the universe has been expanding . for unknown reasons new spaces created everywhere equally . the space between galaxies expands , so they move apart . the space inside galaxies also expands , but here , gravity is strong enough to keep them together . in the big rip scenario , the expansion accelerates up to a point where space expands so fast that gravity can ’ t compensate for this effect anymore . the result is a big rip . at first , only large structures like galaxies are torn apart , since space between the single objects expands very fast . next , big bodies like black holes , stars , and planets die . their gravity isn ’ t strong enough to keep them together , so they dissolve into their components . in the end , space would expand faster than the speed of light . atoms would now be affected , and they would just disband . once space is expanding faster than light , no particle in the universe can interact with any other particle anymore . the universe would dissolve into countless lonely particles that won ’ t be able to touch anything else in a strange , timeless universe . hmm , and you thought you felt lonely ! two : heat death or a big freeze . in a nutshell , the difference between the big rip and heat death is that in a heat death scenario matter stays intact and is converted over an incredibly long but finite period of time into radiation , while the universe expands forever . but how does this work ? let ’ s talk about entropy . every system tends towards the state of highest entropy , like when we have a latte macchiato . initially , it has different regions , but over time , they will cool down and disintegrate , until it ’ s uniform . and this also applies to the universe . so , while the universe gets bigger and bigger , matters slowly decays and spreads out . at some point , after lots of generations of stars , all the gas clouds necessary to form stars will be exhausted , so the universe will turn dark . the remaining suns will die ; black holes will slowly degenerate and evaporate over trillions of years due to what ’ s known as hawking radiation . when this process is complete , only a dilute gas of photons and light particles remains , until even this decays . all activity in the universe ceases at this point ; entropy is at its maximum and the universe is dead forever . unless… theoretically , it might be possible that after an incredibly long amount of time , there might be a spontaneous entropy decrease as a result of something called “ quantum tunneling ” , leading to a new big bang . three : big crunch and big bounce . this is the most uplifting scenario . if there is less dark energy than we think or it decreases over time , gravity will be the dominating force in the universe one day . in a few trillion years , the rate of expansion of the universe will slow down and stop . after that , it reverses . galaxies will race at each other , merging as the universe becomes smaller and smaller . since a smaller universe also means a hotter universe , temperatures rise everywhere all at once . one hundred thousand years before the big crunch , background radiation would be hotter than the surfaces of the most stars , which means that they would be cooked from the outside . minutes before the big crunch happens , atom cores are ripped apart , before supermassive black holes devour everything . finally , all black holes would emerge into a supermassive mega-black hole that contains the entire mass of the universe , and in the last moment before the big crunch it would devour the universe , including itself . the big bounce theory states that this has happened a lot of times and that the universe goes through an infinite cycle of expansion and contraction . well , wouldn ’ t that be nice ? so what will actually happen to the universe in the end ? at the moment , heat death seems the most likely , but we at kurzgesagt hope that this “ dead forever ” stuff is wrong and the universe will start over and over again . we do n't know for sure either way , so let ’ s just assume the most uplifting theory is true . by the way , we have a twitter account . subtitles by the amara.org community
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in the end , space would expand faster than the speed of light . atoms would now be affected , and they would just disband . once space is expanding faster than light , no particle in the universe can interact with any other particle anymore .
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what would happen if our closest star were to disappear ? would we be able to survive ? why or why not ? explain .
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between the first europeans arriving in 1492 and the victorian age , the indigenous population of the new world dropped by at least 90 % . the cause ? not the conquistadors and company -- they killed lots of people but their death count is nothing compared to what they brought with them : small pox , typhus , tuberculosis , influenza , bubonic plague , cholera , mumps , measles and more leapt from those first explorers to the costal tribes , then onward the microscopic invaders spread through a hemisphere of people with no defenses against them . tens of millions died . these germs decided the fate of these battles long before the fighting started . now ask yourself : why did n't the europeans get sick ? if new-worlders were vulnerable to old-world diseases , then surely old-worlders would be vulnerable to new world diseases . yet , there was no americapox spreading eastward infecting europe and cutting the population from 90 million to 9 . had americapox existed it would have rather dampened european ability for transatlantic expansion . to answer why this did n't happen : we need first to distinguish regular diseases -- like the common cold -- from what we 'll call plagues . 1 . spread quickly between people . sneezes spread plagues faster than handshakes which are faster than closeness . plagues use more of this than this . 2 . they kill you quickly or you become immune . catch a plague and you 're dead within seven to thirty days ; survive and you 'll never get it again . your body has learned to fight it . you might still carry it -- the plague lives in you , you can still spread it -- but it ca n't hurt you . the surface answer to this question is n't that europeans had better immune systems to fight off new world plagues -- it 's that the new world did n't have plagues for them to catch . they had regular diseases but there was no americapox to carry . these are history 's biggest killers , and they all come from the old world . but why ? let 's dig deeper , and talk cholera : a plague that spreads if your civilization does a bad job of separating drinking water from pooping water . london was terrible at this , making it the cholera capital of the world . cholera can rip through dense neighborhoods , killing swaths of the population before moving onward . but that 's the key : it has to move on . in a small , isolated group , a plague like cholera can not survive -- it kills all available victims , leaving only the immune and then theres nowhere to go -- it 's a fire that burns through its fuel . but a city -- shining city on the hill -- to which rural migrants flock , where hundreds of babies are born a day : this is sanctuary for the fire of plague ; fresh kindling comes to it . the plague flares and smolders and flares and smolders again -- impossible to extinguish . historically , in city borders , plagues killed faster than people could breed . cities grew because more people moved to them than died inside of them . cities only started growing from their own population in the 1900s when medicine finally left its leaches and bloodletting phase and entered its soap and soup phase , giving humans some tools to slow death . but before that a city was an unintentional playground for plagues and a grim machine to sort the immune from the rest . so the deeper answer is that the new world did n't have plagues because the new world did n't have big , dense , terribly sanitized deeply interconnected cities for plagues to thrive . ok , but the new world was n't completely barren of cities , and tribes were n't completely isolated . otherwise the newly-arrived smallpox in the 1400s could n't have spread . cities are only part of the puzzle : they 're required for plagues , but cities do n't make the germs that start the plagues -- those germs come from the missing piece . now , most germs do n't want to kill you , for the same reason you do n't want to burn down your house ; germs live in you . chronic diseases like leprosy are terrible because they 're very good at living in you and not killing you . plague lethality is an accident , a misunderstanding , because the germs that cause them do n't know they 're in humans ; they think they 're in this . plagues come from animals . whooping cough comes from pigs , as does flu , as well as from birds . our friend the cow alone is responsible for measles , tuberculosis , and smallpox . for the cow these diseases are no big deal -- like colds for us . but when cow germs get in humans , the things they do to make a cow a little sick to spread make humans very sick . deadly sick . now , germs jumping species like this is extraordinarily rare . that 's why generations of humans can spend time around animals just fine . being the patient zero of a new animal-to-human plague is winning a terrible lottery . but a colonial-age city raises the odds : there used to be animals everywhere ; horses , herds of livestock in the streets , open slaughterhouses , meat markets pre-refrigeration , and rivers of human and animal excrement running through it all . a more perfect environment for diseases to jump species could hardly be imagined . so the deeper answer is that plagues come from animals , but so rarely that you have to raise the odds with many chances for infection and even then the new-born plague needs a fertile environment to grow . the old world had the necessary pieces in abundance . but why was a city like london filled with sheep and pigs and cows and tenochtitlan was n't ? this brings us to the final level , for this video anyway . some animals can be put to human use -- this is what domestication means : animals you can breed , not just hunt . forget for a the moment the modern world : go back to 10,000bc when tribes of humans reached just about everywhere . if you were in one of these tribes , what local animals could you capture , alive , and successfully pen to breed ? maybe you 're in north dakota and thinking about catching a buffalo : an unpredictable , violent tank on hooves , that can outrun you across the planes , leap over your head and travels in herds thousands strong . oh , and you have no horses to help you -- because there are no horses on the continent . horses live here -- and wo n't be brought over until too late . it 's just you , a couple buddies , and stone-based tools . american indians did n't fail to domesticate buffalo because they could n't figure it out . they failed because it 's a buffalo . no one could do it -- buffalo would have been amazing creatures to put to human work back in bc , but it 's not going to happen -- humans have only barely domesticated buffalo with all our modern tools . the new world did n't have good animal candidates for domestication . almost everything big enough to be useful is also too dangerous , or too agile . meanwhile the fertile crescent to central europe had cows and pigs and sheep and goats : easy-peasy animals comparatively begging to be domesticated . a wild boar is something to contend with if you only have stone tools but it 's possible to catch and pen and breed and feed to eat -- because pigs ca n't leap to the sky or crush all resistance beneath their hooves . in the new world the only native domestication contestant was : llamas . they 're better than nothing -- which is probably why the biggest cities existed in south america -- but they 're no cow . ever try to manage a heard of llamas in the mountains of peru ? yeah , you can do it , but it 's not fun . nothing but drama , these llamas . these might seem , cherry-picked examples , because are n't there hundreds of thousands of species of animals ? yes , but when you 're stuck at the bottom of the tech tree , almost none of them can be domesticated . from the dawn of man until this fateful meeting , humans domesticated ; maybe a baker 's dozen of unique species the world over . and even to get that high a number you need to stretch it to include honeybees and silkworms ; nice to have , but you ca n't build a civilization on a foundation of honey alone . these early tribes were n't smarter , or better at domestication . the old world had more valuable and easy animals . with dogs , herding sheep and cattle is easier . now humans have a buddy to keep an eye on the clothing factory , and the milk and cheeseburger machine , and the plow-puller . now farming is easier , which means there 's more benefit to staying put , which means more domestication , which means more food which means more people and more density and oh look where we 're going . citiesville : population : lots ; bring your animals ; plagues welcome . that is the full answer : the lack of new world animals to domesticate limited not only exposure to germs sources but also limited food production , which limited population growth , which limited cities , which made plagues in the new world an almost impossibility . in the old [ world ] , exactly the reverse , and thus a continent full of plague and a continent devoid of it . so when ships landed in the new world , there was no americapox to bring back . the game of civilization has nothing to do with the players , and everything to do with the map . access to domesticated animals in numbers and diversity is the key resource to bootstrapping a complex society from nothing -- and that complexity brings with it , unintentionally , a passive biological weaponry devastating to outsiders . start the game again but move the domesticable animals across the sea and history 's arrow of disease and death flows in the opposite direction . this still does leave one last question . just why are some animals domesticable and others not ? why could n't american indians domesticate deer ? why ca n't zebras be domesticated ? they look just like horses . and what does it mean to tame an animal ? to answer that , click here for part 2 . this video has been brought to you by audible.com and was a presentation of diamond 's theory as laid out in his book gun , germs and steel . if you found this video interesting you should go right now to audible.com/grey and get a copy of the book . there is so much more in this than could ever been explained in a short video -- guns , germs and steel is the history book to rule all history books . audible has over 180,000 things for you to listen to . it is an endless source of interestingness . so once again , please to go audible.com/grey get a 30-day free trial and let them know that you came from this channel . audiobooks are a big part of my life and i think they should be a big part of your life . why not get started today ?
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a wild boar is something to contend with if you only have stone tools but it 's possible to catch and pen and breed and feed to eat -- because pigs ca n't leap to the sky or crush all resistance beneath their hooves . in the new world the only native domestication contestant was : llamas . they 're better than nothing -- which is probably why the biggest cities existed in south america -- but they 're no cow . ever try to manage a heard of llamas in the mountains of peru ?
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why does cgp grey hypothesize that the biggest cities in the `` new world '' were in south america ?
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translator : andrea mcdonough reviewer : jessica ruby what 's an algorithm ? in computer science , an algorithm is a set of instructions for solving some problem , step-by-step . typically , algorithms are executed by computers , but we humans have algorithms as well . for instance , how would you go about counting the number of people in a room ? well , if you 're like me , you probably point at each person , one at a time , and count up from 0 : 1 , 2 , 3 , 4 and so forth . well , that 's an algorithm . in fact , let 's try to express it a bit more formally in pseudocode , english-like syntax that resembles a programming language . let n equal 0 . for each person in room , set n = n + 1 . how to interpret this pseudocode ? well , line 1 declares , so to speak , a variable called n and initializes its value to zero . this just means that at the beginning of our algorithm , the thing with which we 're counting has a value of zero . after all , before we start counting , we have n't counted anything yet . calling this variable n is just a convention . i could have called it almost anything . now , line 2 demarks the start of loop , a sequence of steps that will repeat some number of times . so , in our example , the step we 're taking is counting people in the room . beneath line 2 is line 3 , which describes exactly how we 'll go about counting . the indentation implies that it 's line 3 that will repeat . so , what the pseudocode is saying is that after starting at zero , for each person in the room , we 'll increase n by 1 . now , is this algorithm correct ? well , let 's bang on it a bit . does it work if there are 2 people in the room ? let 's see . in line 1 , we initialize n to zero . for each of these two people , we then increment n by 1 . so , in the first trip through the loop , we update n from zero to 1 , on the second trip through that same loop , we update n from 1 to 2 . and so , by this algorithm 's end , n is 2 , which indeed matches the number of people in the room . so far , so good . how about a corner case , though ? suppose that there are zero people in the room , besides me , who 's doing the counting . in line 1 , we again initialize n to zero . this time , though , line 3 does n't execute at all since there is n't a person in the room , and so , n remains zero , which indeed matches the number of people in the room . pretty simple , right ? but counting people one a time is pretty inefficient , too , no ? surely , we can do better ! why not count two people at a time ? instead of counting 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , and so forth , why not count 2 , 4 , 6 , 8 , and so on ? it even sounds faster , and it surely is . let 's express this optimization in pseudocode . let n equal zero . for each pair of people in room , set n = n + 2 . pretty simple change , right ? rather than count people one at a time , we instead count them two at a time . this algorithm 's thus twice as fast as the last . but is it correct ? let 's see . does it work if there are 2 people in the room ? in line 1 , we initialize n to zero . for that one pair of people , we then increment n by 2 . and so , by this algorithm 's end , n is 2 , which indeed matches the number of people in the room . suppose next that there are zero people in the room . in line 1 , we initialize n to zero . as before , line 3 does n't execute at all since there are n't any pairs of people in the room , and so , n remains zero , which indeed matches the number of people in the room . but what if there are 3 people in the room ? how does this algorithm fair ? let 's see . in line 1 , we initialize n to zero . for a pair of those people , we then increment n by 2 , but then what ? there is n't another full pair of people in the room , so line 2 no longer applies . and so , by this algorithm 's end , n is still 2 , which is n't correct . indeed this algorithm is said to be buggy because it has a mistake . let 's redress with some new pseudocode . let n equal zero . for each pair of people in room , set n = n + 2 . if 1 person remains unpaired , set n = n + 1 . to solve this particular problem , we 've introduced in line 4 a condition , otherwise known as a branch , that only executes if there is one person we could not pair with another . so now , whether there 's 1 or 3 or any odd number of people in the room , this algorithm will now count them . can we do even better ? well , we could count in 3 's or 4 's or even 5 's and 10 's , but beyond that it 's going to get a little bit difficult to point . at the end of the day , whether executed by computers or humans , algorithms are just a set of instructions with which to solve problems . these were just three . what problem would you solve with an algorithm ?
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well , if you 're like me , you probably point at each person , one at a time , and count up from 0 : 1 , 2 , 3 , 4 and so forth . well , that 's an algorithm . in fact , let 's try to express it a bit more formally in pseudocode , english-like syntax that resembles a programming language .
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what 's an algorithm ?
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remember the time you fell off your bike or bumped your head on a sharp corner ? childhood injuries are things we 'd often like to forget , but our bodies often carry the memories in the form of scars . so what are these unwanted souvenirs and why do we keep them for so long after that unintended vacation to the emergency room ? the most common place we see scars are on our skin , a patch that looks slightly different from the normal skin around it . often , this is considered an unfortunate disfigurement , while other times , deliberate scarification has been used in both traditional and modern cultures , to mark a rite of passage or simply for aesthetic decoration . but the difference is n't only cosmetic . when we look at healthy skin tissue under a microscope , we see the cells that perform various functions connected by an extracellular matrix , or ecm . this is composed of structural proteins , like collagen , secreted by specialized fibroblast cells . well-arranged ecm allows for transportation of nutrients , cell-to-cell communication , and cell adhesion . but when a deep wound occurs , this arrangement is disrupted . during the process of wound healing , collagen is redeposited at the wound site , but instead of the basket-weave formation found in healthy tissue , the new ecm is aligned in a single direction , impeding inter-cell processes , and reducing durability and elasticity . to make matters worse , the healed tissue contains a higher proportion of ecm than before , reducing its overall function . in the skin , the overabundance of collagen interferes with its original functions , like producing sweat , controlling body temperature and even growing hair . the scar tissue is fragile , sensitive to changes in temperature and sensation , and should be kept in moist environments to maximize healing . this presence of excessive fibrous connective tissue in an organ is known as fibrosis , and if that term sounds familiar , it 's because our skin is not the only organ vulnerable to scarring . cystic fibrosis is a genetic disorder that causes scarring of the pancreas , while pulmonary fibrosis is a scarring of the lungs , resulting in shortness of breath . scarring of the heart and the buildup of ecm following a heart attack can inhibit its beating , leading to further heart problems . what 's common to all these conditions is that although it retains some of the original functions , the scar tissue formed after a wound is inferior to the native tissue it replaces . however , there is hope . medical researchers are now studying what causes fibroblast cells to secrete excessive amounts of collagen and how we can recruit the body 's other cells in regenerating and repopulating the damaged tissue . by learning how to better control wound healing and the formation of scar tissue , we can utilize the multi-billion-dollar budgets currently used to address the aftermath of wounding in a much more efficient manner , and help millions of people live better and healthier lives . but until then , at least some of our scars can help us remember to avoid the sorts of things that cause them .
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to make matters worse , the healed tissue contains a higher proportion of ecm than before , reducing its overall function . in the skin , the overabundance of collagen interferes with its original functions , like producing sweat , controlling body temperature and even growing hair . the scar tissue is fragile , sensitive to changes in temperature and sensation , and should be kept in moist environments to maximize healing .
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imagine if the presence of scars didn ’ t disrupt any physiological or bodily functions . would it still be worth removing due to aesthetic reasons ?
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in 1879 , amateur archaeologist marcelino sanz de sautuola and his young daughter maria explored a dark cave in northern spain . when maria wondered off by herself , she made an amazing discovery . they were standing inside a site of ancient art , the walls and roofs decorated with prehistoric paintings and engravings , ranging from 19,000 to 35,000 years old . similar marks of our ancestors have been preserved in caves all over the world . the oldest we 've found were made up to 40,000 years ago . what do these images tell us about the ancient human mind and the lives of their creators ? these early artists mixed minerals , clay , charcoal , and ochre with spit or animal fat to create paint . they drew with their hands and tools , like pads of moss , twigs , bones , and hair . in many instances , their images follow the contours of the cave to create depth and shade . the most common depictions are of geometric shapes , followed by large mammals , like bison , horses , mammoths , deer , and boars . human figures appear rarely , as well as occasional hand prints . some have theorized that these artworks are the creation of hunters , or of holy men in trance-like states . and we 've found examples created by men , women , and even children . and why did they create this art ? perhaps they were documenting what they knew about the natural world , like modern scientists , or marking their tribal territory . maybe the images were the culmination of sacred hunting rituals or spiritual journeys . or could they be art for art 's sake , the sheer joy and fulfillment of creation ? as with many unsolved mysteries of the ancient world , we may never know for sure , barring the invention of a time machine , that is . but while the answers remain elusive , these images are our earliest proof of human communication , testifying to the human capacity for creativity thousands of years before writing . they are a distinct visual language that imagines the world outside the self , just like modern art forms , from graffiti and painting to animated virtual-reality caves .
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as with many unsolved mysteries of the ancient world , we may never know for sure , barring the invention of a time machine , that is . but while the answers remain elusive , these images are our earliest proof of human communication , testifying to the human capacity for creativity thousands of years before writing . they are a distinct visual language that imagines the world outside the self , just like modern art forms , from graffiti and painting to animated virtual-reality caves .
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the ingredients for the earliest paints included :
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when you think of natural history museums , you probably picture exhibits filled with ancient lifeless things , like dinosaurs meteroites , and gemstones . but behind that educational exterior , which only includes about 1 % of a museum 's collection , there are hidden laboratories where scientific breakthroughs are made . beyond the unmarked doors , and on the floors the elevators wo n't take you to , you 'd find windows into amazing worlds . this maze of halls and laboratories is a scientific sanctuary that houses a seemingly endless variety of specimens . here , researchers work to unravel mysteries of evolution , cosmic origins , and the history of our planet . one museum alone may have millions of specimens . the american museum of natural history in new york city has over 32,000,000 in its collection . let 's take a look at just one of them . scientists have logged exactly where and when it was found and used various dating techniques to pinpoint when it originated . repeat that a million times over , and these plants , animals , minerals , fossils , and artifacts present windows into times and places around the world and across billions of years of history . when a research problem emerges , scientists peer through these windows and test hypotheses about the past . for example , in the 1950s , populations of predatory birds , like peregrine falcons , owls , and eagles started to mysteriously crash , to the point where a number of species , including the bald eagle , were declared endangered . fortunately , scientists in the field museum in chicago had been collecting the eggs of these predatory birds for decades . they discovered that the egg shells used to be thicker and had started to thin around the time when an insecticide called ddt started being sprayed on crops . ddt worked very well to kill insects , but when birds came and ate those heaps of dead bugs , the ddt accumulated in their bodies . it worked its way up the food chain and was absorbed by apex predator birds in such high concentrations that it thinned their eggs so that they could n't support the nesting bird 's weight . there were omelettes everywhere until scientists from the field museum in chicago , and other institutions , helped solve the mystery and save the day . america thanks you , field museum . natural history museums windows into the past have solved many other scientific mysteries . museum scientists have used their collections to sequence the neanderthal genome , discover genes that gave mammoths red fur , and even pinpoint where ancient giant sharks gave birth . there are about 900 natural history museums in the world , and every year they make new discoveries and insights into the earth 's past , present and future . museum collections even help us understand how modern threats , such as global climate change , are impacting our world . for instance , naturalists have been collecting samples for over 100 years from walden pond , famously immortalized by henry david thoreau . thanks to those naturalists , who count thoreau among their number , we know that the plants around walden pond are blooming over three weeks earlier than they did 150 years ago . because these changes have taken place gradually , one person may not have noticed them over the span of a few decades , but thanks to museum collections , we have an uninterrupted record showing how our world is changing . so the next time you 're exploring a natural history museum , remember that what you 're seeing is just one gem of a colossal scientific treasure trove . behind those walls and under your feet are windows into forgotten worlds . and who knows ? one day some future scientist may peer through one and see you .
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when you think of natural history museums , you probably picture exhibits filled with ancient lifeless things , like dinosaurs meteroites , and gemstones . but behind that educational exterior , which only includes about 1 % of a museum 's collection , there are hidden laboratories where scientific breakthroughs are made .
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why should we study science if our results will not have any immediate impact ?
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so this a really beautiful sample of chromium . so chromium is a transition metal , right in the middle of the transition metals series there and it is used to protect metal components and very often you see chromium plated components on cars perhaps some of the older cars , you know , the wheel trims or perhaps the grills on the front , but if you look at the sample it is really lustrous , really beautiful and shiny . so there are some elements that one is really fond of and chromium is one of the metals that i really like . it is a metal you would have seen it in many places it is used for plating materials . this may actually be stainless steel but chromium looks very similar and it was very popular for plating bumpers , all sorts of materials in the 1930s up to the 1950s . so you can get dull chromium as well which is where the surface is very bumpy and the light tends to be absorbed a lot more and not reflected . my interest in chromium is that in the chemistry one of the very first bits of chemistry research i did in school was involving copper chromate . i spent months doing experiments on it . i did not really discover anything about it but it was great fun . at one stage i had a whole row of test tubes of copper chromate above my bed and my bedroom at home and more recently when i starting doing doctorates , i did experiments with chromium , making new complexes of chromium and one of the very first compounds that my research group ever made , that was new that nobody else had made before , was a compound of ethene and chromium - chromium pentacarbonyl ethene so i have very warm feelings about it .
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so there are some elements that one is really fond of and chromium is one of the metals that i really like . it is a metal you would have seen it in many places it is used for plating materials . this may actually be stainless steel but chromium looks very similar and it was very popular for plating bumpers , all sorts of materials in the 1930s up to the 1950s .
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the mineral , crocoite , was used as a strong yellow pigment for school buses in the us and for the postal service in europe . what is the composition of this mineral ?
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what ’ s the next element ? hassium . i know nothing about hassium , shall we make something up ? hassium is an element which i knew nothing about . but now i discover it ’ s much more interesting than i thought . we ’ re here in the german state of hesse at the institute gsi were hassium was first made in 1984 . hassia is the latin name for this part of germany hesse and hence it is named after the place it was discovered . so down here we have the accelerator that accelerated atoms of iron to bang into a lead target to make element 108 hassium . element 108 is actually in the same group of the periodic table as iron , that much i knew when i first talked about it . but what i didn ’ t realise is that the element has a few atoms that are long enough lived that you can really do chemistry . so once the atom flies off from the back of the target when it has been created you can pass it through an atmosphere of oxygen and make the oxide hassium tetroxide hs04 . and the iron of this molecule , this oxide can then be followed to see how volatile it is and compared with osmium tetroxide . osmium tetroxide is a white solid which is quite volatile , it easily evaporates and you can show that hassium tetroxide does not evaporate quite so easily . but it ’ s amazing this is an element only forty atoms have been made but you can tell how its oxide behaves . osmium has one of the highest melting points of any element that ’ s known . the people who make periodic tables where you have a sample of each element have great trouble melting osmium to make a sample , so it may be that hassium would have an even higher melting point , it could be that it ’ s the highest melting point in the periodic table . but one would have to make a lot more atoms than that if you were going to find out what the melting point was . i think people may be able to calculate it , but the melting point depends on the strength of the interaction between the atoms and unless you have quite a few atoms that ’ s very difficult to measure . and quite a few means many tens of millions because even a small particle , a so called nanoparticle , of metal can have quite different properties from a large lump .
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what ’ s the next element ? hassium . i know nothing about hassium , shall we make something up ?
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the professor explained that hassium can form an oxide similar to that of osmium ; what is the preferred oxidation state for hassium ?
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`` hi , bob . '' `` morning , kelly . the tulips looks great . '' have you ever wondered how your dog experiences the world ? here 's what she sees . not terribly interesting . but what she smells , that 's a totally different story . and it begins at her wonderfully developed nose . as your dog catches the first hints of fresh air , her nose 's moist , spongy outside helps capture any scents the breeze carries . the ability to smell separately with each nostril , smelling in stereo , helps to determine the direction of the smell 's source so that within the first few moments of sniffing , the dog starts to become aware of not just what kind of things are out there but also where they 're located . as air enters the nose , a small fold of tissue divides it into two separate folds , one for breathing and one just for smelling . this second airflow enters a region filled with highly specialized olfactory receptor cells , several hundred millions of them , compaired to our five million . and unlike our clumsy way of breathing in and out through the same passage , dogs exhale through slits at the side of their nose , creating swirls of air that help draw in new odor molecules and allow odor concentration to build up over mulitple sniffs . but all that impressive nasal architecture would n't be much help without something to process the loads of information the nose scoops up . and it turns out that the olfactory system dedicated to proessing smells takes up many times more relative brain area in dogs than in humans . all of this allows dogs to distinguish and remember a staggering variety of specific scents at concentrations up to 100 million times less than what our noses can detect . if you can smell a spritz of perfume in a small room , a dog would have no trouble smelling it in an enclosed stadium and distinguishing its ingredients , to boot . and everything in the street , every passing person or car , any contents of the neighbor 's trash , each type of tree , and all the birds and insects in it has a distinct odor profile telling your dog what it is , where it is , and which direction it 's moving in . besides being much more powerful than ours , a dog 's sense of smell can pick up things that ca n't even be seen at all . a whole separate olfactory system , called the vomeronasal organ , above the roof of the mouth , detects the hormones all animals , including humans , naturally release . it lets dogs identify potential mates , or distinguish between friendly and hostile animals . it alerts them to our various emotional states , and it can even tell them when someone is pregnant or sick . because olfaction is more primal than other senses , bypassing the thalamus to connect directly to the brain structures involving emotion and instinct , we might even say a dog 's perception is more immediate and visceral than ours . but the most amazing thing about your dog 's nose is that it can traverse time . the past appears in tracks left by passersby , and by the warmth of a recently parked car where the residue of where you 've been and what you 've done recently . landmarks like fire hydrants and trees are aromatic bulletin boards carrying messages of who 's been by , what they 've been eating , and how they 're feeling . and the future is in the breeze , alerting them to something or someone approaching long before you see them . where we see and hear something at a single moment , a dog smells an entire story from start to finish . in some of the best examples of canine-human collaboration , dogs help us by sharing and reacting to those stories . they can respond with kindness to people in distress , or with aggression to threats because stress and anger manifest as a cloud of hormones recognizable to the dog 's nose . with the proper training , they can even alert us to invisible threats ranging from bombs to cancer . as it turns out , humanity 's best friend is not one who experiences the same things we do , but one whose incredible nose reveals a whole other world beyond our eyes .
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it alerts them to our various emotional states , and it can even tell them when someone is pregnant or sick . because olfaction is more primal than other senses , bypassing the thalamus to connect directly to the brain structures involving emotion and instinct , we might even say a dog 's perception is more immediate and visceral than ours . but the most amazing thing about your dog 's nose is that it can traverse time .
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olfaction bypasses the thalamus and goes directly to the brain , making the dog 's senses _____
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translator : andrea mcdonough reviewer : bedirhan cinar you know what the greatest secret of history is ? it 's that history can be changed . and , yeah , yeah , i know , everyone says history ca n't be changed , but it can . and today we 're going to talk about how history is n't just something that goes backwards , history goes forward too . and all those great things that have n't happened yet , that 's history that 's just waiting to be written . so how do you change history ? i 'm going to tell you by sharing with you the three things that i tell my kids every night when i tuck them into bed . it 's true . i stole the idea from a friend of mine who told me what his father used to share with him . every single night , when i tuck my kids into bed , i tell them these three things : dream big , work hard , and stay humble . so let 's look at them all . first , dream big . you know who has the biggest , best dreams of all ? you , young people . you know how old martin luther king , jr. was when he became the leader of the most famous bus boycott in history ? he was 26 . you know how old amelia earhart was when she broke her first world record ? 25 you know how old steve jobs was when he co-founded apple computer ? 21 and you know how old jerry siegel and joe shuster were when they came up with their idea for the greatest superhero of all time , the first one , that they named `` superman '' ? these guys were 17 years old ! two 17-year-old kids created superman . they were n't good looking . ( look at the picture , right ? ) they were n't popular . they had no money , but they were two best friends with one dream . and with just their imaginations , they gave the world superman . and i know , creating superman is a once-in-a-lifetime big dream , so i want to tell you about alexandra scott . she goes by alex . alex was diagnosed with cancer before she was even a year old , and that was the only life she knew : sickness , chemotherapy , and surgery . when she was four , alex asked her parents could she put a lemonade stand in the front yard ? she did n't want to buy anything for herself , she wanted to use the money to give it to doctors to help other kids with cancer . ok , in a single day , alex 's lemonade stand raised $ 2,000 ! but , here 's what i love : soon after that , other lemonade stands started popping up , all with alex 's name on it . eventually , they raised $ 200,000 . and then alex had a new goal . she said let 's raise $ 1,000,000 . on june 12 , 2004 , hundreds of lemonade stands started opening up in every state in the country . ordinary people selling water and sugar and lemons to help kids with cancer . nearly two months later , alex died while her parents were holding her hands . she was 8 years old . but before she died , alex said that next year 's goal should be $ 5,000,000 . today , her dream has raised over $ 45,000,000 and it is still going strong ! one idea , one girl , one big dream . and you know what she said ? this is a direct quote before she died . she said , `` oh , we can do it ! if other people will help me , i think we can do it . i know we can do it ! '' you dream big , i do n't care how old you are , and do n't let anyone tell you otherwise , you will change history . and that leads me to the second thing i tell my kids : work hard . such a simple one , everyone knows this one . work hard . i saw this one for my father and my father died a few months ago . when i was growing up in brooklyn , ok , my father , he worked hard . he had no money , we had , no money growing up . he worked every saturday , every sunday . i watched first-hand every weekend what hard work was . and i saw that the hardest work of all is being resilient when you 're facing failure . when i started writing my first book , my first book got me 24 rejection letters . to be clear , there are only 20 publishers , i got 24 rejection letters , ok ? that means that some people were writing me twice to make sure i got the point . but it was n't until i was writing my ninth book , a book of heroes for my son , that i found my favorite story of working hard through failure . it was a story that a friend told me about the wright brothers . that every time the wright brothers went out to fly their plane , they would bring enough extra materials for multiple crashes . that means for every time they went out , they knew they would fail . and they would crash and rebuild , and crash and rebuild , and that 's why they took off . i love that story . i wanted my son to hear that story , i wanted my daughter to hear that story , i wanted everyone to know that if you dream big and you work hard and you fight failure , you will change history and do what no one on this planet has ever done before . and that leads me to the final thing i tell them : stay humble . here 's the thing : if you invent the world 's first airplane , or superman , or a multi-million dollar lemonade stand , you do n't need to be humble . you can get a tattoo on your face that says , `` i 'm the best ! '' right ? but pay attention here : no one likes a jerk . in fact , the world needs fewer loudmouths , so stay humble ! when thomas jefferson wrote the declaration of independence , you know he never took credit for writing it while he was alive ? it was n't until he died and it was in his obituary that the average american found out that he was the author . that 's humble . so there 's the big secret : dream big , work hard , stay humble . `` wait , '' you 're saying , `` that 's it ? '' `` what , you tell me a bunch of stories and what ? how do i change history ? '' here 's the answer : all history ever is is a bunch of stories , conflicting stories , big stories , little stories , our stories . so how do you change history ? all you got to do is write your story . ok ? no , i 'm serious , this is it . if people think history is a bunch of facts and dates you got to memorize , that 's not what history is at all . history is a selection process , and it chooses every single one of us every single day . the only question is , do you hear the call ? and that leads me to the most important thing i 'm going to tell you here : you will change history . some of you will change it in big ways , affecting millions of people . others of you will do it in more personal ways , helping a family member or someone who needs it . but let me tell you right now , one is not more important than the other . if you help people in mass or one-by-one , that 's how history gets changed , when you take action . but when you start writing your story and you get scared , as we all inevitably do , i want you to know one thing : no one is born a hero . every single person that we talked about today , whether they were a 26 year old preacher , or two 17 year old nerds , or little girl who had cancer , every single one of them had moments where they doubted themselves , like you , like me . they had moments where they worried about school and friendships and would they be accepted by others , like you , like me . they had moments where they worried about loneliness and failure and would they ever succeed , like you , like me . but the best part is , you do n't have to start a multi-million dollar lemonade stand to change the world , all you got to do is help one person , be kind to one person , that 's the answer . it 's my core belief , it is in every story i just told you . i believe ordinary people change the world . i do n't care how much money you have , i do n't care where you go to school , that is all nonsense to me . i believe in regular people and their ability to affect change in this world . i believe in my father , and a 25 year old daredevil named amelia , and a little girl who sells lemonade like nobody 's business . and it 's why i believe in that very first hero we were talking about today , superman . to me , the most important part of the story is n't superman . the most important part of the story is clark kent . and you want to know why ? because we 're all clark kent . we all know what it 's like to be boring and ordinary and wish we could do something incredibly beyond ourselves . but here 's the real news : we all can do something incredibly beyond ourselves . i got 24 rejection letters on my first book , 24 people who told me to give it up , and i do n't look back on the experience and say , `` i was right , and they were wrong , and haha on them . '' what i look back and realize is that every single one of those rejection letters told me to work harder , to dream bigger , and you better believe it , made me more humble , but it also made me want it more than anything . so whatever it is you dream big about , whatever it is you work hard for , do n't let anyone tell you , you 're too young and do n't let anyone tell you no . every life makes history . and every life is a story . thank you .
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so whatever it is you dream big about , whatever it is you work hard for , do n't let anyone tell you , you 're too young and do n't let anyone tell you no . every life makes history . and every life is a story .
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share about a time in your life when you have changed history .
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every spring , hundreds of adventure-seekers dream of climbing qomolangma , also known as mount everest . at base camp , they hunker down for months waiting for the chance to scale the mountain 's lofty , lethal peak . but why do people risk life and limb to climb everest ? is it the challenge ? the view ? the chance to touch the sky ? for many , the draw is everest 's status as the highest mountain on earth . there 's an important distinction to make here . mauna kea is actually the tallest from base to summit , but at 8850 meters above sea level , everest has the highest altitude on the planet . to understand how this towering formation was born , we have to peer deep into our planet 's crust , where continental plates collide . the earth 's surface is like an armadillo 's armor . pieces of crust constantly move over , under , and around each other . for such huge continental plates , the motion is relatively quick . they move two to four centimeters per year , about as fast as fingernails grow . when two plates collide , one pushes into or underneath the other , buckling at the margins , and causing what 's known as uplift to accomodate the extra crust . that 's how everest came about . 50 million years ago , the earth 's indian plate drifted north , bumped into the bigger eurasian plate , and the crust crumpled , creating huge uplift . mountain everest lies at the heart of this action , on the edge of the indian-eurasian collision zone . but mountains are shaped by forces other than uplift . as the land is pushed up , air masses are forced to rise as well . rising air cools , causing any water vapor within it to condense and form rain or snow . as that falls , it wears down the landscape , dissolving rocks or breaking them down in a process known as weathering . water moving downhill carries the weathered material and erodes the landscape , carving out deep valleys and jagged peaks . this balance between uplift and erosion gives a mountain its shape . but compare the celestial peaks of the himalayas to the comforting hills of appalachia . clearly , all mountains are not alike . that 's because time comes into the equation , too . when continental plates first collide , uplift happens fast . the peaks grow tall with steep slopes . over time , however , gravity and water wear them down . eventually , erosion overtakes uplift , wearing down peaks faster than they 're pushed up . a third factor shapes mountains : climate . in subzero temperatures , some snowfall does n't completely melt away , instead slowly compacting until it becomes ice . that forms the snowline , which occurs at different heights around the planet depending on climate . at the freezing poles , the snowline is at sea level . near the equator , you have to climb five kilometers before it gets cold enough for ice to form . gathered ice starts flowing under its own immense weight forming a slow-moving frozen river known as a glacier , which grinds the rocks below . the steeper the mountains , the faster ice flows , and the quicker it carves the underlying rock . glaciers can erode landscapes swifter than rain and rivers . where glaciers cling to mountain peaks , they sand them down so fast , they lop the tops off like giant snowy buzzsaws . so then , how did the icy mount everest come to be so tall ? the cataclysmic continental clash from which it arose made it huge to begin with . secondly , the mountain lies near the tropics , so the snowline is high , and the glaciers relatively small , barely big enough to widdle it down . the mountain exists in a perfect storm of conditions that maintain its impressive stature . but that wo n't always be the case . we live in a changing world where the continental plates , earth 's climate , and the planet 's erosive power might one day conspire to cut mount everest down to size . for now , at least , it remains legendary in the minds of hikers , adventurers , and dreamers alike .
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that 's because time comes into the equation , too . when continental plates first collide , uplift happens fast . the peaks grow tall with steep slopes .
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how does continental uplift occur ?
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each spring , nature lovers eagerly greet the signs that winter is finally coming to an end . as the days grow warmer , the flowers and trees start to bloom , and the world comes alive with the melodious call of birds in search of a new mate . but where have these enchanting sounds been hiding all winter ? for almost 200 species of song birds , their winters have been spent down in the tropical climates of central and south america . while this may sound ideal , it involves one of the most perilous journeys known in the entire animal kingdom . this journey is called migration , and for song birds , this can involve travelling somewhere between a few hundred to almost 7,000 miles in a period of several weeks to four months . birds spend weeks preparing for the intense journey by gorging on large quantities of food , sometimes doubling their weight prior to departure . while flying , birds can lose almost one percent of their body weight an hour , so packing on the pounds is crucial to their survival . however , more than the physical stress , migrating birds are now facing a new source of hardship : landscape change . just imagine you 're the one getting ready to take a trip . you 've packed the car with everything you think you need , fueled up the tank , eaten a huge breakfast , and hit the road . you 've taken this journey before . you know all your favorite rest stops and little back-alley diners to grab a bite . everything is planned out . but just as your fuel gauge starts dipping into the red zone , you pass by what should have been a gas station , except it 's closed . `` not a problem , '' you think , `` the next one ca n't be too far away . '' but then that next station never appears . unfortunately , as you continue on your route , the reality of the situation starts to set in . more and more stations are closed or just erased from your map . all of a sudden , your routine trip has become a desperate search just to find somewhere safe to rest and refuel for the night . this scenario has become the reality for the majority of migrating song birds as human land development continues unchecked . humans are altering important stop-over sites that birds have been using for generations . as migrators pass over the continent , they run a gauntlet of dangers , including pesticide ingestion in rural farmlands , habitat loss in suburban developments , as well as disorientation from light pollution , and even structure collision with tall , reflective glass buildings in cities . of the estimated 20 billion individual birds that comprise the fall population , only about half will return to breed the following spring . almost one billion of these deaths are attributed just to building collisions . with such astounding yearly losses , humans risk more than just the loss of the beautiful colors and songs of birds , they also play an important role in the ecosystem . birds help with insect control , pollination , and disbursing seeds throughout the landscape . without birds , the natural world would be a very different place . although birds face an on-going threat from human land development , there are actions that we can all take to help . many countries and local governements have already passed important laws that restrict the use of poisonous pesticides . by using more natural , plant-based products , we can maintain our farms and gardens without the dangerous side effects . in addition , as our global populations continue to grow and people need places to call home , green spaces can offer both bird habitat as well as a peaceful and natural place for us to enjoy . small changes at home can also make a huge difference . by hanging up feeders and building bird houses in outdoor areas , we can provide much-needed food and safety during long migrations . turning out lights in suburban and urban environments can also help birds that look for stars to navigate . with our help , these sky travellers can reach their destination safely , and hopefully keep returning year after year .
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almost one billion of these deaths are attributed just to building collisions . with such astounding yearly losses , humans risk more than just the loss of the beautiful colors and songs of birds , they also play an important role in the ecosystem . birds help with insect control , pollination , and disbursing seeds throughout the landscape .
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birds play many important roles in the ecosystem that are beneficial to both nature and humans . what are some other examples of species that provide ecosystem services and how do they help ?
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like many heroes of greek myths , the philosopher hippasus was rumored to have been mortally punished by the gods . but what was his crime ? did he murder guests , or disrupt a sacred ritual ? no , hippasus 's transgression was a mathematical proof : the discovery of irrational numbers . hippasus belonged to a group called the pythagorean mathematicians who had a religious reverence for numbers . their dictum of , `` all is number , '' suggested that numbers were the building blocks of the universe and part of this belief was that everything from cosmology and metaphysics to music and morals followed eternal rules describable as ratios of numbers . thus , any number could be written as such a ratio . 5 as 5/1 , 0.5 as 1/2 and so on . even an infinitely extending decimal like this could be expressed exactly as 34/45 . all of these are what we now call rational numbers . but hippasus found one number that violated this harmonious rule , one that was not supposed to exist . the problem began with a simple shape , a square with each side measuring one unit . according to pythagoras theorem , the diagonal length would be square root of two , but try as he might , hippasus could not express this as a ratio of two integers . and instead of giving up , he decided to prove it could n't be done . hippasus began by assuming that the pythagorean worldview was true , that root 2 could be expressed as a ratio of two integers . he labeled these hypothetical integers p and q . assuming the ratio was reduced to its simplest form , p and q could not have any common factors . to prove that root 2 was not rational , hippasus just had to prove that p/q can not exist . so he multiplied both sides of the equation by q and squared both sides . which gave him this equation . multiplying any number by 2 results in an even number , so p^2 had to be even . that could n't be true if p was odd because an odd number times itself is always odd , so p was even as well . thus , p could be expressed as 2a , where a is an integer . substituting this into the equation and simplifying gave q^2 = 2a^2 once again , two times any number produces an even number , so q^2 must have been even , and q must have been even as well , making both p and q even . but if that was true , then they had a common factor of two , which contradicted the initial statement , and that 's how hippasus concluded that no such ratio exists . that 's called a proof by contradiction , and according to the legend , the gods did not appreciate being contradicted . interestingly , even though we ca n't express irrational numbers as ratios of integers , it is possible to precisely plot some of them on the number line . take root 2 . all we need to do is form a right triangle with two sides each measuring one unit . the hypotenuse has a length of root 2 , which can be extended along the line . we can then form another right triangle with a base of that length and a one unit height , and its hypotenuse would equal root three , which can be extended along the line , as well . the key here is that decimals and ratios are only ways to express numbers . root 2 simply is the hypotenuse of a right triangle with sides of a length one . similarly , the famous irrational number pi is always equal to exactly what it represents , the ratio of a circle 's circumference to its diameter . approximations like 22/7 , or 355/113 will never precisely equal pi . we 'll never know what really happened to hippasus , but what we do know is that his discovery revolutionized mathematics . so whatever the myths may say , do n't be afraid to explore the impossible .
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did he murder guests , or disrupt a sacred ritual ? no , hippasus 's transgression was a mathematical proof : the discovery of irrational numbers . hippasus belonged to a group called the pythagorean mathematicians who had a religious reverence for numbers .
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what are irrational numbers ?
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translator : andrea mcdonough reviewer : bedirhan cinar once upon a time in the magical and very round land of pi , there lived six swashbuckling musketeers . there names were parentheses , exponents , multiplication , division , addition , and subtraction . but each was known best by his or her mark : the two hands ready to catch a fly of parentheses , the small and raised digits of exponents , the mighty x of multiplication , slash of division , plus of addition , and , well , you can guess the symbol by which little subtraction was best known . the land of pi was not necessarily the most peaceful place , and that 's why the numbers of the kingdom needed the musketeers . the land of pi had been ruled by the numbers as anarcho-syndicalist commune , each number with a vote , but , one powerful number from what we 'll call the imperial senate , engineered a war between some robot things and the knights of the kingdom , and then installed himself as supreme emperor , and then puff the magic digit dragon ate him , and a princess or two , and , well , all the other numbers in the land of pi actually . it was kind of a big day . anyway , the musketeers were called to action to save the land of pi from the voracious dragon . they rode towards him on their valiant steeds and attacked . first multiplication , then parentheses , but that did n't work . the dragon continued eating people . so addition tried , but was thrown aside . exponents leaped at the beast and was quickly squashed . nothing was working . the musketeers huddled and formulated a plan . they would attack in sequence , but who should go first ? they bickered for a while , the dragon ate a few more princesses , and then they finally agreed . they jumped into the first , smallest parentheses inside the great puff the digit dragon . parentheses pointed out where to work first and protected exponents , multiplication , division , addition , and subtraction while they diced and sliced . first here , then , move over there , then there . look out ! there 's another set ! parentheses pointed and exponents took the lead . then , it was multiplication , division , addition , and subtraction , each in turn , always the same order . p-e-m-d-a-s when they finished that set , they went to another , and another , always working inside the parentheses in pemdas order . pop ! pop ! pop ! pop ! pop ! pemdas , there is another spot ! do n't forget , there can be parentheses inside parentheses . there 's one ! and that tricky exponent . there we go ! finally , the pemdas musketeers had whittled puff down to his last fearsome roar . but , having vanquished puff the magic digit dragon , all the empire 's numbers sprang again from this tiny little number one , and they all lived happily ever after . except for the emperor number , which they threw into the mouth of an ancient nesting creature in the desert . the end .
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there names were parentheses , exponents , multiplication , division , addition , and subtraction . but each was known best by his or her mark : the two hands ready to catch a fly of parentheses , the small and raised digits of exponents , the mighty x of multiplication , slash of division , plus of addition , and , well , you can guess the symbol by which little subtraction was best known . the land of pi was not necessarily the most peaceful place , and that 's why the numbers of the kingdom needed the musketeers .
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around what other mathematical operations can you craft an imaginary world ? in two sentences , explain the world and how math will play a part .
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imagine a brilliant neuroscientist named mary . mary lives in a black and white room , she only reads black and white books , and her screens only display black and white . but even though she has never seen color , mary is an expert in color vision and knows everything ever discovered about its physics and biology . she knows how different wavelengths of light stimulate three types of cone cells in the retina , and she knows how electrical signals travel down the optic nerve into the brain . there , they create patterns of neural activity that correspond to the millions of colors most humans can distinguish . now imagine that one day , mary 's black and white screen malfunctions and an apple appears in color . for the first time , she can experience something that she 's known about for years . does she learn anything new ? is there anything about perceiving color that was n't captured in all her knowledge ? philosopher frank jackson proposed this thought experiment , called mary 's room , in 1982 . he argued that if mary already knew all the physical facts about color vision , and experiencing color still teaches her something new , then mental states , like color perception , ca n't be completely described by physical facts . the mary 's room thought experiment describes what philosophers call the knowledge argument , that there are non-physical properties and knowledge which can only be discovered through conscious experience . the knowledge argument contradicts the theory of physicalism , which says that everything , including mental states , has a physical explanation . to most people hearing mary 's story , it seems intuitively obvious that actually seeing color will be totally different than learning about it . therefore , there must be some quality of color vision that transcends its physical description . the knowledge argument is n't just about color vision . mary 's room uses color vision to represent conscious experience . if physical science ca n't entirely explain color vision , then maybe it ca n't entirely explain other conscious experiences either . for instance , we could know every physical detail about the structure and function of someone else 's brain , but still not understand what it feels like to be that person . these ineffable experiences have properties called qualia , subjective qualities that you ca n't accurately describe or measure . qualia are unique to the person experiencing them , like having an itch , being in love , or feeling bored . physical facts ca n't completely explain mental states like this . philosophers interested in artificial intelligence have used the knowledge argument to theorize that recreating a physical state wo n't necessarily recreate a corresponding mental state . in other words , building a computer which mimicked the function of every single neuron of the human brain wo n't necessarily create a conscious computerized brain . not all philosophers agree that the mary 's room experiment is useful . some argue that her extensive knowledge of color vision would have allowed her to create the same mental state produced by actually seeing the color . the screen malfunction would n't show her anything new . others say that her knowledge was never complete in the first place because it was based only on those physical facts that can be conveyed in words . years after he proposed it , jackson actually reversed his own stance on his thought experiment . he decided that even mary 's experience of seeing red still does correspond to a measurable physical event in the brain , not unknowable qualia beyond physical explanation . but there still is n't a definitive answer to the question of whether mary would learn anything new when she sees the apple . could it be that there are fundamental limits to what we can know about something we ca n't experience ? and would this mean there are certain aspects of the universe that lie permanently beyond our comprehension ? or will science and philosophy allow us to overcome our mind 's limitations ?
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is there anything about perceiving color that was n't captured in all her knowledge ? philosopher frank jackson proposed this thought experiment , called mary 's room , in 1982 . he argued that if mary already knew all the physical facts about color vision , and experiencing color still teaches her something new , then mental states , like color perception , ca n't be completely described by physical facts .
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which is a criticism of the “ mary ’ s room ” thought experiment ?
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as we walk through our daily environments , we 're surrounded by exotic creatures that are too small to see with the naked eye . we usually imagine these microscopic organisms , or microbes , as asocial cells that float around by themselves . but in reality , microbes gather by the millions to form vast communities known as biofilms . natural biofilms are like miniature jungles filled with many kinds of microbes from across the web of life . bacteria and archaea mingle with other microbes like algae , fungi , and protozoa , forming dense , organized structures that grow on almost any surface . when you pad across a river bottom , touch the rind of an aged cheese , tend your garden soil , or brush your teeth , you 're coming into contact with these invisible ecosystems . to see how biofilms come about , let 's watch one as it develops on a submerged river rock . this type of biofilm might begin with a few bacteria swimming through their liquid environment . the cells use rotating flagella to propel towards the surface of the rock , which they attach to with the help of sticky appendages . then , they start producing an extracellular matrix that holds them together as they divide and reproduce . before long , microcolonies arise , clusters of cells sheathed in this slimy , glue-like material . microcolonies grow to become towers , while water channels flow around them , functioning like a basic circulatory system . but why do microbes build such complex communities when they could live alone ? for one thing , microbes living in a biofilm are rooted in a relatively stable microenvironment where they may have access to a nutrient source . there 's also safety in numbers . out in the deep , dark wilderness of the microbial world , isolated microbes face serious risks . predators want to eat them , immune systems seek to destroy them , and there are physical dangers , too , like running out of water and drying up . however , in a biofilm , the extracellular matrix shields microbes from external threats . biofilms also enable interactions between individual cells . when microbes are packed against each other in close proximity , they can communicate , exchange genetic information , and engage in cooperative and competitive social behaviors . take the soil in your garden , home to thousands of bacterial species . as one species colonizes a plant root , its individual cells might differentiate into various subpopulations , each carrying out a specific task . matrix producers pump out the extracellular goo , swimmers assemble flagella and are free to move about or migrate , and spore-formers produce dormant , tough endospores that survive starvation , temperature extremes , and harmful radiation . this phenomenon is called division of labor . ultimately , it gives rise to a sophisticated system of cooperation that 's somewhat like a multicellular organism in itself . but because biofilms often contain many different microbes that are n't closely related to each other , interactions can also be competitive . bacteria launch vicious attacks on their competitors by secreting chemicals into the environment , or by deploying molecular spears to inject nearby cells with toxins that literally blow them up . in the end , competition is all about resources . if one species eliminates another , it keeps more space and food for itself . although this dramatic life cycle occurs beyond the limits of our vision , microbial communities provide humans and other species with tangible , and sometimes even delicious , benefits . microbes make up a major fraction of the biomass on earth and play a critical role within the global ecosystem that supports all larger organisms , including us . they produce much of the oxygen we breath , and are recruited to clean up environmental pollution , like oil spills , or to treat our waste water . not to mention , biofilms are normal and flavor enhancing parts of many of the foods we enjoy , including cheese , salami , and kombucha . so the next time you brush your teeth , bite into that cheese rind , sift through garden soil , or skip a river stone , look as close as you can . imagine the microbial jungles all around you waiting to be discovered and explored .
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predators want to eat them , immune systems seek to destroy them , and there are physical dangers , too , like running out of water and drying up . however , in a biofilm , the extracellular matrix shields microbes from external threats . biofilms also enable interactions between individual cells .
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a biofilm can be defined as a community of microbes that :
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translator : andrea mcdonough reviewer : bedirhan cinar nameste . i 'm from india , and india is one of the oldest civilizations in the world . it has contributed to the world concepts such as yoga , ayurveda , spicy chicken tikka , and vedic math . vedic math is one of the world 's easiest and simplest way to do math . we are going to combine together and do some number crunching today . so what we are going to first do is multiply by 11 . we 're going to do it together , so if you blink , you 're going to miss it . so just watch it , ok . so we 're going to do 32 times 11 , ok . so we split 3 , and we split 2 , and we add 3 and 2 and paste it on top , and we get the answer as 352 . that 's it . let 's try another sum . 45 times 11 . let 's hear it . exactly , that 's 495 . and 75 times 11 . so it gives you 7,125 , 1 gets carried over and it becomes 825 . that 's how simple it is . ok , this is the principle behind it where a is the coefficient . let 's move on . ok , now what we 're going to do is the base method . ok , this is used to multiply numbers very close to the powers of 10 , like 10 , 100 , 1,000 , and so on . so we have a sum here , say 99 times 97 . ok , now tell me , is 99 more than 100 or less than 100 ? less by how much ? so we write minus 01 . and 97 is less than 100 by how much ? so we write minus 03 . so what we 're going to do is we 're going to cross subtract and get the first part of the answer , like this . we 're going to do cross subtraction . 97 minus 01 would give us 96. and we multiply 03 times 01 vertically , and we get an answer of 03 . let 's check another sum . try and do it yourselves . we got 98 , which is , is it more than a 100 , less than 100 ? by how much ? and 97 is 3 . so we got 98 , we go crosswise , we got 98 minus 3 , or we can do 97 minus 2 , they 'll all give you the same answer . so that would give us 95 . and the second part would be 06 . so that 's our answer . ok , let 's take a bigger number . let 's try this one . here the base is 1,000 . so we got -004 , and 997 would be -003 . we go crosswise like this , and we get 996 minus 003 would give us 993 , and 004 times 003 would give us 012 . and that 's our answer . thank you . 14 times 12 . ok , here the base is 10 . ok , so is 14 more than 10 or less than 10 ? more , so we got plus 4 , and 12 , we got plus 2 . again , we apply the same rule , so we do 12 plus 4 , which gives us 16 , like this . and we multiply 2 and 4 , that gives us 8 . so now , all of us here , we 're going to do mental squaring , ok. everybody is going to participate here , and we 're going to do squares of numbers more than 100 mentally right now . so we got 101 , ok , now visualize on the board , what 's going to be on the right hand side . plus 01 , so we got that . ok , now we add plus sides , right ? yes ? no ? so we got 101 plus 01 , that would give us 102 , and , see here , like this . and 01 is getting squared , right ? so that would give us 01 , and that 's your answer . try the next one . let 's try 102 squared . let 's try , everybody . so 100 , so 102 would be 10404 . ok , now the next one , try it everybody together . i 'll give you 5 seconds . ok , let 's say it together , let 's say it together , ok. [ 10609 ] 10609 and that 's the answer . woo ! 104 squared , how much would that be ? calculate it , 5 seconds . come on , girls in the back . ok , so the answer would be 10816 . ok , let 's do the next one : 105 squared . oh , no , no , no , no , we 're going to try over , we 're going to try over , ok ? ok . i 'll give you 5 seconds , just think about it . ok , now we 're going to go , ok ? 11025 . ok , let 's going to do the next one , 106 squared . try it , come one , everybody , it 's simple and easy . [ 11236 ] ok , let 's do it one more time . 11236 . now 107 , think , hold on , do n't say anything out loud , just think mentally , 107 squared . ok , now let 's say it out loud . 11449 . and 108 squared . [ 11664 ] fantastic , give yourself a round of applause , come on ! and this is the principle behind this , where a and b are the excesses or the deficiency from the base . i 'm going to teach you in vedic math , there are 16 sutras , or word formulas , ok . they are very visual and one of them is called , `` vertically and crosswise , '' through which you can multiply any number by any number in a single line . so i 'm going to do a two-digit by a two-digit multiplication . let 's do this . so we got 31 times 12 . ok , so we 're going to apply the vertically and crosswise sutra . so we 're going to do like this : vertically , and then we 're going to go crosswise , and then we 're going to do vertical again . so , 2 times 1 gives us [ 2 ] , 2 times 3 gives us [ 6 ] , and 1 times 1 gives us [ 1 ] . 6 plus 1 , [ 7 ] . 1 times 3 gives us [ 3 ] . and that 's it , and that 's our answer . no more tedious calculations , no more going through the rough work , it 's simple in one line . i want to show you a sum again , this time with carry-overs . the same formula , all of us here can do this , ok . same formula . so let 's get started . 4 times 2 gives us [ 8 ] . ok , now we go crosswise like this , so we 're going to multiply 4 times 1 , [ 4 ] , and 3 times 2 , [ 6 ] 4 plus 6 gives us [ 10 ] . so we put down 0 , carry the 1 . and 3 times 1 gives us [ 3 ] , plus 1 , [ 4 ] . exactly , that 's our answer , 408 . ok , thank you for being such a participative audience , and we had a great time number crunching . now i want to end with a question : whether you 'd like math to be dull or boring , or fun and interesting ? the choice is yours .
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i 'm from india , and india is one of the oldest civilizations in the world . it has contributed to the world concepts such as yoga , ayurveda , spicy chicken tikka , and vedic math . vedic math is one of the world 's easiest and simplest way to do math .
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from which civilization did vedic mathematics originate ?
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how does your smartphone know exactly where you are ? the answer lies 12,000 miles over your head in an orbiting satellite that keeps time to the beat of an atomic clock powered by quantum mechanics . phew . let 's break that down . first of all , why is it so important to know what time it is on a satellite when location is what we 're concerned about ? the first thing your phone needs to determine is how far it is from a satellite . each satellite constantly broadcasts radio signals that travel from space to your phone at the speed of light . your phone records the signal arrival time and uses it to calculate the distance to the satellite using the simple formula , distance = c x time , where c is the speed of light and time is how long the signal traveled . but there 's a problem . light is incredibly fast . if we were only able to calculate time to the nearest second , every location on earth , and far beyond , would seem to be the same distance from the satellite . so in order to calculate that distance to within a few dozen feet , we need the best clock ever invented . enter atomic clocks , some of which are so precise that they would not gain or lose a second even if they ran for the next 300 million years . atomic clocks work because of quantum physics . all clocks must have a constant frequency . in other words , a clock must carry out some repetitive action to mark off equivalent increments of time . just as a grandfather clock relies on the constant swinging back and forth of a pendulum under gravity , the tick tock of an atomic clock is maintained by the transition between two energy levels of an atom . this is where quantum physics comes into play . quantum mechanics says that atoms carry energy , but they ca n't take on just any arbitrary amount . instead , atomic energy is constrained to a precise set of levels . we call these quanta . as a simple analogy , think about driving a car onto a freeway . as you increase your speed , you would normally continuously go from , say , 20 miles/hour up to 70 miles/hour . now , if you had a quantum atomic car , you would n't accelerate in a linear fashion . instead , you would instantaneously jump , or transition , from one speed to the next . for an atom , when a transition occurs from one energy level to another , quantum mechanics says that the energy difference is equal to a characteristic frequency , multiplied by a constant , where the change in energy is equal to a number , called planck 's constant , times the frequency . that characteristic frequency is what we need to make our clock . gps satellites rely on cesium and rubidium atoms as frequency standards . in the case of cesium 133 , the characteristic clock frequency is 9,192,631,770 hz . that 's 9 billion cycles per second . that 's a really fast clock . no matter how skilled a clockmaker may be , every pendulum , wind-up mechanism and quartz crystal resonates at a slightly different frequency . however , every cesium 133 atom in the universe oscillates at the same exact frequency . so thanks to the atomic clock , we get a time reading accurate to within 1 billionth of a second , and a very precise measurement of the distance from that satellite . let 's ignore the fact that you 're almost definitely on earth . we now know that you 're at a fixed distance from the satellite . in other words , you 're somewhere on the surface of a sphere centered around the satellite . measure your distance from a second satellite and you get another overlapping sphere . keep doing that , and with just four measurements , and a little correction using einstein 's theory of relativity , you can pinpoint your location to exactly one point in space . so that 's all it takes : a multibillion-dollar network of satellites , oscillating cesium atoms , quantum mechanics , relativity , a smartphone , and you . no problem .
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that characteristic frequency is what we need to make our clock . gps satellites rely on cesium and rubidium atoms as frequency standards . in the case of cesium 133 , the characteristic clock frequency is 9,192,631,770 hz .
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what kind of signals do gps satellites transmit to our smartphones ?
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there 's a job out there with a great deal of power , pay , prestige , and near-perfect job security . and there 's only one way to be hired : get appointed to the us supreme court . if you want to become a justice on the supreme court , the highest federal court in the united states , three things have to happen . you have to be nominated by the president of the united states , your nomination needs to be approved by the senate , and finally , the president must formally appoint you to the court . because the constitution does n't specify any qualifications , in other words , that there 's no age , education , profession , or even native-born citizenship requirement , a president can nominate any individual to serve . so far , six justices have been foreign-born , at least one never graduated from high school , and another was only 32 years old when he joined the bench . most presidents nominate individuals who broadly share their ideological view , so a president with a liberal ideology will tend to appoint liberals to the court . of course , a justice 's leanings are not always so predictable . for example , when president eisenhower , a republican , nominated earl warren for chief justice , eisenhower expected him to make conservative decisions . instead , warren 's judgements have gone down as some of the most liberal in the court 's history . eisenhower later remarked on that appointment as `` the biggest damned-fool mistake '' he ever made . many other factors come up for consideration , as well , including experience , personal loyalties , ethnicity , and gender . the candidates are then thoroughly vetted down to their tax records and payments to domestic help . once the president interviews the candidate and makes a formal nomination announcement , the senate leadership traditionally turns the nomination over to hearings by the senate judiciary committee . depending on the contentiousness of the choice , that can stretch over many days . since the nixon administration , these hearings have averaged 60 days . the nominee is interviewed about their law record , if applicable , and where they stand on key issues to discern how they might vote . and especially in more recent history , the committee tries to unearth any dark secrets or past indiscretions . the judiciary committee votes to send the nomination to the full senate with a positive or negative recommendation , often reflective of political leanings , or no recommendation at all . most rejections have happened when the senate majority has been a different political party than the president . when the senate does approve , it 's by a simple majority vote , with ties broken by the vice president . with the senate 's consent , the president issues a written appointment , allowing the nominee to complete the final steps to take the constitutional and judicial oaths . in doing so , they solemnly swear to administer justice without respect to persons and do equal right to the poor and the rich and faithfully and impartially discharge and perform all the duties incumbent upon a us supreme court justice . this job is for life , barring resignation , retirement , or removal from the court by impeachment . and of the 112 justices who have held the position , not one has yet been removed from office as a result of an impeachment . one of their roles is to protect the fundamental rights of all americans , even as different parties take power . with the tremendous impact of this responsibility , it 's no wonder that a us supreme court justice is expected to be , in the words of irving r. kaufman , `` a paragon of virtue , an intellectual titan , and an administrative wizard . '' of course , not every member of the court turns out to be an exemplar of justice . each leaves behind a legacy of decisions and opinions to be debated and dissected by the ultimate judges , time and history .
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and there 's only one way to be hired : get appointed to the us supreme court . if you want to become a justice on the supreme court , the highest federal court in the united states , three things have to happen . you have to be nominated by the president of the united states , your nomination needs to be approved by the senate , and finally , the president must formally appoint you to the court .
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which of the following is false when it comes to the 112 united states supreme court justices that have served today ?
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created by logician raymond smullyan and popularized by his colleague george boolos , this riddle has been called the hardest logic puzzle ever . you and your team have crash-landed on an ancient planet . the only way off is to appease its three alien overlords , tee , eff , and arr , by giving them the correct artifacts . unfortunately , you do n't know who is who . from an inscription , you learn that you may ask three yes or no questions , each addressed to any one lord . tee 's answers are always true , eff 's are always false , and arr 's answer is random each time . but there 's a problem . you 've deciphered the language enough to ask any question , but you do n't know which of the two words 'ozo ' and 'ulu ' means yes and which means no . how can you still figure out which alien is which ? pause here if you want to figure it out for yourself ! answer in : 3 2 1 at first , this puzzle seems not just hard , but downright impossible . what good is asking a question if you can neither understand the answer nor know if it 's true ? but it can be done . the key is to carefully formulate our questions so that any answer yields useful information . first of all , we can get around to not knowing what 'ozo ' and 'ulu ' mean by including the words themselves in the questions , and secondly , if we load each question with a hypothetical condition , whether an alien is lying or not wo n't actually matter . to see how that could work , imagine our question is whether two plus two is four . instead of posing it directly , we say , `` if i asked you whether two plus two is four , would you answer 'ozo ' ? '' if 'ozo ' means yes and the overlord is tee , it truthfully replies , `` ozo . '' but what if we ask eff ? well , it would answer `` ulu , '' or no to the embedded question , so it lies and replies 'ozo ' instead . and if 'ozo ' actually means no , then the answer to our embedded question is 'ulu , ' and both tee and eff still reply 'ozo , ' each for their own reasons . if you 're confused about why this works , the reason involves logical structure . a double positive and a double negative both result in a positive . now , we can be sure that asking either tee or eff a question put this way will yield 'ozo ' if the hypothetical question is true and 'ulu ' if it 's false regardless of what each word actually means . unfortunately , this does n't help us with arr . but do n't worry , we can use our first question to identify one alien lord that definitely is n't arr . then we can use the second to find out whether its tee or eff . and once we know that , we can ask it to identify one of the others . so let 's begin . ask the alien in the middle , `` if i asked you whether the overlord on my left is arr , would you answer 'ozo ' ? '' if the reply is 'ozo , ' there are two possibilities . you could already be talking to arr , in which case the answer is meaningless . but otherwise , you 're talking to either tee or eff , and as we know , getting 'ozo ' from either one means your hypothetical question was correct , and the left overlord is indeed arr . either way , you can be sure the alien on the right is not arr . similarly , if the answer is 'ulu , ' then you know the alien on the left ca n't be arr . now go to the overlord you 've determined is n't arr and ask , `` if i asked 'are you eff ? ' would you answer 'ozo ' ? '' since you do n't have to worry about the random possibility , either answer will establish its identity . now that you know whether its answers are true or false , ask the same alien whether the center overlord is arr . the process of elimination will identify the remaining one . the satisfied overlords help you repair your ship and you prepare for takeoff . allowed one final question , you ask tee if it 's a long way to earth , and he answers `` ozo . '' too bad you still do n't know what that means .
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if 'ozo ' means yes and the overlord is tee , it truthfully replies , `` ozo . '' but what if we ask eff ? well , it would answer `` ulu , '' or no to the embedded question , so it lies and replies 'ozo ' instead .
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why can ’ t you just directly ask each alien about their identities ?
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a national hero ? or public enemy number one ? historical figures are often controversial , but few were as deified or vilified in their lifetime as the seventh president of the united states . this is history vs. andrew jackson . `` order , order , hm , uh , what were we ... ah yes , mr. jackson ! you stand accused of degrading the office of the presidency , causing financial collapse and wanton cruelty against american indians . how do you plead ? '' `` now , your honor , i am not a big city lawyer , but i do know a few things . and i know that president jackson was a self-made frontiersman , a great general , a real man of the people . '' `` your honor , this 'man of the people ' was a gambler , a drunk , and a brawler . why , i 've heard it said that he would fight at the drop of the hat and then drop the hat himself . i ask you , was such a man fit for the most distinguished office in the nation ? can we forget the debacle of his inauguration ? who ever heard of inviting a drunken mob into the white house ? it took ages to get the upholstery clean . '' `` that drunken mob , sir , was the american people , and they deserve to celebrate their victory . '' `` order , order ! now , did this celebration have pie ? '' `` very well . mr. jackson , is it not the case that immediately upon assuming office you introduced the spoils system , replacing hundreds of perfectly good federal employees with incompetent party loyalists ? '' `` your honor , the president did no such thing . he tried to institute rotation in office to avoid any profiteering or funny business . it was the rest of the party who insisted on giving posts to their lackeys . '' `` but mr. jackson complied , did he not ? '' `` now , uh , see here . '' `` moving on . mr. jackson , did you not help to cause the financial panic of 1837 , and the ensuing economic depression with your obsessive war against the bank of the united states ? was not vetoing its reauthorization , as you did in 1832 , an act of irresponsible populace pandering that made no economic sense ? '' `` your honor , the gentleman has quite the imagination . that bank was just a way for rich yanks to get richer . and all that money panic was caused when british banks raised interest rates and cut lending . to blame it on the president is preposterous , i say . '' `` but if mr. jackson had not destroyed the national bank , it would have been able to lend to farmers and businesses when other credit dried up , would it not ? '' `` hm , this is all highly speculative . can we move on ? '' `` certainly , your honor . we now come to mr. jackson 's most terrible offense : forcing entire tribes out of their native lands via the indian removal act . '' `` i resent that accusation , sir . the u.s. of a. bought that land from the indians fair and square . '' `` do you call coercion and threats by a nation with a far more powerful army fair and square ? or signing a treaty for removing the cherokee with a small group that did n't include their actual leaders ? they did n't have time to properly supply themselves before the army came and forced them to march the trail of tears . '' `` now , hold on a minute . this was all van buren 's doing after president jackson left office . '' `` but mr. jackson laid the groundwork and made sure the treaty was ratified . all president van buren had to do afterwards was enforce it . '' `` look here , your honor . our government 's been purchasing indian land since the beginning , and my client was negotiating these deals even before he was president . president jackson truly believed it was best for the indians to get compensated for their land and move out west , where there was plenty of space for them to keep living the way they were accustomed , rather than stick around and keep butting heads with the white settlers . some of whom , i remind our court , wanted to exterminate them outright . it was a different time . '' `` and yet , even in this different time , there were many in congress and even the supreme court who saw how wrong the removal act was and loudly opposed it , were there not ? '' `` my client was under a great deal of pressure . i say , do you think it 's easy governing such a huge country and keeping the union together , when states are fixing to nullify federal laws ? president jackson barely got south carolina to back down over those import tariffs , and then georgia had to go discover gold and start grabbing up cherokee land . it was either get the indians to move or get in another fight with a state government . '' `` so , you admit that mr. jackson sacrified moral principles to achieve some political goals ? '' `` i do declare , show me one leader who has n't . '' as societies change and morals evolve , yesterday 's hero may become tomorrow 's villain , or vice versa . history may be past , but our understanding of it is always on trial .
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historical figures are often controversial , but few were as deified or vilified in their lifetime as the seventh president of the united states . this is history vs. andrew jackson . `` order , order , hm , uh , what were we ... ah yes , mr. jackson !
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common people most identified all of jackson ’ s characteristics except ________ .
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what is reality , knowledge , the meaning of life ? big topics you might tackle figuratively explaining existence as a journey down a road or across an ocean , a climb , a war , a book , a thread , a game , a window of opportunity , or an all-too-short-lived flicker of flame . 2,400 years ago , one of history 's famous thinkers said life is like being chained up in a cave , forced to watch shadows flitting across a stone wall . pretty cheery , right ? that 's actually what plato suggested in his allegory of the cave , found in book vii of `` the republic , '' in which the greek philosopher envisioned the ideal society by examining concepts like justice , truth and beauty . in the allegory , a group of prisoners have been confined in a cavern since birth , with no knowledge of the outside world . they are chained , facing a wall , unable to turn their heads , while a fire behind them gives off a faint light . occasionally , people pass by the fire , carrying figures of animals and other objects that cast shadows on the wall . the prisoners name and classify these illusions , believing they 're perceiving actual entities . suddenly , one prisoner is freed and brought outside for the first time . the sunlight hurts his eyes and he finds the new environment disorienting . when told that the things around him are real , ` while the shadows were mere reflections , he can not believe it . the shadows appeared much clearer to him . but gradually , his eyes adjust until he can look at reflections in the water , at objects directly , and finally at the sun , whose light is the ultimate source of everything he has seen . the prisoner returns to the cave to share his discovery , but he is no longer used to the darkness , and has a hard time seeing the shadows on the wall . the other prisoners think the journey has made him stupid and blind , and violently resist any attempts to free them . plato introduces this passage as an analogy of what it 's like to be a philosopher trying to educate the public . most people are not just comfortable in their ignorance but hostile to anyone who points it out . in fact , the real life socrates was sentenced to death by the athenian government for disrupting the social order , and his student plato spends much of `` the republic '' disparaging athenian democracy , while promoting rule by philosopher kings . with the cave parable , plato may be arguing that the masses are too stubborn and ignorant to govern themselves . but the allegory has captured imaginations for 2,400 years because it can be read in far more ways . importantly , the allegory is connected to the theory of forms , developed in plato 's other dialogues , which holds that like the shadows on the wall , things in the physical world are flawed reflections of ideal forms , such as roundness , or beauty . in this way , the cave leads to many fundamental questions , including the origin of knowledge , the problem of representation , and the nature of reality itself . for theologians , the ideal forms exist in the mind of a creator . for philosophers of language viewing the forms as linguistic concepts , the theory illustrates the problem of grouping concrete things under abstract terms . and others still wonder whether we can really know that the things outside the cave are any more real than the shadows . as we go about our lives , can we be confident in what we think we know ? perhaps one day , a glimmer of light may punch a hole in your most basic assumptions . will you break free to struggle towards the light , even if it costs you your friends and family , or stick with comfortable and familiar illusions ? truth or habit ? light or shadow ? hard choices , but if it 's any consolation , you 're not alone . there are lots of us down here .
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the prisoners name and classify these illusions , believing they 're perceiving actual entities . suddenly , one prisoner is freed and brought outside for the first time . the sunlight hurts his eyes and he finds the new environment disorienting .
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why would the other prisoners resist being freed after seeing the first prisoner return ?
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in the early 1960s , dick fosbury tried his hand at almost every sport , but never excelled at anything , until , at the age of 16 , he turned to the high jump . but when he could n't compete against the strong athletes at his college using the standard high jump techniques of the time , fosbury tried to jump a different way : backwards . instead of jumping with his face towards the bar , bringing each leg over in the traditional straddle method , he jumped with his back towards the bar . fosbury improved his record by over half a foot , and left his coaches amazed by this strange new style of high jumping . during the next few years , fosbury perfected his high jump style , won the u.s. national trials , and assured his place in the 1968 olympics in mexico . in the olympic games , fosbury amazed the world with his new technique , winning a gold metal with an olympic record leap of 2.24 meters . by the next olympic games , almost all of the competing of high jumpers had adopted what came to be known as the fosbury flop . what 's the secret behind the technique ? it lies in a physics concept called the center of mass . for every object , we can locate the average position of all of its mass by taking into account how the mass is spread around the object . for instance , the center of mass of a flat , rectangular object of uniform density will be in the intersection of both diagonals , in equal distance from each corner . we can find the center of mass for other objects by similar calculations , or by finding the object 's balancing point , which lies right underneath its center of mass . try balancing a broom by holding it and slowly bringing your hands together until they meet . this balancing point lies right underneath the broom 's center of mass . we humans also have a center of mass . when most people stand up , their center of mass is around the belly , but what happens to your center of mass when you lift your hands in the air ? your center of mass moves upwards . it moves all the time as you move through the day , based on how your body is positioned . it can even move outside of your body . when you bend forward , your center of mass is located below your bent belly in a place where there is no mass at all . weird to think about , but that 's the average position of all your mass . many objects ' center of mass are outside their bodies . think of doughnuts or boomerangs . now look at the fosbury flop , and follow the position of the center of mass of the jumper . the jumper runs very fast , so he can divert his horizontal velocity to vertical velocity , and jumps . wait for it ... there . look at the jumper 's center of mass as his body bends backward . it 's below the bar . that is the secret behind the jump . with the old , pre-fosbury techniques , the jumper had to apply enough force to lift his center of mass above the bar by a few inches in order to clear it . the fosbury flopper does n't have to do that . the genius of the fosbury flop is that the jumper can apply the same amount of force , but raise his body much higher than before . that means he can raise the bar so high that even when his center of mass ca n't go any higher , his arching body can . fosbury 's technique brought the high jump to new heights by splitting the jumper 's body away from his center of mass , giving it that much more room to clear higher and higher bars . so the fosbury flop may be sports history 's only great leap forward , that is also a great leap backward .
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when most people stand up , their center of mass is around the belly , but what happens to your center of mass when you lift your hands in the air ? your center of mass moves upwards . it moves all the time as you move through the day , based on how your body is positioned .
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you can locate the center of mass of an object by doing what ? choose all answers that apply .
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how old is the earth ? well , by counting the number of isotopes in a sample of rock that 's undergone radioactive decay , geologists have estimated the earth 's birthday , when it first formed from a solar nebula , to be 4.6 billion years ago . but just how long is that really ? here 's some analogies that might help you understand . for example , let 's imagine the entire history of earth until the present day as a single calendar year . on january 1st , the earth begins to form . by march 3rd , there 's the first evidence of single-celled bacteria . life remains amazingly unicellular until november 11th when the first multicellular organisms , known as the ediacaran fauna , come along . shortly thereafter , on november 16th at 6:08 p.m. is the cambrian explosion of life , a major milestone , when all of the modern phyla started to appear . on december 10th at 1:26 p.m. , the dinosaurs first evolve but are wiped out by an asteroid just two weeks later . on december 31st , the mighty roman empire rises and falls in just under four seconds . and columbus sets sail for what he thinks is india at three seconds to midnight . if you try to write the history of the earth using just one page per year , your book would be 145 miles thick , more than half the distance to the international space station . the story of the 3.2 million year-old australopithecine fossil known as lucy would be found on the 144th mile , just over 500 feet from the end of the book . the united states of america 's declaration of independence would be signed in the last half-inch . or if we compared geologic time to a woman stretching her arms to a span of six feet , the simple act of filing her nails would wipe away all of recorded human history . finally , let 's imagine the history of the earth as your life : from the moment you 're born to your first day of high school . your first word , first time sitting up , and first time walking would all take place while life on earth was comprised of single-celled organisms . in fact , the first multicellular organism would n't evolve until you were 12 years old and starting 7th grade , right around the time your science teacher is telling the class how fossils are formed . the dinosaurs do n't appear until three months into 8th grade and are soon wiped out right around spring break . three days before 9th grade begins , when you realize summer is over and you need new school supplies , lucy , the australopithecine , is walking around africa . as you finish breakfast and head outside to catch your bus 44 minutes before school , the neanderthals are going extinct throughout europe . the most recent glacial period ends as your bus drops you off 16 minutes before class . columbus sets sail 50 seconds before class as you 're still trying to find the right classroom . the declaration of independence is signed 28 seconds later as you look for an empty seat . and you were born 1.3 seconds before the bell rings . so , you see , the earth is extremely , unbelievably old compared to us humans with a fossil record hiding incredible stories to tell us about the past and possibly the future as well . but in the short time we 've been here , we 've learned so much and will surely learn more over the next decades and centuries , near moments in geological time .
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and you were born 1.3 seconds before the bell rings . so , you see , the earth is extremely , unbelievably old compared to us humans with a fossil record hiding incredible stories to tell us about the past and possibly the future as well . but in the short time we 've been here , we 've learned so much and will surely learn more over the next decades and centuries , near moments in geological time .
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calculate how many generations of humans it would take for us to exist on this planet as long as the dinosaurs ruled ? ( assume average life span of 80 years ) ( what must we humans do to ensure we are able to exist this many generations ?
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in 1898 , marie and pierre curie discovered radium . claimed to have restorative properties , radium was added to toothpaste , medicine , water , and food . a glowing , luminous green , it was also used in beauty products and jewelry . it was n't until the mid-20th century we realized that radium 's harmful effects as a radioactive element outweighed its visual benefits . unfortunately , radium is n't the only pigment that historically seemed harmless or useful but turned out to be deadly . that lamentable distinction includes a trio of colors and pigments that we 've long used to decorate ourselves and the things we make : white , green , and orange . our story begins with white . as far back as the 4th century bce , the ancient greeks treated lead to make the brilliant white pigment we know today . the problem ? in humans , lead is directly absorbed into the body and distributed to the blood , soft tissues , and mineralized tissues . once in the nervous system , lead mimics and disrupts the normal functions of calcium , causing damages ranging from learning disabilities to high blood pressure . yet the practice of using this toxic pigment continued across time and cultures . lead white was the only practical choice for white oil or tempera paint until the 19th century . to make their paint , artists would grind a block of lead into powder , exposing highly toxic dust particles . the pigment 's liberal use resulted in what was known as painter 's colic , or what we 'd now call lead poisoning . artists who worked with lead complained of palseys , melancholy , coughing , enlarged retinas , and even blindness . but lead white 's density , opacity , and warm tone were irresistible to artists like vermeer , and later , the impressionists . its glow could n't be matched , and the pigment continued to be widely used until it was banned in the 1970s . as bad as all that sounds , white 's dangerous effects pale in comparison to another , more wide-spread pigment , green . two synthetic greens called scheele 's green and paris green were first introduced in the 18th century . they were far more vibrant and flashy than the relatively dull greens made from natural pigments , so they quickly became popular choices for paint as well as dye for textiles , wallpaper , soaps , cake decorations , toys , candy , and clothing . these green pigments were made from a compound called cupric hydrogen arsenic . in humans , exposure to arsenic can damage the way cells communicate and function . and high levels of arsenic have been directly linked to cancer and heart disease . as a result , 18th century fabric factory workers were often poisoned , and women in green dresses reportedly collapsed from exposure to arsenic on their skin . bed bugs were rumored not to live in green rooms , and it 's even been speculated that napoleon died from slow arsenic poisoning from sleeping in his green wallpapered bedroom . the intense toxicity of these green stayed under wraps until the arsenic recipe was published in 1822 . and a century later , it was repurposed as an insecticide . synthetic green was probably the most dangerous color in widespread use , but at least it did n't share radium 's property of radioactivity . another color did , though - orange . before world war ii , it was common for manufacturers of ceramic dinnerware to use uranium oxide in colored glazes . the compound produced brilliant reds and oranges , which were appealing attributes , if not for the radiation they emitted . of course , radiation was something we were unaware of until the late 1800s , let alone the associated cancer risks , which we discovered much later . during world war ii , the u.s. government confiscated all uranium for use in bomb development . however , the atomic energy commission relaxed these restrictions in 1959 , and depleted uranium returned to ceramics and glass factory floors . orange dishes made during the next decade may still have some hazardous qualities on their surfaces to this day . most notably , vintage fiestaware reads positive for radioactivity . and while the levels are low enough that they do n't officially pose a health risk if they 're on a shelf , the u.s. epa warns against eating food off of them . though we still occasionally run into issues with synthetic food dyes , our scientific understanding has helped us prune hazardous colors out of our lives .
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yet the practice of using this toxic pigment continued across time and cultures . lead white was the only practical choice for white oil or tempera paint until the 19th century . to make their paint , artists would grind a block of lead into powder , exposing highly toxic dust particles .
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despite its deadly side effects , lead white was so popular that it wasn ’ t banned until the 1970s . what was it about this pigment that made it so popular ?
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translator : andrea mcdonough reviewer : bedirhan cinar i got in my first car accident when i was sixteen . i had just gotten my license and i was driving home when a car pulled into the intersection and bang ! it hit me . it had happened that quick . bang ! but when i play that memory back , it does n't take two seconds . i see the tires of the car rolling through the stop sign , i have time to think , `` you know , i think that car is going to hit me . '' i see the right-hand corner of the hood crumple up like tin foil , i see the red paint flake off and drift off into the air , i can see all of that , like it 's happening in slow motion . in my memory , that experience takes ten seconds . but why ? why did that memory play back longer than the actual time it took ? this is an interesting phenomenon and it 's not just for car accidents , a roller coaster , or a first kiss . these events seem to take longer than they actually take . but why ? and when it comes to writing about that experience , how do i get that peculiar feeling across ? how do i slow down time as a writer ? to get the answer , we have to visit hollywood . you see , the way filmmakers create slow motion will tell us a lot about how writers can create slow motion . first , let 's remember how film works . when the camera turns on , it 's not recording motion , it 's taking lots and lots of individual pictures . then when those pictures are played back in the projector , they blend together and create the appearance of motion , like a flip book . so , let 's imagine that a camera man needs to film his actress skipping through a field of daisies in regular motion . ready , action . she skips across the field , he records it , and ... cut . let 's say for the sake of easy math that our camera man took 50 pictures , 50 little frames on that length of film . now , let 's take that film and play it back at the rate of 50 frames per 5 seconds . this rate is constant , the projector will always go at the same speed . it 's easy , we got 50 frames , so our film takes 5 seconds . she skips across the field ... ... and cut ! so , then , how do we slow down time in film ? how do we create slow motion ? maybe this is a surprise , but we do n't take less pictures , we take more pictures . ready , action ! she skips across the field , he records it , and cut . now we have a lot of film , a long length , let 's say 100 frames long . now , when we play it back , it takes a longer time to get through , and there 's the actress in slow motion . skipping through the field of daisies ! which brings us now to writing . when you 're writing a narrative , you may want to use slow motion in one of your scenes . it 's a cool effect , just like it is in hollywood , and it draws the reader 's attention to important moments . well , here 's how you do it . you see , when we read , our brain makes the words into pictures and the pictures blend into action . so what we read is what we see in the time it takes us to read it . for example , imagine you 're writing a narrative about your game-winning free throw in the championship game . here 's a moment as a writer that you might want to slow down time to really capture the second-by-second tension produced by the scene . you concentrate , you put the pencil to paper , you really want to slow down time , you write , `` i shot the ball in the hoop . time slowed down . then we won . '' to read that , takes two seconds ; therefore , your reader imagines a scene that takes two seconds . ball goes up , comes down , done . see , even though you wrote , `` time slowed down , '' you did n't achieve that effect for your reader . just saying it does n't make it happen . now , let 's take what we make about film , time slows down with more pictures , and try again . this time write a lot more . `` i bent my knees and held the ball loosely . letting the ball bounce on the floor once more , i gathered my thoughts . this was the moment . my right arm extended as i released the ball with a gentle flick , it rotated slightly as it arched toward the rim . i held my breath . the ball nudged the back rim , falling through the net with a gentle , satisfying swish . and the crowd exploded from their seats . '' see , we just slowed down time through our writing . the bottom line is this : there are moments in life that take longer than they actually take . when you 're planning out your narrative , think about those moments , those snippets of life that took longer than the watch : the moment of hearing bad news , the moment of hearing good news , the moment of exhilaration when you realize you hit the jump , or the moment when you realize you are n't going to land it . once you identify these moments in your narrative , you can use this effect of slow motion when you write . just remember , it 's not enough to say , `` time slowed down '' and it 's not enough to throw a couple adjectives in a sentence and call it done either . descriptive writing is good writing , that 's true . but if you want to express the feeling of slow motion in life , you have to actually take up more physical space on the page , use more film so to speak . in doing so , you will create tension and keep your reader interested . and that way , the next time you write , you 'll control the camera of your own writing .
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so , then , how do we slow down time in film ? how do we create slow motion ? maybe this is a surprise , but we do n't take less pictures , we take more pictures .
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what 's your favorite slow motion scene from a movie ?
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one of the most remarkable aspects of the human brain is its ability to recognize patterns and describe them . among the hardest patterns we 've tried to understand is the concept of turbulent flow in fluid dynamics . the german physicist werner heisenberg said , `` when i meet god , i 'm going to ask him two questions : why relativity and why turbulence ? i really believe he will have an answer for the first . '' as difficult as turbulence is to understand mathematically , we can use art to depict the way it looks . in june 1889 , vincent van gogh painted the view just before sunrise from the window of his room at the saint-paul-de-mausole asylum in saint-rémy-de-provence , where he 'd admitted himself after mutilating his own ear in a psychotic episode . in `` the starry night , '' his circular brushstrokes create a night sky filled with swirling clouds and eddies of stars . van gogh and other impressionists represented light in a different way than their predecessors , seeming to capture its motion , for instance , across sun-dappled waters , or here in star light that twinkles and melts through milky waves of blue night sky . the effect is caused by luminance , the intensity of the light in the colors on the canvas . the more primitive part of our visual cortex , which sees light contrast and motion , but not color , will blend two differently colored areas together if they have the same luminance . but our brains ' primate subdivision will see the contrasting colors without blending . with these two interpretations happening at once , the light in many impressionist works seems to pulse , flicker and radiate oddly . that 's how this and other impressionist works use quickly executed prominent brushstrokes to capture something strikingly real about how light moves . 60 years later , russian mathematician andrey kolmogorov furthered our mathematical understanding of turbulence when he proposed that energy in a turbulent fluid at length r varies in proportion to the 5/3rds power of r. experimental measurements show kolmogorov was remarkably close to the way turbulent flow works , although a complete description of turbulence remains one of the unsolved problems in physics . a turbulent flow is self-similar if there is an energy cascade . in other words , big eddies transfer their energy to smaller eddies , which do likewise at other scales . examples of this include jupiter 's great red spot , cloud formations and interstellar dust particles . in 2004 , using the hubble space telescope , scientists saw the eddies of a distant cloud of dust and gas around a star , and it reminded them of van gogh 's `` starry night . '' this motivated scientists from mexico , spain and england to study the luminance in van gogh 's paintings in detail . they discovered that there is a distinct pattern of turbulent fluid structures close to kolmogorov 's equation hidden in many of van gogh 's paintings . the researchers digitized the paintings , and measured how brightness varies between any two pixels . from the curves measured for pixel separations , they concluded that paintings from van gogh 's period of psychotic agitation behave remarkably similar to fluid turbulence . his self-portrait with a pipe , from a calmer period in van gogh 's life , showed no sign of this correspondence . and neither did other artists ' work that seemed equally turbulent at first glance , like munch 's `` the scream . '' while it 's too easy to say van gogh 's turbulent genius enabled him to depict turbulence , it 's also far too difficult to accurately express the rousing beauty of the fact that in a period of intense suffering , van gogh was somehow able to perceive and represent one of the most supremely difficult concepts nature has ever brought before mankind , and to unite his unique mind 's eye with the deepest mysteries of movement , fluid and light .
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that 's how this and other impressionist works use quickly executed prominent brushstrokes to capture something strikingly real about how light moves . 60 years later , russian mathematician andrey kolmogorov furthered our mathematical understanding of turbulence when he proposed that energy in a turbulent fluid at length r varies in proportion to the 5/3rds power of r. experimental measurements show kolmogorov was remarkably close to the way turbulent flow works , although a complete description of turbulence remains one of the unsolved problems in physics . a turbulent flow is self-similar if there is an energy cascade .
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write a short paragraph ( 3-5 sentences ) that summarizes the history of turbulence . how would you describe the scientific problem-solving processes described in the video ?
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translator : tom carter reviewer : bedirhan cinar take an adjective such as `` implacable , '' or a verb like `` proliferate , '' or even another noun , `` crony , '' and add a suffix , such as `` -ity , '' or `` -tion , '' or `` -ism . '' you 've created a new noun . `` implacability , '' `` proliferation , '' `` cronyism . '' sounds impressive , right ? wrong ! you 've just unleashed a flesh-eating zombie . nouns made from other parts of speech are called nominalizations . academics love them . so do lawyers , bureaucrats , business writers . i call them zombie nouns , because they consume the living . they cannibalize active verbs , they suck the lifeblood from adjectives , and they substitute abstract entities for human beings . here 's an example . `` the proliferation of nominalizations in a discursive formation may be an indication of a tendency towards pomposity and abstraction . '' huh ? this sentence contains no fewer than seven nominalizations , yet it fails to tell us who is doing what . when we eliminate , or reanimate , most of the zombie nouns , so `` tendency '' becomes `` tend , '' `` abstraction '' becomes `` abstract , '' then we add a human subject and some active verbs , the sentence springs back to life . `` writers who overload their sentences with nominalizations tend to sound pompous and abstract . '' only one zombie noun -- the key word `` nominalizations '' -- has been allowed to remain standing . at their best , nominalizations help us express complex ideas , perception , intelligence , epistemology . at their worst , they impede clear communication . to get a feeling for how zombie nouns work , release a few of them into a lively sentence and watch them sap all its energy . george orwell played this game in his essay `` politics in the english language . '' he started with a well-known verse from the book of ecclesiastes in the bible . it says `` i returned and saw under the sun , that the race is not to the swift , nor the battle to the strong , neither yet bread to the wise , nor yet riches to men of understanding , nor yet favor to men of skill ; but time and chance happeneth to them all . '' now here 's orwell 's modern english version . `` objective considerations of contemporary phenomena compel the conclusion that success or failure in competitive activities exhibits no tendency to be commensurate with innate capacity , but that a considerable element of the unpredictable must invariably be taken into account . '' the bible passage speaks to our senses and emotions with concrete nouns , descriptions of people , and punchy , abstract nouns such as `` race , '' `` battle , '' `` riches , '' `` time , '' `` chance . '' not a zombie among them . orwell 's satirical translation , on the other hand , is teeming with nominalizations and other vague abstractions . the zombies have taken over , and the humans have fled the village . zombie nouns do their worst damage when they gather in jargon-generating packs and swallow every noun , verb and adjective in sight . so `` globe '' becomes `` global , '' becomes `` globalize , '' becomes `` globalization . '' the grandfather of all nominalizations , antidisestablishmentarianism , contains at least two verbs , three adjectives , and six other nouns inside its distended belly . a paragraph heavily populated by nominalizations will send your readers straight to sleep . rescue them from the zombie apocalypse with vigorous verb-driven sentences that are concrete and clearly structured . you want your sentences to live , not to join the living dead .
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only one zombie noun -- the key word `` nominalizations '' -- has been allowed to remain standing . at their best , nominalizations help us express complex ideas , perception , intelligence , epistemology . at their worst , they impede clear communication .
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“ at their best , nominalizations help us express complex ideas . at their worst , they impede clear communication. ” when should we use nominalizations , and why ? when and why should we avoid them ?
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good afternoon , ladies and gentlemen . let us welcome you to the final day of dramatic battle between great tragedians . it is a spring day here in ancient greece . nearly 17,000 patrons are filing into the theatre of dionysus to watch top playwrights , including favorites aeschylus and sophocles duke it out to see whose hero may be deemed most tragic , whose story most awful . well seacrestopolis , in last week 's battle of the choruses , all 50 members of each playwright 's chorus traveled back and forth across the stage , singing the strophe and antistrophe , telling misbegotten tales of woe . today 's first chorus is entering through the parados , taking their positions in the orchestra at the bottom of the stage . mario lopedokia , this is nothing we have n't seen before . all 50 members speaking from the depths of their souls . wait , what is this ? i 've not seen this before , seacrestopolis . there is one actor stepping out of choral formation , assuming an independent role in this play . can you make out who it is ? that looks like thespis . it seems he 's changing his mask , and taking on the role of another character . incredible . surely , thespis will go down in history as the very first actor . he has changed the face of theater forever . and that was just the warm-up act . on to the main attraction . aeschylus will have the stage first . let 's see what he does . we expect great things . last competition , sophocles beat him by a smidge , but aeschylus is still considered the father of tragedy . now , aeschylus frequently competes at this festival , the city dionysia . though his plays are violent , the bloodshed is never seen by the audience , which allows the dramatic tension to take center stage . let 's see what he does today to try to win his title back . here comes aeschylus 's chorus , but they seem to be missing quite a few people . what is going on here ? not only are they down a few people . there are two actors taking center stage . this is absolutely unheard of . he has build on thespis 's idea and added a second actor to the mix . aeschylus is relying on the two individuals to tell the story . the dialogue possible in tragedy now has taken precedence over the chorus . no wonder he drastically shrunk its size . this applause is well deserved . the crowd has hushed . sophocles 's actors and chorus are taking the stage for the play , `` oedipus rex . '' as usual , the chorus is set up in the orchestra . and what 's this ? sophocles has added a third actor . will this one-upmanship never end ? three actors , and they are changing their masks to take on several different roles as they weave the tale of oedipus , a nice fellow who kills his father and marries his mother . kills his father and marries his mother . that sounds pretty tragic to me . it is most tragic , mario lopedokia . call me crazy , but i 'm willing to bet that future generations will hold this play up as the perfect example of tragedy . excuse me , seacrestopolis . oedipus has left the stage after realizing jocasta was his wife and also his mother . where has he gone ? i ca n't even imagine . wait . the messenger has stepped on stage and is telling us of the great king 's actions . he says that oedipus , upon finding his mother , wife , whatever , jocasta , dead of her own hand in their incestuous bedroom , took the broaches from her dress and stabbed his eyes repeatedly . you ca n't blame the guy , can you ? bedded his mother , killed his father , is father and brother to his children . i might do the same . my friend , i do believe we 've seen it all . indeed , we have . there is nothing more tragic than oedipus . and sure enough , the judges who have been chosen by lot from all over greece are ready to announce the winner . oh , folks ! this is one for the history books . dark horse playwright , philocles , has taken first prize . what an upset . what a tragedy . what a night , folks . we have witnessed the laying of the foundation of modern theater and some great innovations : the shrinking of the chorus , the addition of three actors , and such catharsis . does n't a great tragedy just make you feel renewed and cleansed ? it sure does , but now we are out of time . i 'm seacrestopolis , and i 'm mario lopedokia . peace , love and catharsis .
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the crowd has hushed . sophocles 's actors and chorus are taking the stage for the play , `` oedipus rex . '' as usual , the chorus is set up in the orchestra .
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thespis , aeschylus and sophocles were some of the key players innovating theater in their time . their innovations changed the way stories were told . what was gained theatrically by shrinking the role of the chorus and increasing the number of actors on stage ?
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imagine you 're walking through a forest . everything might seem quiet ... but beneath your feet is a flurry of conversation . all the plants around you are actually talking to each other . the trees and the shrubs and the flowers are passing information back and forth , with serious life and death consequences . so , how are they communicating ? they ’ re using a giant network of fungi—one so pervasive and powerful that some scientists have started comparing it to the internet . they ’ re calling it the “ wood wide web. ” i ’ m anna , and this is gross science . the so-called wood wide web is made up of what are called “ mycorrhizal fungi. ” there are many different types of mycorrhizal fungi , but generally these little guys will grow on the roots of plants and provide them with water and nutrients—like nitrogen and phosphorus—in exchange for sugars from the plant . while they ’ re incredibly thin , the threads of the fungi can be up to 1000 times the length of a tree root . this allows the fungi to connect together many different plants . once connections are made , the fungi can act almost like the neurons in our brain , transporting signals from plant to plant . and these networks are everywhere . it ’ s estimated that around 90 % of land plants are connected to some kind of mycorrhizal network . so , how can plants use these networks ? well , to begin with , they can help each other out in times of stress . for example , during the fall months , when paper birch trees lose their leaves and can ’ t produce sugar , douglas-fir trees may shuttle them nutrients through the fungal network . and in the summer , when paper birch trees have lots of leaves , they send sugars to young douglas-fir saplings growing in their shadows . plants can also warn each other of danger . douglas-fir trees connected by a fungal network can alert their ponderosa pine neighbors if they ’ re attacked by budworms . in response , the neighboring ponderosa pine trees will produce insect-repelling chemicals—even though they haven ’ t been directly exposed to the insects themselves . mycorrhizal fungi can also enable parental care of among plants . some adult trees will help out their younger relatives by sending those seedlings more nutrients through the fungal network than they send to strangers . the adults may even make more room for them in the soil by reducing the number of their own roots . but not everyone is so generous . much like our internet , things can sometimes get a little nasty on the wood wide web . take black walnut trees , for example . they can spread poison through the network , hindering the growth of their neighbors . and the fungi making up the network can be just as tricky . mycorrhizal fungi tend to pick favorites . they may share resources with one species of tree , but bleed another species dry without giving anything back in return . the fungi may also judge a plant 's health . if they think it ’ s too weak or sick , they may not allow it to receive nutrients or danger signals from the network . now , we ’ re only beginning to understand how complex these relationships get . but imagine the possibilities for agriculture and forestry . if we find out certain species share well across the network , maybe we can plant them near each other to yield better harvests , or grow healthier forests . so next time you ’ re walking through the woods or the park don ’ t forget to thank the fungal web beneath your feet . ew .
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they ’ re calling it the “ wood wide web. ” i ’ m anna , and this is gross science . the so-called wood wide web is made up of what are called “ mycorrhizal fungi. ” there are many different types of mycorrhizal fungi , but generally these little guys will grow on the roots of plants and provide them with water and nutrients—like nitrogen and phosphorus—in exchange for sugars from the plant . while they ’ re incredibly thin , the threads of the fungi can be up to 1000 times the length of a tree root .
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mycorrhizal fungi grow on the roots of plants and give them nitrogen and phosphorus in exchange for what ?
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how is it that so many intergalactic species in movies and tv just happen to speak perfect english ? the short answer is that no one wants to watch a starship crew spend years compiling an alien dictionary . but to keep things consistent , the creators of star trek and other science-fiction worlds have introduced the concept of a universal translator , a portable device that can instantly translate between any languages . so is a universal translator possible in real life ? we already have many programs that claim to do just that , taking a word , sentence , or entire book in one language and translating it into almost any other , whether it 's modern english or ancient sanskrit . and if translation were just a matter of looking up words in a dictionary , these programs would run circles around humans . the reality , however , is a bit more complicated . a rule-based translation program uses a lexical database , which includes all the words you 'd find in a dictionary and all grammatical forms they can take , and set of rules to recognize the basic linguistic elements in the input language . for a seemingly simple sentence like , `` the children eat the muffins , '' the program first parses its syntax , or grammatical structure , by identifying the children as the subject , and the rest of the sentence as the predicate consisting of a verb `` eat , '' and a direct object `` the muffins . '' it then needs to recognize english morphology , or how the language can be broken down into its smallest meaningful units , such as the word muffin and the suffix `` s , '' used to indicate plural . finally , it needs to understand the semantics , what the different parts of the sentence actually mean . to translate this sentence properly , the program would refer to a different set of vocabulary and rules for each element of the target language . but this is where it gets tricky . the syntax of some languages allows words to be arranged in any order , while in others , doing so could make the muffin eat the child . morphology can also pose a problem . slovene distinguishes between two children and three or more using a dual suffix absent in many other languages , while russian 's lack of definite articles might leave you wondering whether the children are eating some particular muffins , or just eat muffins in general . finally , even when the semantics are technically correct , the program might miss their finer points , such as whether the children `` mangiano '' the muffins , or `` divorano '' them . another method is statistical machine translation , which analyzes a database of books , articles , and documents that have already been translated by humans . by finding matches between source and translated text that are unlikely to occur by chance , the program can identify corresponding phrases and patterns , and use them for future translations . however , the quality of this type of translation depends on the size of the initial database and the availability of samples for certain languages or styles of writing . the difficulty that computers have with the exceptions , irregularities and shades of meaning that seem to come instinctively to humans has led some researchers to believe that our understanding of language is a unique product of our biological brain structure . in fact , one of the most famous fictional universal translators , the babel fish from `` the hitchhiker 's guide to the galaxy '' , is not a machine at all but a small creature that translates the brain waves and nerve signals of sentient species through a form of telepathy . for now , learning a language the old fashioned way will still give you better results than any currently available computer program . but this is no easy task , and the sheer number of languages in the world , as well as the increasing interaction between the people who speak them , will only continue to spur greater advances in automatic translation . perhaps by the time we encounter intergalactic life forms , we 'll be able to communicate with them through a tiny gizmo , or we might have to start compiling that dictionary , after all .
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the difficulty that computers have with the exceptions , irregularities and shades of meaning that seem to come instinctively to humans has led some researchers to believe that our understanding of language is a unique product of our biological brain structure . in fact , one of the most famous fictional universal translators , the babel fish from `` the hitchhiker 's guide to the galaxy '' , is not a machine at all but a small creature that translates the brain waves and nerve signals of sentient species through a form of telepathy . for now , learning a language the old fashioned way will still give you better results than any currently available computer program .
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why is it difficult to construct a machine that translates perfectly ?
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this room may appear to be holding 600 people , but there 's actually so many more , because in each one of us there is a multitude of personalities . i have two primary personalities that have been in conflict and conversation within me since i was a little girl . i call them `` the mystic '' and `` the warrior . '' i was born into a family of politically active , intellectual atheists . there was this equation in my family that went something like this : if you are intelligent , you therefore are not spiritual . i was the freak of the family . i was this weird little kid who wanted to have deep talks about the worlds that might exist beyond the ones that we perceive with our senses . i wanted to know if what we human beings see and hear and think is a full and accurate picture of reality . so , looking for answers , i went to catholic mass . i tagged along with my neighbors . i read sartre and socrates . and then a wonderful thing happened when i was in high school : gurus from the east started washing up on the shores of america . and i said to myself , `` i wan na get me one of them . '' and ever since , i 've been walking the mystic path , trying to peer beyond what albert einstein called `` the optical delusion of everyday consciousness . '' so what did he mean by this ? i 'll show you . take a breath right now of this clear air in this room . now , see this strange , underwater , coral reef-looking thing ? it 's actually a person 's trachea , and those colored globs are microbes that are actually swimming around in this room right now , all around us . if we 're blind to this simple biology , imagine what we 're missing at the smallest subatomic level right now and at the grandest cosmic levels . my years as a mystic have made me question almost all my assumptions . they 've made me a proud i-don't-know-it-all . now when the mystic part of me jabbers on and on like this , the warrior rolls her eyes . she 's concerned about what 's happening in this world right now . she 's worried . she says , `` excuse me , i 'm pissed off , and i know a few things , and we better get busy about them right now . '' i 've spent my life as a warrior , working for women 's issues , working on political campaigns , being an activist for the environment . and it can be sort of crazy-making , housing both the mystic and the warrior in one body . i 've always been attracted to those rare people who pull that off , who devote their lives to humanity with the grit of the warrior and the grace of the mystic -- people like martin luther king , jr. , who wrote , `` i can never be what i ought to be until you are what you ought to be . this , '' he wrote , `` is the interrelated structure of reality . '' then mother teresa , another mystic warrior , who said , `` the problem with the world is that we draw the circle of our family too small . '' and nelson mandela , who lives by the african concept of `` ubuntu , '' which means `` i need you in order to be me , and you need me in order to be you . '' now we all love to trot out these three mystic warriors as if they were born with the saint gene . but we all actually have the same capacity that they do , and we need to do their work now . i 'm deeply disturbed by the ways in which all of our cultures are demonizing `` the other '' by the voice we 're giving to the most divisive among us . listen to these titles of some of the bestselling books from both sides of the political divide here in the u.s. `` liberalism is a mental disorder , '' `` rush limbaugh is a big fat idiot , '' `` pinheads and patriots , '' `` arguing with idiots . '' they 're supposedly tongue-in-cheek , but they 're actually dangerous . now here 's a title that may sound familiar , but whose author may surprise you : `` four-and-a-half-years of struggle against lies , stupidity and cowardice . '' who wrote that ? that was adolf hitler 's first title for `` mein kampf '' -- `` my struggle '' -- the book that launched the nazi party . the worst eras in human history , whether in cambodia or germany or rwanda , they start like this , with negative other-izing . and then they morph into violent extremism . this is why i 'm launching a new initiative . and it 's to help all of us , myself included , to counteract the tendency to `` otherize . '' and i realize we 're all busy people , so do n't worry , you can do this on a lunch break . i 'm calling my initiative , `` take the other to lunch . '' if you are a republican , you can take a democrat to lunch , or if you 're a democrat , think of it as taking a republican to lunch . now if the idea of taking any of these people to lunch makes you lose your appetite , i suggest you start more local , because there is no shortage of the other right in your own neighborhood . maybe that person who worships at the mosque , or the church or the synagogue , down the street . or someone from the other side of the abortion conflict . or maybe your brother-in-law who does n't believe in global warming . anyone whose lifestyle may frighten you , or whose point of view makes smoke come out of your ears . a couple of weeks ago , i took a conservative tea party woman to lunch . now on paper , she passed my smoking ears test . she 's an activist from the right , and i 'm an activist from the left . and we used some guidelines to keep our conversation elevated , and you can use them too , because i know you 're all going to take an other to lunch . so first of all , decide on a goal : to get to know one person from a group you may have negatively stereotyped . and then , before you get together , agree on some ground rules . my tea party lunchmate and i came up with these : do n't persuade , defend or interrupt . be curious ; be conversational ; be real . and listen . from there , we dove in . and we used these questions : share some of your life experiences with me . what issues deeply concern you ? and what have you always wanted to ask someone from the other side ? my lunch partner and i came away with some really important insights , and i 'm going to share just one with you . i think it has relevance to any problem between people anywhere . i asked her why her side makes such outrageous allegations and lies about my side . `` what ? '' she wanted to know . `` like we 're a bunch of elitist , morally-corrupt terrorist-lovers . '' well , she was shocked . she thought my side beat up on her side way more often , that we called them brainless , gun-toting racists , and we both marveled at the labels that fit none of the people we actually know . and since we had established some trust , we believed in each other 's sincerity . we agreed we 'd speak up in our own communities when we witnessed the kind of `` otherizing '' talk that can wound and fester into paranoia and then be used by those on the fringes to incite . by the end of our lunch , we acknowledged each other 's openness . neither of us had tried to change the other . but we also had n't pretended that our differences were just going to melt away after a lunch . instead , we had taken first steps together , past our knee-jerk reactions , to the ubuntu place , which is the only place where solutions to our most intractable-seeming problems will be found . who should you invite to lunch ? next time you catch yourself in the act of otherizing , that will be your clue . and what might happen at your lunch ? will the heavens open and `` we are the world '' play over the restaurant sound system ? probably not . because ubuntu work is slow , and it 's difficult . it 's two people dropping the pretense of being know-it-alls . it 's two people , two warriors , dropping their weapons and reaching toward each other . here 's how the great persian poet rumi put it : `` out beyond ideas of wrong-doing and right-doing , there is a field . i 'll meet you there . '' ( applause )
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i have two primary personalities that have been in conflict and conversation within me since i was a little girl . i call them `` the mystic '' and `` the warrior . '' i was born into a family of politically active , intellectual atheists .
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describe the two sides of human nature ( the mystic and the warrior ) that lesser describes in her talk .
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translator : andrea mcdonough reviewer : jessica ruby the next time you see a news report of a hurricane or a tropical storm showing high winds battering trees and houses , ask yourself , `` how did the wind get going so fast ? '' amazingly enough , this is a motion that started more than five billion years ago . but , to understand why , we need to understand spin . in physics , we talk about two types of motion . the first is straight-line motion . you push on something , and it moves forward . the second type , spin , involves an object rotating , or turning on its axis in place . an object in straight-line motion will move forever unless something , like the friction of the ground beneath it , causes it to slow down and stop . the same thing happens when you get something spinning . it will keep on spinning until something stops it . but the spin can speed up . if an ice skater is gliding across the ice in straight-line motion and she pulls her arms in , she keeps on gliding at the same speed . but if she is spinning on the ice and she pulls her arms in , you know what happens next . she spins faster . this is called the conservation of angular momentum . mathematically , angular momentum is a product of two numbers , one that gives the spin rate and one that gives the distance of the mass from the axis . if something is freely spinning , as one number gets bigger , the other gets smaller . arms closer , spin faster . arms farther , spin slower . spin causes other effects , too . if you are riding on a spinning merry-go-round and you toss a ball to a friend , it will appear to follow a curving path . it does n't actually curve , though . it really goes in a straight line . you were the one who was following a curving path , but , from your point of view , the ball appears to curve . we call this the coriolis effect . oh , and you are riding on a speeding merry-go-round right now at this very moment . we call it the earth . the earth spins on its axis once each day . but why does the earth spin ? now , that 's a story that starts billions of years ago . a cloud of dust and gas that form the sun and the earth and the planets and you and me started to collapse as gravity pulled it all together . before it started to collapse , this cloud had a very gentle spin . and , as it collapsed , like that ice skater pulling her arms in , the spin got faster and faster . and everything that formed out of the cloud , the sun and the planets around the sun and the moons around the planets , all inherited this spin . and this inherited spin is what gives us night and day . and this day-night cycle is what drives our weather . the earth is warm on the daytime side , cool on the nighttime side , and it 's warmer at the equator than at the poles . the differences in temperature make differences in air pressure , and the differences in air pressure make air move . they make the wind blow . but , because the earth spins , the moving air curves to the right in the northern hemisphere because of the coriolis effect . if there 's a region of low pressure in the atmosphere , air is pushed toward it , like water going down a drain . but the air curves to the right as it goes , and this gives it a spin . with the dramatic low pressure in a storm , the air gets pulled in tighter and tighter , so it gets going faster and faster , and this is how we get the high winds of a hurricane . so , when you see a spinning storm on a weather report , think about this : the spin ultimately came from the spin of the earth , and the earth 's spin is a remnant , a fossil relic , of the gentle spin of the cloud of dust and gas that collapsed to make the earth some five billion years ago . you are watching something , the spin , that is older than dirt , that 's older than rocks , that 's older than the earth itself .
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oh , and you are riding on a speeding merry-go-round right now at this very moment . we call it the earth . the earth spins on its axis once each day . but why does the earth spin ?
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billions of years ago , the spin of the earth was much faster than it is now ; in the time of the dinosaurs , the day was much less than 24 hours long . suppose the earth spun twice as fast , so a day was 12 hours long . what changes would this make in the earth ’ s weather ?
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when you hear the word art , what comes to mind ? a painting , like the mona lisa , or a famous sculpture or a building ? what about a vase or a quilt or a violin ? are those things art , too , or are they craft ? and what 's the difference anyway ? it turns out that the answer is not so simple . a spoon or a saddle may be finely wrought , while a monument may be , well , uninspired . just as not every musical instrument is utilitarian , not every painting or statue is made for its own sake . but if it 's so tricky to separate art from craft , then why do we distinguish objects in this way ? you could say it 's the result of a dramatic historical turn of events . it might seem obvious to us today to view people , such as da vinci or michelangelo , as legendary artists , and , of course , they possessed extraordinary talents , but they also happened to live in the right place at the right time , because shortly before their lifetimes the concept of artists hardly existed . if you had chanced to step into a medieval european workshop , you would have witnessed a similar scene , no matter whether the place belonged to a stonemason , a goldsmith , a hatmaker , or a fresco painter . the master , following a strict set of guild statutes , insured that apprentices and journeymen worked their way up the ranks over many years of practice and well-defined stages of accomplishment , passing established traditions to the next generation . patrons regarded these makers collectively rather than individually , and their works from murano glass goblets , to flemish lace , were valued as symbols of social status , not only for their beauty , but their adherence to a particular tradition . and the customer who commissioned and paid for the work , whether it was a fine chair , a stone sculpture , a gold necklace , or an entire building , was more likely to get credit than those who designed or constructed it . it was n't until around 1400 that people began to draw a line between art and craft . in florence , italy , a new cultural ideal that would later be called renaissance humanism was beginning to take form . florentine intellectuals began to spread the idea of reformulating classical greek and roman works , while placing greater value on individual creativity than collective production . a few brave painters , who for many centuries , had been paid by the square foot , successfully petitioned their patrons to pay them on the basis of merit instead . within a single generation , people 's attitudes about objects and their makers would shift dramatically , such that in 1550 , giorgio vasari , not incidentally a friend of michelangelo , published an influential book called , `` lives of the most excellent painters , sculptors and architects , '' elevating these types of creators to rock star status by sharing juicy biographical details . in the mind of the public , painting , sculpture and architecture were now considered art , and their makers creative masterminds : artists . meanwhile , those who maintained guild traditions and faithfully produced candelsticks , ceramic vessels , gold jewelery or wrought iron gates , would be known communally as artisans , and their works considered minor or decorative arts , connoting an inferior status and solidifying the distinction between art and craft that still persists in the western world . so , if we consider a painting by rembrandt or picasso art , then where does that leave an african mask ? a chinese porclein vase ? a navajo rug ? it turns out that in the history of art , the value placed on innovation is the exception rather than the rule . in many cultures of the world , the distinction between art and craft has never existed . in fact , some works that might be considered craft , a peruvian rug , a ming dynasty vase , a totem pole , are considered the cultures ' preeminent visual forms . when art historians of the 19th century saw that the art of some non-western cultures did not change for thousands of years , they classified the works as primitive , suggesting that their makers were incapable of innovating and therefore were not really artists . what they did n't realize was that these makers were not seeking to innovate at all . the value of their works lay precisely in preserving visual traditions , rather than in changing them . in the last few decades , works such as quilts , ceramics and wood carvings have become more prominently included in art history textbooks and displayed in museums alongside paintings and sculpture . so maybe it 's time to dispense with vague terms like art and craft in favor of a word like visual arts that encompasses a wider array of aesthetic production . after all , if our appreciation of objects and their makers is so conditioned by our culture and history , then art and its definition are truly in the eye of the beholder .
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it turns out that in the history of art , the value placed on innovation is the exception rather than the rule . in many cultures of the world , the distinction between art and craft has never existed . in fact , some works that might be considered craft , a peruvian rug , a ming dynasty vase , a totem pole , are considered the cultures ' preeminent visual forms .
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many cultures of the world , especially non-western cultures , place a high value on __________ visual traditions .
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just a minute ago , this oil helped make a delicious meal possible . but now , it 's just some nasty goop . what should we do with it ? well , the easiest thing would be to pour it down the drain ; that makes it seem like it 's gone , but it 's not really gone . instead , it 's collecting bits of food and other random stuff , producing monstrous , greasy blockages that clog not only your own drain but entire sewage systems , causing flooding and pollution . many places have laws for proper disposal of grease , but we can go one step further . instead of just throwing it away safely , we can turn it into something useful . and if you 're wondering what anyone could possibly want with a bunch of digusting , used cooking oil , the answer is : biodiesel . you 've probably heard of diesel engines . they power farming and construction equipment , trucks , buses , ships , trains , backup generators , and even some cars . most of the fuel that feeds these engines is refined from petroleum , which comes from long-dead dinosaurs and other ancient fossils . but diesel fuel can also be derived from more recently-dead organisms , like plants and animals . and this type of fuel is what we call biodiesel . biodiesel is a biodegradable energy source , made from plant oils or animal fats , that can usually be burned in regular diesel engines . you guessed it , it 's the 'bio ' version of diesel . it 's cleaner than normal diesel , so there has been a push to generate it from crops like soybeans . now , growing plants for fuel , instead of food , comes with its own problems . but fortunately , we already have some oils and fats right here . preparing your used cooking grease for recycling is easy . first , let it cool down to room temperature . then , transfer it to a clean container . you can use any old bottles you have lying around , like milk jugs , as long as they 're completely empty , rinsed , and dried . use a funnel to avoid spills and a sieve to filter out any small food particles . you can even add bacon grease and other animal fats or the excess oil from canned food , like tuna or sardines , just make sure it 's really oil and not brine . so , what happens now that your oil is safely contained ? well , many cities have recycling services that will pick up large amounts of grease from restaurants and other establishments . but there are locations where individuals can drop off their containers , as well . all of this grease will end up at a processing plant , where it can be converted to useable biodiesel . how does this conversion work ? well , all these oils and fats you donated are made up of triglycerides , a glycerol molecule connected to three fatty acid chains . to convert fats to fuel , they react with an alcohol , usually methanol or ethanol , which produces long-chain esters and glycerol . to compare , here are some molecules of regular diesel fuel . now , here are the molecules we created by breaking apart the triglycerides . glycerol is the odd man out , so it 's removed at the end of the process . but look at these esters ! if you squint , their structures look pretty similar to those of the long-chain hydrocarbons in regular diesel . and diesel engines , with a few small modifications , can also be made to squint and burn these esters like regular diesel fuel . et voila ! biodiesel . now , you might be wondering whether all this hassle over recycling used cooking oil is even worth it . after all , how much energy can it possibly generate ? well , if all the grease that new yorkers throw away in one day were converted to jet fuel , it would be enough to power several hundred flights from new york to los angeles . and let 's not forget that using waste oil instead of burning more fossil fuels will limit our negative effects on the environment . recycling used cooking grease turns goop into good . by contributing a little bit , individuals and businesses can help create an alternative , stable source of diesel oil , while protecting the environment and keeping our cities cleaner . and that 's pretty slick .
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biodiesel . now , you might be wondering whether all this hassle over recycling used cooking oil is even worth it . after all , how much energy can it possibly generate ?
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what do most people do with their used vegetable oil ?
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hafnium is , i think , an element to watch . at the moment , it does not have many uses but there is a strong opinion that hafnium is going to be used in making layers on computer chips like this , and that hafnium oxide will have better properties than some of the other oxides that are used . so i think that hafnium is certainly something that ’ s way up on the charts and soon may be much higher than its existing number on the periodic table - in the elements popularity .
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hafnium is , i think , an element to watch . at the moment , it does not have many uses but there is a strong opinion that hafnium is going to be used in making layers on computer chips like this , and that hafnium oxide will have better properties than some of the other oxides that are used .
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from where is hafnium´s name derived ?
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tens of millions of years ago , a force of nature set two giant masses on an unavoidable collision course that would change the face of the earth and spell life or death for thousands of species . the force of nature was plate tectonics , and the bodies were north and south america . and even though they were hurdling towards each other at an underwhelming 2.5 cm per year , their collision actually did have massive biological reprocussions by causing one of the greatest episodes of biological migration in earth 's history : the great american biotic interchange . our story begins 65 million years ago , the beginning of the age of mammals , when what is now north and south america were continents separated by a marine connection between the pacific and atlantic oceans . during this time , south america was the home of fauna that included armored glyptodonts as large as compact cars , giant ground sloths weighing more than a ton , opossums , monkeys , and carnivorous terror birds . north america had its own species , such as horses , bears , and saber-toothed cats . over 20 million years , the shifting of the farallon and caribbean plates produced the central america volcanic arc , a peninsula connected to north america , with only a very narrow seaway separating it from south america . as these plates continued to surf the earth 's magma layer far beneath the pacific ocean floor , the caribbean plate migrated eastward , and about 15 million years ago , south america finally collided with this central american arc . this gradually closed the water connection between the pacific and the caribbean , creating a land bridge , which connected north america to south america . terrestrial organisms could now cross between the two continents , and from the fossil records , it 's evident that different waves of their dispersals took place . even though plants do n't physically move , they are easily dispersed by wind and waves , so they migrated first , along with a few species of birds . they were followed by some freshwater fishes and amphibians , and finally , various mammals began to traverse the bridge . from south america , mammals like ground sloths and glyptodonts were widly distributed in north america . moreover , many south american tropical mammals , like monkeys and bats , colonized the forests of central america , and are very abundant today . south american predator marsupials went extinct 3 million years ago , at which point north american predators , such as cats , bears and foxes , migrated south and occupied the ecological space left behind . horses , llamas , tapirs , cougars , saber-toothed cats , gomphotheres , and later humans also headed south across the land bridge . but what happened on land is only half the story . what had been one giant ocean was now two , creating differences in temperature and salinity for the two bodies of water . the isthmus also became a barrier for many marine organisms , like mollusks , crustaceans , foraminifera , bryozoans , and fish , and separated the populations of many marine species . it also allowed the establishment of the thermohaline circulation , a global water conveyor belt , which transports warm water across the atlantic , and influences the climate of the east coast of north america , the west coast of europe , and many other areas . it 's a challenge to track all of the ways the collision of the americas changed the world , but it 's safe to say that the ripples of the great american biotic interchange have propagated through the history of life on the planet , and that of mankind . what if these species had n't gone extinct , or if there were no monkeys in central america , or jaguars in south america ? what if the thermohaline circulation was n't flowing ? would the east coast of north america be much colder ? it all goes to show some of the most impactful transformations of our planet are n't the explosive ones that happen in an instant , but the ones that crawl towards irreversible change . we are the product of history .
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what had been one giant ocean was now two , creating differences in temperature and salinity for the two bodies of water . the isthmus also became a barrier for many marine organisms , like mollusks , crustaceans , foraminifera , bryozoans , and fish , and separated the populations of many marine species . it also allowed the establishment of the thermohaline circulation , a global water conveyor belt , which transports warm water across the atlantic , and influences the climate of the east coast of north america , the west coast of europe , and many other areas .
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the isthmus of panama became a barrier that separates the pacific ocean and caribbean sea . what consequences had the raise of the isthmus of panama for the marine diversity in both oceans ?
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they say , 'time is money , ' but what does one really have to do with the other ? meet sheila ! she just got her first big bonus . sheila knows exactly what she wants to do with that money . she 's had her eye on a nice convertible for a while now . yes , sheila , that 's a nice car ! oh , looks like sheila is a little short . but wait ! she has an idea . sheila is a smart cookie . she knows that if she deposits the money for a year instead of buying the car today , she will earn interest . then she 'll be able to afford the car . sheila knows that the value of her deposit one year from now will equal the money deposited today plus the interest earned . we call sheila 's money deposited today the present value of money . and the value of sheila 's deposit next year is the future value of money . what connects one to the other ? the interest rate , also known as the time value of money . now , with a little bit of rearranging , we can figure out the future value of sheila 's money with this equation . so in a year , the future value will be $ 11,000 . well , it 's been a year ! and there 's sheila , with enough money to buy the car . sheila really understands the future value of money . now , i just hope she understands the speed limit ! now , meet timmy . he 's also gotten his bonus . the money seems to be burning a hole in his pocket . yes , timmy , that 's a nice car that will surely impress people . oh ! looks like you 're a little short . maybe you can follow sheila 's example . you see , timmy , just like sheila , after the first year , you 'll have $ 11,000 . but timmy , that is still not enough to buy that fancy car . why do n't you leave the money deposited for another year ? let 's see how your deposit will be doing in two years . with a little bit of rearranging , it becomes the value of your money next year , times one plus the interest rate . we can then convert the future value one year from now to the present value times one plus the interest rate . we can even simplify this further by just squaring the value of one plus the interest rate . sorry , timmy , you 'll have more money after two years , but you still ca n't afford the car ! i do n't know how many more years you 'll have to wait , but i can tell you one way we can figure it out . do you see that little number two in the equation ? any number that you put in there is the number of years that you are waiting , also known as the period . sure , timmy , we can see how much you 'll have in five years . let 's connect future value and present value across five years . let 's watch the period increase from two to five . after 5 years , you 'll have $ 16,105.10 . sorry , timmy , you have to wait a little longer . 10 years ? yeah ! let 's see if you 'll be able to buy the car then . not quite . well , timmy , it looks like you 'll need 26 years to afford this car . you should ask sheila for a ride to the beach . maybe a bicycle will suit you better ? i hear the bus is pretty cheap !
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what connects one to the other ? the interest rate , also known as the time value of money . now , with a little bit of rearranging , we can figure out the future value of sheila 's money with this equation .
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if we know the value of an investment today , the investment period and the interest rate we can then calculate its ________ .
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in the late 17th century , a medical student named johannes hofer noticed a strange illness affecting swiss mercenaries serving abroad . its symptoms , including fatigue , insomnia , irregular heartbeat , indigestion , and fever were so strong , the soldiers often had to be discharged . as hofer discovered , the cause was not some physical disturbance , but an intense yearning for their mountain homeland . he dubbed the condition nostalgia , from the greek `` nostos '' for homecoming and `` algos '' for pain or longing . at first , nostalgia was considered a particularly swiss affliction . some doctors proposed that the constant sound of cowbells in the alps caused trauma to the ear drums and brain . commanders even forbade their soldiers from singing traditional swiss songs for fear that they 'd lead to desertion or suicide . but as migration increased worldwide , nostalgia was observed in various groups . it turned out that anyone separated from their native place for a long time was vulnerable to nostalgia . and by the early 20th century , professionals no longer viewed it as a neurological disease , but as a mental condition similar to depression . psychologists of the time speculated that it represented difficulties letting go of childhood , or even a longing to return to one 's fetal state . but over the next few decades , the understanding of nostalgia changed in two important ways . its meaning expanded from indicating homesickness to a general longing for the past . and rather than an awful disease , it began to be seen as a poignant and pleasant experience . perhaps the most famous example of this was captured by french author marcel proust . he described how tasting a madeleine cake he had not eaten since childhood triggered a cascade of warm and powerful sensory associations . so what caused such a major reversal in our view of nostalgia ? part of it has to do with science . psychology shifted away from pure theory and towards more careful and systematic empirical observation . so professionals realized that many of the negative symptoms may have been simply correlated with nostalgia rather than caused by it . and , in fact , despite being a complex emotional state that can include feelings of loss and sadness , nostalgia does n't generally put people in a negative mood . instead , by allowing individuals to remember personally meaningful and rewarding experiences they shared with others , nostalgia can boost psychological well-being . studies have shown that inducing nostalgia in people can help increase their feelings of self-esteem and social belonging , encourage psychological growth , and even make them act more charitably . so rather than being a cause of mental distress , nostalgia can be a restorative way of coping with it . for instance , when people experience negative emotional states , they tend to naturally use nostalgia to reduce distress and restore well-being . today , it seems that nostalgia is everywhere , partially because advertisers have discovered how powerful it is as a marketing technique . it 's tempting to think of this as a sign of us being stuck in the past , but that 's not really how nostalgia works . instead , nostalgia helps us remember that our lives can have meaning and value , helping us find the confidence and motivation to face the challenges of the future .
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instead , by allowing individuals to remember personally meaningful and rewarding experiences they shared with others , nostalgia can boost psychological well-being . studies have shown that inducing nostalgia in people can help increase their feelings of self-esteem and social belonging , encourage psychological growth , and even make them act more charitably . so rather than being a cause of mental distress , nostalgia can be a restorative way of coping with it .
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nostalgia has been shown to increase self-esteem , feelings of belongingness , and perceptions of meaning in life . how might nostalgia be used to help people find the motivation to take on new challenges and goals ?
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translator : andrea mcdonough reviewer : jessica ruby in all times and places in our history , human beings have wondered , `` where did we come from ? what 's our place in the world ? what happens to us after we die ? '' religions are systems of belief that have developed and evolved over time in response to these and other eternal mysteries , driven by the feeling that some questions can only be answered by faith and based on an intuition that there is something greater than ourselves , a higher power we must answer to , or some source we all spring from and to which we must return . hinduism means the religions of india . it 's not a single religion but rather a variety of related beliefs and spiritual practices . it dates back five millennia to the time of krishna , a man of such virtue that he became known as an avatar of vishnu , an incarnation of the god in human form . he taught that all life follows karma , the law of cause and effect , and our job is to do our duty , or dharma , according to our place in society without worrying how things turn out . when we die , we are reincarnated into a new body . if we followed our dharma and did our proper duty in our past life , we get good karma , which sends our soul upward in the social scale . our rebirth into the next life is thus determined by what we do in this one . the wheel of rebirths is called samsara . it 's possible for a very holy person to lead a life with enough good karma to escape the wheel . this escape is called moksha . hinduism teaches that everything is one . the whole universe is one transcendent reality called brahman , and there 's just one brahman but many gods within it , and their roles , aspects , and forms differ according to various traditions . brahma is the creator , vishnu is the preserver who sometimes takes on human form , and shiva is the transformer , or lord of the dance . durga is the fiercely protective divine mother . ganesha has an elephant head and is the wise patron of success . hinduism is the third largest religion in the world . and although most hindus live in india , they can be found on every continent , one billion strong . now , let 's travel west , across deserts and mountains to the fertile crescent about 4,000 years ago . judaism began with god calling abraham and sarah to leave mesopotamia and migrate to the land of canaan . in return for their faith in the one true god , a revolutionary concept in the polytheistic world of that time , they would have land and many descendants . from this promise came the land of israel and the chosen people , but staying in that land and keeping those people together was going to be very difficult . the israelites were enslaved in egypt , but god freed them with the help of the prophet moses , who received the ten commandments and later hundreds more . they conquered the promised land , but could only keep it for a few hundred years . israel sits at a crossroads through which many armies marched over the centuries . and in the year 70 , the romans destroyed the temple in their capital , jerusalem . so , the religion transformed itself from a temple religion with sacrifices and priests to a religion of the book . because of this , judaism is a faith of symbolism , reverence , and deep meanings tied to the literature of its history . the many sacred scriptures make up the hebrew bible , or tanakh , and hundreds of written discussions and interpretations are contained in an expansive compendium of deeper meanings , called the talmud . jews find rich , symbolic meaning in daily life . at the passover meal , every item on the menu symbolizes an aspect of the escape from slavery . the importance of growing up is emphasized when young people reach the age of bar and bat mitzvah , ceremonies during which they assume responsibility for their actions and celebrate the weaving of their own lives into the faith , history , and texts of the jewish people . there are 14 million jews in the world today , 6 million in israel , which became independent following the horrors of genocide in world war ii , and 5 million in the united states . but now let 's go back 2500 years and return to india where buddhism began with a young prince named siddhartha . on the night he was conceived , his mother , queen maya , is said to have been visited in her sleep by a white elephant who entered her side . ten months later , prince siddartha was born into a life of luxury . venturing forth from his sheltered existence as a young man , he witnessed the human suffering that had been hidden from him and immediately set out to investigate its sources . why must people endure suffering ? must we reincarnate through hundreds of lives ? at first he thought the problem was attachment to material things , so he gave up his possessions . he became a wandering beggar , which he discovered certainly made him no happier . then he overheard a music teacher telling a student , `` do n't tighten the string too much , it will break . but do n't let it go too slack , or it will not sound . '' in a flash , he realized that looking for answers at the extremes was a mistake . the middle way between luxury and poverty seemed wisest . and while meditating under a bodhi tree , the rest of the answer came to him . all of life abounds with suffering . it 's caused by selfish craving for one 's own fulfillment at the expense of others . following an eight-step plan can teach us to reduce that craving , and thus reduce the suffering . on that day , siddhartha became the buddha , the enlightened one . not the only one , but the first one . the buddhist plan is called the eightfold path , and though it is not easy to follow , it has pointed the way for millions to enlightenment , which is what buddhahood means , a state of compassion , insight , peace , and steadfastness . from the time he got up from under that tree to the moment of his death as an old man , the buddha taught people how to become enlightened : right speech , right goals , a mind focused on what is real , and a heart focused on loving others . many buddhists believe in god or gods , but actions are more important than beliefs . there are nearly a billion buddhists in the world today , mostly in east , southeast , and south asia . 2,000 years ago in judaism 's promised land , christianity was born . just as hindus called krishna `` god in human form , '' christians say the same thing about jesus , and christianity grew out of judaism just as buddhism grew out of hinduism . the angel gabriel was sent by the god of abraham to ask a young woman named mary to become the mother of his son . the son was jesus , raised as a carpenter by mary and her husband joseph , until he turned 30 , when he began his public career as the living word of god . less interested in religiousness than in justice and mercy , jesus healed the sick in order to draw crowds and then taught them about his heavenly father -- affectionate , forgiving , and attentive . then , he would invite everyone to a common table to illustrate his kingdom of god , outcasts , sinners , and saints all eating together . he had only three years before his unconventional wisdom got him into trouble . his enemies had him arrested , and he was executed by rome in the standard means by which rabble-rousers were put to death , crucifixion . but shortly after he was buried , women found his tomb empty and quickly spread word , convinced that he had been raised from the dead . the first christians described his resurrected appearances , inspiring confidence that his message was true . the message : love one another as i have loved you . christians celebrate the birth of jesus in december at christmas , and his suffering , death , and resurrection during holy week in the spring . in the ceremony of baptism , a washing away of sin and welcoming into the christian community , recall jesus 's own baptism when he left his life as a carpenter . in the rite of communion , christians eat the bread and drink the wine blessed as the body and blood of jesus , recalling jesus 's last supper . there are two billion christians worldwide , representing almost a third of the world 's people . islam began 1400 years ago with a man of great virtue , meditating in a mountain cave in the arabian desert . the man was muhammad . he was visited by a divine messenger , again the angel gabriel , in arabic , jibril , delivering to him the words of allah , the one god of abraham . in the next few years , more and more messages came , and he memorized and taught them . the verses he recited were full of wise sayings , beautiful rhymes , and mysterious metaphors . but muhammad was a merchant , not a poet . many agreed the verses were indeed the words of god , and these believers became the first muslims . the word muslim means one who surrenders , meaning a person who submits to the will of god . a muslim 's five most important duties are called the five pillars : shahada , muslims declare publicly , there is no other god but allah , and muhammad is his final prophet ; salat , they pray five times a day facing mecca ; zakat , every muslim is required to give 2 or 3 % of their net worth to the poor ; sawm , they fast during daylight hours for the lunar month of ramadan to strengthen their willpower and their reliance on god ; and hajj , once in a lifetime , every muslim who is able must make a pilgrimage to the holy city of mecca , rehearsing for the time when they will stand before god to be judged worthy or unworthy of eternal life with him . the words of god , revealed to the prophet over 23 years , are collected in the quran , which literally translates into `` the recitation . '' muslims believe it to be the only holy book free of human corruption . it 's also considered by many to be the finest work of literature in the arabic language . islam is the world 's second largest religion , practiced by over one and a half billion muslims around the globe . religion has been an aspect of culture for as long as it has existed , and there are countless variations of its practice . but common to all religions is an appeal for meaning beyond the empty vanities and lowly realities of existence , beyond sin , suffering , and death , beyond fear , and beyond ourselves .
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at the passover meal , every item on the menu symbolizes an aspect of the escape from slavery . the importance of growing up is emphasized when young people reach the age of bar and bat mitzvah , ceremonies during which they assume responsibility for their actions and celebrate the weaving of their own lives into the faith , history , and texts of the jewish people . there are 14 million jews in the world today , 6 million in israel , which became independent following the horrors of genocide in world war ii , and 5 million in the united states .
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the bar or bat mitzvah is a coming-of-age ceremony in ________ .
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the politics of 19th century europe were messy . ( what 's changed ? ) it was made up of various empires spreading across the world , trying to show each other who was the biggest power . they each built up massive armies to stave off war , thinking that everyone else would be too scared to fight against them , or so they thought ... things all changed when a gang of yugoslav nationalists who did n't like being part of austria-hungary shot the austro-hungarian archduke franz ferdinand while he was in sarajevo . swiftly the austro-hungarian empire declared war on serbia . russia came in to aid serbia , so germany decided to declare war on russia ! knowing that france would go to war with germany , germany decided to attack france quickly and invaded via neutral belgium and luxembourg and because of this , great britain stepped in to stop the germans getting any closer . it was a mess of allegiances and old rivalries with two sides forming the allies and the central powers . and so began what became known at the time as the great war ; the war to end all wars ! a new form of warfare evolved as these fully industrialized armies with engines , machine guns , airplanes and new chemical gas weapons fought against each other . it was the dawn of modern warfare . at the time , national pride was at an all-time high and men were proud to go off and fight for their country . it was seen as a romantic idea to go off and be a hero ! boys as young as 12 managed to lie their way into the army ranks only to discover that it was not such a sweet and honourable thing to die for one 's country ! germany marched on paris but was stopped by the french and both sides dug themselves into trenches in what became known as the western front . on the eastern front , the russians invaded austria-hungary but were stopped in eastern prussia by the germans . the ottoman empire joined in on the site of the central powers in 1914 . more and more nations from all over the world joined the fight as the war spread across europe . trench warfare was quite terrible . each army would dig a long network of trenches in the ground , fortifying the front with barbed wire and sandbags . i was a long stalemate where neither side dared advance on the other . machine guns were a new and very effective weapon . when the time was right , the army would climb up over the top and charge across no-man 's land to the enemy trench and capture it , thus gaining more land and taking another step towards their goal ! at least that was the plan ... spirits were high at least when the first christmas came by . both forces climbed out of their trenches to celebrate christmas together , talk , share stories and play football . when christmas ended , they would climb back into their trenches to become enemies once again . conditions in the trenches were dreadful . soldiers in france and belgium found their feet rotting away from the constant damp . in contrast , australian , new zealand and ottoman soldiers fighting in gallipoli had blisteringly hot trenches where rain and cold were replaced with dehydration and overheating . disease was everywhere in the trenches . 1916 saw a renewed push on the western front from both sides . thousands of french died at verdun as the germans unleashed their chlorine gas . the infamous battle of the somme was a long and grueling battle that lasted from july to november . the first day alone saw over 80,000 men wounded or killed ; mostly british , due to disastrous attacks . fundamental errors and contradictions from the high command led to confusion and unclear plans . in places , soldiers were n't organized in time to charge so by the time that they got going , the artillery had stopped firing on the germans , allowing them to easily fire upon their attackers . planes and artillery were supposed to clear the german barbed wire , but the shrapnel was ineffective against the wire . when the order came to go over the top , thousands of men ran out to their death to be caught on the barbed wire and picked off one by one by the german machine guns . this battle saw the first use of tanks by the british . ultimately , france and britain pushed against germany and gained much ground . by christmas 1916 , no man wanted good cheer wished upon their faceless enemy . during 1916 also , before the somme , irish republicans staged an uprising in dublin in the hopes to catch britain while they were distracted by the war . it was crushed by britain but after executing the rebel leaders irish support for britain and the war dropped , at least in the south of ireland . most irish troops after that came from the protestant north . on the sea britain mined many patches of international water to stop movement of german ships . germany was blockaded . after many naval battles , britain tried to stay in control of the seas , above the water at least ! germany were on the attack with the u-boat submarines adding a new dimension to naval warfare ; they could attack without warning ! they sank many ships including the ship the lusitania and because this broke loads of war rules , it ultimately influenced the united states of america to enter the war ... two years later ! the british pushed up through the arabian peninsula with t.e . lawrence aka lawrence of arabia helping to organize the arab revolt against the ottoman empire . in 1917 , the russians had a series of revolutions . in the february revolution , the tsars were gotten rid of , but russia remained in the war , and the october revolution , the bolsheviks took control and brought power to the people and sowed the seeds for communism in russia . the russians signed a treaty with germany and pulled out of the war causing an initial difficulty for the enemies of the central powers . the allies however became refreshed with reinforcements from the united states of america who eventually decided to enter the war in 1917 after germany tried to convince mexico to attack them . germany made a fierce and effective push before the allies could use their advantage . however , american troops continued to arrive in such great numbers that germany 's army could n't last any longer . the allies pushed up from italy , the balkans , and the middle east putting austria-hungary , bulgaria and the ottoman empire out of the war . as the allies advanced the western front , germany called for an armistice to stop the fighting , bringing victory to the allies and an end to the war . the fighting stopped on the 11th hour of the 11th day of the 11th month , 1918 . it took six months to negotiate terms and it was ultimately decided that the central powers were to pay for the damages they had caused in the war . germany only fully paid off this debt in 2010 . the map of europe was redrawn . soldiers who made it home again were changed men . they were haunted by the horrors which they had seen in the trenches . gas attacks , friends dying by their side , and the constant shelling of enemy artillery ; they were shell-shocked and so many found it impossible to go back to normal life after the trenches . many great poets and writers were inspired by their hell in the trenches such as wilfred owen , jrr tolkien and ernest hemingway of the so-called lost generation ? some survived , many did not . the world was a changed place after the world war . people had seen the death and destruction that could be dealt by mankind . the men who left to become heroes came back scarred , or worse never returned at all . the poppy is used to remember the millions who died in this war as it was just about the only flower to grow in the carnage-ridden wasteland between the trenches . the world was now a darker place . people hoped that it would indeed be the war to end all wars ! unfortunately , they were mistaken ... if you liked this video , please subscribe and you can follow me on twitter at @ johndruddy or find me on facebook through manny man comic and john d ruddy artisty actory guy and if you want to find out more about world war one and also the easter rising of 1916 i 'll be doing an irish tour of the play the rising by joe o ' byrne where we tell the story of the easter rising through the eyes of two friendly foes . billy mckeague , a loyalist from belfast and paddy o'brien , a republican from dublin . the dates are up here and you can find out more on facebook . thanks so much for the support glad you enjoy it !
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thousands of french died at verdun as the germans unleashed their chlorine gas . the infamous battle of the somme was a long and grueling battle that lasted from july to november . the first day alone saw over 80,000 men wounded or killed ; mostly british , due to disastrous attacks . fundamental errors and contradictions from the high command led to confusion and unclear plans .
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which wwi battle caused more than 80,000 deaths in the first day of the battle ?
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in 2010 , $ 30 billion worth of fruits and vegetables were wasted by american retailers and shoppers in part because of cosmetic problems and perceived spoilage . that 's a poor use of about 30 % of the produce on the market , not to mention the water and energy required to grow and transport it , and the landfill space getting used up by rotting fruit . so what are those cosmetic problems ? you 've probably passed over a spotty apple in the grocery store , or accidentally sunk your thumb into a mushy patch on a tomato . these blemishes can doom produce to the trash can . but what are they anyway , and are they actually bad for you ? those spots are evidence of an epic battle between plants and microbes . like humans , plants coexist with billions of fungi and bacteria . some of these microbes are beneficial to the plant , suppressing disease and helping it extract nutrients . others are pathogens , attacking the produce , still alive as it sits in a store display or your refrigerator and siphoning off molecules they can use themselves . the good news is they 're almost never bad for you . these fungi and bacteria have spent millions of years developing strategies to overcome a plant 's immune system . but healthy human immune systems are different enough that those strategies just do n't work on us . so in a plant , what does this process look like ? microbes can reach plants in a number of ways , like getting splashed onto it during watering or fertilization . under the right conditions , the microbes grow into large enough colonies to attack the waxy outer layer of fruit or leaves . their target : the delicious sugars and nutrients inside . this type of pathogen often makes spots like this . a clump of bacteria drains the nutrients and color from the fruit 's cells making that yellow halo . it then moves outward , leaving a black spot of dead cells in its wake . each spot , which could contain hundreds of thousands of microbes is actually caused by a combination of microbial attack and the host defending itself . for example , this is the bacterial pathogen pseudomonas syringae . once on a tomato , it enters the fruit and leaves , multiplies in the space between the cells , and produces toxins and proteins that allow it to disrupt the plant 's immune response . one toxin coronatine makes plants ' stomata open up , allowing bacteria to enter more freely . coronatine also activates pathways leading to chlorophyll degradation , which you can see as yellow spots . as the bacteria continue to feed and multiply , they start to kill off the plant cells . that explains spots , but what about mushy blemishes ? those are usually caused when the fruit is attacked by microbes after it 's detached from the plant . if the plant is wounded during transport , necrotic fungi can infiltrate through the wound , kill the cells , absorb their nutrients , and leave your food looking mushy or brown . those spots in particular can taste pretty bad . you 're eating dead and decomposing tissue , after all . but you can usually salvage the rest of the fruit . the non-mushy spots , like the ones you typically see on apples or tomatoes , are just on the surface and do n't usually affect flavor . of course , microbes that do make us sick , like e. coli and salmonella , can hitch a ride on vegetables , too . but because they 're not plant pathogens , they do n't typically cause spots . they just hang out invisibly on the surface . so it 's washing fruit and veggies , not avoiding the spotty ones , that will help you avoid getting sick . so the next time you 're at the grocery store , do n't be afraid to pick up funky-looking fruit . some stores will even give you a discount . wash them well and store them properly , as some produce like apples and cabbages will keep in the fridge for weeks . the spotty ones may not be eye candy , but they 're safe and just as delicious .
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but what are they anyway , and are they actually bad for you ? those spots are evidence of an epic battle between plants and microbes . like humans , plants coexist with billions of fungi and bacteria . some of these microbes are beneficial to the plant , suppressing disease and helping it extract nutrients .
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domestication often increases susceptibility to diseases . how different are the plants that you see in the grocery store from their ‘ wild ’ ancestor ? how might the changes in features make the plants more attractive to a pathogen ?
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when we watch a film or a play , we know that the actors probably learned their lines from a script , which essentially tells them what to say and when to say it . a piece of written music operates on exactly the same principle . in a very basic sense , it tells a performer what to play and when to play it . aesthetically speaking , there 's a world of difference between , say , beethoven and justin bieber , but both artists have used the same building blocks to create their music : notes . and although the end result can sound quite complicated , the logic behind musical notes is actually pretty straightforward . let 's take a look at the foundational elements to music notation and how they interact to create a work of art . music is written on five parallel lines that go across the page . these five lines are called a staff , and a staff operates on two axes : up and down and left to right . the up-and-down axis tells the performer the pitch of the note or what note to play , and the left-to-right axis tells the performer the rhythm of the note or when to play it . let 's start with pitch . to help us out , we 're going to use a piano , but this system works for pretty much any instrument you can think of . in the western music tradition , pitches are named after the first seven letters of the alphabet , a , b , c , d , e , f , and g. after that , the cycle repeats itself : a , b , c , d , e , f , g , a , b , c , d , e , f , g , and so on . but how do these pitches get their names ? well , for example , if you played an f and then played another f higher or lower on the piano , you 'd notice that they sound pretty similar compared to , say , a b . going back to the staff , every line and every space between two lines represents a separate pitch . if we put a note on one of these lines or one of these spaces , we 're telling a performer to play that pitch . the higher up on the staff a note is placed , the higher the pitch . but there are obviously many , many more pitches than the nine that these lines and spaces gives us . a grand piano , for example , can play 88 separate notes . so how do we condense 88 notes onto a single staff ? we use something called a clef , a weird-looking figure placed at the beginning of the staff , which acts like a reference point , telling you that a particular line or space corresponds to a specific note on your instrument . if we want to play notes that are n't on the staff , we kind of cheat and draw extra little lines called ledger lines and place the notes on them . if we have to draw so many ledger lines that it gets confusing , then we need to change to a different clef . as for telling a performer when to play the notes , two main elements control this : the beat and the rhythm . the beat of a piece of music is , by itself , kind of boring . it sounds like this . ( ticking ) notice that it does n't change , it just plugs along quite happily . it can go slow or fast or whatever you like , really . the point is that just like the second hand on a clock divides one minute into sixty seconds , with each second just as long as every other second , the beat divides a piece of music into little fragments of time that are all the same length : beats . with a steady beat as a foundation , we can add rhythm to our pitches , and that 's when music really starts to happen . this is a quarter note . it 's the most basic unit of rhythm , and it 's worth one beat . this is a half note , and it 's worth two beats . this whole note here is worth four beats , and these little guys are eighth notes , worth half a beat each . `` great , '' you say , `` what does that mean ? '' you might have noticed that across the length of a staff , there are little lines dividing it into small sections . these are bar lines and we refer to each section as a bar . at the beginning of a piece of music , just after the clef , is something called the time signature , which tells a performer how many beats are in each bar . this says there are two beats in each bar , this says there are three , this one four , and so on . the bottom number tells us what kind of note is to be used as the basic unit for the beat . one corresponds to a whole note , two to a half note , four to a quarter note , and eight to an eighth note , and so on . so this time signature here tells us that there are four quarter notes in each bar , one , two , three , four ; one , two , three , four , and so on . but like i said before , if we just stick to the beat , it gets kind of boring , so we 'll replace some quarter notes with different rhythms . notice that even though the number of notes in each bar has changed , the total number of beats in each bar has n't . so , what does our musical creation sound like ? ( music ) eh , sounds okay , but maybe a bit thin , right ? let 's add another instrument with its own pitch and rhythm . now it 's sounding like music . sure , it takes some practice to get used to reading it quickly and playing what we see on our instrument , but , with a bit of time and patience , you could be the next beethoven or justin bieber .
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with a steady beat as a foundation , we can add rhythm to our pitches , and that 's when music really starts to happen . this is a quarter note . it 's the most basic unit of rhythm , and it 's worth one beat .
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a quarter note is worth :
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take a moment to think about the us constitution . what 's the first thing that comes to mind ? freedom of speech ? protection from illegal searches ? the right to keep and bear arms ? these passages are cited so often that we can hardly imagine the document without them , but that 's exactly what the writers of the constitution did . the list of individual freedoms known as the bill of rights was not in the original text and was n't added for another three years . so does this mean the founders did n't consider them ? the answer goes back to the very origins of the constitution itself . even prior to the first shots of the american revolution , the thirteen colonies worked together through a provisional government called the continental congress . during the war in 1781 , the articles of confederation were ratified as the first truly national government . but establishing a new nation would prove easier than running it . congress had no power to make the states comply with their laws . when the national government proved unable to raise funds , enforce foreign treaties , or suppress rebellions , it was clear reform was needed . so in may 1787 , all the states but rhode island sent delegates to philidelphia for a constitutional convention . a majority of these delegates favored introducing a new national constitution to create a stronger federal government . thanks to compromises on issues like state representation , taxation power , and how to elect the president , their proposal gradually gained support . but the final text drafted in september still had to be approved by conventions held in the states . so over the next few months , ratification would be debated across the young nation . among those who championed the new document were leading statesmen alexander hamilton , james madison , and john jay . together , they laid out eloquent philosophical arguments for their positions in a series of 85 essays now known as the federalist papers . but others felt the constitution was overreaching and that more centralized authority would return the states to the sort of tyranny they had just escaped . these anti-federalists were especially worried by the text 's apparent lack of protections for individual liberties . as the conventions proceeded , many of these critics shifted from opposing the constitution entirely to insisting on adding an explicit declaration of rights . so what was the federalists problem with this idea ? while their opponents accused them of despotism , wanting to maintain absolute power in the central government , their real motives were mostly practical . changing the constitution when it had already been ratified by some states could complicate the entire process . more importantly , madison felt that people 's rights were already guaranteed through the democratic process , while adding extra provisions risked misinterpretation . and some feared that creating an explicit list of things the government ca n't do would imply that it can do everything else . after the first five states ratified the constitution quickly , the debate grew more intense . massachusetts and several other states would only ratify if they could propose their own amendments for consideration . leading federalists recognized the need to compromise and promised to give them due regard . once ratification by nine states finally brought the constitution into legal force , they made good on their promise . during a meeting of the first united states congress , representative james madison stood on the house floor to propose the very amendments he had previously believed to be unnecessary . after much debate and revision , first in the congress , and then in the states , ten amendments were ratified on december 15 , 1791 , over three years after the us constitution had become law . today , every sentence , word , and punctuation mark in the bill of rights is still considered fundamental to the freedoms americans enjoy , even though the original framers left them out .
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leading federalists recognized the need to compromise and promised to give them due regard . once ratification by nine states finally brought the constitution into legal force , they made good on their promise . during a meeting of the first united states congress , representative james madison stood on the house floor to propose the very amendments he had previously believed to be unnecessary .
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those opposed to ratification of the constitution were called :
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in 1861 , two scientists got into a very brainy argument . specifically , they had opposing ideas of how speech and memory operated within the human brain . ernest aubertin , with his localistic model , argued that a particular region or the brain was devoted to each separate process . pierre gratiolet , on the other hand , argued for the distributed model , where different regions work together to accomplish all of these various functions . the debate they began reverberated throughout the rest of the century , involving some of the greatest scientific minds of the time . aubertin and his localistic model had some big names on his side . in the 17th century , rené descartes had assigned the quality of free will and the human soul to the pineal gland . and in the late 18th century , a young student named franz joseph gall had observed that the best memorizers in his class had the most prominent eyes and decided that this was due to higher development in the adjacent part of the brain . as a physician , gall went on to establish the study of phrenology , which held that strong mental faculties corresponded to highly developed brain regions , observable as bumps in the skull . the widespread popularity of phrenology throughout the early 19th century tipped the scales towards aubertin 's localism . but the problem was that gall had never bothered to scientifically test whether the individual brain maps he had constructed applied to all people . and in the 1840 's , pierre flourens challenged phrenology by selectively destroying parts of animal brains and observing which functions were lost . flourens found that damaging the cortex interfered with judgement or movement in general , but failed to identify any region associated with one specific function , concluding that the cortex carried out brain functions as an entire unit . flourens had scored a victory for gratiolet , but it was not to last . gall 's former student , jean-baptiste bouillaud , challenged flourens ' conclusion , observing that patients with speech disorders all had damage to the frontal lobe . and after paul broca 's 1861 autopsy of a patient who had lost the power to produce speech , but not the power to understand it , revealed highly localized frontal lobe damage , the distributed model seemed doomed . localism took off . in the 1870 's , karl wernicke associated part of the left temporal lobe with speech comprehension . soon after , eduard hitzig and gustav fritsch stimulated a dog 's cortex and discovered a frontal lobe region responsible for muscular movements . building on their work , david ferrier mapped each piece of cortex associated with moving a part of the body . and in 1909 , korbinian brodmann built his own cortex map with 52 separate areas . it appeared that the victory of aubertin 's localistic model was sealed . but neurologist karl wernicke had come up with an interesting idea . he reasoned that since the regions for speech production and comprehension were not adjacent , then injuring the area connecting them might result in a special type of language loss , now known as receptive aphasia . wernicke 's connectionist model helped explain disorders that did n't result from the dysfunction of just one area . modern neuroscience tools reveal a brain more complex than gratiolet , aubertin , or even wernicke imagined . today , the hippocampus is associated with two distinct brain functions : creating memories and processing location in space . we also now measure two kinds of connectivity : anatomical connectivity between two adjoining regions of cortex working together , and functional connectivity between separated regions working together to accomplish one process . a seemingly basic function like vision is actually composed of many smaller functions , with different parts of the cortex representing shape , color and location in space . when certain areas stop functioning , we may recognize an object , but not see it , or vice versa . there are even different kinds of memory for facts and for routines . and remembering something like your first bicycle involves a network of different regions each representing the concept of vehicles , the bicycle 's shape , the sound of the bell , and the emotions associated with that memory . in the end , both gratiolet and aubertin turned out to be right . and we still use both of their models to understand how cognition happens . for example , we can now measure brain activity on such a fine time scale that we can see the individual localized processes that comprise a single act of remembering . but it is the integration of these different processes and regions that creates the coherent memory we experience . the supposedly competing theories prove to be two aspects of a more comprehensive model , which will in turn be revised and refined as our scientific techologies and methods for understanding the brain improve .
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and in the late 18th century , a young student named franz joseph gall had observed that the best memorizers in his class had the most prominent eyes and decided that this was due to higher development in the adjacent part of the brain . as a physician , gall went on to establish the study of phrenology , which held that strong mental faculties corresponded to highly developed brain regions , observable as bumps in the skull . the widespread popularity of phrenology throughout the early 19th century tipped the scales towards aubertin 's localism .
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gall 's once popular method of measuring bumps on the skull to determine a person 's strongest and weakest brain functions is called :
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you know , i had a real rough time in school with add , and i have a phd . i earned a phd , but ... tough to pay attention -- biology , geology , physics , chemistry -- really tough for me . only one thing grabbed my attention , and it 's that planet called earth . but in this picture here , you 'll see that earth is mostly water . that 's the pacific . seventy percent of earth is covered with water . you can say , `` hey , i know earth . i live here . '' you do n't know earth . you do n't know this planet , because most of it 's covered with that -- average depth , two miles . and when you go outside and look up at the empire state building , chrysler building , the average depth of the ocean is 15 of those on top of one another . we 've explored about five percent of what 's in that water . `` explored , '' meaning , for the first time , go peek and see what 's there . so what i want to do today is show you some things about this planet , about the oceans . i want to take you from shallow water down to the deep water , and hopefully , like me , you 'll see some things that get you hooked on exploring planet earth . you know things like corals ; you 've seen plenty of corals , those of you who 've been to the beach , snorkeling , know corals are an amazing place to go -- full of life , some big animals , small animals , some nice , some dangerous , sharks , whales , all that stuff . they need to be protected from humanity . they 're great places . but what you probably do n't know is in the very deep part of the ocean , we have volcanic eruptions . most volcanoes on earth are at the bottom of the sea -- more than 80 percent . and we actually have fire , fire deep inside the ocean , going on right now . all over the world -- in the pacific , the atlantic , the indian ocean . in this place , the ocean floor , the rocks actually turn to liquid . so you actually have waves on the ocean floor . you 'd say nothing could live there , but when we look in detail , even there , in the deepest , darkest places on earth , we find life , which tells us that life really wants to happen . so , pretty amazing stuff . every time we go to the bottom of the sea , we explore with our submarines , with our robots , we see something that 's usually surprising , sometimes it 's startling and sometimes revolutionary . you see that puddle of water sitting there . and all around the water there 's a little cliff , there 's a little white sandy beach . we 'll get closer , you 'll see the beach a little bit better , some of the waves in that water , down there . the thing that 's special about this water is that it 's at the bottom of the gulf of mexico . so you 're sitting inside a submarine , looking out the window at a little pond of water beneath the sea . we see ponds , we see lakes , we see rivers -- in fact , right here is a river at the bottom of the ocean going from the lower left to the upper right . water is actually flowing through there . this totally blew our minds . how can you have this at the bottom ? you 're in the ocean looking at more water . and there 's animals that only live in that water . so , the bottom of the ocean -- i love this map , because it shows in the middle of the ocean , there 's a mountain range . it 's the greatest mountain range on earth , called the mid-ocean ridge -- 50,000 miles long , and we 've hardly had a peek at it . hardly had a peek at it . we find valleys , many thousands of valleys , larger , wider , deeper than the grand canyon . we find , as i said , underwater lakes , rivers , waterfalls . the largest waterfall on the planet is actually under the ocean , up near iceland . all that stuff is in that five percent that we 've explored . so the deal about the ocean is that to explore it , you 've got to have technology . not only technology , but it 's not just dave gallo or one person exploring , it 's a team of people . you 've got to have the talent , the team . you 've got to have the technology . in this case , it 's our ship , atlantis , and the submarine , alvin . inside that submarine -- this is an alvin launch -- there 's three people . they 're being wheeled out onto deck . there 's 47 other people , the teamwork on that ship , making sure that these people are okay . everybody in that submarine is thinking one thing right now : should i have gone to the bathroom one more time ? because you 're in there for 10 hours -- 10 hours in that little sphere . three of you together and nobody is going to be around you . you go into the water and once you hit the water , it 's amazing . there 's a lovely color blue that penetrates right inside you . you do n't hear the surface ship anymore , you hear that pinging of a sonar . if you 've got an iphone you 've got sonar on there -- it 's that same pinging that goes down to the bottom and comes back up . divers check out the sub to make sure the outside is okay , and then they say `` go , '' and down you go to the bottom of the ocean and it 's an amazing trip . so for two and a half hours , you sink down to the bottom . and two hours of it is totally pitch black . we thought that nothing could live inside that world at the bottom of the ocean . and when we look , we find some amazing things . all the way down -- we call it the mid-water -- from the top of the ocean down to the bottom , we find life . whenever we stop and look , we find life . i 'm going to show you some jellies . they 're absolutely some of the coolest creatures on earth . look at that thing , just flailing his arms around . that 's like a little lobster . that one is like all these animals with their mouths hooked together , the colonial animals . some animals are tiny , some can be longer than this stage . just amazing animals . and you ca n't collect them with a net -- we have to go with our cameras and take a look at them . so every time we go , new species of life . the ocean is full of life . and yet the deepest part of the ocean -- when we go to that mountain range , we find hot springs . now we were sure -- because this is poisonous water , because it 's so deep it would crush the titanic the same way you crush an empty cup in your hand -- we were sure there would be no life there at all . instead , we find more life and diversity and density than in the tropical rainforest . so , in one instance , in one peek out the window of the sub , we discover something that revolutionizes the way we think about life on earth ; and that is , you do n't always have to have sunlight to get life going . there 's big animals down there too , some that look familiar . that guy 's called dumbo . i love him . dumbo 's great . this guy -- oh man , i wish i had more footage of this . we 're trying to get an expedition together to go look at this and maybe in a year we 'll have that . go online and look . vampyroteuthis infernalis . the vampire squid . incredibly cool . in the darkness of the deep sea , he 's got glowing tentacles , so if i 'm coming at you like him , i put my arms out in the darkness so all you see are little glowing things over here . meanwhile , i 'm coming at you . when he wants to escape , he 's got these glowing pods on his butt that look like eyes . glowing eyes on his butt . how cool is that ? just an amazing animal . ( laughter ) `` vampire '' squid , because when it gets protective , it pulls this black cape over its whole body , and curls up into a ball . outrageous animal . this ship , `` the ship of dreams '' -- a hundred years ago this coming april , this ship was supposed to show up in new york . it 's the titanic . i co-led an expedition out there last year . we are learning so much about that ship . the titanic is an interesting place for biology , because animals are moving in to live on the titanic . microbes are actually eating the hull of the titanic . that 's where jack was king of the world there on the bow of the titanic . so we 're doing real good . and what 's exciting to me is that we 're making a virtual titanic , so you can sit there at home with your joystick and your headset on , and you can actually explore the titanic for yourself . that 's what we want to do , make these virtual worlds , so it 's not dave gallo or someone else exploring the world ; it 's you . you explore it for yourself . so here 's the bottom line : the oceans are unexplored and i ca n't begin to tell you how important that is , because they 're important to us . seven billion people live on this planet and all of us are impacted by the sea , because the oceans control the air you breathe , the water you drink , the food you eat . all those are controlled in some way by the ocean , and this is a thing that we have n't even explored -- five percent . the thing i want to leave you with is , in that five percent , i showed you some cool stuff . there 's a lot more cool stuff -- every dive we go on in the ocean , we find something new about the sea . so what 's in that other 95 percent ? did we get the exciting stuff or is there more out there ? and i 'm here to tell you that the ocean is full of surprises . there 's a quote i love by marcel proust : `` the true voyage of exploration is not so much in seeking new landscapes , '' which we do , `` but in having new eyes . '' and so i hope today , by showing you some of this , it 's given you some new eyes about this planet , and for the first time , i want you to think about it differently . thank you very much . thank you . ( applause )
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so the deal about the ocean is that to explore it , you 've got to have technology . not only technology , but it 's not just dave gallo or one person exploring , it 's a team of people . you 've got to have the talent , the team .
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what was the most incredible statistic , organism , or geological feature that gallo shared in his talk ?
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in the early 1960s , dick fosbury tried his hand at almost every sport , but never excelled at anything , until , at the age of 16 , he turned to the high jump . but when he could n't compete against the strong athletes at his college using the standard high jump techniques of the time , fosbury tried to jump a different way : backwards . instead of jumping with his face towards the bar , bringing each leg over in the traditional straddle method , he jumped with his back towards the bar . fosbury improved his record by over half a foot , and left his coaches amazed by this strange new style of high jumping . during the next few years , fosbury perfected his high jump style , won the u.s. national trials , and assured his place in the 1968 olympics in mexico . in the olympic games , fosbury amazed the world with his new technique , winning a gold metal with an olympic record leap of 2.24 meters . by the next olympic games , almost all of the competing of high jumpers had adopted what came to be known as the fosbury flop . what 's the secret behind the technique ? it lies in a physics concept called the center of mass . for every object , we can locate the average position of all of its mass by taking into account how the mass is spread around the object . for instance , the center of mass of a flat , rectangular object of uniform density will be in the intersection of both diagonals , in equal distance from each corner . we can find the center of mass for other objects by similar calculations , or by finding the object 's balancing point , which lies right underneath its center of mass . try balancing a broom by holding it and slowly bringing your hands together until they meet . this balancing point lies right underneath the broom 's center of mass . we humans also have a center of mass . when most people stand up , their center of mass is around the belly , but what happens to your center of mass when you lift your hands in the air ? your center of mass moves upwards . it moves all the time as you move through the day , based on how your body is positioned . it can even move outside of your body . when you bend forward , your center of mass is located below your bent belly in a place where there is no mass at all . weird to think about , but that 's the average position of all your mass . many objects ' center of mass are outside their bodies . think of doughnuts or boomerangs . now look at the fosbury flop , and follow the position of the center of mass of the jumper . the jumper runs very fast , so he can divert his horizontal velocity to vertical velocity , and jumps . wait for it ... there . look at the jumper 's center of mass as his body bends backward . it 's below the bar . that is the secret behind the jump . with the old , pre-fosbury techniques , the jumper had to apply enough force to lift his center of mass above the bar by a few inches in order to clear it . the fosbury flopper does n't have to do that . the genius of the fosbury flop is that the jumper can apply the same amount of force , but raise his body much higher than before . that means he can raise the bar so high that even when his center of mass ca n't go any higher , his arching body can . fosbury 's technique brought the high jump to new heights by splitting the jumper 's body away from his center of mass , giving it that much more room to clear higher and higher bars . so the fosbury flop may be sports history 's only great leap forward , that is also a great leap backward .
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when most people stand up , their center of mass is around the belly , but what happens to your center of mass when you lift your hands in the air ? your center of mass moves upwards . it moves all the time as you move through the day , based on how your body is positioned .
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what is the best definition for the center of mass of an object ?
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we all know about the dinosaurs that once roamed the planet , but long after they went extinct , great beasts we call the megafauna lived on every continent . in the americas , ground sloths the size of elephants pulled down trees with their claws . saber-toothed cats the size of brown bears hunted in packs , but they were no match for short-faced bears , which stood thirteen feet on their hind legs , and are likely to have driven these cats away from their prey . there were armadillos as big as small cars , an eight foot beaver , and a bird with a 26 foot wingspan . almost everywhere , the world 's megafauna were driven to extinction , often by human hunters . some species still survive in parts of africa and asia . in other places , you can still see the legacy of these great beasts . most trees are able to resprout where their trunk is broken to withstand the loss of much of their bark and to survive splitting , twisting and trampling , partly because they evolved to survive attacks by elephants . the american pronghorn can run so fast because it evolved to escape the american cheetah . the surviving animals live in ghost ecosystems adapted to threats from species that no longer exist . today , it may be possible to resurrect those ghosts , to bring back lost species using genetic material . for instance , there 's been research in to cloning woolly mammoths from frozen remains . but even if it 's not possible , we can still restore many of the ecosystems the world has lost . how ? by making use of abandoned farms . as the market for food is globalized , infertile land becomes uncompetitive . farmers in barren places ca n't compete with people growing crops on better land elsewhere . as a result , farming has started to retreat from many regions , and trees have started to return . one estimate claims that two-thirds of land in the us that was once forested but was cleared for farming has become forested again . another estimate suggests that by 2030 , an area in europe the size of poland will be vaccated by farmers . so even if we ca n't use dna to bring back ground sloths and giant armadillos , we can restore bears , wolves , pumas lynx , moose and bison to the places where they used to live . some of these animals can reshape their surroundings , creating conditions that allow other species to thrive . when wolves were reintroduced to the yellowstone national park in 1995 , they quickly transformed the ecosystem . where they reduced the numbers of overpopulated deer , vegetation began to recover . the height of some trees quintupled in just six years . as forests returned , so did songbirds . beavers , which eat trees , multiplied in the rivers , and their dams provided homes for otters , muskrats , ducks , frogs and fish . the wolves killed coyotes , allowing rabbits and mice to increase , providing more food for hawks , weasels , foxes and badgers . bald eagles and ravens fed on the carrion that the wolves abandoned . so did bears , which also ate the berries on the returning shrubs . bison numbers rose as they browsed the revitalized forests . the wolves changed almost everything . this is an example of a trophic cascade , a change at the top of the food chain that tumbles all the way to the bottom , affecting every level . the discovery of widespread trophic cascades may be one of the most exciting scientific findings of the past half century . they tell us that ecosystems that have lost just one or two species of large animals can behave in radically different ways from those that retain them . all over the world , new movements are trying to catalyze the restoration of nature in a process called rewilding . this means undoing some of the damage we 've caused , reestablishing species which have been driven out , and then stepping back . there is no attempt to create an ideal ecosystem , to produce a heath , a rainforest or a coral reef . rewilding is about bringing back the species that drive dynamic processes and then letting nature take its course . but it 's essential that rewilding must never be used as an excuse to push people off the land . it should happen only with the consent and enthusiasm of the people who work there . imagine standing on a cliff in england , watching sperm whales attacking shoals of herring as they did within sight of the shore until the 18th century . by creating marine reserves in which no commerical fishing takes place , that can happen again . imagine a european serengeti full of the animals that used to live there : hippos , rhinos , elephants , hyenas and lions . what rewilding reintroduces , alongside the missing animals and plants , is that rare species called hope . it tells us that ecological change need not always proceed in the same direction . the silent spring could be followed by a wild summer .
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there were armadillos as big as small cars , an eight foot beaver , and a bird with a 26 foot wingspan . almost everywhere , the world 's megafauna were driven to extinction , often by human hunters . some species still survive in parts of africa and asia .
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which aspects of human life would be enhanced by a mass restoration of the natural world in places vacated by farming , and which would be impoverished ?
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gravity . it controls the universe . everything attracts everything else . ouch ! including you . ow ! in this final lesson , we 'll explore what gravity means for space-time , or rather what space-time means for gravity . until now , we 've been dealing with things moving at constant speeds , with straight world lines in space-time . but once you add gravity , if you measure a speed at one moment , then again a bit later , the speed may have changed . in other words , as i discovered , gravity causes acceleration , so we need the world line to look different from one moment to the next . as we saw in the last lesson , the correct way to tilt an object 's world line is using a lorentz transformation : einstein 's stretch and squash trick . so , to map out what gravity is doing to tom 's motion , we need to create a whole load of little patches of space-time , each transformed by different amounts . so that my world line is at a different angle in each one . and then , we 're ready to stitch everything together . we assemble a cozy quilt of space-time where world lines look curved . where the world lines join , the objects collide . by making these connections between the patches , a curvature gets built into space-time itself . but einstein 's true genius was to describe precisely how each patch is stretched and squashed according to nearby mass and energy . the mere presence of stuff curves the space-time , and curving space-time moves the stuff around . this is gravity , according to einstein . previously , isaac newton had explained gravity using the ideas of force and acceleration , without any wibbily wobbly space-time , and that did pretty well . but einstein 's theory does just slightly better at predicting , for example , the orbit of mercury around the sun , or the way that light rays are deflected by massive objects . more importantly , einstein 's theory predicts things that simply do n't exist in older theories where space , time and gravity were separate . the stitching can leave wrinkles in the space-time material . these are called gravitational waves , which should be detectable as tiny , repetitive , subtle squashes and stretches in space . so we 're building experiments to check if they are there . in the meantime , indirect evidence , most recently in the polarization patterns of light left over from the big bang , strongly suggest that they are . but despite einstein 's successes , when too much stuff gets concentrated in too small a space , like in a black hole , the curvature of space-time becomes so large , that his equations collapse . we need a new picture of space-time that incorporates quantum mechanics to unlock the secret at the heart of black holes . which means there 's plenty more to be discovered about space , time , and space-time in the future .
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ow ! in this final lesson , we 'll explore what gravity means for space-time , or rather what space-time means for gravity . until now , we 've been dealing with things moving at constant speeds , with straight world lines in space-time .
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you may have learned about gravity as a force that acts instantly between two objects , pulling them together . looking back over lessons 1 , 2 and 3 , why do you think this idea doesn ’ t work in einstein ’ s space-time ?
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translator : andrea mcdonough reviewer : bedirhan cinar it is only in the last 100 or so years that human kind has understood that the nucleus of the chemical elements is not always fixed . it can change spontaneously from one element to another . the name for this process is radioactivity . you probably already know something about the nucleus : it 's much tinier than the atom , it 's made of particles called protons and neutrons , there are electrons orbiting around it . and though the atoms can share or swap electrons when they bond together , the nuclei themselves never change . right ? well , no . certain nuclei are not stable in that way . this means they may change suddenly , spontaneously . the radioactive nucleus flings out a small particle and transforms into another element , just like that . for example , the carbon nucleus can eject a fast-moving electron and turn into a nitrogen nucleus . there are two different particles that can be emitted from radioactive nuclei , but never together . the very fast electron is known as a beta particle . if you know a little bit about electrons , you may be thinking , `` what was the electron doing in the nucleus in the first place ? '' the answer is there is a neutron in nucleus spontaneously changed into a proton , which stayed behind , and the electron flew out as a beta particle . this is not what chemistry has taught us to expect . the nucleus is supposed to be stable . neutrons do n't change into protons . except , sometimes they do ! the other particle it emits spontaneously from an unstable nucleus is alpha . an alpha particle is 8,000 times more massive than beta , and it 's a bit slower . alpha is made from two protons and two neutrons . if we trap all those alpha particles together , we get helium gas . alpha is a helium nucleus . like the beta particle , you would not have expected a heavier nucleus to throw out helium . but again , it happens , and the nucleus becomes a new element . so , is radioactivity useful or just dangerous ? wherever you are sitting , it is quite likely that there is a device nearby which contains a source of alpha particles : a smoke detector . the source is radioactive americium . you are totally safe from these alpha particles , which can not travel more than a few centimeters in air . beta particles penetrate much farther through materials than alpha can . radioactive atoms are used in medicine as traces , to show where chemicals travel in the patient . beta particles are emitted and have enough energy to emerge from the body and be detected . there is a third type of nuclear radiation : gamma , which is not a particle at all . it is an electromagnetic wave , like microwaves , or light , but it is actually 1,000 times more energentic than visible light . gamma rays may pass right through your body . gamma is used to zap the bacteria in fruit to increase its shelf life , or in radiotherapy to kill cancer cells . radioactive substances get hot , and this heat can be used to generate power . this heat has been brought to you since space probes , and , in the past , in pacemakers for hearts . the more abruptly nuclear radiation is slowed down , the more damage it does to the atoms it hits . this is called ionization . alpha causes the most ionization as it crashes into other atoms and gamma the least . in humans , the most serious effect of radiation is the damage that it can cause to our dna . although alpha can not penetrate your skin , if you inhale or injest a radioactive nucleus , the health consequences can be severe . radioactivity is both useful and deadly , but it is all around us as a background to the natural world .
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if we trap all those alpha particles together , we get helium gas . alpha is a helium nucleus . like the beta particle , you would not have expected a heavier nucleus to throw out helium .
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alpha radiation :
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what 's the worst bug on the planet ? you might vote for the horsefly or perhaps the wasp , but for many people , the worst offender is by far the mosquito . the buzzing , the biting , the itching , the mosquito is one of the most commonly detested pests in the world . in alaska , swarms of mosquitos can get so thick that they actually asphyxiate caribou . and mosquito-borne diseases kill millions of people every year . the scourge that is the mosquito is n't new . mosquitoes have been around for over a hundred million years and over that time have coevolved with all sorts of species , including our own . there are actually thousands of species of mosquitos in the world , but they all share one insidious quality : they suck blood , and they 're really , really good at sucking blood . here 's how they do it . after landing , a mosquito will slather some saliva onto the victim 's skin , which works like an antiseptic , numbing the spot so we do n't notice their attack . this is what causes the itchy , red bumps , by the way . then the bug will use its serrated mandibles to carve a little hole in your skin , allowing it to probe around with its proboscis , searching for a blood vessel . when it hits one , the lucky parasite can suck two to three times its weight in blood . turns out we do n't really like that too much . in fact , humans hate mosquitos so much that we spend billions of dollars worldwide to keep them away from us -- from citronella candles to bug sprays to heavy-duty agricultural pesticides . but it 's not just that mosquitos are annoying , they 're also deadly . mosquitos can transmit everything from malaria to yellow fever to west nile virus to dengue . over a million people worldwide die every year from mosquito-borne diseases , and that 's just people . horses , dogs , cats , they can all get diseases from mosquitoes too . so , if these bugs are so dastardly , why do n't we just get rid of them ? we are humans after all , and we 're pretty good at getting rid of species . well , it 's not quite so simple . getting rid of the mosquito removes a food source for lots of organisms , like frogs and fish and birds . without them , plants would lose a pollinator . but some scientists say that mosquitos are n't actually all that important . if we got rid of them , they argue , another species would simply take their place and we 'd probably have far fewer deaths from malaria . the problem is that nobody knows what would happen if we killed off all the mosquitos . something better might take their spot or perhaps something even worse . the question is , are we willing to take that risk ? ( buzzing )
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what 's the worst bug on the planet ? you might vote for the horsefly or perhaps the wasp , but for many people , the worst offender is by far the mosquito .
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how long have mosquitos been on the planet ?
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selenium . so selenium is an element that ’ s quite like sulphur . but , sulphur has its common form in s8 rings whereas selenium exists in its more common form as long chains of selenium atoms and if you shine light on these chains they start conducting electricity . so selenium was the material that was used in the early photo cells for things like burglar alarms and doors that open themselves and so on . so here is a sample of selenium and we ’ re going to unpack it from the box here . and it ’ s in the form of a shot . selenium has a number of other applications and perhaps the one that amuses me most is that it ’ s used in shampoos . some people , as you know , get dandruff which is caused by bacteria on their scalp and if you use a compound which is a ring , which is a mixture of sulphur and selenium , this can be added to shampoo and will act as a bactericide and will kill bacteria that cause dandruff . so let ’ s see what comes out . i can hear it and here you can see the selenium , wonderful black compound . beautiful element , again this is a mineral which is useful for us and in fact many people often take selenium as an additive to their diet . however you have to be careful because the compounds that make our sweat smell are sulphur compounds , so if you get selenium into the body then you make similar compounds of selenium but which smell much worse . and so it is said that people get off the bus when selenium chemists get on . and tellurium is even worse still .
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selenium . so selenium is an element that ’ s quite like sulphur .
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selenium compounds are used in glassmaking . what color do selenium compounds confer to glass ?
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translator : andrea mcdonough reviewer : morton bast i 'm a mechanical engineering professor at the university of pennsylvania , and my favorite hobby is photography . and as i travel around the world , i love taking photographs like these , so i can remember all the beautiful and interesting things that i 've seen . but what i ca n't do is record and share how these objects feel to touch . and that 's kind of surprising , because your sense of touch is really important . it 's involved in every physical interaction you do every day , every manipulation task , anything you do in the world . so the sense of touch is actually pretty interesting . it has two main components . the first is tactile sensations , things you feel in your skin . and the second is kinesthetic sensations . this has to do with the position of your body and how it 's moving , and the forces you encounter . and you 're really good at incorporating both of these types of sensations together to understand the physical interactions you have with the world and understand as you touch a surface : is it a rock , is it a cat , is it a bunny , what is it ? and so , as an engineer , i 'm really fascinated and i have a lot of respect for how good people are with their hands . and i 'm intrigued and curious about whether we could make technology better by doing a better job at leveraging the human capability with the sense of touch . could i improve the interfaces to computers and machines by letting you take advantage of your hands ? and indeed , i think we can , and that 's at the core of a field called haptics , and this is the area that i work in . it 's all about interactive touch technology . and the way it works is , as you move your body through the world , if , as an engineer , i can make a system that can measure that motion , and then present to you sensations over time that kind of make sense , that match up with what you might feel in the real world , i can fool you into thinking you 're touching something even though there 's nothing there . so here are three examples and these are all done from research in my lab at penn . the first one is all about that same problem that i was showing you : how can we capture how objects feel and recreate those experiences ? so the way we solve this problem is by creating a hand-held tool that has many different sensors inside . it has a force sensor , so we can tell how hard you 're pushing ; it has motion tracking , so we can tell exactly where you 've moved it ; and it has a vibration sensor , an accelerometer , inside , that detects the shaking back and forth of the tool that lets you know that 's a piece of canvas and not a piece of silk or something else . then we take the data we record from these interactions . here 's ten seconds of data . you can see how the vibrations get larger and smaller , depending on how you move . and we make a mathematical model of those relationships and program them into a tablet computer so that when you take the stylus and go and touch the screen , that voice-coil actuator in the white bracket plays vibrations to give you the illusion that you 're touching the real surface , just like if you touched , dragged back and forth , on the real canvas . we can create very compelling illusions . we can do this for all kinds of surfaces and it 's really a lot of fun . we call it haptography -- haptic photography . and i think it has potential benefits in all sorts of areas like online shopping , maybe interactive museum exhibits , where you 're not supposed to touch the precious artifacts , but you always want to . the second example i want to tell you about comes from a collaboration i have with dr. margrit maggio at the penn dental school . part of her job is to teach dental students how to tell where in a patient 's mouth there are cavities . of course they look at x-rays , but a large part of this clinical judgment comes from what they feel when they touch your teeth with a dental explorer . you 've all had this happen , they go across . what they 're feeling for is if the tooth is really hard , then it 's healthy , but if it 's kind of soft and sticky , that 's a signal that the enamel is starting to decay . these types of judgments are hard for a new dental student to make , because they have n't touched a lot of teeth yet . and you want them to learn this before they start practicing on real human patients . so what we do is add an accelerometer on to the dental explorer , and then we record what dr. maggio feels as she touches different extracted teeth . and we can play it back for you as a video with a touch track -- not just a sound track , but also a touch track , that you can feel by holding that repeating tool . you feel the same things the dentist felt when they did the recording , and practice making judgments . so here 's a sample one . here 's a tooth that looks kind of suspicious , right ? it has all those brown stains . you might be thinking , `` we should definitely put a filling in this tooth . '' but if you pay attention to how it feels , all the surfaces of this tooth are hard and healthy , so this patient does not need a filling . and these are exactly the kind of judgments doctors make every day and i think this technology we 've invented has a lot of potential for many different things in medical training , because it 's really simple and it does a great job at recreating what people feel through tools . i think it could also help make games more interactive and fun and more realistic in the sensations that you feel . the last example i want to tell you about is again about human movement . so if any of you have ever learned sports , how do you get good at something like surfing ? you practice . you practice some more and more , right ? making small corrections , maybe getting some input from a coach , learning how to improve your motions . i think we could use computers to help make that process more efficient and more fun . and so here , for example , if i have six different arm movements that i want you to learn , you come into my lab at penn and try out our system . we use a kinect to measure your motions , we show graphics on the screen , and then we also give you touch cues , haptic feedback on your arm , delivered by these haptic arm bands which have motors inside , and guide you as you move . so , if we put it together , as you 're trying to track this motion , if you deviate -- say , maybe , your arm is a little too high -- we turn on the motors right there on the skin to let you know you should move down , almost like a coach gently guiding you and helping you master these movements more quickly and make more precise corrections . we developed this system for use in stroke rehabilitation , but i think there are a lot of applications , like maybe dance training or all sorts of sports training as well . so now you know a little bit about the field of haptics , which i think you 'll hear more about in the coming years . i 've shown you three examples . i just want to take a moment to acknowledge the great students who work with me in my lab at penn and my collaborators . they 're a great group . i also want to thank you for your kind attention . ( applause )
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so the sense of touch is actually pretty interesting . it has two main components . the first is tactile sensations , things you feel in your skin .
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what are the two main components of the sense of touch ?
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bean bags are awesome . but i see a few people out there who are standing , we 've got some over here , and standing takes more work than lounging . using the live strong organization 's online database of weight loss resources , you can calculate that by the time i 'm done with this speech , those of you who are standing will have burned 7.5 more calories than those of you who are bean-bagging it . ( laughter ) okay , here 's a question , speaking of weight loss , specifically weight , this speech is live . i 'm actually here in front of you guys , we 're all here together . but this speech is being recorded and it will become a video that people can access all over the world on computers , mobile devices , televisions . i weight about 190 pounds . how much will the video weigh ? asking questions like that is what i do every week on my channel vsauce . for the last two years , i have been asking really fun questions , mind-boggling questions , and approaching them as sincerely as i can , celebrating scientific concepts and scientists . and i research and write and produce and host and edit and upload and run the social media all by myself , but it 's not lonely , because vsauce has more than 2 million subscribers , and every month , my videos are seen by more than 20 million people . yeah . ( applause ) it 's very exciting . i 've found that asking a strange question is a great way to get people in , not just people , but fans . and fans are different than just viewers or an audience , because fans want to come back . they subscribe to you on youtube and they want to watch everything you 've made and everything you plan to make in the future because we are curious people and sparking curiosity is great bait . it 's a great way to catch a human . and once you 've caught them , you have this captive audience that you can , with the goal in mind of answering the question , accidentally teach a lot of things to . so , let 's take a look at some of my videos . here are eight of them . but down here in the lower-right corner , `` what color is a mirror ? '' when people see that , it 's very difficult not to click , because you think , `` come on , are you serious ? how could you possibly answer that question ? '' well , so far , 7.6 million people have watched this five-minute video about what color a mirror is . and in that episode , i answer the question and i get a chance to explain what would normally be kind of dry topics : optics , diffuse versus specular reflection , how light works , how light works on the retina , and even the etymology of color terms like white and black . okay , spoiler alert : mirrors are not clear , they are not silvery , like they 're often illustrated . mirrors , technically speaking , are just a tiny , tiny , little bit ... green . you can demonstrate this by putting two mirrors next to each other , facing so they reflect back and forth forever . look down that infinite reflection , and it will get dimmer , because some light is lost or absorbed every time , but it will also become greener , because green light , that is light of a wavelength that we perceive as green , is best reflected by most mirrors . okay , so , how much does a video weigh ? well , when you stream a video onto your computer , that information is temporarily stored using electrons . and the number of electrons on your device wo n't actually increase or decrease . but it takes energy to store them in one place , and , thanks to our friend albert einstein , we know that energy and mass are related . okay , so here 's the thing : let 's say you 're watching a youtube video at a really nice resolution , 720p . assuming a typical bit rate , we can figure that a minute of youtube video is going to need to involve about 10 million electrons on your device . plugging all those electrons and the energy it takes to hold them in the correct place for you to see the video , into that formula , we can figure out that one minute of youtube video increases the mass of your computer by about 10 to the negative 19th grams . written out , it looks like this . ( whistle ) that 's like nothing . you could call that nothing , and you would n't really get in trouble , because the best scales we 've ever invented that we could try to use to actually to detect that change are only accurate to 10 to the negative 9th grams . so , we ca n't measure it , but we can , like we just did , calculate it . and that 's really cool because when i was a kid , my school had two shelves of science books . that was really cool , but i read all of them within , like , two grades , and it was hard to get more books because books are heavy , you need space for them and moving books around is tougher than what we can do today . with numbers that small , i can fit thousands of books on my own little personal electronic reader . i can stream hours and hours and days and days of youtube video without my computer ever getting measurably heavier . and as information becomes that light , it becomes a lot more democratic , meaning that more teachers and presenters and creators and viewers than ever before can be involved . right now , on youtube , there is an explosion of content like this happening . the three vsauce channels are down there in the corner . but everyone else , all together , collectively , their views dwarf what i can do alone or with the people that i work with , and that is really , really exciting . it turns out that tapping into people 's curiosity and responsibly answering their questions is a brilliant way to build fans and an audience and get in viewers . it 's even a great way for brands and companies to build trust . so , calculating the weight of a video is kind of a funny question , but i can not wait to see what we ask and answer next . as always , thanks for watching . ( applause )
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i weight about 190 pounds . how much will the video weigh ? asking questions like that is what i do every week on my channel vsauce .
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explain why it 's beneficial to have an information media that does n't weigh anything ( or at least weighs a minute amount ) .
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in the early 1960s , dick fosbury tried his hand at almost every sport , but never excelled at anything , until , at the age of 16 , he turned to the high jump . but when he could n't compete against the strong athletes at his college using the standard high jump techniques of the time , fosbury tried to jump a different way : backwards . instead of jumping with his face towards the bar , bringing each leg over in the traditional straddle method , he jumped with his back towards the bar . fosbury improved his record by over half a foot , and left his coaches amazed by this strange new style of high jumping . during the next few years , fosbury perfected his high jump style , won the u.s. national trials , and assured his place in the 1968 olympics in mexico . in the olympic games , fosbury amazed the world with his new technique , winning a gold metal with an olympic record leap of 2.24 meters . by the next olympic games , almost all of the competing of high jumpers had adopted what came to be known as the fosbury flop . what 's the secret behind the technique ? it lies in a physics concept called the center of mass . for every object , we can locate the average position of all of its mass by taking into account how the mass is spread around the object . for instance , the center of mass of a flat , rectangular object of uniform density will be in the intersection of both diagonals , in equal distance from each corner . we can find the center of mass for other objects by similar calculations , or by finding the object 's balancing point , which lies right underneath its center of mass . try balancing a broom by holding it and slowly bringing your hands together until they meet . this balancing point lies right underneath the broom 's center of mass . we humans also have a center of mass . when most people stand up , their center of mass is around the belly , but what happens to your center of mass when you lift your hands in the air ? your center of mass moves upwards . it moves all the time as you move through the day , based on how your body is positioned . it can even move outside of your body . when you bend forward , your center of mass is located below your bent belly in a place where there is no mass at all . weird to think about , but that 's the average position of all your mass . many objects ' center of mass are outside their bodies . think of doughnuts or boomerangs . now look at the fosbury flop , and follow the position of the center of mass of the jumper . the jumper runs very fast , so he can divert his horizontal velocity to vertical velocity , and jumps . wait for it ... there . look at the jumper 's center of mass as his body bends backward . it 's below the bar . that is the secret behind the jump . with the old , pre-fosbury techniques , the jumper had to apply enough force to lift his center of mass above the bar by a few inches in order to clear it . the fosbury flopper does n't have to do that . the genius of the fosbury flop is that the jumper can apply the same amount of force , but raise his body much higher than before . that means he can raise the bar so high that even when his center of mass ca n't go any higher , his arching body can . fosbury 's technique brought the high jump to new heights by splitting the jumper 's body away from his center of mass , giving it that much more room to clear higher and higher bars . so the fosbury flop may be sports history 's only great leap forward , that is also a great leap backward .
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think of doughnuts or boomerangs . now look at the fosbury flop , and follow the position of the center of mass of the jumper . the jumper runs very fast , so he can divert his horizontal velocity to vertical velocity , and jumps .
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what is the main difference between the traditional straddle method and the fosbury flop regarding the center of mass of the jumper ?
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what if william shakespeare had a sister who matched his imagination , his wit , and his way with words ? would she have gone to school and set the stage alight ? in her essay `` a room of one 's own , '' virginia woolf argues that this would have been impossible . she concocts a fictional sister who 's stuck at home , snatching time to scribble a few pages before she finds herself betrothed and runs away . while her brother finds fame and fortune , she remains abandoned and anonymous . in this thought experiment , woolf demonstrates the tragedy of genius restricted , and looks back through time for hints of these hidden histories . she wrote , `` when one reads of a witch being ducked , of a woman possessed by devils , of a wise woman selling herbs , or even a very remarkable man who had a mother , then i think we 're on the track of a lost novelist , a suppressed poet , of some mute and inglorious jane austen . '' `` a room of one 's own '' considers a world denied great works of art due to exclusion and inequality . how best can we understand the internal experience of alienation ? in both her essays and fiction , virginia woolf shapes the slippery nature of subjective experience into words . her characters frequently lead inner lives that are deeply at odds with their external existence . to help make sense of these disparities , the next time you read woolf , here are some aspects of her life and work to consider . she was born adeline virginia stephen in 1882 to a large and wealthy family , which enabled her to pursue a life in the arts . the death of her mother in 1895 was followed by that of her half-sister , father , and brother within the next ten years . these losses led to woolf 's first depressive episode and subsequent institutionalization . as a young woman , she purchased a house in the bloomsbury area of london with her siblings . this brought her into contact with a circle of creatives , including e.m. forster , clive bell , roger fry , and leonard woolf . these friends became known as the bloomsbury group , and virginia and leonard married in 1912 . the members of this group were prominent figures in modernism , a cultural movement that sought to push the boundaries of how reality is represented . key features of modernist writing include the use of stream of consciousness , interior monologue , distortions in time , and multiple or shifting perspectives . these appear in the work of ezra pound , gertrude stein , james joyce , and woolf herself . while reading joyce 's `` ulysses , '' woolf began writing `` mrs . dalloway . '' like `` ulysses , '' the text takes place over the course of a single day and opens under seemingly mundane circumstances . `` mrs. dalloway said she would buy the flowers herself . '' but the novel dives deeply into the characters ' traumatic pasts , weaving the inner world of numbed socialite clarissa dalloway , with that of the shell-shocked veteran septimus warren smith . woolf uses interior monologue to contrast the rich world of the mind against her characters ' external existences . in her novel `` to the lighthouse , '' mundane moments , like a dinner party , or losing a necklace trigger psychological revelations in the lives of the ramsay 's , a fictionalized version of woolf 's family growing up . `` to the lighthouse '' also contains one of the most famous examples of woolf 's radical representation of time . in the time passes section , ten years are distilled into about 20 pages . here , the lack of human presence in the ramsays ' beach house allows woolf to reimagine time in flashes and fragments of prose . `` the house was left . the house was deserted . it was left like a shell on a sand hill to fill with dry salt grains now that life had left it . '' in her novel `` the waves , '' there is little distinction between the narratives of the six main characters . woolf experiments with collective consciousness , at times collapsing the six voices into one . `` it is not one life that i look back upon : i am not one person : i am many people : i do not altogether know who i am , jinny , susan , neville , rhoda or louis , or how to distinguish my life from their 's . '' in `` the waves , '' six become one , but in the gender-bending `` orlando , '' a single character inhabits multiple identities . the protagonist is a poet who switches between genders and lives for 300 years . with its fluid language and approach to identity , `` orlando '' is considered a key text in gender studies . the mind can only fly so far from the body before it returns to the constraints of life . like many of her characters , woolf 's life ended in tragedy when she drowned herself at the age of 59 . yet , she expressed hope beyond suffering . through deep thought , woolf 's characters are shown to temporarily transcend their material reality , and in its careful consideration of the complexity of the mind , her work charts the importance of making our inner lives known to each other .
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while reading joyce 's `` ulysses , '' woolf began writing `` mrs . dalloway . '' like `` ulysses , '' the text takes place over the course of a single day and opens under seemingly mundane circumstances .
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`` mrs. dalloway '' can be classified as :
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i love astronomy . you may have noticed . but there ’ s one really frustrating aspect of it : everything we study is really far away . nearly everything we understand about the universe comes from light emitted or reflected by objects . it ’ d be nice if we could get actual samples from them ; physical specimens we could examine in the lab . welp , sometimes the universe can be accommodating , and allows us to hold it in our hands . cambot , can we get this up on still store ? if you go outside on a clear , dark , moonless night — and you really should — chances are pretty good that within a few minutes you ’ ll see a shooting star . it ’ ll zip across the sky , a fiery dot leaving a long glowing trail behind it . they ’ re one of the most exciting and fun things you ’ ll see when you look up , and they always get a gasp and a squeal of delight from people someone who ’ s stargazing . what you ’ re actually seeing is a tiny bit of interplanetary debris : rock , ice , or metal ramming through the earth ’ s atmosphere , heated to incandescence . most are faint , but some can be astonishingly bright ; i saw one once that left an afterimage on my eye ! obviously , shooting stars aren ’ t really stars . so what do we call them ? sometimes it seems like astronomers use different names for objects to keep things as confusing as possible . but really , we do that to separate out different things . in this case , the actual bit of solid stuff coming from space is called a meteoroid . the phenomenon of the meteoroid getting hot and blazing across the sky is called a meteor . and finally , if it hits the ground , we call it a meteorite . i think the second best way to tick off an astronomer is to mix up meteor and meteorite . sometimes astronomers can be pretty pedantic about such things . oh , the best way to tick off an astronomer ? ask them , “ hey , what ’ s your sign ? ” amazingly , a typical meteor that you ’ ll see is due to a meteoroid that ’ s tiny , probably smaller than a grain of sand ! how can that be ? it ’ s because they ’ re hauling mass . you heard me . the meteoroid is orbiting the sun , probably at speeds of a few dozen kilometers per second . as it approaches the earth , our planet ’ s gravity accelerates it an additional 11 kilometers per second — earth ’ s escape velocity . and when it enters our atmosphere it ’ s moving incredibly fast , up to 70 km/sec or more . the energy of motion is called kinetic energy . if you want to get something moving , you have to give it energy , and if you want it to stop , you have to take that energy away . this kinetic energy depends on the mass of the object and how fast it ’ s moving . in fact , it depends on the square of the velocity ; double its speed and it ’ ll have four times the kinetic energy . meteoroids may usually be small , but they ’ re screaming fast , and have a huge amount of kinetic energy . as they hit our atmosphere they slow from their ridiculous orbital speed to nearly a standstill , and all that energy has to go somewhere . it gets converted into light and heat , and that ’ s what we see as a meteor . a big misconception about meteors is that they get hot due to friction with air . actually , a far bigger contributor to their heat is compression . one of the most basic laws of physics is that when you compress a gas it heats up . and a meteoroid coming in at hypersonic speeds compresses the air in front of it a lot , heating it hugely . the gas can reach temperatures of thousands of degrees celsius for a few seconds . the air radiates away this heat , in turn heating up the meteoroid . the material on the surface vaporizes and blows away—a process called ablation . that ablated material leaves a glowing trail behind the meteor , which we call a train . sometimes it can glow for several minutes , getting twisted up in high altitude winds , leaving behind an eerie , ghost-like persistent train . this all happens high above your head , about 90 – 100 km above the ground . typically , from any one location , you can see a few meteors per hour . it may not seem like much , but when you add them up all over the planet you find the earth is getting pelted to the tune of about 100 tons of material a day . but again , most of these meteoroids are teeny tiny . those random meteors are called sporadic meteors . they tend to be rocky in composition , and generally come from asteroids . if two asteroids smack into each other , the collision can eject little bits of material that then orbit the sun on their own . if their orbit crosses the earth , then you have a potential meteor . it may take a few million years , but at some point the earth and the meteoroid are at the same place at the same time , and boom . but sometimes meteoroids travel in packs . when that happens , we can get meteor showers , many dozens or even hundreds of meteors per hour . with one exception , those don ’ t come from asteroids : they come from comets . when a comet orbits the sun , the ice on it turns to gas , dislodging dust and gravel mixed in . this material leaves the comet and tends to stay more or less in the same orbit as the comet itself . over time , that material gets scattered all along the orbit , creating a puffy ribbon of tiny pieces of space debris around the sun . when the earth plows through that cloud of debris , we get a meteor shower . from our viewpoint on earth we see meteors shooting across the sky , apparently radiating away from a single point . that ’ s a perspective effect ; it ’ s like driving through a tunnel and seeing the tiles on the wall and ceiling flying past you , all apparently coming from a point ahead of you . the point in the sky where the meteors come from is called the radiant , and the shower is named after the constellation the radiant ’ s in . so we have the perseid meteor shower , the leonids , the camelopardalids . or the camelopardalids . and , since the earth hits a specific comet stream around the same time every year , the showers are annual . the perseids are in august , and the leonids in november . watching a meteor shower is easy : just go outside and look up ! generally , they ’ re better after local midnight . the earth plows into the meteoroids , so facing the direction of earth ’ s orbital motion means more meteors , just like you get more raindrops on the front windshield of your car than than on the back when driving through a storm . after local midnight you ’ re on the part of the earth facing into the orbit , so you see more meteors . by the way , if you happen to be on the international space station , you have to look down to see a meteor . in 2011 , astronaut ron garan photographed a perseid burning up below him ! but don ’ t worry : the odds of the space station getting hit are extremely low . space is big . oh , and that one exception i mentioned before ? that ’ s the annual geminids shower , which occurs in december . that comes from the asteroid 3200 phaethon , which is on an orbit that takes it very close to the sun . it ’ s possible it gets so hot that the rock vaporizes , making it act like a comet . the vast majority of meteoroids are small and tend to burn up in our atmosphere . but they can be bigger . a bolide , or fireball , is an extremely bright meteor , and those can be about the size of a grapefruit . those happen pretty often somewhere over the earth . i ’ ve seen a few myself . very rarely , an incoming meteoroid will survive all the way to the ground and become a meteorite . sometimes , the immense pressure of ramming earth ’ s air causes the incoming meteoroid to crumble or even explode , raining down dozens or hundreds of smaller pieces . typically , they slow rapidly after their blaze of glory , and simply fall the rest of the way to the ground . the air up there is cold , and their interiors are cold from being in space so long . so , despite what you might think , meteorites don ’ t cause fires when they hit the ground . in fact , they can be quite chilly ! meteorites are classified into three broad categories : stony , which are mostly rock ; iron , which are mostly metal ; and stony iron , which are a mixture of the two . the majority of meteorites we find are stony . the stony meteorites are subdivided into two kinds : chondrites , and achondrites . chondrites contain chondrules , small grains of minerals . these are very primitive , and are thought to have condensed out of the original disk of material that formed the solar system . their age can be found by looking at ratios of elements in them formed from radioactive decay . the oldest known meteorite formed 4.568 billion years ago : before the earth itself formed ! achondrites don ’ t have chondrules in them . most likely they came from a bigger asteroid , one that was once molten through , mixing the minerals . a big collision disrupted the parent body , creating the achondritic meteoroids . iron meteorites most likely come from the center of a large asteroid , one big enough that metals fell to the center via gravity . again , a big impact blew the asteroid up , scattering its material around the asteroid belt , and with some on orbits that eventually intersected earth . stony irons are the rarest . some have green or orange crystals of a mineral called olivine embedded in a web of metal . called pallasites , they may be the most beautiful of all meteorites . i actually collect meteorites . it ’ s fun but can be a somewhat pricey hobby . if you ’ re interested , make sure you get ‘ em from a licensed dealer . we have links to some in the dooblydoo . of course , on occasion the meteoroid coming in can be a tad bigger . and when that happens , well , all hell can break loose . on february 15 , 2013 , residents of the russian city of chelyabinsk got a rude awakening . at 9:20 a.m. local time , a rock about 19 meters across came in at a low angle . it got nearly as bright as the sun as it slammed into the atmosphere , and the pressure of its passage broke it up into several chunks , which broke up again . in a moment ’ s time , the sudden energy released was equivalent to the detonation of a half million tons of tnt — as much as a small atomic bomb ! while no one was killed , over a thousand people were injured by flying glass , shattered by the explosion . no doubt they were at their windows gawking at the huge vapor trail in the sky when the shock wave hit . there was no warning for this event ; the asteroid was essentially too small to detect while it was out in space . well , for now at least . telescopes are coming online soon that should be able to find smaller asteroids and give us some warning . astronomers are more worried about ones roughly a hundred meters across or bigger ; these can do serious damage on a city-wide scale or larger , but at the moment aren ’ t easy to spot much in advance . and what do we do if we do see one headed our way ? as of right now , there ’ s not much we can do . studies have been done to determine the best course of action ; maybe lobbing a nuke at it , or simply ramming it with a spaceprobe to change the orbit and make sure it misses earth . these ideas look good on paper , but they haven ’ t been tested yet . we ’ re still a few years from that . the good news is that objects that size hitting the earth are rare ; maybe once every century or three . but if we do nothing , it will happen eventually . as science fiction writer larry niven points out , the dinosaurs went extinct because they didn ’ t have a space program . hopefully , we ’ re smarter than they were . today you learned that meteors are small bits of interplanetary debris sloughed off by asteroids and comets . when the earth plows through the stream emitted by a comet we get a meteor shower . meteors burn up about 100 km above the earth , but some survive to hit the ground . most of these meteorites are rocky , some are metallic , and a few are a mix of the two . very big meteorites can be a very big problem , but there are plans in the works to prevent us from going the way of the dinosaurs . crash course astronomy - hey crash course , meteors ! cool ! crash course astronomy is produced in association with pbs digital studios . head over to their channel for even more awesome videos . this episode was written by me , phil plait . the script was edited by blake de pastino , and our consultant is dr. michelle thaller . it was directed by nicholas jenkins , the script supervisor and editor is nicole sweeney , the sound designer was michael aranda , and the graphics team is thought café .
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typically , from any one location , you can see a few meteors per hour . it may not seem like much , but when you add them up all over the planet you find the earth is getting pelted to the tune of about 100 tons of material a day . but again , most of these meteoroids are teeny tiny .
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roughly 100 tons of material pelts the earth 's atmosphere each day , why is this not a catastrophic problem ?
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[ go project films ] [ when a town runs dry ] [ ♪ music ♪ ] my grandfather started the farm . and we 've been farming here ever since . for the last couple years , we have n't had the crop production that we 're used to when we have adequate water . we 're struggling . i 've had to sell some property to try to keep in business . the little bit of land that we did sell was a very emotional thing to do because that 's land that i worked with my dad and it 's gone . growing up in stratford was a wonderful thing as a child . [ children talking ] the canals were always filled with water . we could spend a whole day at the canal trying to catch crawdads , hunting for frogs , fishing . we 'd ride our bikes off into the river . and we would swim in it . nowadays , there 's no water there . i grew up in yemen . living over there was really hard . so that is why we came to the united states . first we moved to oakland but i did n't feel like home there . i wanted to move to a smaller city . that 's when i found stratford . i really like living here but sometimes it gets hard with the work . since the drought has started we lost half the business . most of the people that come to my store they work for the farmers . most of the farmers they get broke , the workers they go somewhere else to find work . i really feel bad about the people . they have a rough time . this makes me sad because we were welcomed by all the people here . being able to work with the ground and with nature has been very satisfying . but of late when the water has become scarce we do n't get a lot of help from the people who want the food that we grow . this year probably two-thirds to half of our farm has not been put into cultivation because of lack of water . without food production , there 's no jobs out in the rural communities . when you have the commodity we tend to not plan for the future . otherwise we should have been planning years ago . you do n't start thinking about reality until you start seeing the writing on the wall . water is one thing , but you take a step back and you look at what 's going on in the community , and it 's heartbreaking . you 've got to be grateful for the people that are there from dusk to dawn or even later than that . when those stores close their doors , we 're really going to be hurting in that little community . you know , where are our kids going to be able to go to go get a snack ? when people do n't have the money i start to run a tab with them . some people they pay me back , some people they ca n't because no work . okay kenny , thank you . - you have a good day . - we 'll see you next time . when you know the people when they ca n't make no money , no work , it 's hard to say `` you know '' pay me my money back and you know they do n't have it . we lost a lot . sometimes you think i do n't know what to do anymore and we just keep going . anything helps , you know , anything helps . any time someone puts a little bit more effort into the community , [ whistle ] the community stands stronger . and you just hope that it grasps and it keeps moving forward . i would like my kids to take over the farm and keep it going but if it continues to deteriorate then the future is not bright in agriculture . [ cheering ] the only thing we can do is sell more land and that 's like selling part of yourself . [ screams ] there 's no better life . it 's not fast . there 's not a lot of money in it , but it 's a fair living . so it would really be sad for me to see this lifestyle come to an end . i hope the water is coming back . when the rain comes back i hope a lot of work and a lot of people come back . i really like living in this town . i do n't want to leave this town . [ credits ] [ ©2016 go project films ]
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but of late when the water has become scarce we do n't get a lot of help from the people who want the food that we grow . this year probably two-thirds to half of our farm has not been put into cultivation because of lack of water . without food production , there 's no jobs out in the rural communities .
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how much of the farmer 's land was not put into cultivation this past year due to the drought ?
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translator : andrea mcdonough reviewer : bedirhan cinar one of the grandest scientific tools ever made by mankind is called an atom smasher . and i mean literally grand . the biggest one ever built , the large hadron collider , or lhc , is a ring with a circumference of about 18 miles . that 's more than the entire length of manhattan . so what is an atom smasher ? it is a device that collides atomic nuclei together at extremely high energy . the most powerful one scientists have ever built can heat matter to the hottest temperatures ever achieved , temperatures last seen at a trillionth of second after the universe began . our accelerators are full of engineering superlatives . the beam-containing region of the lhc is a vacuum , with lower pressure than what surrounds the international space station , and is 456 degrees fahrenheit below zero , colder than the temperature of deepest space . a previous accelerator sitting in the lhc tunnel holds the world record for velocity , accelerating an electron to a speed so fast that if it were to race a photon of light , it would take about 14 minutes for the photon to get a lead of about 10 feet . if that does n't impress you , remember the photon is fastest thing in the universe , it goes about 186,000 miles per second . so how do these subatomic particle accelerators work ? well , they use electric fields . electric fields make charged particles move in the same way that gravity will pull a dropped baseball . the force from the electric field will pull a particle to make it move . the speed will continue to increase until the charged particle is moving incredibly fast . a simple particle accelerator can be made by hooking two parallel metal plates to a battery . the charge from the battery moves on to the two metal plates and makes an electric field that pulls the particle along . and that 's it , you got a particle accelerator . the problem is that an accelerator built this way is very weak . building a modern accelerator like the lhc this way would take over five trillion standard d-cell batteries . so scientists use much stronger batteries and put them one after another . an earlier accelerator used this method and was about a mile long and was equivalent to 30 billion batteries . however , to make an accelerator that is equivalent to five trillion batteries would require an accelerator 150 miles long . scientists needed another way . while electric fields would make a particle go faster , magnetic fields make them move in a circular path . if you put an electric field along the circle , you do n't need to use miles of electric fields , you can use a single electric field over and over again . the beams go around the circle , and each time they gain more energy . so very high-energy accelerators consist of a short region with accelerating electric fields , combined with long series of magnets that guide the particles in a circle . the strength of the magnets and the radius of the circular path determines the maximum energy of the beam . once the beam is zooming along , then the real fun begins , the smashing . the reason physicists want to get those particles moving so fast is so that they can slam them into one another . these collisions can teach us about the fundamental rules that govern matter , but they 'd be impossible without the feat of engineering that is the particle accelerator .
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the charge from the battery moves on to the two metal plates and makes an electric field that pulls the particle along . and that 's it , you got a particle accelerator . the problem is that an accelerator built this way is very weak .
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why is gravity not a useful force to exploit in building a particle accelerator ?
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there are few places on earth less hospitable to life than the bone-dry sahara desert . yet it was n't always this way . 100 million years ago , during a period known as the mid-cretaceous , a gargantuan river system flowed across the region from modern day egypt to morocco . the whole world at that time would look rather different to us . the continents had yet to assume their current positions . extreme temperatures were common and fierce storms made life unpredictable . dinosaurs flourished on land , pterosaurs roamed the skies , and giant marine reptiles and sharks swam in warm seas . small mammals , our ancestors , lived quite literally in the shadow of these extraordinary creatures . in this world of huge predators , the river of giants , which is what some call this region of what is now northern africa , stood out as particularly dangerous . in most ecosystems , it 's lonely at the top of the food chain . there usually is n't enough prey to sustain many predators . yet an incredible variety of aquatic prey species in the river-based ecosystem may have allowed a large and diverse population of apex predators to coexist . we know this thanks to a wealth of fossils we found in an area called the kem kem beds . many of the predators we 've discovered had head and body shapes that made them uniquely adapted to hunt the different types and sizes of aquatic prey . this allowed many kem kem predators to take full advantage of the one abundant food source in this environment : fish . this also allowed them to avoid direct competition with the predators going after land-loving animals . prey species in the river system had to contend with attacks from all sides , including from above . flying reptiles dominated the skies . alanqa saharica had a wingspan of up to nine meters , and long slender jaws that helped it snatch fish and small terrestrial animals . at least seven different types of crocodile-like predators patrolled the waterways , including the roughly ten-meter-long elosuchus . and multiple species of t-rex-sized carnivorous dinosaurs called theropods , lived side by side . in the river of giants , spinosaurus was king . this 15-meter-long dinosaur was even longer than t-rex , with short muscular hind legs , a flexible tail , and broad feet . it 's two-meter-high sail warned other creatures of its fearsome size and may have also been used to attract mates . spinosaurus ' long slender jaws were spiked with conical teeth , perfect for swiftly clamping down on slippery aquatic prey . this apex predator , as well as its ecosystem , is unparalleled in the history of life on earth . all that 's left of these fearsome predators are fossils . about 93 million years ago , sea levels rose , submerging the kem kem region in a shallow sea . tens of millions of years later , an asteroid impact , volcanic eruptions , and associated changes in climate wiped out the dinosaurs , pterosaurs , and many other groups of animals and plants , including their unique ecoysystems . that mass extinction paved the way for the rise of new kinds of birds , larger mammals , and eventually us .
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extreme temperatures were common and fierce storms made life unpredictable . dinosaurs flourished on land , pterosaurs roamed the skies , and giant marine reptiles and sharks swam in warm seas . small mammals , our ancestors , lived quite literally in the shadow of these extraordinary creatures . in this world of huge predators , the river of giants , which is what some call this region of what is now northern africa , stood out as particularly dangerous .
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what can we learn from the fact that , in the triassic , jurassic , and cretaceous , dinosaurs ( and other reptiles ) , not mammals ( which were around at the time ) , were the dominant creatures on land ?
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( music ) sometimes when i 'm on a long plane flight , i gaze out at all those mountains and deserts and try to get my head around how vast our earth is . and then i remember that there 's an object we see every day that would literally fit one million earths inside it . the sun seems impossibly big , but in the great scheme of things , it 's a pinprick , one of about 400 billion stars in the milky way galaxy , which you can see on a clear night as a pale , white mist stretched across the sky . and it gets worse . there are maybe 100 billion galaxies detectable by our telescopes , so if each star was the size of a single grain of sand , just the milky way has enough stars to fill a 30 foot by 30 foot stretch of beach three feet deep with sand . and the entire earth does n't have enough beaches to represent the stars in the overall universe . such a beach would continue for literally hundreds of millions of miles . holy stephen hawking , that is a lot of stars . but he and other physicists now believe in a reality that is unimaginably bigger still . i mean , first of all , the 100 billion galaxies within range of our telescopes are probably a minuscule fraction of the total . space itself is expanding at an accelerating pace . the vast majority of the galaxies are separating from us so fast that light from them may never reach us . still , our physical reality here on earth is intimately connected to those distant , invisible galaxies . we can think of them as part of our universe . they make up a single , giant edifice , obeying the same physical laws and all made from the same types of atoms , electrons , protons , quarks , neutrinos that make up you and me . however , recent theories in physics , including one called string theory , are now telling us there could be countless other universes , built on different types of particles , with different properties , obeying different laws . most of these universes could never support life , and might flash in and out of existence in a nanosecond , but nonetheless , combined they make up a vast multiverse of possible universes . in up to 11 dimensions , featuring wonders beyond our wildest imagination . and the leading version of string theory predicts a multiverse made of up to 10 to the 500 universes . that 's a one followed by 500 zeroes , a number so vast that if every atom in our observable universe had its own universe and all of the atoms in all of those universes each had their own universe , and you repeated that for two more cycles , you 'd still be at a tiny fraction of the total -- namely , one trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillionth . but even that number is minuscule compared to another number : infinity . some physicists think the space-time continuum is literally infinite , and that it contains an infinite number of so-called pocket universes with varying properties . how 's your brain doing ? but quantum theory adds a whole new wrinkle . i mean , the theory 's been proven true beyond all doubt , but interpreting it is baffling . and some physicists think you can only un-baffle it if you imagine that huge numbers of parallel universes are being spawned every moment , and many of these universes would actually be very like the world we 're in , would include multiple copies of you . in one such universe , you 'd graduate with honors and marry the person of your dreams . in another , not so much . there are still some scientists who would say , hogwash . the only meaningful answer to the question of how many universes there are is one , only one universe . and a few philosophers and mystics might argue that even our own universe is an illusion . so , as you can see , right now there is no agreement on this question , not even close . all we know is , the answer is somewhere between zero and infinity . well , i guess we know one other thing : this is a pretty cool time to be studying physics . we just might be undergoing the biggest paradigm shift in knowledge that humanity has ever seen .
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there are still some scientists who would say , hogwash . the only meaningful answer to the question of how many universes there are is one , only one universe . and a few philosophers and mystics might argue that even our own universe is an illusion .
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approximately how many galaxies are there in our own universe
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i was walking my mountain the other day , and i was feeling really at home with the forest . and i was so grateful to it for showing me that forests are built on relationships which form networks , like these beautiful river networks . and i thought , `` wow , forests are just like human families . '' and i was so taken by the beauty of this idea that i fell and i crashed down on the ground , and i hit my head on this new stump . and i was so angry ! then , i was so heartbroken because there was a whole family of trees cut down . thing is , where i 'm from in western canada , there 's clearcuts like this hidden everywhere , and it was n't until google earth starting sending images , like this , that we realized the whole world was wiping its noses on our old-growth forests . did you know that deforestation like this around the world causes more greenhouse gas emissions than all the trains , planes and automobiles combined ? yeah , i 'm really upset about this , but i 'm also really hopeful because i 've also discovered in my research that forest networks are organized in the same way as our own neural networks and our social networks . and i believe that if we can learn to integrate these into a whole that we can change this dangerous pathway of global warming because i believe we are wired for healing . so , here 's the science : the most ancient of these networks is this below-ground fungal network , or mushroom network . and it evolved over a billion years ago to allow organisms to migrate from the ocean onto the land . and eventually , they got together with plants in this symbiosis . and this allowed plants to photosynthesize , pulling co2 , which is our biggest greenhouse gas , out of the atmosphere and giving off oxygen , which allows us to breathe and actually allowed humans to eventually evolve . now , we call this symbiosis a mycorrhiza , myco for fungus , rrhiza for root . so , the fungus and root get together , and they trade for mutual benefit . now , all trees in all forests all over the world depend on these mycorrhizas for their very survival . they ca n't live without them . and the way it works is that a seed falls on the forest floor , it germinates , it sends a root down into the soil , and it starts sending out chemical signals to the fungi to grow towards the root . and the fungus communicates back with its own signals , and it says to the root , 'you need to grow towards me and branch and soften . ' and so by this communication , they grow together into this magical symbiosis . and the way that symbiosis works is the plant takes its hard-earned carbon from photosynthesis and brings it to the fungus because the fungus ca n't photosynthesize . and the fungus takes nutrients and water it gathers from the soil , where plant roots ca n't grow , and they give it to the plant . and so they 're both benefiting in this cooperation . now , as the fungus grows through the soil , it starts linking plant and plant and tree and tree together until the whole forest is linked together . did you know that a single tree can be literally linked up to hundreds of other trees as far as the eye can see ? and as you 're walking through the forest , what you see , the trees , the roots , the mushrooms , are just the tip of the iceberg . under a single footstep , there are 300 miles of fungal cells stacked end on end moving stuff around . and if you could look down into the ground , it would be like this super highway with cars going everywhere . now , all networks are made of nodes and links . in forests , those nodes would be trees and the links fungi . it 's kind of like in your facebook network , where nodes would be friends and links would be your friendships . now , we all know that some of those nodes , or friends , are busier than others , like that friend who is always sending out group messages . well , it 's the same in forests , and these nodes in forests , we call them hubs , they 're the big trees in the forests with roots going everywhere . now , we also have learned that the systems organized around these hubs , these big old trees , so in forests , that 's where the regeneration occurs . in your facebook network , that might be how parties are organized , around that hub that 's always sending out the group messages . we call those hubs in forests mother trees ; they 're the big old trees in the forest . and they fix the carbon in their leaves , and they send it down through their massive trunks and into the networks all around them that are linked up to all the other trees and seedlings , the young ones , and they start sending that carbon everywhere . the more those seedlings are stressed out , maybe from drought or shade , the more the mother tree sends to them . it 's kind of like in your families , where if you 're kind of stressed out , mom and dad kick in and help you out a bit more , right ? well , it 's the same in forests . the other thing that we 've recently discovered is that mother trees will preferentially send more signals to her own kids , her own children . and then , this way she helps them do better , and then they survive more , and then they can pass their genes on to future generations . so , how natural selection works . now , the way these forests are organized makes them both resilient and vulnerable . they 're resilient because there 's many mother trees , and there 's many fungal species linking them together . and that network is really hard to break . it 's pretty darn tough . but of course , we humans have figured out how to do that . and what we do is we take out the mother trees . and maybe taking one out wo n't make much difference but when you take more and more and more and clearcut and more and more and more that it can cause the system to collapse and fall down , like dominoes . and we can cross tipping points and cause more forest death and more global warming , and we 're doing that . so what we do , our choices we make , can lead us towards global heatlh or global sickness . we do have choices . and i 'm going to leave you with four ideas that i think are worth spreading . first one : to love the forest you have to go spend time in it . go be in the forest , connect with it . and then you 'll fight hard enough to protect them . second : learn how they work . learn how those networks link things together in organized forests . and to do that , you got ta go out there take risks , make mistakes . third : protect forests . they need you to do that because they ca n't do it themselves . they 're stuck in one spot . they ca n't run away from humans , and they ca n't run away from global warming . they need you . and finally , and most importantly , use your own very clever , brilliant , neural and social networks to create amazing messages , and spread the word that forests are worth saving because you 're worth saving , and i believe that together we 're all wired for healing .
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and as you 're walking through the forest , what you see , the trees , the roots , the mushrooms , are just the tip of the iceberg . under a single footstep , there are 300 miles of fungal cells stacked end on end moving stuff around . and if you could look down into the ground , it would be like this super highway with cars going everywhere .
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under a single footstep in the forest , there are ________ .
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in 1796 , the scientist edward jenner injected material from a cowpox virus into an eight-year-old boy with a hunch that this would provide the protection needed to save people from deadly outbreaks of the related smallpox virus . it was a success . the eight-year-old was inoculated against the disease and this became the first ever vaccine . but why did it work ? to understand how vaccines function , we need to know how the immune system defends us against contagious diseases in the first place . when foreign microbes invade us , the immune system triggers a series of responses in an attempt to identify and remove them from our bodies . the signs that this immune response is working are the coughing , sneezing , inflammation and fever we experience , which work to trap , deter and rid the body of threatening things , like bacteria . these innate immune responses also trigger our second line of defense , called adaptive immunity . special cells called b cells and t cells are recruited to fight microbes , and also record information about them , creating a memory of what the invaders look like , and how best to fight them . this know-how becomes handy if the same pathogen invades the body again . but despite this smart response , there 's still a risk involved . the body takes time to learn how to respond to pathogens and to build up these defenses . and even then , if a body is too weak or young to fight back when it 's invaded , it might face very serious risk if the pathogen is particularly severe . but what if we could prepare the body 's immune response , readying it before someone even got ill ? this is where vaccines come in . using the same principles that the body uses to defend itself , scientists use vaccines to trigger the body 's adaptive immune system , without exposing humans to the full strength disease . this has resulted in many vaccines , which each work uniquely , separated into many different types . first , we have live attenuated vaccines . these are made of the pathogen itself but a much weaker and tamer version . next , we have inactive vaccines , in which the pathogens have been killed . the weakening and inactivation in both types of vaccine ensures that pathogens do n't develop into the full blown disease . but just like a disease , they trigger an immune response , teaching the body to recognize an attack by making a profile of pathogens in preparation . the downside is that live attenuated vaccines can be difficult to make , and because they 're live and quite powerful , people with weaker immune systems ca n't have them , while inactive vaccines do n't create long-lasting immunity . another type , the subunit vaccine , is only made from one part of the pathogen , called an antigen , the ingredient that actually triggers the immune response . by even further isolating specific components of antigens , like proteins or polysaccharides , these vaccines can prompt specific responses . scientists are now building a whole new range of vaccines called dna vaccines . for this variety , they isolate the very genes that make the specific antigens the body needs to trigger its immune response to specific pathogens . when injected into the human body , those genes instruct cells in the body to make the antigens . this causes a stronger immune response , and prepares the body for any future threats , and because the vaccine only includes specific genetic material , it does n't contain any other ingredients from the rest of the pathogen that could develop into the disease and harm the patient . if these vaccines become a success , we might be able to build more effective treatments for invasive pathogens in years to come . just like edward jenner 's amazing discovery spurred on modern medicine all those decades ago , continuing the development of vaccines might even allow us to treat diseases like hiv , malaria , or ebola , one day .
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in 1796 , the scientist edward jenner injected material from a cowpox virus into an eight-year-old boy with a hunch that this would provide the protection needed to save people from deadly outbreaks of the related smallpox virus . it was a success .
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edward jenner succeeded in creating a vaccine against smallpox by injecting patients with material of which disease ?
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french fries are delicious . french fries with ketchup are a little slice of heaven . the problem is it 's basically impossible to pour the exactly right amount . we 're so used to pouring ketchup that we do n't realize how weird its behavior is . imagine a ketchup bottle filled with a straight up solid like steel . no amount of shaking would ever get the steel out . now imagine that same bottle full of a liquid like water . that would pour like a dream . ketchup , though , ca n't seem to make up its mind . is it is a solid ? or a liquid ? the answer is , it depends . the world 's most common fluids like water , oils and alcohols respond to force linearly . if you push on them twice as hard , they move twice as fast . sir isaac newton , of apple fame , first proposed this relationship , and so those fluids are called newtonian fluids . ketchup , though , is part of a merry band of linear rule breakers called non-newtonian fluids . mayonnaise , toothpaste , blood , paint , peanut butter and lots of other fluids respond to force non-linearly . that is , their apparent thickness changes depending on how hard you push , or how long , or how fast . and ketchup is actually non-newtonian in two different ways . way number one : the harder you push , the thinner ketchup seems to get . below a certain pushing force , ketchup basically behaves like a solid . but once you pass that breaking point , it switches gears and becomes a thousand times thinner than it was before . sound familiar right ? way number two : if you push with a force below the threshold force eventually , the ketchup will start to flow . in this case , time , not force , is the key to releasing ketchup from its glassy prison . alright , so , why does ketchup act all weird ? well , it 's made from tomatoes , pulverized , smashed , thrashed , utterly destroyed tomatoes . see these tiny particles ? this is what remains of tomatoes cells after they go through the ketchup treatment . and the liquid around those particles ? that 's mostly water and some vinegar , sugar , and spices . when ketchup is just sitting around , the tomato particles are evenly and randomly distributed . now , let 's say you apply a weak force very quickly . the particles bump into each other , but ca n't get out of each other 's way , so the ketchup does n't flow . now , let 's say you apply a strong force very quickly . that extra force is enough to squish the tomato particles , so maybe instead of little spheres , they get smushed into little ellipses , and boom ! now you have enough space for one group of particles to get passed others and the ketchup flows . now let 's say you apply a very weak force but for a very long time . turns out , we 're not exactly sure what happens in this scenario . one possibility is that the tomato particles near the walls of the container slowly get bumped towards the middle , leaving the soup they were dissolved in , which remember is basically water , near the edges . that water serves as a lubricant betwen the glass bottle and the center plug of ketchup , and so the ketchup flows . another possibility is that the particles slowly rearrange themselves into lots of small groups , which then flow past each other . scientists who study fluid flows are still actively researching how ketchup and its merry friends work . ketchup basically gets thinner the harder you push , but other substances , like oobleck or some natural peanut butters , actually get thicker the harder you push . others can climb up rotating rods , or continue to pour themselves out of a beeker , once you get them started . from a physics perspective , though , ketchup is one of the more complicated mixtures out there . and as if that were n't enough , the balance of ingredients and the presence of natural thickeners like xanthan gum , which is also found in many fruit drinks and milkshakes , can mean that two different ketchups can behave completely differently . but most will show two telltale properties : sudden thinning at a threshold force , and more gradual thinning after a small force is applied for a long time . and that means you could get ketchup out of the bottle in two ways : either give it a series of long , slow languid shakes making sure you do n't ever stop applying force , or you could hit the bottle once very , very hard . what the real pros do is keep the lid on , give the bottle a few short , sharp shakes to wake up all those tomato particles , and then take the lid off and do a nice controlled pour onto their heavenly fries .
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that is , their apparent thickness changes depending on how hard you push , or how long , or how fast . and ketchup is actually non-newtonian in two different ways . way number one : the harder you push , the thinner ketchup seems to get .
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is pure water newtonian ?
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as a wildfire rages through the grasslands , three lions and three wildebeest flee for their lives . to escape the inferno , they must cross over to the left bank of a crocodile-infested river . fortunately , there happens to be a raft nearby . it can carry up to two animals at a time , and needs as least one lion or wildebeest on board to row it across the river . there 's just one problem . if the lions ever outnumber the wildebeest on either side of the river , even for a moment , their instincts will kick in , and the results wo n't be pretty . that includes the animals in the boat when it 's on a given side of the river . what 's the fastest way for all six animals to get across without the lions stopping for dinner ? pause here if you want to figure it out for yourself . answer in : 3 answer in : 2 answer in : 1 if you feel stuck on a problem like this , try listing all the decisions you can make at each point , and the consequences each choice leads to . for instance , there are five options for who goes across first : one wildebeest , one lion , two wildebeest , two lions , or one of each . if one animal goes alone , it 'll just have to come straight back . and if two wildebeest cross first , the remaining one will immediately get eaten . so those options are all out . sending two lions , or one of each animal , can actually both lead to solutions in the same number of moves . for the sake of time , we 'll focus on the second one . one of each animal crosses . now , if the wildebeest stays and the lion returns , there will be three lions on the right bank . bad news for the two remaining wildebeest . so we need to have the lion stay on the left bank and the wildebeest go back to the right . now we have the same five options , but with one lion already on the left bank . if two wildebeest go , the one that stays will get eaten , and if one of each animal goes , the wildebeest on the raft will be outnumbered as soon as it reaches the other side . so that 's a dead end , which means that at the third crossing , only the two lions can go . one gets dropped off , leaving two lions on the left bank . the third lion takes the raft back to the right bank where the wildebeest are waiting . what now ? well , since we 've got two lions waiting on the left bank , the only option is for two wildebeest to cross . next , there 's no sense in two wildebeest going back , since that just reverses the last step . and if two lions go back , they 'll outnumber the wildebeest on the right bank . so one lion and one wildebeest take the raft back leaving us with one of each animal on the left bank and two of each on the right . again , there 's no point in sending the lion-wildebeest pair back , so the next trip should be either a pair of lions or a pair of wildebeest . if the lions go , they 'd eat the wildebeest on the left , so they stay , and the two wildebeest cross instead . now we 're quite close because the wildebeest are all where they need to be with safety in numbers . all that 's left is for that one lion to raft back and bring his fellow lions over one by one . that makes eleven trips total , the smallest number needed to get everyone across safely . the solution that involves sending both lions on the first step works similarly , and also takes eleven crossings . the six animals escape unharmed from the fire just in time and begin their new lives across the river . of course , now that the danger 's passed , it remains to be seen how long their unlikely alliance will last .
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all that 's left is for that one lion to raft back and bring his fellow lions over one by one . that makes eleven trips total , the smallest number needed to get everyone across safely . the solution that involves sending both lions on the first step works similarly , and also takes eleven crossings . the six animals escape unharmed from the fire just in time and begin their new lives across the river .
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what is another solution that leads to the same number of efficient crossings ?
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translator : andrea mcdonough reviewer : bedirhan cinar you might have heard that we 're running out of fresh water . this might sound strange to you because , if you live in a place where water flows freely from the tap or shower at any time , it sure does n't seem like a big deal . it 's just there , right ? wrong ! the only obvious thing about fresh water is how much we need it . because it 's essential to life , we need to think about it carefully . right now , at this very moment , some people , women and girls in particular , walk hours and miles per day to get fresh water , and even then , it may not be clean . every 15 seconds , a child dies due to water-born diseases . this is tragic ! the most compelling reasons to think about fresh water , therefore , have to do with what we might call the global common good . this is not something we normally think about , but it means recognizing how much fresh water matters for the flourishing of human and non-human life on earth now and in the future . how do we think about something as local as our faucets and as global as fresh water ? is there a connection between them ? many people assume that fresh water shortages are due to individual wastefulness : running the water while you brush your teeth , for example , or taking really long showers . most of us assume , therefore , that water shortages can be fixed by improving our personal habits : taking shorter showers or turning off the water while we brush our teeth . but , global fresh water scarcity neither starts nor ends in your shower . globally , domestic use of fresh water accounts for only 8 % of consumption , 8 % ! ! compare that to the 70 % that goes to agriculture and the 22 % that goes to industrial uses . now , hold up - you 're not off the hook ! individual habits are still part of the puzzle . you should still cultivate water virtue in your daily life , turn off the tap when you brush your teeth . but still , it 's true . taking shorter showers wo n't solve global problems , which is too bad . it would be much more straightforward and easier if virtuous , individual actions could do the trick . you 'd just stand there for 30 seconds less , and you 'd be done with that irksome , planet-saving task for the day . well , that 's not so much the case . agricultural and industrial patterns of water use need serious attention . how do our societies value water ? distribute it ? subsidize its use in agriculture ? incentivize its consumption or pollution ? these are all questions that stem from how we think about fresh water 's value . is it an economic commodity ? a human right ? a public good ? nobel prize winners , global water justice activists , transnational institutions like the united nations , and even the catholic church are at work on the issue . but , it 's tricky , too , because the business of water became very profitable in the 20th century . and profit is not the same thing as the common good . we need to figure out how to value fresh water as a public good , something that 's vital for human and non-human life , now and in the future . now that 's a virtuous , collective task that goes far beyond your shower .
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most of us assume , therefore , that water shortages can be fixed by improving our personal habits : taking shorter showers or turning off the water while we brush our teeth . but , global fresh water scarcity neither starts nor ends in your shower . globally , domestic use of fresh water accounts for only 8 % of consumption , 8 % ! ! compare that to the 70 % that goes to agriculture and the 22 % that goes to industrial uses .
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devise a solution for providing unlimited amounts of fresh water . in a few bullet points , explain your idea .
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translator : andrea mcdonough reviewer : bedirhan cinar have you heard the one about thomas jefferson and the louisiana territory ? thomas jefferson , author of the declaration of independence , was not a fan of the new constitution presented in 1787 . he was very worried that the constitution gave too much power to the new , national government , and not enough power to the states , an issue known as `` big government '' . jefferson only reluctantly agreed to support it when his friend , james madison , promised to propose a bill of rights after it was ratified . but jefferson 's fears about big government did not go away . for example , secretary of the treasury , alexander hamilton , proposed a national bank in 1790 , and jefferson knew there was no provision in the constitution to permit such a thing . hamilton claimed some sort of implied powers mumbo-jumbo . sure , it was n't written in the constitution , but the constitution implied that it could be done . but , jefferson was n't buying it . nonetheless , the bank was established by hamilton and president washington . when jefferson was sworn in as president in 1801 , he pledged to reduce the size and scope of the national government . but , of course , things did n't go exactly as he had planned . spain secretly transferred the louisiana territory to france right beneath jefferson 's nose . when congress found out , they quickly began discussions with france to buy a piece of the territory along the mississippi river for about $ 2 million . but , there was one little problem : jefferson knew there was no provision in the constitution to buy foreign territory . so what was a strict constructionist to do ? first , he tried to get an amendment to the constitution passed that would expressly permit the purchase , but congress was n't willing to do it . then , without permission , the u.s. negotiators in france cut a deal for all of the territory for a cool $ 15 million dollars . that new land doubled the size of the nation ! now jefferson was really stuck . he knew that the territory would be a great acquisition for the country , providing lots of new land for farmers and other settlers , but how could he constitutionally justify it ? in the end , jefferson turned to the argument used by his old foe alexander hamilton . he claimed that the power to purchase the territory is implied in the constitution 's treaty-making power . this was the exact argument that he had mocked openly a decade before , so it must have crushed his pride to have to use it . but more importantly , he may have committed the biggest big government play ever ! how ironic is it that one of the biggest opponents of big government doubled the size of the young country and did so while openly questioning its constitutionality ? at $ 15 million , which is about three cents an acre , it has been called by many the greatest real estate deal in the history of the united states .
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but , of course , things did n't go exactly as he had planned . spain secretly transferred the louisiana territory to france right beneath jefferson 's nose . when congress found out , they quickly began discussions with france to buy a piece of the territory along the mississippi river for about $ 2 million .
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why did the idea of france on its doorstep bother the united states more than spain on its doorstep ?
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your favorite band is great at playing music , but not so great at being organized . they keep misplacing their instruments on tour , and it 's driving their manager mad . on the day of the big concert , the band wakes up to find themselves tied up in a windowless , soundproof practice room . their manager explains what 's happening . outside , there are ten large boxes . each contains one of your instruments , but do n't be fooled by the pictures - they 've been randomly placed . i 'm going to let you out one at a time . while you 're outside , you can look inside any five boxes before security takes you back to the tour bus . you ca n't touch the instruments or in any way communicate what you find to the others . no marking the boxes , shouting , nothing . if each one of you can find your own instrument , then you can play tonight . otherwise , the label is dropping you . you have three minutes to think about it before we start . the band is in despair . after all , each musician only has a 50 % chance of finding their instrument by picking five random boxes . and the chances that all ten will succeed are even lower - just 1 in 1024 . but suddenly , the drummer comes up with a valid strategy that has a better than 35 % chance of working . can you figure out what it was ? pause the video on the next screen if you want to figure it out for yourself ! answer in : 3 answer in : 2 answer in : 1 here 's what the drummer said : everyone first open the box with the picture of your instrument . if your instrument is inside , you 're done . otherwise , look at whatever 's in there , and then open the box with that picture on it . keep going that way until you find your instrument . the bandmates are skeptical , but amazingly enough , they all find what they need . and a few hours later , they 're playing to thousands of adoring fans . so why did the drummer 's strategy work ? each musician follows a linked sequence that starts with the box whose outside matches their instrument and ends with the box actually containing it . note that if they kept going , that would lead them back to the start , so this is a loop . for example , if the boxes are arranged like so , the singer would open the first box to find the drums , go to the eighth box to find the bass , and find her microphone in the third box , which would point back to the first . this works much better than random guessing because by starting with the box with the picture of their instrument , each musician restricts their search to the loop that contains their instrument , and there are decent odds , about 35 % , that all of the loops will be of length five or less . how do we calculate those odds ? for the sake of simplicity , we 'll demonstrate with a simplified case , four instruments and no more than two guesses allowed for each musician . let 's start by finding the odds of failure , the chance that someone will need to open three or four boxes before they find their instrument . there are six distinct four-box loops . one fun way to count them is to make a square , put an instrument at each corner , and draw the diagonals . see how many unique loops you can find , and keep in mind that these two are considered the same , they just start at different points . these two , however , are different . we can visualize the eight distinct three-box loops using triangles . you 'll find four possible triangles depending on which instrument you leave out , and two distinct paths on each . so of the 24 possible combinations of boxes , there are 14 that lead to faliure , and ten that result in success . that computational strategy works for any even number of musicians , but if you want a shortcut , it generalizes to a handy equation . plug in ten musicians , and we get odds of about 35 % . what if there were 1,000 musicians ? 1,000,000 ? as n increases , the odds approach about 30 % . not a guarantee , but with a bit of musician 's luck , it 's far from hopeless . hi everybody , if you liked this riddle , try solving these two .
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see how many unique loops you can find , and keep in mind that these two are considered the same , they just start at different points . these two , however , are different . we can visualize the eight distinct three-box loops using triangles .
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can you suggest a different solution whose success rate is higher than ( 1/2 ) 20 , but not necessarily as high as 30 % ?
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o polônio foi outro elemento descoberto por madame curie , a madame curie ela polonesa , mas fez boa parte da pesquisa , se não toda , em paris . polônio é um nome por causa da polônia polônio é um elemento que tem sido não muito importante , até a invenção da bomba atômica , e o polônio tornou-se um material absolutamente crucial pq é usado , ou foi usado , como um gatilho no centro da bomba atômica original . uma das dificuldades é que tem uma meia-vida muito curta . se vc tem um pedaço de polônio , metade dele decai em 138 dias se vc mantém por muito tempo , ele se vai , ou quase todo se vai , e portanto , no início da produção de bombas atômicas , das de hiroshima e nagasaki , o fator limitante na produção de bombas era a produção de polônio para o gatilho . em vez do enriquecimento de urânio ou plutônio , que eram usados para as bombas . bem recentemente o polônio teve uma nova notoriedade , pq foi usado neste caso trágico de envenenamento . no qual uma grande dose de polônio foi dado a um infeliz cidadão russo , que visitava a inglaterra . e ainda não está claro de onde veio o polônio . mas é um material bem pouco comum . e difícil para alguém comum encontrar . se for ingerido , pq decai muito rápido , a radioatividade pode causar todo tipo de efeitos desagradáveis . e , novamente , é provavelmente venenoso ele mesmo . traduzido por prof. dr. luís brudna
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o polônio foi outro elemento descoberto por madame curie , a madame curie ela polonesa , mas fez boa parte da pesquisa , se não toda , em paris . polônio é um nome por causa da polônia polônio é um elemento que tem sido não muito importante , até a invenção da bomba atômica , e o polônio tornou-se um material absolutamente crucial pq é usado , ou foi usado , como um gatilho no centro da bomba atômica original .
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polonium is named after which country ?
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translator : andrea mcdonough reviewer : jessica ruby how big was that fish you caught ? this big ? this big ? this big ? without photographic evidence , there 's nothing that proves you caught a whopper , and that 's been true since the dawn of fishing . in fact , hundreds of years ago , long before photography could capture the moment , japanese fishermen invented their own way to record trophy catches . they called it gyotaku . gyotaku is the ancient art of printing fish that originated in japan as a way to record trophy catches prior to the modern day camera . gyo means fish and taku means impression . there are several different stories about how gyotaku came about , but it basically started with fishermen needing a way to record the species and size of the fish they caught over 100 years ago . fishermen took paper , ink , and brushes out to sea with them . they told stories of great adventures at sea . since the japanese revered certain fish , the fishermen would take a rubbing from these fish and release them . to make the rubbing , they would paint the fish with non-toxic sumi-e ink and print them on rice paper . this way they could be released or cleaned and sold at market . the first prints like this were for records only with no extra details . it was n't until the mid 1800 's that they began painting eye details and other embellishments onto the prints . one famous nobleman , lord sakai , was an avid fisherman , and , when he made a large catch , he wanted to preserve the memory of the large , red sea bream . to do so , he commissioned a fisherman to print his catch . after this , many fisherman would bring their gyotaku prints to lord sakai , and if he liked their work , he would hire them to print for him . many prints hung in the palace during the edo period . after this period , gyotaku was not as popular and began to fade away . today , gyotaku has become a popular art form , enjoyed by many . and the prints are said to bring good luck to the fishermen . but the art form is quite different than it used to be . most artists today learn on their own by trial and error . before the artist begins to print , the fish needs to be prepared for printing . first , the artist places the fish on a hollowed out surface . then the artist spreads the fins out and pins them down on the board to dry . they then clean the fish with water . when it comes time to print , there are two different methods . the indirect method begins with pasting moist fabric or paper onto the fish using rice paste . then , the artist uses a tompo , or a cotton ball covered in silk , to put ink on the fabric or paper to produce the print . this method requires more skill and great care needs to be taken when pulling the paper off the fish so the paper does n't tear . in the direct method , the artist paints directly on the fish , and then gently presses the moist fabric or paper into the fish . with both of these methods , no two prints are exactly alike , but both reveal dramatic images of the fish . for the final touch , the artist uses a chop , or a stamp , and signs their work , and can hold it up to say , `` the fish was exactly this big ! ''
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the first prints like this were for records only with no extra details . it was n't until the mid 1800 's that they began painting eye details and other embellishments onto the prints . one famous nobleman , lord sakai , was an avid fisherman , and , when he made a large catch , he wanted to preserve the memory of the large , red sea bream .
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when did eye details and other embellishments start showing up on gyotaku ?
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translator : andrea mcdonough reviewer : bedirhan cinar have you ever wondered who has the authority to make laws or punish people who break them ? when we think of power in the united states , we usually think of the president , but he does not act alone . in fact , he is only one piece of the power puzzle and for very good reason . when the american revolution ended in 1783 , the united states government was in a state of change . the founding fathers knew that they did not want to establish another country that was ruled by a king , so the discussions were centered on having a strong and fair national government that protected individual freedoms and did not abuse its power . when the new constitution was adopted in 1787 , the structure of the infant government of the united states called for three separate branches , each with their own powers , and a system of checks and balances . this would ensure that no one branch would ever become too powerful because the other branches would always be able to check the power of the other two . these branches work together to run the country and set guidelines for us all to live by . the legislative branch is described in article 1 of the u.s. constitution . many people feel that the founding fathers put this branch in the document first because they thought it was the most important . the legislative branch is comprised of 100 u.s . senators and 435 members in the u.s. house of representatives . this is better known as the u.s. congress . making laws is the primary function of the legislative branch , but it is also responsible for approving federal judges and justices , passing the national budget , and declaring war . each state gets two senators and some number of representatives , depending on how many people live in that state . the executive branch is described in article 2 of the constitution . the leaders of this branch of government are the president and vice president , who are responsible for enforcing the laws that congress sets forth . the president works closely with a group of advisors , known as the cabinet . these appointed helpers assist the president in making important decisions within their area of expertise , such as defense , the treasury , and homeland security . the executive branch also appoints government officials , commands the armed forces , and meets with leaders of other nations . all that combined is a lot of work for a lot of people . in fact , the executive branch employs over 4 million people to get everything done . the third brand of the u.s. government is the judicial branch and is detailed in article 3 . this branch is comprised of all the courts in the land , from the federal district courts to the u.s. supreme court . these courts interpret our nation 's laws and punish those who break them . the highest court , the supreme court , settles disputes among states , hears appeals from state and federal courts , and determines if federal laws are constitutional . there are nine justices on the supreme court , and , unlike any other job in our government , supreme court justices are appointed for life , or for as long as they want to stay . our democracy depends on an informed citizenry , so it is our duty to know how it works and what authority each branch of government has over its citizens . besides voting , chances are that some time in your life you 'll be called upon to participate in your government , whether it is to serve on a jury , testify in court , or petition your congress person to pass or defeat an idea for a law . by knowning the branches , who runs them , and how they work together , you can be involved , informed , and intelligent .
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the founding fathers knew that they did not want to establish another country that was ruled by a king , so the discussions were centered on having a strong and fair national government that protected individual freedoms and did not abuse its power . when the new constitution was adopted in 1787 , the structure of the infant government of the united states called for three separate branches , each with their own powers , and a system of checks and balances . this would ensure that no one branch would ever become too powerful because the other branches would always be able to check the power of the other two .
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when was the new constitution adopted ?
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you 're in line at the grocery store when , uh oh , someone sneezes on you . the cold virus is sucked inside your lungs and lands on a cell on your airway lining . every living thing on earth is made of cells , from the smallest one-celled bacteria to the giant blue whale to you . each cell in your body is surrounded by a cell membrane , a thick flexible layer made of fats and proteins , that surrounds and protects the inner components . it 's semipermeable , meaning that it lets some thing pass in and out but blocks others . the cell membrane is covered with tiny projections . they all have functions , like helping cells adhere to their neighbors or binding to nutrients the cell will need . animal and plant cells have cell membranes . only plant cells have a cell wall , which is made of rigid cellulose that gives the plant structure . the virus cell that was sneezed into your lungs is sneaky . pretending to be a friend , it attaches to a projection on the cell membrane , and the cell brings it through the cell membrane and inside . when the virus gets through , the cell recognizes its mistake . an enemy is inside ! special enzymes arrive at the scene and chop the virus to pieces . they then send one of the pieces back through the cell membrane , where the cell displays it to warn neighboring cells about the invader . a nearby cell sees the warning and immediately goes into action . it needs to make antibodies , proteins that will attack and kill the invading virus . this process starts in the nucleus . the nucleus contains our dna , the blueprint that tells our cells how to make everything our bodies need to function . a certain section of our dna contains instructions that tell our cells how to make antibodies . enzymes in the nucleus find the right section of dna , then create a copy of these instructions , called messenger rna . the messenger rna leaves the nucleus to carry out its orders . the messenger rna travels to a ribosome . there can be as many as 10 million ribosomes in a human cell , all studded along a ribbon-like structure called the endoplasmic reticulum . this ribosome reads the instructions from the nucleus . it takes amino acids and links them together one by one creating an antibody protein that will go fight the virus . but before it can do that , the antibody needs to leave the cell . the antibody heads to the golgi apparatus . here , it 's packed up for delivery outside the cell . enclosed in a bubble made of the same material as the cell membrane , the golgi apparatus also gives the antibody directions , telling it how to get to the edge of the cell . when it gets there , the bubble surrounding the antibody fuses to the cell membrane . the cell ejects the antibody , and it heads out to track down the virus . the leftover bubble will be broken down by the cell 's lysosomes and its pieces recycled over and over again . where did the cell get the energy to do all this ? that 's the roll of the mitochondria . to make energy , the mitochondria takes oxygen , this is the only reason we breathe it , and adds electrons from the food we eat to make water molecules . that process also creates a high energy molecule , called atp which the cell uses to power all of its parts . plant cells make energy a different way . they have chloroplasts that combine carbon dioxide and water with light energy from the sun to create oxygen and sugar , a form of chemical energy . all the parts of a cell have to work together to keep things running smoothly , and all the cells of your body have to work together to keep you running smoothly . that 's a whole lot of cells . scientists think there are about 37 trillion of them .
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to make energy , the mitochondria takes oxygen , this is the only reason we breathe it , and adds electrons from the food we eat to make water molecules . that process also creates a high energy molecule , called atp which the cell uses to power all of its parts . plant cells make energy a different way .
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the nucleus of the cell contains an important molecule found in all cells . this molecule is “ the blueprint of life ” and is called :
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imagine a brilliant neuroscientist named mary . mary lives in a black and white room , she only reads black and white books , and her screens only display black and white . but even though she has never seen color , mary is an expert in color vision and knows everything ever discovered about its physics and biology . she knows how different wavelengths of light stimulate three types of cone cells in the retina , and she knows how electrical signals travel down the optic nerve into the brain . there , they create patterns of neural activity that correspond to the millions of colors most humans can distinguish . now imagine that one day , mary 's black and white screen malfunctions and an apple appears in color . for the first time , she can experience something that she 's known about for years . does she learn anything new ? is there anything about perceiving color that was n't captured in all her knowledge ? philosopher frank jackson proposed this thought experiment , called mary 's room , in 1982 . he argued that if mary already knew all the physical facts about color vision , and experiencing color still teaches her something new , then mental states , like color perception , ca n't be completely described by physical facts . the mary 's room thought experiment describes what philosophers call the knowledge argument , that there are non-physical properties and knowledge which can only be discovered through conscious experience . the knowledge argument contradicts the theory of physicalism , which says that everything , including mental states , has a physical explanation . to most people hearing mary 's story , it seems intuitively obvious that actually seeing color will be totally different than learning about it . therefore , there must be some quality of color vision that transcends its physical description . the knowledge argument is n't just about color vision . mary 's room uses color vision to represent conscious experience . if physical science ca n't entirely explain color vision , then maybe it ca n't entirely explain other conscious experiences either . for instance , we could know every physical detail about the structure and function of someone else 's brain , but still not understand what it feels like to be that person . these ineffable experiences have properties called qualia , subjective qualities that you ca n't accurately describe or measure . qualia are unique to the person experiencing them , like having an itch , being in love , or feeling bored . physical facts ca n't completely explain mental states like this . philosophers interested in artificial intelligence have used the knowledge argument to theorize that recreating a physical state wo n't necessarily recreate a corresponding mental state . in other words , building a computer which mimicked the function of every single neuron of the human brain wo n't necessarily create a conscious computerized brain . not all philosophers agree that the mary 's room experiment is useful . some argue that her extensive knowledge of color vision would have allowed her to create the same mental state produced by actually seeing the color . the screen malfunction would n't show her anything new . others say that her knowledge was never complete in the first place because it was based only on those physical facts that can be conveyed in words . years after he proposed it , jackson actually reversed his own stance on his thought experiment . he decided that even mary 's experience of seeing red still does correspond to a measurable physical event in the brain , not unknowable qualia beyond physical explanation . but there still is n't a definitive answer to the question of whether mary would learn anything new when she sees the apple . could it be that there are fundamental limits to what we can know about something we ca n't experience ? and would this mean there are certain aspects of the universe that lie permanently beyond our comprehension ? or will science and philosophy allow us to overcome our mind 's limitations ?
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for instance , we could know every physical detail about the structure and function of someone else 's brain , but still not understand what it feels like to be that person . these ineffable experiences have properties called qualia , subjective qualities that you ca n't accurately describe or measure . qualia are unique to the person experiencing them , like having an itch , being in love , or feeling bored .
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what is the philosophical term for ineffable properties of experiences ?
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dating back at least to the time of socrates , some early societies decided that certain disputes , such as whether a person committed a particular crime , should be heard by a group of citizens . several centuries later , trial by jury was introduced to england , where it became a fundamental feature of the legal system , checking the government and involving citizens in decision-making . juries decided whether defendants would be tried on crimes , determined whether the accused defendants were guilty , and resolved monetary disputes . while the american colonies eventually cast off england 's rule , its legal tradition of the jury persisted . the united states constitution instructed a grand jury to decide whether criminal cases proceeded , required a jury to try all crimes , except impeachment , and provided for juries in civil cases as well . yet , in the us today , grand juries often are not convened , and juries decide less than 4 % of criminal cases and less than 1 % of civil cases filed in court . that 's at the same time as jury systems in other countries are growing . so what happened in the u.s. ? part of the story lies in how the supreme court has interpreted the constitution . it 's permitted plea bargaining , which now occurs in almost every criminal case . the way it works is the prosecutor presents the accused with a decision of whether to plead guilty . if they accept the plea , the case wo n't go in front of a jury , but they 'll receive a shorter prison sentence than they 'd get if a jury did convict them . the risk of a much greater prison sentence after a trial can frighten even an innocent defendant into taking a plea . between the 19th century and the 21st century , the proportion of guilty pleas has increased from around 20 % to 90 % , and the numbers continue to grow . the supreme court has permitted the use of another procedure that interferes with the jury called summary judgement . using summary judgement , judges can decide that civil trials are unnecessary if the people who sue have insufficient evidence . this is intended only for cases where no reasonable jury would disagree . that 's a difficult thing to determine , yet usage of summary judgement has stretched to the point where some would argue it 's being abused . for instance , judges grant fully , or in part , over 70 % of employers ' requests to dismiss employment discrimination cases . in other cases , both the person who sues and the person who defends forgo their right to go to court , instead resolving their dispute through a professional arbitrator . these are generally lawyers , professors , or former judges . arbitration can be a smart decision by both parties to avoid the requirements of a trial in court , but it 's often agreed to unwittingly when people sign contracts like employment applications and consumer agreements . that can become a problem . for example , some arbitrators may be biased towards the companies that give them cases . these are just some of the ways in which juries have disappeared . but could the disappearance of juries be a good thing ? well , juries are n't perfect . they 're costly , time-consuming , and may make errors . and they 're not always necessary , like when people can simply agree to settle their disputes . but juries have their advantages . when properly selected , jurors are more representative of the general population and do n't have the same incentives as prosecutors , legislators , or judges seeking reelection or promotion . the founders of the united states trusted in the wisdom of impartial groups of citizens to check the power of all three branches of government . and the jury trial itself has given ordinary citizens a central role in upholding the social fabric . so will the jury system in the u.s. survive into the future ?
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while the american colonies eventually cast off england 's rule , its legal tradition of the jury persisted . the united states constitution instructed a grand jury to decide whether criminal cases proceeded , required a jury to try all crimes , except impeachment , and provided for juries in civil cases as well . yet , in the us today , grand juries often are not convened , and juries decide less than 4 % of criminal cases and less than 1 % of civil cases filed in court . that 's at the same time as jury systems in other countries are growing .
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in the united states today , juries do not decide many cases . what reasons can be given for giving them more or less authority ?
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the year was 1816 . europe and north america had just been through a devastating series of wars , and a slow recovery seemed to be underway , but nature had other plans . after two years of poor harvests , the spring brought heavy rains and cold , flooding the rivers and causing crop failures from the british isles to switzerland . while odd-colored snow fell in italy and hungary , famine , food riots and disease epidemics ensued . meanwhile , new england was blanketed by a strange fog that would not disperse as the ground remained frozen well into june . in what came to be known as `` the year without a summer , '' some thought the apocalypse had begun . a mood captured in lord byron 's poem `` darkness '' : `` i had a dream which was not all a dream . the bright sun was extinguish 'd , and the stars did wander darkling in the eternal space , rayless , and pathless , and the icy earth swung blind and blackening in the moonless air ; morn came and went -- and came , and brought no day . '' they had no way of knowing that the real source of their misfortunes had occurred a year ago thousands of miles away . the 1815 eruption of mount tambora on the indonesian island of sumbawa was what is known as a supervolcano , characterized by a volume of erupted material , many times greater than that of ordinary volcanoes . and while the popular image of volcanic destruction is molten rock engulfing the surrounding land , far greater devastation is caused by what remains in the air . volcanic ash , dispersed by wind , can blanket the sky for days , while toxic gases , such as sulfur dioxide , react in the stratosphere , blocking out solar radiation and drastically cooling the atmosphere below . the resulting volcanic winter , along with other effects such as acid rain , can effect multiple continents , disrupting natural cycles and annihilating the plant life on which other organisms , including humans , depend . releasing nearly 160 cubic kilometers of rock , ash and gas , the mount tambora eruption was the largest in recorded history , causing as many as 90,000 deaths . but previous eruptions have been even more deadly . the 1600 eruption of peru 's huaynaputina is likely to have triggered the russian famine , that killed nearly two million , while more ancient eruptions have been blamed for major world events , such as the fall of the chinese xia dynasty , the disappearance of the minoan civilization , and even a genetic bottleneck in human evolution that may have resulted from all but a few thousand human beings being wiped out 70,000 years ago . one of the most dangerous types of supervolcano is an explosive caldera , formed when a volcanic mountain collapses after an eruption so large that the now-empty magma chamber can no longer support its weight . but though the above-ground volcano is gone , the underground volcanic activity continues . with no method of release , magma and volcanic gases continue to accumulate and expand underground , building up pressure until a massive and violent explosion becomes inevitable . and one of the largest active volcanic calderas lies right under yellowstone national park . the last time it erupted , 650,000 years ago , it covered much of north america in nearly two meters of ash and rock . scientists are currently monitoring the world 's active volcanoes , and procedures for predicting eruptions , conducting evacuations and diverting lava flows have improved over the years . but the massive scale and global reach of a supervolcano means that for many people there would be nowhere to run . fortunately , the current data shows no evidence of such an eruption occurring in the next few thousand years . but the idea of a sudden and unavoidable civilization-destroying apocalypse caused by events half a globe away will remain a powerful and terrifying vision . less fictional than we would like to believe . `` the winds were withered in the stagnant air , and the clouds perish 'd ; darkness had no need of aid from them -- she was the universe . '' - lord byron
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volcanic ash , dispersed by wind , can blanket the sky for days , while toxic gases , such as sulfur dioxide , react in the stratosphere , blocking out solar radiation and drastically cooling the atmosphere below . the resulting volcanic winter , along with other effects such as acid rain , can effect multiple continents , disrupting natural cycles and annihilating the plant life on which other organisms , including humans , depend . releasing nearly 160 cubic kilometers of rock , ash and gas , the mount tambora eruption was the largest in recorded history , causing as many as 90,000 deaths .
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which of the following contribute to a ‘ volcanic winter ’ ?
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translator : andrea mcdonough reviewer : bedirhan cinar it 's that time again . you need another internship to bolster your college applications . last year you worked at a local art museum , helping organize their collection and giving tours to visitors . this year , it 's going to be much more difficult . you want to work on an organic farm across the country in california . that 's your real passion . unfortunately , your friends ' list of contacts does n't include organic farmers . the same for your parents ' group of friends . they want to help you , but they simply do n't know of any internships in agriculture . the school counselor , she just laughed . to make your farming dreams come true , you 're going to have to press beyond your strong ties , people like your family and closest friends , and try tapping into your weaker ties . weak ties are a broader network , your friends of friends of friends . they 're important because they have access to resources that your strong ties do n't have . this works in both directions , by the way - you have access to resources that they do n't have . let 's say most people speak to three close friends on a regular basis . each time you reach beyond the next degree of contacts , you have access to three more people , like a tree that branches out three times per node , so you can look beyond your closest circles . during the last family get-together , did n't you hear that your aunt 's friend studied lighting with a nature photographer on the west coast ? in fact , you recall this because you saw a recent image by said photographer on the front cover of < i > the new york times < /i > . so , you email him and learn that the photographer 's wife 's cousin publishes a sustainability magazine , which employs a staff writer who pitches on a local baseball team with an umpire who , wait for it , is an organic farmer . bingo ! get ready to trade in those cuff links for some apple seeds , all because you reached out to your weak ties . that 's your key , remember ? every conversation is an opportunity . moreover , do n't wait for opportunity , make it happen . take kathryn minshew for example . she went from not knowing anyone at yahoo to three warm introductions to major executives in 30 days . here are her suggestions for three steps to networking . 1 - always say yes to invitations , even if it 's not clear what you 'll get out of the meeting . many of kathryn 's most productive relationships resulted from a meeting or call without a clear agenda . 2 - when you want something , broadcast it to everyone you meet . that does n't mean you beg everyone for help as soon as you meet them , but talk about what you 're trying to do . be excited , ask for feedback , and try to get them excited too . 3 - show up and often . be at the forefront of other 's minds when opportunities arise . you do n't want to be that person who only shows up when he needs something . be the one that people think of and want to reach out to when a new opportunity presents itself . so while networking may not be the most intuitive , or even for some of you introverts , the most comfortable skill , it 's a helpful tool to have as you think about getting a job , going to school , or most importantly , learning from others . good luck !
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translator : andrea mcdonough reviewer : bedirhan cinar it 's that time again . you need another internship to bolster your college applications .
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what makes someone memorable ?
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translator : bedirhan cinar why do we cringe when we hear `` shakespeare ? '' if you ask me , it 's usually because of his words . all those thines and thous and therefores and wherefore-art-thous can be more than a little annoying . but you have to wonder , why is he so popular ? why have his plays been made and remade more than any other playwright ? it 's because of his words . back in the late 1500s and early 1600s , that was the best tool that a person had , and there was a lot to talk about . however , most of it was pretty depressing . you know , with the black plague and all . shakespeare does use a lot of words . one of his most impressive accomplishments is his use of insults . they would unify the entire audience ; and no matter where you sat , you could laugh at what was going on onstage . words , specifically dialogue in a drama setting , are used for many different reasons : to set the mood of the scene , to give some more atmosphere to the setting , and to develop relationships between characters . insults do this in a very short and sharp way . let 's first go to `` hamlet . '' right before this dialogue , polonius is the father of ophelia , who is in love with prince hamlet . king claudius is trying to figure out why prince hamlet is acting so crazy since the king married prince hamlet 's mother . polonius offers to use his daughter to get information from prince hamlet . then we go into act ii scene 2 . polonius : `` do you know me , my lord ? '' hamlet : `` excellent well . you 're a fishmonger . '' polonius : `` not i , my lord . '' hamlet : `` then i would you were so honest a man . '' now , even if you did not know what `` fishmonger '' meant , you can use some contextual clues . one : polonius reacted in a negative way , so it must be bad . two : fish smell bad , so it must be bad . and three : `` monger '' just does n't sound like a good word . so from not even knowing the meaning , you 're beginning to construct some characterization of the relationship between hamlet and polonius , which was not good . but if you dig some more , `` fishmonger '' means a broker of some type , and in this setting , would mean like a pimp , like polonius is brokering out his daughter for money , which he is doing for the king 's favor . this allows you to see that hamlet is not as crazy as he 's claiming to be , and intensifies the animosity between these two characters . want another example ? `` romeo and juliet '' has some of the best insults of any of shakespeare 's plays . it 's a play about two gangs , and the star-crossed lovers that take their own lives . well , with any fisticuffs you know that there is some serious smack talk going on . and you are not disappointed . in act i scene 1 , right from the get-go we are shown the level of distrust and hatred the members of the two families , the capulets and montagues , meet . gregory : `` i will frown as i pass by , and let them take it as they list . '' sampson : `` nay , as they dare , i will bite my thumb at them , which is a disgrace to them , if they bear it . '' enter abraham and balthasar . abraham : `` do you bite your thumb at us , sir ? '' sampson : `` i do bite my thumb , sir . '' abraham : `` do you bite your thumb at us , sir ? '' okay , so how does this development help us understand mood or character ? well , let 's break it down to the insult . biting your thumb today may not seem like a big deal , but sampson says it is an insult to them . if they take it so , it must have been one . this begins to show us the level of animosity between even the men who work for the two houses . and you normally would not do anything to someone unless you wanted to provoke them into a fight , which is exactly what 's about to happen . looking deeper , biting your thumb in the time in which the play was written is like giving someone the finger today . a pretty strong feeling comes with that , so we now are beginning to feel the tension in the scene . later on in the scene , tybalt , from the house of the capulets , lays a good one on benvolio from the house of the montagues . tybalt : `` what , art thou drawn among these heartless hinds ? turn thee , benvolio , and look upon thy death . '' benvolio : `` i do but keep the peace ; put up thy sword , or manage it to part these men with me . '' tybalt : `` what , drawn and talk of peace ! i hate the word , as i hate hell , all montagues , and thee . have at thee , coward ! '' okay , heartless hinds . we know that once again , it 's not a good thing . both families hate each other , and this is just adding fuel to the fire . but just how bad is this stinger ? a heartless hind is a coward , and calling someone that in front of his own men , and the rival family , means there 's going to be a fight . tybalt basically calls out benvolio , and in order to keep his honor , benvolio has to fight . this dialogue gives us a good look at the characterization between these two characters . tybalt thinks that the montagues are nothing but cowardly dogs , and has no respect for them . once again , adding dramatic tension to the scene . okay , now here 's a spoiler alert . tybalt 's hotheadedness and severe hatred of the montagues is what we literature people call his hamartia , or what causes his downfall . oh , yes . he goes down at the hands of romeo . so when you 're looking at shakespeare , stop and look at the words , because they really are trying to tell you something .
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polonius : `` do you know me , my lord ? '' hamlet : `` excellent well . you 're a fishmonger . ''
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theatre in the 1600 ’ s was very limited compared to the entertainment options available to writers and directors . to demonstrate your understanding of this , please select a scene from movie that you have seen in the past year and in a well developed paragraph , describe how it might have been laid out by shakespeare .
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what do fans of atmospheric post-punk music have in common with ancient barbarians ? not much . so why are both known as goths ? is it a weird coincidence or a deeper connection stretching across the centuries ? the story begins in ancient rome . as the roman empire expanded , it faced raids and invasions from the semi-nomadic populations along its borders . among the most powerful were a germanic people known as goths who were composed of two tribal groups , the visigoths and ostrogoths . while some of the germanic tribes remained rome 's enemies , the empire incorporated others into the imperial army . as the roman empire split in two , these tribal armies played larger roles in its defense and internal power struggles . in the 5th century , a mercenary revolt lead by a soldier named odoacer captured rome and deposed the western emperor . odoacer and his ostrogoth successor theoderic technically remained under the eastern emperor 's authority and maintained roman traditions . but the western empire would never be united again . its dominions fragmented into kingdoms ruled by goths and other germanic tribes who assimilated into local cultures , though many of their names still mark the map . this was the end of the classical period and the beginning of what many call the dark ages . although roman culture was never fully lost , its influence declined and new art styles arose focused on religious symbolism and allegory rather than proportion and realism . this shift extended to architecture with the construction of the abbey of saint denis in france in 1137 . pointed arches , flying buttresses , and large windows made the structure more skeletal and ornate . that emphasized its open , luminous interior rather than the sturdy walls and columns of classical buildings . over the next few centuries , this became a model for cathedrals throughout europe . but fashions change . with the italian renaissance 's renewed admiration for ancient greece and rome , the more recent style began to seem crude and inferior in comparison . writing in his 1550 book , `` lives of the artists , '' giorgio vasari was the first to describe it as gothic , a derogatory reference to the barbarians thought to have destroyed classical civilization . the name stuck , and soon came to describe the medieval period overall , with its associations of darkness , superstition , and simplicity . but time marched on , as did what was considered fashionable . in the 1700s , a period called the enlightenment came about , which valued scientific reason above all else . reacting against that , romantic authors like goethe and byron sought idealized visions of a past of natural landscapes and mysterious spiritual forces . here , the word gothic was repurposed again to describe a literary genre that emerged as a darker strain of romanticism . the term was first applied by horace walpole to his own 1764 novel , `` the castle of otranto '' as a reference to the plot and general atmosphere . many of the novel 's elements became genre staples inspiring classics and the countless movies they spawned . the gothic label belonged to literature and film until the 1970s when a new musical scene emerged . taking cues from artists like the doors and the velvet underground , british post-punk groups , like joy division , bauhaus , and the cure , combined gloomy lyrics and punk dissonance with imagery inspired by the victorian era , classic horror , and androgynous glam fashion . by the early 1980s , similar bands were consistently described as gothic rock by the music press , and the stye 's popularity brought it out of dimly lit clubs to major labels and mtv . and today , despite occasional negative media attention and stereotypes , gothic music and fashion continue as a strong underground phenomenon . they 've also branched into sub-genres , such as cybergoth , gothabilly , gothic metal , and even steampunk . the history of the word gothic is embedded in thousands of years worth of countercultural movements , from invading outsiders becoming kings to towering spires replacing solid columns to artists finding beauty in darkness . each step has seen a revolution of sorts and a tendency for civilization to reach into its past to reshape its present .
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here , the word gothic was repurposed again to describe a literary genre that emerged as a darker strain of romanticism . the term was first applied by horace walpole to his own 1764 novel , `` the castle of otranto '' as a reference to the plot and general atmosphere . many of the novel 's elements became genre staples inspiring classics and the countless movies they spawned .
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the first use of the term “ gothic ” in relation to literature was in reference to :
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i am sitting in the control room of the gsi institute , the control room of the linear accelerator that was used to create element 111 and five of the other super-heavy elements . the idea of this is that you have a metal target , usually lead or bismuth , elements 82 or 83 . and you take a lighter element , say copper and bang the copper at huge velocity into the lead or the bismuth , depending the element that you want to make . the idea is that you have to accelerate them very fast so that the two positively charged nuclei can come together . but not so fast that you have a lot of energy and they immediately fall apart again . ok , this is the periodic table of the elements that was used for the christening of element 111 which was called roentgenium . and you see you can remove this cube here and sigurd hofmann the head of the group who discovered the elements and our minister annette schavan together inserted the cube into the periodic table of the elements and it actually started to glow . oh it was an amazing day , we had a huge ceremony , 1000 people came here for the christening and afterwards there was cake and champagne and it was really good . element 111 has a name which is really difficult to pronounce - roentgenium which is named after rontgen the discoverer of x-rays . i just find that it is a combination of letters that people in england find difficult to pronounce . however rontgen was , i believe , the first nobel prize winner or one of the first nobel prize winners and so it is really quite fitting that he should have an element named after him . the first discovery was of three atoms , of this element and then the experiments were repeated , and another three were found , so it was relatively still relatively quite a small number , but it is really important when somebody does a series of these experiments that you have to repeat them to make sure that you have really seen what you think you want . you are really excited you want to make a new element and so it is quite easy to fool yourself . or sometimes people could be tempted to cheat so you really have to repeat it . ideally you get a different lab in a different place using a different route and if two people get the same results you are pretty sure . but in this case i think the two runs were repeated here and it was still a whole period of 10 or 12 years between the discovery of the element and it being finally named . because people want to be absolutely sure that the data are correct . the machines that makes these ions is enormous and it takes a whole team of operators to control it . and all this stuff behind me is to control the power , the voltages and so on , and the different parts of the accelerator that takes the ion beam to this tiny chamber . it is really only about this size , where the actual experiment took place and once the atom is made it then flies off to the detector that is two rooms away down a long tube . yeah , of course we are waiting now for the final confirmation to christen element 112 which is going to be copernicium , but well we don ’ t know yet what we are going to do for the christening . we are having discussions what we are going to do and i think it will be a big surprise .
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i just find that it is a combination of letters that people in england find difficult to pronounce . however rontgen was , i believe , the first nobel prize winner or one of the first nobel prize winners and so it is really quite fitting that he should have an element named after him . the first discovery was of three atoms , of this element and then the experiments were repeated , and another three were found , so it was relatively still relatively quite a small number , but it is really important when somebody does a series of these experiments that you have to repeat them to make sure that you have really seen what you think you want .
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roentgen was the first scientist to be awarded the nobel prize in physics . when was that ?
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translator : jessica ruby reviewer : caroline cristal you may not realize it , but from the moment you got out of bed today to the point where you sat down to watch this video , you 've essentially been swimming . why ? because air is a fluid just like water . it has waves and eddies . it flows . and when you push air out of the way , it rushes around you into a wake . so why do n't we notice it most of the time ? we commonly think of air as empty space . but while one cubic centimeter of interstellar space , the volume in the tip of your pinky finger , contains roughly one atom , the same volume of air has about 10 quintillion molecules . if that sounds hard to wrap your head around , it happens to be about the same as the number of insects alive on the planet , all crawling , climbing , and flying over each other in an enormous , tightly packed swarm . when this swarm of molecules runs into things , it exerts a force , pressing against the boundaries of the fluid , like water pressing against the glass of a bottle . this is known as air pressure . and while air is lighter than water , all those molecules still get pretty heavy , with the total air filling a typical school gym , weighing about as much as an adult elephant . so when you walk into a gym , how come you 're not immediately crushed by the elephant of air in the room ? well , first of all , because most of it is pressing on the floor and the walls , and the part that is pressing on you is pushed back by the pressure inside you ! you see , the air , as well as the water and everything else , that fills our bodies exerts an amount of pressure equal to that of the air outside . of course , this is no accident . it 's precisely what allows us to survive in the normal atmosphere , and what makes it more difficult at high altitudes or deep water . and we normally do n't feel the air pressing on us because it 's generally uniform . so even though different amounts of air molecules are hitting you at different times , the swarm is so thick that all those little differences average out . what happens when air pressure is n't uniform ? this means that the molecules are pushing harder in one region of air than another , driving the air flow from the higher pressure region to the lower . we feel this flow directly as wind , and the pressure systems that meteorologists are always going on about are responsible for other weather changes , from the mundane to the catastrophic . but differences in air pressure do more than just let us complain about the weather ; they 're the very reason we 're alive . we breathe by lowering the pressure in our lungs , allowing air to rush in . so the next time you take a deep breath , think of the unfathomable number of air molecules you 're commanding to move . we look up at the night sky to ponder the infinity of space , but unless you 're watching this video from that deep space , there are more air molecules in and around your body than there are grains of sand in all the world 's beaches and deserts , stars in the visible universe , or both of those numbers combined . the vastness of the universe is right in front of you and inside you .
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translator : jessica ruby reviewer : caroline cristal you may not realize it , but from the moment you got out of bed today to the point where you sat down to watch this video , you 've essentially been swimming . why ?
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if you filled a balloon on earth and brought it to the moon , it would ________ .
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