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you probably already know everything is made up of little tiny things called atoms or even that each atom is made up of even smaller particles called protons , neutrons and electrons . and you 've probably heard that atoms are small . but i bet you have n't ever thought about how small atoms really are . well , the answer is that they are really , really small . so you ask , just how small are atoms ? to understand this , let 's ask this question : how many atoms are in a grapefruit ? well , let 's assume that the grapefruit is made up of only nitrogen atoms , which is n't at all true , but there are nitrogen atoms in a grapefruit . to help you visualize this , let 's blow up each of the atoms to the size of a blueberry . and then how big would the grapefruit have to be ? it would have to be the same size of -- well , actually , the earth . that 's crazy ! you mean to say that if i filled the earth with blueberries , i would have the same number of nitrogen atoms as a grapefruit ? that 's right ! so how big is the atom ? well , it 's really , really small ! and you know what ? it gets even more crazy . let 's now look inside of each atom -- and thus the blueberry , right ? -- what do you see there ? in the center of the atom is something called the nucleus , which contains protons and neutrons , and on the outside , you 'd see electrons . so how big is the nucleus ? if atoms are like blueberries in the earth , how big would the nucleus be ? you might remember the old pictures of the atom from science class , where you saw this tiny dot on the page with an arrow pointing to the nucleus . well , those pictures , they 're not drawn to scale , so they 're kind of wrong . so how big is the nucleus ? so if you popped open the blueberry and were searching for the nucleus ... you know what ? it would be invisible . it 's too small to see ! ok. let 's blow up the atom -- the blueberry -- to the size of a house . so imagine a ball that is as tall as a two-story house . let 's look for the nucleus in the center of the atom . and do you know what ? it would just barely be visible . so to get our minds wrapped around how big the nucleus is , we need to blow up the blueberry , up to the size of a football stadium . so imagine a ball the size of a football stadium , and right smack dab in the center of the atom , you would find the nucleus , and you could see it ! and it would be the size of a small marble . and there 's more , if i have n't blown your mind by now . let 's consider the atom some more . it contains protons , neutrons and electrons . the protons and neutrons live inside of the nucleus , and contain almost all of the mass of the atom . way on the edge are the electrons . so if an atom is like a ball the size of a football stadium , with the nucleus in the center , and the electrons on the edge , what is in between the nucleus and the electrons ? surprisingly , the answer is empty space . ( wind noise ) that 's right . empty ! between the nucleus and the electrons , there are vast regions of empty space . now , technically there are some electromagnetic fields , but in terms of stuff , matter , it is empty . remember this vast region of empty space is inside the blueberry , which is inside the earth , which really are the atoms in the grapefruit . ok , one more thing , if i can even get more bizarre . since virtually all the mass of an atom is in the nucleus -- now , there is some amount of mass in the electrons , but most of it is in the nucleus -- how dense is the nucleus ? well , the answer is crazy . the density of a typical nucleus is four times 10 to the 17th kilograms per meter cubed . but that 's hard to visualize . ok , i 'll put it in english units . 2.5 times 10 to the 16th pounds per cubic feet . ok , that 's still kind of hard to figure . ok , here 's what i want you to do . make a box that is one foot by one foot by one foot . now let 's go and grab all of the nuclei from a typical car . now , cars on average weigh two tons . how many cars ' nuclei would you have to put into the box to have your one-foot-box have the same density of the nucleus ? is it one car ? two ? how about 100 ? nope , nope and nope . the answer is much bigger . it is 6.2 billion . that is almost equal to the number of people in the earth . so if everyone in the earth owned their own car -- and they do n't -- ( cars honking ) and we put all of those cars into your box ... that would be about the density of a nucleus . so i 'm saying that if you took every car in the world and put it into your one-foot box , you would have the density of one nucleus . ok , let 's review . the atom is really , really , really small . think atoms in a grapefruit like blueberries in the earth . the nucleus is crazy small . now look inside the blueberry , and blow it up to the size of a football stadium , and now the nucleus is a marble in the middle . the atom is made up of vast regions of empty space . that 's weird . the nucleus has a crazy-high density . think of putting all those cars in your one-foot box . i think i 'm tired .
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that 's right ! so how big is the atom ? well , it 's really , really small !
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do some research on dwarf stars . then comment on how the density of an atom is related to dwarf stars .
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how can you play a rubik 's cube ? not play with it , but play it like a piano ? that question does n't make a lot of sense at first , but an abstract mathematical field called group theory holds the answer , if you 'll bear with me . in math , a group is a particular collection of elements . that might be a set of integers , the face of a rubik 's cube , or anything , so long as they follow four specific rules , or axioms . axiom one : all group operations must be closed or restricted to only group elements . so in our square , for any operation you do , like turn it one way or the other , you 'll still wind up with an element of the group . axiom two : no matter where we put parentheses when we 're doing a single group operation , we still get the same result . in other words , if we turn our square right two times , then right once , that 's the same as once , then twice , or for numbers , one plus two is the same as two plus one . axiom three : for every operation , there 's an element of our group called the identity . when we apply it to any other element in our group , we still get that element . so for both turning the square and adding integers , our identity here is zero , not very exciting . axiom four : every group element has an element called its inverse also in the group . when the two are brought together using the group 's addition operation , they result in the identity element , zero , so they can be thought of as cancelling each other out . so that 's all well and good , but what 's the point of any of it ? well , when we get beyond these basic rules , some interesting properties emerge . for example , let 's expand our square back into a full-fledged rubik 's cube . this is still a group that satisfies all of our axioms , though now with considerably more elements and more operations . we can turn each row and column of each face . each position is called a permutation , and the more elements a group has , the more possible permutations there are . a rubik 's cube has more than 43 quintillion permutations , so trying to solve it randomly is n't going to work so well . however , using group theory we can analyze the cube and determine a sequence of permutations that will result in a solution . and , in fact , that 's exactly what most solvers do , even using a group theory notation indicating turns . and it 's not just good for puzzle solving . group theory is deeply embedded in music , as well . one way to visualize a chord is to write out all twelve musical notes and draw a square within them . we can start on any note , but let 's use c since it 's at the top . the resulting chord is called a diminished seventh chord . now this chord is a group whose elements are these four notes . the operation we can perform on it is to shift the bottom note to the top . in music that 's called an inversion , and it 's the equivalent of addition from earlier . each inversion changes the sound of the chord , but it never stops being a c diminished seventh . in other words , it satisfies axiom one . composers use inversions to manipulate a sequence of chords and avoid a blocky , awkward sounding progression . on a musical staff , an inversion looks like this . but we can also overlay it onto our square and get this . so , if you were to cover your entire rubik 's cube with notes such that every face of the solved cube is a harmonious chord , you could express the solution as a chord progression that gradually moves from discordance to harmony and play the rubik 's cube , if that 's your thing .
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so for both turning the square and adding integers , our identity here is zero , not very exciting . axiom four : every group element has an element called its inverse also in the group . when the two are brought together using the group 's addition operation , they result in the identity element , zero , so they can be thought of as cancelling each other out . so that 's all well and good , but what 's the point of any of it ?
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in a group containing the integers 0 , 1 , 2 , and 3 and using addition as the operation , 3 + 3 = _____
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using the word shakespeare within any classroom in the 21st century has become almost as dangerous for teachers as putting balloons in a toaster . after uttering this simple word , the common teacher is met with a mass of groans , moans , devastated looks , and the occasional chair tossed in his or her direction . but shakespearean works are not boring , confusing , long and painful plays written more than 400 years ago . they 're adventures relating to the extremities of human nature : love , hate , jealousy , zealous ambition , fear , mistrust , deception , and murder . we owe much of our own language to his invention . he invented over 2,000 words for use in his plays , which still remain in the oxford english dictionary . words like `` countless '' and `` assassination '' as well as phrases like `` one fell swoop , '' `` foul play , '' and even `` to be in a pickle '' all originated from william 's brilliant brain . and there are many echoes of shakespeare 's romantic language too . if you read < em > romeo and juliet < /em > , you 'll come across sentences like , `` she doth teach the torches to burn bright , '' and , `` so shows a snowy dove trooping with crows . '' both are quite clever metaphors , suggesting that juliet is both exceptionally beautiful and far moreso than anyone else . `` for thou art as glorious to this night , being o'er my head , as is a winged messenger of heaven , '' is a simile suggesting angelic qualities of the lady in question . this is not too different from today 's comments like , `` hey , beautiful ! '' and , `` you 're the hottest girl in the room . '' shakespeare also uses slightly more complex metaphors to describe the intentions of a mischievous man . for instance , `` this holy shrine , the gentle sin is this : my lips , two blushing pilgrims , ready stand to smooth that rough touch with a tender kiss , '' essentially means , `` i wish to kiss you . '' such male intentions were not limited to simple pecks on the cheek either . an intentional ambiguity was often used as a cheeky means to proposition marriage or a more intimate relationship . therefore , instead of viewing shakespearean works as out-dated , boring , and unhelpful , start reading today and discover the best ways to get the one you love to love you back .
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shakespeare also uses slightly more complex metaphors to describe the intentions of a mischievous man . for instance , `` this holy shrine , the gentle sin is this : my lips , two blushing pilgrims , ready stand to smooth that rough touch with a tender kiss , '' essentially means , `` i wish to kiss you . '' such male intentions were not limited to simple pecks on the cheek either .
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`` this holy shrine , the gentle sin is this my lips , two blushing pilgrims , ready stand to smooth that rough touch with a tender kiss '' means : _______ .
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three and a half thousand years ago in egypt , a noble pharaoh was the victim of a violent attack . but the attack was not physical . this royal had been dead for 20 years . the attack was historical , an act of damnatio memoriae , the damnation of memory . somebody smashed the pharaoh 's statues , took a chisel and attempted to erase the pharaoh 's name and image from history . who was this pharaoh , and what was behind the attack ? here 's the key : the pharaoh hatshepsut was a woman . in the normal course of things , she should never have been pharaoh . although it was legal for a woman to be a monarch , it disturbed some essential egyptian beliefs . firstly , the pharaoh was known as the living embodiment of the male god horus . secondly , disturbance to the tradition of rule by men was a serious challenge to maat , a word for `` truth , '' expressing a belief in order and justice , vital to the egyptians . hatshepsut had perhaps tried to adapt to this belief in the link between order and patriarchy through her titles . she took the name maatkare , and sometimes referred to herself as hatshepsu , with a masculine word ending . but apparently , these efforts did n't convince everyone , and perhaps someone erased hatshepsut 's image so that the world would forget the disturbance to maat , and egypt could be balanced again . hatshepsut , moreover , was not the legitimate heir to the thrown , but a regent , a kind of stand-in co-monarch . the egyptian kingship traditionally passed from father to son . it passed from thutmose i to his son thutmose ii , hatshepsut 's husband . it should have passed from thutmose ii directly to his son thutmose iii , but thutmose iii was a little boy when his father died . hatshepsut , the dead pharaoh 's chief wife and widow , stepped in to help as her stepson 's regent but ended up ruling beside him as a fully fledged pharaoh . perhaps thutmose iii was angry about this . perhaps he was the one who erased her images . it 's also possible that someone wanted to dishonor hatshepsut because she was a bad pharaoh . but the evidence suggests she was actually pretty good . she competently fulfilled the traditional roles of the office . she was a great builder . her mortuary temple , djeser-djeseru , was an architectural phenomenon at the time and is still admired today . she enhanced the economy of egypt , conducting a very successful trade mission to the distant land of punt . she had strong religious connections . she even claimed to be the daughter of the state god , amun . and she had a successful military career , with a nubian campaign , and claims she fought alongside her soldiers in battle . of course , we have to be careful when we assess the success of hatshepsut 's career , since most of the evidence was written by hatshepsut herself . she tells her own story in pictures and writing on the walls of her mortuary temple and the red chapel she built for amun . so who committed the crimes against hatshepsut 's memory ? the most popular suspect is her stepson , nephew and co-ruler , thutmose iii . did he do it out of anger because she stole his throne ? this is unlikely since the damage was n't done until 20 years after hatshepsut died . that 's a long time to hang onto anger and then act in a rage . maybe thutmose iii did it to make his own reign look stronger . but it is most likely that he or someone else erased the images so that people would forget that a woman ever sat on egypt 's throne . this gender anomaly was simply too much of a threat to maat and had to be obliterated from history . happily , the ancient censors were not quite thorough enough . enough evidence survived for us to piece together what happened , so the story of this unique powerful woman can now be told .
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but it is most likely that he or someone else erased the images so that people would forget that a woman ever sat on egypt 's throne . this gender anomaly was simply too much of a threat to maat and had to be obliterated from history . happily , the ancient censors were not quite thorough enough .
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what is maat ?
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deep underground lies stores of once inaccessible natural gas . this gas was likely formed over millions of years as layers of decaying organisms were exposed to intense heat and pressure under the earth 's crust . there 's a technology called hydraulic fracturing , or fracking , that can extract this natural gas , potentially powering us for decades to come . so how does fracking work , and why it is a source of such heated controversy ? a fracking site can be anywhere with natural gas , from a remote desert to several hundred feet from your backyard . it starts out with a long vertical hole known as a wellbore drilled down through layers of sediment . when the well reaches 2500 - 3000 meters , it 's at its kickoff point where it can begin the process of horizontal drilling . it turns 90 degrees and extends horizontally for about 1.5 kilometers through a compressed black layer called the shale rock formation . a specialized perforating gun is then lowered and fired , creating a series of small , inch-long holes that burst through the well 's casing into the rock layer . about three to four months after the initial drilling , the well is ready for fracking to begin . fracking fluid is pumped down into the well at a pressure so high , it cracks the shale rock , creating fractures through which the trapped gas and oil can escape . the fluid itself is more than 90 % water . the rest is made up of concentrated chemical additives . these vary depending on the specific characteristics of the fracking site , but usually fall into three categories : acids for clearing debris and dissolving minerals , friction-reducing compounds to create a slippery form of water known as slickwater , and disinfectant to prevent bacteria growth . sand or clay is also mixed into the water to prop open the fissures so the gas and oil can keep leaking out , even after the pressure is released . it 's estimated that all of fracking 's intense pumping and flushing uses an average of 3-6 million gallons of water per well . that 's actually not a lot compared to agriculture , power plants , or even golf course maintenance , but it can have a notable impact on local water supply . and disposing of used fracking water is also an issue . along with the trapped gas that 's pumped up to the surface , millions of gallons of flow-back liquid come gushing up . this liquid containing contaminants like radioactive material , salts , heavy metals , and hydrocarbons , needs to be stored and disposed of . that 's usually done in pits on-site in deep wells or off-site at water treatment facilities . another option is to recycle the flow-back liquid , but the recycling process can actually increase levels of contamination since the water is more toxic with each use . wells are typically encased in steel and cement to prevent contaminants from leaking into groundwater . but any negligence or fracking-related accidents can have devastating effects . fracturing directly into underground water hazardous underground seepage and leakage , and inadequate treatment and disposal of highly-toxic waste water can potentially contaminate drinking water around a fracking site . there 's also concern about the threat of earthquakes and damaged infrastructure from pressure and waste water injection . links between fracking and increased seismic activity leave unresolved questions about long-term pressure imbalances that might be happening deep beneath our feet . fracking 's biggest controversy , though , is happening above the ground . the general consensus is that burning natural gas is better for the environment than burning coal since the gas collected from fracking emits only half the carbon dioxide as coal per unit of energy . the pollution caused by the fracking itself , though , is n't negligible . methane that leaks out during the drilling and pumping process is many times more potent than carbon dioxide as a greenhouse gas . some scientists argue that methane eventually dissipates , so has a relatively low long-term impact . but a greater question hangs in the air . does fracking take time , money , and research away from the development of cleaner renewable energy sources ? natural gas is non-renewable , and the short-run economic interests supporting fracking may fall short in the face of global climate change . experts are still examining fracking 's overarching effects . although modern fracking has been around since the 1940s , it 's boomed in the last few decades . as other sources of natural gas decrease , the costs of non-renewable energies rise , and cutting-edge technologies make it so accessible . but many countries and regions have already banned fracking in response to environmental concerns . it 's undeniable that fracking has reshaped the energy landscape around the world , but for what long-term benefit and at what cost ?
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that 's actually not a lot compared to agriculture , power plants , or even golf course maintenance , but it can have a notable impact on local water supply . and disposing of used fracking water is also an issue . along with the trapped gas that 's pumped up to the surface , millions of gallons of flow-back liquid come gushing up .
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what are some concerns associated with the disposal of used fracking water ?
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what makes a good horror story ? sure , you could throw in some hideous monsters , fountains of blood , and things jumping out from every corner , but as classic horror author h.p . lovecraft wrote , `` the oldest and strongest kind of fear is fear of the unknown . '' and writers harness that fear not by revealing horrors , but by leaving the audience hanging in anticipation of them . that is , in a state of suspense . the most familiar examples of suspense come from horror films and mystery novels . what 's inside the haunted mansion ? which of the dinner guests is the murderer ? but suspense exists beyond these genres . will the hero save the day ? will the couple get together in the end ? and what is the dark secret that causes the main character so much pain ? the key to suspense is that it sets up a question , or several , that the audience hopes to get an answer to and delays that answer while maintaining their interest and keeping them guessing . so what are some techniques you can use to achieve this in your own writing ? limit the point of view . instead of an omniscient narrator who can see and relay everything that happens , tell the story from the perspective of the characters . they may start off knowing just as little as the audience does , and as they learn more , so do we . classic novels , like `` dracula , '' for example , are told through letters and diary entries where characters relate what they 've experienced and fear what 's to come . next , choose the right setting and imagery . old mansions or castles with winding halls and secret passageways suggest that disturbing things are being concealed . nighttime , fog , and storms all play similar roles in limiting visibility and restricting characters ' movements . that 's why victorian london is such a popular setting . and even ordinary places and objects can be made sinister as in the gothic novel `` rebecca '' where the flowers at the protagonist 's new home are described as blood red . three : play with style and form . you can build suspense by carefully paying attention not just to what happens but how it 's conveyed and paced . edgar allan poe conveys the mental state of the narrator in `` the tell-tale heart '' with fragmented sentences that break off suddenly . and other short declarative sentences in the story create a mix of breathless speed and weighty pauses . on the screen , alfred hitchcock 's cinematography is known for its use of extended silences and shots of staircases to create a feeling of discomfort . four : use dramatic irony . you ca n't just keep the audience in the dark forever . sometimes , suspense is best served by revealing key parts of the big secret to the audience but not to the characters . this is a technique known as dramatic irony , where the mystery becomes not what will happen but when and how the characters will learn . in the classic play `` oedipus rex , '' the title character is unaware that he has killed his own father and married his mother . but the audience knows , and watching oedipus gradually learn the truth provides the story with its agonizing climax . and finally , the cliffhanger . beware of overusing this one . some consider it a cheap and easy trick , but it 's hard to deny its effectiveness . this is where a chapter , episode , volume , or season cuts off right before something crucial is revealed , or in the midst of a dangerous situation with a slim chance of hope . the wait , whether moments or years , makes us imagine possibilities about what could happen next , building extra suspense . the awful thing is almost always averted , creating a sense of closure and emotional release . but that does n't stop us from worrying and wondering the next time the protagonists face near-certain disaster .
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and writers harness that fear not by revealing horrors , but by leaving the audience hanging in anticipation of them . that is , in a state of suspense . the most familiar examples of suspense come from horror films and mystery novels .
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what is meant by the term ‘ a state of suspense ’ ?
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you 've probably heard of the human genome , the huge collection of genes inside each and every one of your cells . you probably also know that we 've sequenced the human genome , but what does that actually mean ? how do you sequence someone 's genome ? let 's back up a bit . what is a genome ? well , a genome is all the genes plus some extra that make up an organism . genes are made up of dna , and dna is made up of long , paired strands of a 's , t 's , c 's , and g 's . your genome is the code that your cells use to know how to behave . cells interacting together make tissues . tissues cooperating with each other make organs . organs cooperating with each other make an organism , you ! so , you are who you are in large part because of your genome . the first human genome was sequenced ten years ago and was no easy task . it took two decades to complete , required the effort of hundreds of scientists across dozens of countries , and cost over three billion dollars . but some day very soon , it will be possible to know the sequence of letters that make up your own personal genome all in a matter of minutes and for less than the cost of a pretty nice birthday present . how is that possible ? let 's take a closer look . knowing the sequence of the billions of letters that make up your genome is the goal of genome sequencing . a genome is both really , really big and very , very small . the individual letters of dna , the a 's , t 's , g 's , and c 's , are only eight or ten atoms wide , and they 're all packed together into a clump , like a ball of yarn . so , to get all that information out of that tiny space , scientists first have to break the long string of dna down into smaller pieces . each of these pieces is then separated in space and sequenced individually , but how ? it 's helpful to remember that dna binds to other dna if the sequences are the exact opposite of each other . a 's bind to t 's , and t 's bind to a 's . g 's bind to c 's , and c 's to g 's . if the a-t-g-c sequence of two pieces of dna are exact opposites , they stick together . because the genome pieces are so very small , we need some way to increase the signal we can detect from each of the individual letters . in the most common method , scientists use enzymes to make thousands of copies of each genome piece . so , we now have thousands of replicas of each of the genome pieces , all with the same sequence of a 's , t 's , g 's , and c 's . but we have to read them all somehow . to do this , we need to make a batch of special letters , each with a distinct color . a mixture of these special colored letters and enzymes are then added to the genome we 're trying to read . at each spot on the genome , one of the special letters binds to its opposite letter , so we now have a double-stranded piece of dna with a colorful spot at each letter . scientists then take pictures of each snippet of genome . seeing the order of the colors allows us to read the sequence . the sequences of each of these millions of pieces of dna are stitched together using computer programs to create a complete sequence of the entire genome . this is n't the only way to read the letter sequences of pieces of dna , but it 's one of the most common . of course , just reading the letters in the genome does n't tell us much . it 's kind of like looking through a book written in a language you do n't speak . you can recognize all the letters but still have no idea what 's going on . so , the next step is to decipher what the sequence means , how your genome and my genome are different . interpreting the genes of the genome is the part scientists are still working on . while not every difference is consequential , the sum of these differences is responsible for differences in how we look , what we like , how we act , and even how likely we are to get sick or respond to specific medicines . better understanding of how disparities between our genomes account for these differences is sure to change the way we think not only about how doctors treat their patients , but also how we treat each other .
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you probably also know that we 've sequenced the human genome , but what does that actually mean ? how do you sequence someone 's genome ? let 's back up a bit .
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why is it necessary to generate so much dna sequence data all at once when sequencing a genome ?
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if you think of culture as an iceberg , only a small fraction of it is visible . food , flags , and festivals , which are often talked about in schools , are the visible parts that we rightly celebrate . however , only when we look deeper , under the water , are we able to focus on the common values that connect us . in what seems to be an increasingly troubled world , where social and political systems are being stretched , conflict within and between countries is at times heightened , while human rights are being ignored , this desire for peace grows ever stronger . sometimes we see this common value emerging above the surface and becoming visible . for example , it is part of everyday language used when people greet one another and welcome the new day . in many parts of the arab world and parts of south asia , such as bangladesh for example , the greeting of `` as-salamu alaykum '' can be translated to `` peace be with you . '' the same is true as you walk through markets or into schools each morning in india , or nepal , or bhutan , where greetings of `` namaste , '' which has not only a strong message of peace - `` the spirit in me greets the spirit in you '' - but also its physical gesture , the palms brought together slowly at the heart , to honor a special place in each of us . in myanmar , greetings of `` mingalarbar '' are met by bowing monks as they internalize a message where others add blessing to enhance the auspiciousness of the moment , or by giggling children as they scurry off to school . after many hours of hiking through the mountains of lesotho , surrounded by the tranquility and rugged terrain , you are likely to meet a herdboy who has slept the night in a vacant rondoval and bellows out greetings of `` lumela '' or `` khotso '' , which means `` peace be with you . '' if you took a moment to research further the meanings behind `` shalom , '' or the korean greeting , you would find that they too have deeply-seated connections to peace . however , they have become quick comments made to welcome , greet , and say hello , and in this overuse , have likely lost the focus that was originally intended when put into practice hundreds or thousands of years ago . in highlighting this simple evidence of ingrained behavior , we can create the necessary shift in thinking needed to incorporate flexibility and open-mindedness in us all when looking at the globalization of the world .
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if you think of culture as an iceberg , only a small fraction of it is visible . food , flags , and festivals , which are often talked about in schools , are the visible parts that we rightly celebrate . however , only when we look deeper , under the water , are we able to focus on the common values that connect us .
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jenkins lists three visible representations of culture that we most often celebrate . which of the things listed below is not included in her list ?
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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 .
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plants in the wild also sometimes get spots and infections . how do you think pathogens might spread differently in the wild compared to in an agricultural setting ?
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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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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 .
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true or false ? in the big rip scenario galaxies , black holes , stars , and planets are ripped apart and die .
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whether you ’ re swimming or washing the dishes or just taking nice , long , well-deserved bath -- - if you ’ re immersed in water for longer than 10 minutes , chances are your fingers and toes will emerge looking like raisins . so what ’ s up with the wrinkled digits ? for years , scientists thought the phenomenon was the result of a type of osmosis , caused by water passing into the dry outer layer of skin . the influx of water , the thinking went , would expand the skin ’ s surface area , but not the tissue below it , so the skin would bunch up and wrinkle . but in 1935 , a pair of doctors noticed that this effect didn ’ t happen in their patients with nerve damage . one patient , for example , was a boy who had lost the feeling in three of his fingers . the researchers found that , when his hand got wet , the fingers that he could feel wrinkled as normal , but the ones that were numb remained smooth . it turned out that pruney digits weren ’ t caused just by the passive flow of water through the skin -- it was an active response of the nervous system to prolonged moisture . the nervous system causes the wrinkling by constricting blood vessels below the skin , which causes the upper layers of skin to pucker . since the phenomenon is caused by an involuntary nerve response , some biologists have thought that it must have some evolutionary function . but what possible purpose could it serve ? one recent theory suggests that wrinkly skin may have given our ancestors a better grip while working in wet conditions -- like gathering food from a stream or damp vegetation . and it may also have given us better footing while walking across slippery landscapes in the rain . in a 2013 study , evolutionary biologists tested this theory by asking subjects with either wrinkly and non-wrinkly fingers to pick up a variety of wet and dry objects , like marbles . they found that the subjects with wrinkly digits picked up the wet objects 12 percent faster than their counterparts . but there was no difference when it came to picking up dry objects . the wrinkles apparently helped channel the water away , much like the treads on your car ’ s tires . but then this raises the question : if wrinkly skin gives us a better grip , then why isn ’ t our skin wrinkly all of the time ? well , maybe because shriveled fingers and toes are less sensitive , which is no advantage at all . thanks for asking ! and if you ’ d like to submit questions for us to answer , or get these quick questions a few days early , check out patreon.com/scishow . and don ’ t forget to go to youtube.com/scishow and subscribe !
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the nervous system causes the wrinkling by constricting blood vessels below the skin , which causes the upper layers of skin to pucker . since the phenomenon is caused by an involuntary nerve response , some biologists have thought that it must have some evolutionary function . but what possible purpose could it serve ?
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what did scientist think used to cause this phenomenon ?
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we 've all seen movies about terrible insects from outer space or stories of abduction by little green men , but the study of life in the universe , including the possibility of extraterrestrial life , is also a serious , scientific pursuit . astrobiology draws on diverse fields , such as physics , biology , astronomy , and geology , to study how life was formed on earth , how it could form elsewhere , and how we might detect it . many ancient religions described other worlds inhabited by known human beings , but these are more like mythical realms or parallel universes than other planets existing in the same physical world . it is only within the last century that scientists have been able to seriously undertake the search for extraterrestrial life . we know that at the most basic level organisms on earth need three things : liquid water , a source of energy , and organic , carbon-based material . we also know that the earth is just the right distance from the sun , so as not to be either frozen or molten . so , planets within such a habitable range from their own stars may be able to support life . but while we used to think that life could only exist in such earth-like environments , one of the most amazing discoveries of astrobiology has been just how versatile life is . we now know that life can thrive in some of the most extreme environments that 'd be fatal for most known organisms . life is found everywhere , from black smoke of hydrothermal vents in the dark depths of earth 's oceans , to bubbling , hot , acidic springs on the flanks of volcanoes , to high up in the atmosphere . organisms that live in these challenging environments are called extremophiles , and they can survive at extremes of temperature , pressure , and radiation , as well as salinity , acidity , and limited availability of sunlight , water , or oxygen . what is most remarkable about these extremophiles is that they are found thriving in environments that mimic those on alien worlds . one of the most important of these worlds is our red and dusty neighbor , mars . today , astrobiologists are exploring places where life might once have existed on mars using nasa 's curiosity rover . one of these is gale crater , an impact crater created when a meteor hit the surface of mars nearly 3.8 billions years ago . evidence from orbit suggest past traces of water , which means the crater might once have supported life . planets are not the only places astrobiologists are looking at . for example , europa , one of the moons of jupiter , and enceladus and titan , two of saturn 's moons , are all exciting possibilities . although these moons are extremely cold and two are covered in thick ice , there is evidence of liquid oceans beneath the shell . could life be floating around in these oceans , or could it be living around black smoker vents at the bottom ? titan is particularly promising as it has an atmosphere and earth-like lakes , seas , and rivers flowing across the surface . it is very cold , however , too cold for liquid water , so these rivers may instead be flowing with liquid hydrocarbons such as methane and ethane . these are composed of hydrogen , and , more importantly , carbon , which is the basic building block of all life as we know it . so , could life be found in these lakes ? although instruments are being designed to study these distant worlds , it takes many years to build them and even longer to get them where they need to be . in the meantime , astrobiologists work in our own natural laboratory , the earth , to learn about all the weird and wonderful forms of life that can exist and to help us one day answer one of humanity 's oldest questions : are we alone ?
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one of the most important of these worlds is our red and dusty neighbor , mars . today , astrobiologists are exploring places where life might once have existed on mars using nasa 's curiosity rover . one of these is gale crater , an impact crater created when a meteor hit the surface of mars nearly 3.8 billions years ago . evidence from orbit suggest past traces of water , which means the crater might once have supported life .
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nasa ’ s curiosity rover is exploring gale crater , an impact crater created by a meteor 3.8 billion years ago . nasa chose the site because there are past traces of water . where else on mars might the rover want to explore to look for signs of life ?
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some of the best opportunities to learn are the moments in which we are perplexed . those moments in which you begin to wonder and question . these moments have happened throughout history . and have led to some truly amazing discoveries . take this story , for example . there once was a fellow named archimedes . he was born in 287 b.c . in the city of syracuse in sicily . he was a greek mathematician , physicist , engineer , inventor , and astronomer . one day , archimedes was summoned by the king of sicily to investigate if he had been cheated by a goldsmith . the king said he had given a goldsmith the exact amount of gold needed to make a crown . however , when the crown was ready , the king suspected that the goldsmith cheated and slipped some silver into the crown , keeping some of the gold for himself . the king asked archimedes to solve the problem . but there was a catch : he could n't do any damage to the crown . one day , while taking his bath , archimedes noticed that the water level in the bathtub rose and overflowed as he immersed himself into the tub . he suddenly realized that how much water was displaced depended on how much of his body was immersed . this discovery excited him so much that he jumped out of the tub and ran through the streets naked , shouting `` eureka ! '' which comes from the ancient greek meaning `` i found it . '' what did he find ? well , he found a way to solve the king 's problem . you see , archimedes needed to check the crown 's density to see if it was the same as the density of pure gold . density is a measure of an object 's mass divided by its volume . pure gold is very dense , while silver is less dense . so if there was silver in the crown , it would be less dense than if it were made of pure gold . but no matter what it was made of , the crown would be the same shape , which means the same volume . so if archimedes could measure the mass of the crown first , and then measure its volume , he could find out how dense it was . but it is not easy to measure a crown 's volume - it has an irregular shape , that 's different from a simple box or ball . you ca n't measure its size and multiply like you might for other shapes . the solution , archimedes realized , was to give the crown a bath . by placing it in water and seeing how much water was displaced , he could measure the volume , and he 'd calculate the density of the crown . if the crown was less dense than pure gold , then the goldsmith most definitely cheated the king . when archimedes went back to the king and did his test , the story says , he found that the goldsmith had indeed cheated the king , and slipped some silver in . these days , using the way an object displaces water to measure volume is called archimedes ' principle . the next time you take a bath , you can see archimedes ' principle in action , and maybe you 'll have a genius idea of your own .
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density is a measure of an object 's mass divided by its volume . pure gold is very dense , while silver is less dense . so if there was silver in the crown , it would be less dense than if it were made of pure gold .
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list five objects that you think are more dense than water . how will you test your prediction about the five objects ? how will you determine which objects are the most dense ?
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the dead coming back to life sounds scary . but for scientists , it can be a wonderful opportunity . of course , we 're not talking about zombies . rather , this particular opportunity came in the unlikely form of large , slow-moving fish called the coelacanth . this oddity dates back 360 million years , and was believed to have died out during the same mass extinction event that wiped out the dinosaurs 65 million years ago . to biologists and paleontologists , this creature was a very old and fascinating but entirely extinct fish , forever fossilized . that is , until 1938 when marjorie courtenay-latimer , a curator at a south african museum , came across a prehistoric looking , gleaming blue fish hauled up at the nearby docks . she had a hunch that this strange , 1.5 meter long specimen was important but could n't preserve it in time to be studied and had it taxidermied . when she finally was able to reach j.l.b . smith , a local fish expert , he was able to confirm , at first site , that the creature was indeed a coelacanth . but it was another 14 years before a live specimen was found in the comoros islands , allowing scientists to closely study a creature that had barely evolved in 300 million years . a living fossil . decades later , a second species was found near indonesia . the survival of creatures thought extinct for so long proved to be one of the biggest discoveries of the century . but the fact that the coelacanth came back from the dead is n't all that makes this fish so astounding . even more intriguing is the fact that genetically and morphologically , the coelacanth has more in common with four-limbed vertebrates than almost any other fish , and its smaller genome is ideal for study . this makes the coelacanth a powerful link between aquatic and land vertebrates , a living record of their transition from water to land millions of years ago . the secret to this transition is in the fins . while the majority of ocean fish fall into the category of ray-finned fishes , coelacanths are part of a much smaller , evolutionarily distinct group with thicker fins known as lobe-finned fish . six of the coelacanth 's fins contain bones organized much like our limbs , with one bone connecting the fin to the body , another two connecting the bone to the tip of the fin , and several small , finger-like bones at the tip . not only are those fins structured in pairs to move in a synchronized way , the coelacanth even shares the same genetic sequence that promotes limb development in land vertebrates . so although the coelacanth itself is n't a land-walker , its fins do resemble those of its close relatives who first hauled their bodies onto land with the help of these sturdy , flexible appendages , acting as an evolutionary bridge to the land lovers that followed . so that 's how this prehistoric fish helps explain the evolutionary movement of vertebrates from water to land . over millions of years , that transition led to the spread of all four-limbed animals , called tetrapods , like amphibians , birds , and even the mammals that are our ancestors . there 's even another powerful clue in that unlike most fish , coelacanths do n't lay eggs , instead giving birth to live , young pups , just like mammals . and this prehistoric fish will continue to provide us with fascinating information about the migration of vertebrates out of the ocean over 300 million years ago . a journey that ultimately drove our own evolution , survival and existence . today the coelacanth remains the symbol of the wondrous mysteries that remain to be uncovered by science . with so much left to learn about this fish , the ocean depths and evolution itself , who knows what other well-kept secrets our future discoveries may bring to life !
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but it was another 14 years before a live specimen was found in the comoros islands , allowing scientists to closely study a creature that had barely evolved in 300 million years . a living fossil . decades later , a second species was found near indonesia .
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what is so extraordinary about the discovery of the living coelacanth ?
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translator : ido dekkers reviewer : emma gon ( music ) every movie you 've ever seen , every tv show , every magazine , every time you surf the internet , you 're absorbing information , a bit like a sponge absorbs water . the words on the screen , the images , the colors , the sounds , the angle of the camera , every detail is designed to make you think , act or feel a certain way . your brain is subconsciously decoding images and sounds , and just by being alive today , by interacting with and reading all these different types of media , you 're already an expert at decoding and understanding these hidden messages . a set of codes and conventions that work together to make you feel happy , angry , afraid , excited . to make you want to buy a particular product -- a refreshing drink , a new phone . to style your hair a certain way . to cheer for the hero or boo the villain . welcome to the family tree of technical codes . so what constitutes a code ? first of all , it has to be recognized by all who read it . imagine a busy city where motorists do n't know how to read the traffic signals . we all have to know red equals stop , green means go , for the system to work . otherwise it would be chaos . secondly , codes are made meaningful by their context . we ca n't fully interpret or decipher a code until we see how it relates to other signs and symbols . look at these two intersecting lines . without any context , things around the code to help you understand or make meaning from it , it 's hard to know exactly what these lines represent . they could be a cross , symbolizing religion , an add sign , symbolizing a mathematical concept , the letter t from the alphabet , or they could just be two lines intersecting . if we add a crescent moon shape , and a circle with a line on it in front , the two lines now have a context , a relationship to their surroundings , and are magically revealed as the letter t. by adding additional information around the code , we 've changed its context , and therefore given it a concrete meaning . let 's meet the family . technical codes , senior has three sons : symbolic codes , written codes and technical codes , junior . symbolic codes has three sons : symbolic color , symbolic objects and symbolic animals . this branch of the family is all about representation . red represents hot or stop or danger , depending on its context . so if you see a red light above a yellow and a green light on a pole above the road , you know by this context that the light represents stop . written codes has three sons : you and only you , buzzwords and catchphrase . these guys are all about saying a lot with a little , or planting a word in your subconscious that triggers a response whenever you hear or read it . have you noticed how many times i 've said the word `` you ? '' you should feel like it 's directed specifically at you , and only you , that it 's addressing your needs and desire to learn about your world . if i tell you that all the cool , fresh and hip people are buying a new drink or wearing a particular brand , the buzzwords `` new , '' `` fresh '' or `` free '' make the product seem more interesting and appealing . if i wrap that product or idea in a simple phrase that 's easy to remember and becomes part of your everyday speech , then every time you hear or say those few words , your brain connects them to the product . so just do it , think different , and enjoy the power of the catchphrase . and technical codes , junior has three sons : camera angles , framing and lighting . for these boys , it 's all about how the camera is placed , how objects , people and places are shot , and what we see on screen -- or just as importantly , what we do n't see . when the camera is placed high above the subject , it makes you look small , insignificant and powerless . and the reverse is also true , when the camera is below . so is this video trying to manipulate you to buy something ? yes , an idea . the idea that understanding the relationship between technical codes and the role they play in shaping your understanding of the world around us through the media we consume is fun and interesting . is it trying to make you feel a certain way ? absolutely . every image , every word , has been carefully crafted to work together to make you feel positive about the idea that you need to be educated to engage with what you read , watch and listen to in movies , tv shows , magazines and on the internet . by understanding these codes , and how they work together to subconsciously change the way you think , feel and act towards products and ideas , you 'll be aware of these techniques and able to identify their impact on you . one of the most powerful advertising mediums in the world is word of mouth . if you 've ever recommended a product or movie , a service , or even a video online , then you 've played your part in passing the message . so soak all this information up . recognize how the family tree of technical codes works on you , and those around you , to make an impact find excellent examples , and spread the word .
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let 's meet the family . technical codes , senior has three sons : symbolic codes , written codes and technical codes , junior . symbolic codes has three sons : symbolic color , symbolic objects and symbolic animals .
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technical codes sr. has three sons . which of the following is not one of his sons ?
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so when i was taught as a student , i was taught by a chemist at cambridge school alfie maddock . who during the second world war was working in canada on plutonium chemistry . and one night he managed to spill the entire uk 's supply of plutonium . which was only 10 milligrams onto the bench in the lab . and so rather then saying 'oh dear i have spilt it ' , he went and got a saw and sawed a large chunk out of the bench , and burned the wood , and got back 9.5 of the 10 mg that he spilled . and nobody would have known except at that point , he was too tired to repair the bench . so they came down in the morning , and there was a large hole in the bench , to show what he had done . ok so plutonium . i think plutonium is quite well known for the fact its been used in certain types of nuclear bombs . it 's a fairly interesting element , it 's incredibly dense . if you hold a golf ball size shape of plutonium in your hand , it would weigh in excess of half a kilogram . which is one heavy golf ball . and if you were holding it , you would have to be holding it through several layers of gloves , at least one of which would be lead lined . and as you held it , it would be like having a really hot cup of tea in your hand . and that 's from the radioactivity coming out . just the shear heat of the radioactivity which you would be feeling . i also had an interesting experience with ... at a conference , i was sitting next to a lady , who i asked her why she was at the conference , which was about super critical fluids . high pressure gases , solvents . and i asked her why she was there and she said she worked with weapons grade plutonium . what is used in making atom bombs . and she said she was worried about the environmental effects of using chlorinated solvents . there are compounds of carbon and chlorine , for removing the greace from the plutonium that we are using to make the bombs . so she was at the conference to see whether you could use high pressure carbon dioxide or as an alternative to make the making of atomic bombs environmentally friendly . that was slightly macabre . worrying about the environment . i like that , wanting to make more environmentaly friendly bombs . i have not seen any because the sort of facilities you need to be able to handle it are way beyond what you find in a normal university . i 've had some fascinating stories about it , it 's incredibly dense . and a few people at the atomic weapons agency wanted to cut a little piece off , it took three of them with a hacksaw several hours , and several hacksaw blades , before they got a tiny little chip off . so it 's incredibly dense and hard . hence the high weight for its size . plutonium is quite a poisonous element , and there have been a number of cases . particularly the famous case in america , with karen silkwood , who was poisoned , or had traces of poisonous plutonium found in her refrigerator , and all through her flat . which in fact inspired my brother to write a play called `` stronger then the sun '' in the early 1970s . one of his first successful television films . perhaps a little known thing about plutonium , 'cause obviously it has a pretty bad image in terms of its use in nuclear weapons , is that it is what helped power the astronauts on the moon landings in the 60s and 70s . captions by www.subply.com
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it 's a fairly interesting element , it 's incredibly dense . if you hold a golf ball size shape of plutonium in your hand , it would weigh in excess of half a kilogram . which is one heavy golf ball . and if you were holding it , you would have to be holding it through several layers of gloves , at least one of which would be lead lined . and as you held it , it would be like having a really hot cup of tea in your hand .
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according to steve , if you held a sample of plutonium in your hand ( with several layers of gloves , of course ) , why would it feel so heavy ?
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in 2011 , a team of physicists reported a startling discovery : neutrinos traveled faster than the speed of light by 60 billionths of a second in their 730 kilometer trip from geneva to a detector in italy . despite six months of double checking , the bizarre discovery refused to yield . but rather than celebrating a physics revolution , the researchers published a cautious paper arguing for continued research in an effort to explain the observed anomaly . in time , the error was tracked to a single incorrectly connected fiber optic cable . this example reminds us that real science is more than static textbooks . instead , researchers around the world are continuously publishing their latest discoveries with each paper adding to the scientific conversation . published studies can motivate future research , inspire new products , and inform government policy . so it 's important that we have confidence in the published results . if their conclusions are wrong , we risk time , resources , and even our health in the pursuit of false leads . when findings are significant , they are frequently double-checked by other researchers , either by reanalyzing the data or by redoing the entire experiment . for example , it took repeated investigation of the cern data before the timing error was tracked down . unfortunately , there are currently neither the resources nor professional incentives to double check the more than 1 million scientific papers published annually . even when papers are challenged , the results are not reassuring . recent studies that examined dozens of published pharmaceutical papers managed to replicate the results of less than 25 % of them . and similar results have been found in other scientific disciplines . there are a variety of sources for irreproducible results . errors could hide in their original design , execution , or analysis of the data . unknown factors , such as patients ' undisclosed condition in a medical study , can produce results that are not repeatable in new test subjects . and sometimes , the second research group ca n't reproduce the original results simply because they do n't know exactly what the original group did . however , some problems might stem from systematic decisions in how we do science . researchers , the institutions that employ them , and the scientific journals that publish findings are expected to produce big results frequently . important papers can advance careers , generate media interest , and secure essential funding , so there 's slim motivation for researchers to challenge their own exciting results . in addition , little incentive exists to publish results unsupportive of the expected hypothesis . that results in a deluge of agreement between what was expected and what was found . in rare occasions , this can even lead to deliberate fabrication , such as in 2013 , when a researcher spiked rabbit blood with human blood to give false evidence that his hiv vaccine was working . the publish or perish mindset can also compromise academic journals ' traditional peer-review processes which are safety checks where experts examine submitted papers for potential shortcomings . the current system , which might involve only one or two reviewers , can be woefully ineffective . that was demonstrated in a 1998 study where eight weaknesses were deliberately inserted into papers , but only around 25 % were caught upon review . many scientists are working toward improving reproducibility in their fields . there 's a push to make researchers raw data , experimental procedures , and analytical techniques more openly available in order to ease replication efforts . the peer review process can also be strengthened to more efficiently weed out weak papers prior to publication . and we could temper the pressure to find big results by publishing more papers that fail to confirm the original hypothesis , an event that happens far more than current scientific literature suggests . science always has , and always will , encounter some false starts as part of the collective acquisition of new knowledge . finding ways to improve the reproducibility of our results can help us weed out those false starts more effectively , keeping us moving steadily toward exciting new discoveries .
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recent studies that examined dozens of published pharmaceutical papers managed to replicate the results of less than 25 % of them . and similar results have been found in other scientific disciplines . there are a variety of sources for irreproducible results .
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what steps does a scientist take in order to share her results with scientific community ?
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way before the first selfie , the ancient greeks and romans had a myth about someone a little too obsessed with his own image . in one telling , narcissus was a handsome guy wandering the world in search of someone to love . after rejecting a nymph named echo , he caught a glimpse of his own reflection in a river , and fell in love with it . unable to tear himself away , narcissus drowned . a flower marked the spot of where he died , and we call that flower the narcissus . the myth captures the basic idea of narcissism , elevated and sometimes detrimental self-involvement . but it 's not just a personality type that shows up in advice columns . it 's actually a set of traits classified and studied by psychologists . the psychological definition of narcissism is an inflated , grandiose self-image . to varying degrees , narcissists think they 're better looking , smarter , and more important than other people , and that they deserve special treatment . psychologists recognize two forms of narcissism as a personality trait : grandiose and vulnerable narcissism . there 's also narcissistic personality disorder , a more extreme form , which we 'll return to shortly . grandiose narcissism is the most familiar kind , characterized by extroversion , dominance , and attention seeking . grandiose narcissists pursue attention and power , sometimes as politicians , celebrities , or cultural leaders . of course , not everyone who pursues these positions of power is narcissistic . many do it for very positive reasons , like reaching their full potential , or helping make people 's lives better . but narcissistic individuals seek power for the status and attention that goes with it . meanwhile , vulnerable narcissists can be quiet and reserved . they have a strong sense of entitlement , but are easily threatened or slighted . in either case , the dark side of narcissism shows up over the long term . narcissists tend to act selfishly , so narcissistic leaders may make risky or unethical decisions , and narcissistic partners may be dishonest or unfaithful . when their rosy view of themselves is challenged , they can become resentful and aggressive . it 's like a disease where the sufferers feel pretty good , but the people around them suffer . taken to the extreme , this behavior is classified as a psychological disorder called narcissistic personality disorder . it affects one to two percent of the population , more commonly men . it is also a diagnosis reserved for adults . young people , especially children , can be very self-centered , but this might just be a normal part of development . the fifth edition of the american psychiatric association 's diagnostic and statistical manual describes several traits associated with narcissistic personality disorder . they include a grandiose view of oneself , problems with empathy , a sense of entitlement , and a need for admiration or attention . what makes these trait a true personality disorder is that they take over people 's lives and cause significant problems . imagine that instead of caring for your spouse or children , you used them as a source of attention or admiration . or imagine that instead of seeking constructive feedback about your performance , you instead told everyone who tried to help you that they were wrong . so what causes narcissism ? twin studies show a strong genetic component , although we do n't know which genes are involved . but environment matters , too . parents who put their child on a pedestal can foster grandiose narcissism . and cold , controlling parents can contribute to vulnerable narcissism . narcissism also seems to be higher in cultures that value individuality and self-promotion . in the united states , for example , narcissism as a personality trait has been rising since the 1970s , when the communal focus of the 60s gave way to the self-esteem movement and a rise in materialism . more recently , social media has multiplied the possibilities for self-promotion , though it 's worth noting that there 's no clear evidence that social media causes narcissism . rather , it provides narcissists a means to seek social status and attention . so can narcissists improve on those negative traits ? yes ! anything that promotes honest reflection on their own behavior and caring for others , like psychotherapy or practicing compassion towards others , can be helpful . the difficulty is it can be challenging for people with narcissistic personality disorder to keep working at self-betterment . for a narcissist , self-reflection is hard from an unflattering angle .
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to varying degrees , narcissists think they 're better looking , smarter , and more important than other people , and that they deserve special treatment . psychologists recognize two forms of narcissism as a personality trait : grandiose and vulnerable narcissism . there 's also narcissistic personality disorder , a more extreme form , which we 'll return to shortly .
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all narcissism is heritable , but grandiose narcissism is linked to ____ parenting whereas vulnerable narcissism is linked to ____ parenting .
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[ ♪sustained note♪ ] [ flag flapping in breeze ] [ path of freedom ] [ ♪ music ♪ ] [ prisoners chattering ] [ ♪ music ♪ ] - this is a tough guy world , and we have to control all of their movement and their behavior [ roberta richman - rhode island dept . of corrections ] because that 's the way you keep an institution safe for everybody who lives in it . [ ♪ music ♪ ] we have everybody here— murderers and rapists , sex offenders , drug addicts— everybody . [ 1 out of every 100 americans is currently behind bars ] my name is dennis . i 'm 52 years old . i 'm serving a 15-year sentence for assaulting my wife . my name is louis , 35 . i sold narcotics [ clears throat ] since i was about 13 or so . my name is juan . i 'm 34 years old . i 'm here for second degree murder . yeah . sadly , this is my charge . my name is celine . i 'm 39 . i 'll be 40 soon . i was given a life term . [ ♪ music ♪ ] a lot of times what lands people in prison [ fleet maull - prison mindfulness institute ] and what brings them back is a lack of good problem-solving skills and good communication skills . [ ♪ music ♪ ] [ richman ] fleet approached us asking if he could do some work in here . we were challenged . our union wanted to know how we could possibly bring an ex-offender in . [ maull ] i served 14½ years on a 25-year , no parole sentence . hello . [ ♪ music ♪ ] having served 14 years boosts his credibility— boosts his credibility with inmates . how 's your week been ? - it 's good . [ maull ] yeah ? good . what 's up ? yeah . hey . welcome . when i got locked up , i really hit a wall of just seeing the craziness of my life path up until then and the incredible selfish decisions i 'd been making . my son was 9 years old . he was going to grow up without his dad . and i was just so deeply full of remorse and regret that i just literally started practicing meditation like my hair was on fire . so i became extremely motivated to turn my life around . [ ♪ music ♪ ] and so i was living the life of this prison monk . [ ♪ music ♪ ] i was sourcing a meditation group twice a week in the chapel . [ ♪ music ♪ ] i started receiving letters from prisoners while i was in prison . i had published some articles ; people knew about me out in the world a little bit , and they started sending some of these letters to me thinking i would know what to do with them . i worked in the education department , and i had access to a copy machine . i would copy articles out of books , and i 'd put together a little thing and i 'd send it off to a prisoner . so it started off that way , and i decided it was a much bigger deal than i could do from my prison cells . i think we have a co-creative relationship with our life . we ca n't control other people , we do n't control life , but is there some relationship between what we put out and what comes back ? freedom before i came here was just another word . i had never been to prison before . all you know is what the media and the movies say about prison— `` take care of yourself , man . '' `` somebody 's going to try to take your manhood or something . '' you know what i mean ? i 'm thinking i 'm going to come in here and fight the world . [ maull ] in a prison like moran , there 's a serious conflict waiting around any corner . it 's an environment where people 's worst behaviors are just right there just under the surface . [ ♪ music ♪ ] when i first came in , i fought with officers , would beat up anyone , would do the unthinkable just because . [ dennis ] it 's a vicious cycle because once you come to prison your life just keeps tumbling , tumbling , tumbling , and it 's like a never-ending wall that wo n't stop building unless you find some way to get over that wall or at least in front of it . [ richman ] what circumstances did they have to survive on the street to bring them to where they are now ? do we want to save those lives , or do we want to discard them ? the crimes i committed , i brought shame to not only myself but to those who i love . so i 'm just really trying to do something to get out of that cycle . somebody 's given us an opportunity just to meditate and connect ourselves , and that 's golden . so sit up with that good posture , just rest your hands on your legs , and just take a moment to just feel . [ ♪ music ♪ ] [ richman ] i 've always thought that the people who survive are so much stronger than i could ever be . i asked fleet how he survived and thrived the way he has . he credits meditation for having given him the strength to live his life in prison and come out not as much the worse for wear as most people do . i do n't have a release date . so i can only go home when they decide i can . so i learned to live day by day , and that helped me to deal with prison , and i could only do that being in the moment , being in the now . [ ♪ music ♪ ] it 's like if i do n't like what 's going on , what can i do to shift it ? if i do n't like the relationship i have with my boss or with one of the cos or something , could i approach that person in a different way ? can i get creative about what i 'm doing to bring about a shift in the way things are— in other words , owning my own situation . so how do you resolve that ? i take a breath and then [ chuckles ] i step back . really , you have to . [ maull ] then suddenly get that there 's this whole thing there that they thought was who they are . that 's the only reality they knew . suddenly they get to step outside of that a little bit . you just see the lights go on . it 's like this sudden illumination . it 's like a mini enlightenment of sorts . and that 's very powerful . that 's what keeps me coming . the reality of it is i 'm living life , and meditation it has brought a new perspective in the way that it gave me like a tool to really look inside myself and change the way i am . [ richman ] people do n't understand the value of what they call the soft stuff , and i sometimes think without the soft stuff , no matter how much hard stuff you have , you 're bound to fail . you can live your life . you can be yourself . you can show others that this is n't a place to breed a better criminal ; this could actually be a place to breed a better person . you 're here because the way that you were did n't work . so why not be better ? [ prisoners chattering ] [ richman ] the people in prison are us . they 're not monsters . and more importantly , whether we want them to or not , they 're getting out . so do you want them to come out angrier and meaner and more dangerous than they were when they came in , or do you want to do whatever you can to change their behavior while they 're here ? we need people to see and experience prisoners stepping out of that culture and doing something transformative with their lives , and then people will start to have faith , people will see people coming back to their community and they realize these are human beings and that human beings ' lives have value and they 're not expendable . [ ♪ music ♪ ] [ this year 700,000 people will return home from prison ] [ ♪ music ♪ ] [ directed by emmanuel vaughan-lee , produced by dorothee royal-hedinger ] [ cinematography by elias koch , edited by adam loften , sound recording by emmanuel vaughan-lee ] [ music by h. scott salinas , sound mix by d. chris smith ] [ www.globalonenessproject.org ]
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so why not be better ? [ prisoners chattering ] [ richman ] the people in prison are us . they 're not monsters .
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how can prisoners benefit from this program ?
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a boy named prince tamino runs through a dark wood pursued by a dragon . just as it rears up to devour him , three mysterious ladies appear and slay the dragon with their fierce battle cry . so begins wolfgang amadeus mozart 's `` die zauberflöte , '' or `` the magic flute . '' this fantasy singspiel , a type of folk opera with music and dialogue , premiered in 1791 in vienna . though it may seem like a childish fairytale , this intricate opera is full of subversive symbolism , and it 's now regarded as one of the most influential operas in history . tamino 's run in with the dragon is only the start of his journey . the three women summon their leader , the queen of the night . she , in turn , sends tamino on a quest to rescue her daughter pamina from the evil sorcerer , sarastro . and to help him on his journey , she gives him the titular magic flute . tamino eventually finds pamina at sarastro 's temple , but behind enemy lines , tamino and pamina learn that they 're on the wrong side . the queen of night actually wants to plunge the world into darkness . everything tamino thought he knew was wrong , filling him with doubt and confusion . so , a new quest begins for tamino and pamina . they must pass three trials of wisdom , and only then can the day vanquish the night . helped by the flute 's magic power , the two youths overcome these trials and the queen 's attempts to sabotage them . they 're finally initiated into the temple having restored balance to the kingdom . many elements in this peculiar fairytale were inspired by mozart 's involvement in freemasonry , a network of fraternal organizations throughout europe . much of their history , symbolism , and ritual came from the middle ages . but the freemasons of mozart 's time were also influenced by 18th century european ideals - rationalism , humanism , and skepticism towards traditional authorities , like monarchy and the church . the symbols of freemasonry and these ideals of the enlightenment are found throughout the opera . if this sounds like a conspiracy theory , that 's because it sort of was at the time , but it 's now taken quite seriously and has been the subject of considerable scholarly publication . for example , some mozart scholars believe the queen of the night symbolizes maria theresa , the empress of the holy roman empire who opposed freemasonry and banned it in austria . while there continues to be debate as to the specific meaning , interpretation , and location of these masonic references , scholars agree that they 're there and are fully intentional . one of these symbols is the number three , which represented balance and order to freemasons . now the number three is , of course , easy to find in any work of storytelling , but it 's particularly prominent in `` the magic flute '' : three trials , three ladies , three spirits , and three doors , much of the music is written in e-flat major , which has three flats in its key signature , and historically , masonic rituals began with three knocks . the opera references them by opening with three majestic chords complete with dramatic pauses . those chords , which reoccur throughout the opera , serve another purpose . they capture the dramatic arc of the opera in miniature . the first chord , e-flat major , is in its most natural root position , simple and unadorned . it echoes the child-like prince tamino , who , in his naiveté , accepts everything the queen and her ladies say without question . the second chord is c minor , a sour sonority that mirrors tamino 's sadness and doubt in the middle of the opera . that 's when his world and notions of good and evil get turned on their heads . and good and evil are just two of the opera 's extreme opposites . it features some of the highest and lowest notes in opera , day and night , simple hummable melodies and complicated forward-looking music . the opera 's central theme concerns balancing these extremes to achieve perfect harmony . to reflect this , the final chord in the opening restores musical order . it returns to the triumphant e-flat major , the same chord it started with but inverted , meaning mozart moved the bottom note to the top . although it retains its original harmony , the chord sounds higher , pointing towards enlightenment . that 's similar to tamino , who in passing his trials restores balance to the kingdom while growing stronger , wiser , and more complete .
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tamino eventually finds pamina at sarastro 's temple , but behind enemy lines , tamino and pamina learn that they 're on the wrong side . the queen of night actually wants to plunge the world into darkness . everything tamino thought he knew was wrong , filling him with doubt and confusion .
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the queen of the night ''
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françois-marie arouet was born in paris in 1694 his father , a well-established lawyer , sent him to the best school in the capital , and by all accounts , he was a brilliant student . the young arouet , decided at an early age to make his name as a writer , or rather to remake his name , as the first thing he did was to change his name to voltaire . the 18th century is often referred to as the age of reason , or the age of enlightenment , but sometimes more fairly simply as the age of voltaire . so , changing his name was a good call . the age of arouet , which is not of work quite as well . voltaire was precociously talented as a poet . at the age of only 24 , he had his first verse tragedy performed at the comédie-française . by then , he 'd already begun work on an epic poem about the french religious civil wars of the 16th century , about the french religious civil wars of the 16th century , by pragmatically converting from protestantism to catholicism . this was to be a subject dear to voltaire 's heart , for under the guise of writing a national epic , he was dwelling at length on the bloody consequences of religious intolerance . right from the start , voltaire 's views on religion were expressed robustly . he was not an atheist . in part , because he thought that some minimal belief in a deity was useful for social cohesion . voltaire 's god had created the world , instilled in us a sense of good and evil and then basically taken a back seat . this was known as rational religion , or in the 18th century called natural religion , or deism . and it had no truck with metaphysics of any kind . voltaire was basically a man of reason , who loathed fanaticism , idolatry and superstition . that men can kill each other to defend some bit of religious doctrine , which they scarcely understand , is something he found repellent . and he reserved his greatest hatred for the clerics , who exploited the credulity of believers to maintain their own power base . voltaire wanted religion but not the church . for obvious reasons , the catholic authorities were not keen for voltaire 's poem about henry iv , la henriade , to be published in france . so voltaire decided to go and publish it in london instead , and in 1726 , went and traveled to england . what began as a business trip soon turned , however , into something quite different . and voltaire ended up staying in england for some two and a half years . he learned to speak english fluently , got to know writers and politicians , and became a great admirer of english protestant culture . he decided to write a book about his experience of england . and the letters concerning the english nation appeared first in english in 1733 . the french authorities were horrified . the book was censored and voltaire only narrowly avoided prison . that 's because the book presented an informal portrait of english culture , in a witty and ironical style looking in turn at religion , politics , science and literature , in ways that were critical implicitly of french culture and politics . here , for example , is how voltaire presents the royal exchange , a handsome building in the heart of the city of london , where merchants from across the world would meet to transact business . `` take a view of the royal exchange , '' voltaire wrote , where the representatives of all nations meet for the benefit of mankind . there the jew , the muhammadan and a christian transact together as though they all profess the same religion , and give the name of infidel to none but the bankrupts . there the presbyterian confides in the anabaptist , and the churchman depends on the quaker ’ s word . at the breaking up of this pacific and free assembly , some will withdraw to the synagogue , and others to take a glass . this man goes and is baptised in a great tub , in the name of the father , son and holy ghost : that man has his son ’ s foreskin cut off , whilst a set of hebrew words ( quite unintelligible to him ) are mumbled over his child . if one religion only were allowed in england , the government would very possibly become arbitrary ; if there were but two , the people would cut one another ’ s throats ; but as there as such a multitude , they all live happy and in peace . '' voltaire 's message is clear . religious differences are trivial and separate men , while trade is important and brings them together . his conclusion , that the plurality of religions in england leads to a more peaceful society , is , of course , a covert criticism of france , where the catholic church was so dominant . the letters concerning the english nation , also discuss locke and newton , thinkers then poorly known in france the subject-matter might seem challenging , but voltaire is a past master popularising difficult material . ask any schoolchild today what they know about newton , and they 'll tell you about the apple falling on his head , and the survival of this anecdote is due entirely to voltaire . he heard it from newton 's niece and immediately understood that this simple homely image was the perfect way of conveying the simplicity of newton 's explanation of the force of gravity . after voltaire used the story in his letters concerning the english nation , everyone remembered it and voltaire left his mark on english popular culture . voltaire struggled with the question of good and evil the problem at the heart of his best-known work , candide which was published in 1759 and was a best seller from the moment it appeared . translated into every possible language , it remains the most widely read work of the european enlightenment . it 's even left its mark on our language expressions like 'pour encourager les autres ' to encourage the others or 'il faut cultiver le jardin ' , we must cultivate our garden have entered common usage . 'in the best of all possible worlds ' , yes , that 's another one speakers of french or english quote candide , without even realising it . and that 's the sure mark of a classic . candide is a timeless work , as satire of the human condition , but it 's also work of the enlightenment and its philosophical theme is announced in the title : `` candide '' or `` optimism '' . the hero of candide , as his name tells us , is an innocent anti-hero . he is in thrall to his tutor , pangloss , who preaches the philosophy of optimism . this is not 'optimism ' in the modern sense of looking on the bright side . optimism , spelled with a capital o and as expounded by the german philosopher , leibniz , was an attempt to answer the age-old problem of evil . why , if god is good , does he permit the existence of evil in the world ? to which the 18th century leibnizian optimist replies , evil is all part of some greater pattern of good : 'all partial evil , universal good ' as the english poet `` pope '' put it . in other words , evil does n't really exist at all . it 's just something which man imagines because of his limited view of the world . you might think this sounds like a bit of a confidence trick , voltaire certainly did , but this idea did find widespread acceptance in the 18th century . candide 's great mission was to put this philosophy to the test . ejected from his comfortable home in an obscure german castle , after trying to seduce the baron 's beautiful daughter , cunégonde , voltaire 's hero , candide , undergoes many trials and tribulations : conscripted into the army , he fights in a war , then deserts , only to find himself a witness to an earthquake in lisbon . candide is repeatedly brought face to face with evil in its most extreme forms : moral evil , in the case of the earthquake , where man is not apparently to blame ; and most of all human evil , such as the war , where man is very definitely to blame . pangloss 's breezy optimism is clearly an inadequate response to enormities of evil on this scale . eventually , even candide comes to realize this : to quote from the book , 'and sometimes pangloss would say to candide : after 1760 , voltaire took up residence in the château at ferney , just outside geneva . by now , he was the most famous living writer in europe , and he became widely known as the ‘ patriarch of ferney ’ . he took up a number of public causes . in 1761 , a protestant merchant jean calas , was accused of murdering his son and sentenced by the judges of toulouse to be tortured and then broken on the wheel . the legal processes were , to say the least , irregular , and the suspicions grew that the judges in his catholic city had acted with excessive zeal out of religious bigotry . voltaire became involved in the case and mounted an energetic campaign to rehabilitate calas ’ memory and help the members of his family , who had been left destitute . he wrote letters to those in authority and published a stream of pamphlets , culminating in 1763 in his traité sur la tolérance , which begins with the historical facts of the calas case and broadens out into a history of religious intolerance in european culture . voltaire 's writings had enormous impact on public opinion , and eventually the judges in paris quashed the judgment of the toulouse court . too late to save calas , but a huge victory for voltaire , who had learnt an important lesson about how change could be brought about through the pressure of public opinion . voltaire said of himself that he ‘ wrote to act ’ , and he wanted his writings to change the way people thought and behaved . in leading his crusades against fanaticism , he even invented a campaign slogan , ecrasez l ’ infâme ! , which translates roughly as ‘ crush the despicable ! ’ . l ’ infâme stands here for everything that voltaire hates , everything that he had spent his life fighting : superstition , intolerance , irrational behaviour of every kind . we should never forget that voltaire was also a brilliant writer , one of the greatest stylist the french language has ever known . the power of his ideas had a lot to do with the power of his expression . many writers made fun of miracles . no one did so hilariously as voltaire . always , voltaire had an ear for the telling phrase : it 's a good line , even in english , and better still in the original french where it is more memorable because it is a classical alexandrine line in 12 syllables : si dieu n ’ existait pas , il faudrait l ’ inventer . voltaire 's legacy in our present debates about religious toleration remain extremely potent . hardly a week passes without an article in the press quoting : ‘ i disapprove of what you say , but i will defend to the death your right to say it. ’ this rallying cry of tolerant multiculturalism is so potent that if voltaire had n't said it , we would have had to invent it , which is what happened . the expression was invented by an english woman in 1906 . no matter , it expresses a truth which is fundamentally important to our culture , so we have adopted the phrase and decided that voltaire said it . voltaire , his name has become synonymous with a set of liberal values : freedom of speech , rejection of bigotry and superstition , belief in reason and tolerance . it 's a unique , and nowadays , extremely precious legacy .
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françois-marie arouet was born in paris in 1694 his father , a well-established lawyer , sent him to the best school in the capital , and by all accounts , he was a brilliant student . the young arouet , decided at an early age to make his name as a writer , or rather to remake his name , as the first thing he did was to change his name to voltaire . the 18th century is often referred to as the age of reason , or the age of enlightenment , but sometimes more fairly simply as the age of voltaire .
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what was voltaire 's name before he changed it ?
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communicating underwater is challenging . light and odors do n't travel well , so it 's hard for animals to see or smell . but sound moves about four times faster in water than in air , so in this dark environment , marine mammals often rely on vocalization to communicate . that 's why a chorus of sounds fills the ocean . clicks , pulses , whistles , groans , boings , cries , and trills , to name a few . but the most famous parts of this underwater symphony are the evocative melodies , or songs , composed by the world 's largest mammals , whales . whale songs are one of the most sophisticated communication systems in the animal kingdom . only a few species are known to sing . blue , fin , bowhead minke whales , and of course humpback whales . these are all baleen whales which use hairy baleen plates instead of teeth to trap their prey . meanwhile , toothed whales do use echolocation , and they and other species of baleen whales make social sounds , such as cries and whistles , to communicate . but those vocalizations lack the complexity of songs . so how do they do it ? land mammals like us generate sound by moving air over our vocal cords when we exhale , causing them to vibrate . baleen whales have a u-shaped fold of tissue between their lungs and their large inflatable organs called laryngeal sacs . we do n't know this for sure because it 's essentially impossible to observe the internal organs of a living , singing whale , but we think that when a whale sings , muscular contractions in the throat and chest move air from the lungs across the u-fold and into the laryngeal sacs , causing the u-fold to vibrate . the resulting sound resonates in the sacs like a choir singing in a cathedral making songs loud enough to propagate up to thousands of kilometers away . whales do n't have to exhale to sing . instead , the air is recycled back into the lungs , creating sound once more . one reason whale songs are so fascinating is their pattern . units , like moans , cries , and chirps are arranged in phrases . repeated phrases are assembled into themes . multiple themes repeated in a predictable pattern create a song . this hierarchical structure is a kind of grammar . whale songs are extremely variable in duration , and whales can repeat them over and over . in one recorded session , a humpback whale sang for 22 hours . and why do they do it ? we do n't yet know the exact purpose , but we can speculate . given that the singers are males and they mostly sing during the mating season , songs might be used to attract females . or perhaps they 're territorial , used to deter other males . whales return to the same feeding and breeding grounds annually , and each discrete population has a different song . songs evolve over time as units or phrases are added , changed , or dropped . and when males from different populations are feeding within earshot , phrases are often exchanged , maybe because new songs make them more attractive to breeding females . this is one of the fastest examples of cultural transmission , where learned behaviors are passed between unrelated individuals of the same species . we can eavesdrop on these songs using underwater microphones called hydrophones . these help us track species when sightings or genetic samples are rare . for example , scientists have been able to differentiate the elusive blue whale 's populations worldwide based on their songs . but the oceans are getting noisier as a result of human activity . boating , military sonar , underwater construction , and seismic surveys for oil are occurring more often which may interfere with whale 's communication . some whales will avoid key feeding or breeding grounds if human noise is too loud . and humpback whales have been observed to reduce their singing in response to noise 200 kilometers away . limiting human activity along migratory routes and in other critical habitats , and reducing noise pollution throughout the ocean would help ensure whales continued survival . if the whales can keep singing and we can keep listening , maybe one day we 'll truly understand what they 're saying .
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the resulting sound resonates in the sacs like a choir singing in a cathedral making songs loud enough to propagate up to thousands of kilometers away . whales do n't have to exhale to sing . instead , the air is recycled back into the lungs , creating sound once more .
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how long can whales sing for ?
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let 's say there 's a disaster that sends humanity back to the stone age . can our knowledge and history survive ? the printed page will decompose . hard drive storage will deteriorate . even stones will eventually crumble . but we might have something inside us that can outlast these physical limitations : deoxyribonucleic acid . dna already stores our biological information . from eye color to skin tone , it programs our entire bodies . dna is made of four organic bases : adenine , guanine , cytosine , and thymine , or a , g , c , and t. the specific sequence of these bases into groups of three , known as codons , gives our cells instructions to make each of the proteins in our bodies . but this code can be used for other things , too , like secret messages . in 1999 , scientists in new york created an alphabet in which each of the 64 possible dna codons substituted for a specific letter , number , or grammar symbol . they spliced a 22-character message into a long strand of dna and surrounded it with specific genetic markers . they then hid the dna over a period in a type-written letter with only a small smudge to give the location away . they mailed the letter back to themselves . then they examined the letter looking for the dna strand . once the dna strand was located , they found the genetic markers . then , they sequenced the dna and successfully decoded the message . it soon became obvious that dna cryptography could code for much more than simple text . by translating the 1 's and 0 's of binary code into dna codons , digital data could be programmed into synthetic dna , then decoded back into its original form . in 2012 , uk scientists encoded 739 kilobytes of computer files into dna strands , including all 154 shakespeare sonnets and an excerpt from martin luther king 's `` i have a dream '' speech . and four years later , researchers at microsoft and the university of washington broke that record . they used binary coding to capture a whopping 200 megabytes of data , including the universal declaration of human rights and a high-def ok go music video , all in strings of dna . as far as storage capacity goes , dna stands out because of the surprising amount of information it can hold in so little space . the current theoretical limit of dna 's storage capacity is so high that you could fit 100 million hd movies on a pencil eraser . it 's even conceivable that one day we could fit all of the information currently on the internet into the space of a shoe box . also , computers and the magnetic tape and discs that their information is stored on only last for a few decades , at most , before degrading and becoming unreliable . meanwhile , dna has a half-life of 500 years , meaning that 's how long it takes for half of its bonds to break . and if left in a cold and dark environment , dna could potentially last for hundreds of thousands of years . and if that is n't long enough , scientists experimented with having synthetic dna auto-reproduce . after creating their own strands of dna that spelled out the lyrics to the children 's song `` it 's a small world , '' they placed them into the genome of a microbe nicknamed conan the bacterium . conan belongs to a species which can survive in a vacuum , or without water , for six years , or come out unscathed after being exposed to a dose of radiation 1,000 times that which would kill a human . according to the experiment , the bacterium was able to reproduce at least 100 generations without data loss . theoretically , if the organism had redundant copies of the information that could be used to automatically correct mistakes , the information could stay preserved even longer . so one day , you might be able to create a living , growing , knowledge archive in your own backyard , and its seeds might carry your family 's history , a detailed breakdown of the world 's political upheavals , or the sum of humanity 's knowledge into forests and across continents . perhaps even into the far reaches of space . though we might one day disappear , perhaps our legacy can still live on , if anyone would think to find it .
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they used binary coding to capture a whopping 200 megabytes of data , including the universal declaration of human rights and a high-def ok go music video , all in strings of dna . as far as storage capacity goes , dna stands out because of the surprising amount of information it can hold in so little space . the current theoretical limit of dna 's storage capacity is so high that you could fit 100 million hd movies on a pencil eraser . it 's even conceivable that one day we could fit all of the information currently on the internet into the space of a shoe box . also , computers and the magnetic tape and discs that their information is stored on only last for a few decades , at most , before degrading and becoming unreliable .
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if the entire internet was encoded into dna , the smallest space that could fill it would be approximately the size of :
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translator : andrea mcdonough reviewer : jessica ruby nowadays , we take curiosity for granted . we believe that if we put in the hard work , we might one day stand before the pyramids , discover a new species of flower , or even go to the moon . but , in the 18th and 19th century , female eyes gazed out windows at a world they were unlikely to ever explore . life for women in the time of queen victoria was largely relegated to house chores and gossip . and , although they devoured books on exotic travel , most would never would leave the places in which they were born . however , there were a few victorian women , who , through privilege , endurance , and not taking `` no '' for an answer , did set sail for wilder shores . in 1860 , marianne north , an amateur gardener and painter , crossed the ocean to america with letters of introduction , an easel , and a love of flowers . she went on to travel to jamaica , peru , japan , india , australia . in fact , she went to every continent except antarctica in pursuit of new flowers to paint . `` i was overwhelmed with the amount of subjects to be painted , '' she wrote . `` the hills were marvelously blue , piled one over the other beyond them . i never saw such abundance of pure color . '' with no planes or automobiles and rarely a paved street , north rode donkeys , scaled cliffs , and crossed swamps to reach the plants she wanted . and all this in the customary dress of her day , floor-length gowns . as photography had not yet been perfected , marianne 's paintings gave botanists back in europe their first glimpses of some of the world 's most unusual plants , like the giant pitcher plant of borneo , the african torch lily , and the many other species named for her as she was the first european to catalog them in the wild . meanwhile , back in london , miss mary kingsley was the sheltered daughter of a traveling doctor who loved hearing her father 's tales of native customs in africa . midway through writing a book on the subject , her father fell ill and died . so , kingsley decided she would finish the book for him . peers of her father advised her not to go , showing her maps of tropical diseases , but she went anyhow , landing in modern-day sierra leone in 1896 with two large suitcases and a phrase book . traveling into the jungle , she was able to confirm the existence of a then-mythical creature , the gorilla . she recalls fighting with crocodiles , being caught in a tornado , and tickling a hippopotamus with her umbrella so that he 'd leave the side of her canoe . falling into a spiky pit , she was saved from harm by her thick petticoat . `` a good snake properly cooked is one of the best meals one gets out here , '' she wrote . think indiana jones was resourceful ? kingsley could out-survive him any day ! but when it comes to breaking rules , perhaps no female traveler was as daring as alexandra david-neel . alexandra , who had studied eastern religions at home in france , wanted desperately to prove herself to parisian scholars of the day , all of whom were men . she decided the only way to be taken seriously was to visit the fabled city of lhasa in the mountains of tibet . `` people will have to say , 'this woman lived among the things she 's talking about . she touched them and she saw them alive , ' '' she wrote . when she arrived at the border from india , she was forbidden to cross . so , she disguised herself as a tibetan man . dressed in a yak fur coat and a necklace of carved skulls , she hiked through the barren himilayas all the way to lhasa , where she was subsequently arrested . she learned that the harder the journey , the better the story , and went on to write many books on tibetan religion , which not only made a splash back in paris but remain important today . these brave women , and others like them , went all over the world to prove that the desire to see for oneself not only changes the course of human knowledge , it changes the very idea of what is possible . they used the power of curiosity to try and understand the viewpoints and peculiarities of other places , perhaps because they , themselves , were seen as so unusual in their own societies . but their journeys revealed to them something more than the ways of foreign lands , they revealed something only they , themselves , could find : a sense of their own self .
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but , in the 18th and 19th century , female eyes gazed out windows at a world they were unlikely to ever explore . life for women in the time of queen victoria was largely relegated to house chores and gossip . and , although they devoured books on exotic travel , most would never would leave the places in which they were born .
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independence takes a lot of courage . can you think of a time when you were afraid to say or do something that was different than the group , and a time when you were brave enough to ‘ march to your own drummer ? ’ how did each situation feel at the time ? how do you feel looking back on them ?
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the city has just opened its one-of-a-kind fabergé egg museum with a single egg displayed on each floor of a 100-story building . and the world 's most notorious jewel thief already has her eyes on the prize . because security is tight and the eggs are so large , she 'll only get the chance to steal one by dropping it out the window into her waiting truck and repelling down before the police can arrive . all eggs are identical in weight and construction , but each floor 's egg is more rare and valuable than the one below it . while the thief would naturally like to take the priceless egg at the top , she suspects it wo n't survive a 100-story drop . being pragmatic , she decides to settle for the most expensive egg she can get . in the museum 's gift shop , she finds two souvenir eggs , perfect replicas that are perfectly worthless . the plan is to test drop them to find the highest floor at which an egg will survive the fall without breaking . of course , the experiment can only be repeated until both replica eggs are smashed . and throwing souvenirs out the window too many times is probably going to draw the guards ' attention . what 's the least number of tries it would take to guarantee that she find the right floor ? pause here if you want to figure it out for yourself ! answer in : 3 answer in : 2 answer in : 1 if you 're having trouble getting started on the solution , it might help to start with a simpler scenario . imagine our thief only had one replica egg . she 'd have a single option : to start by dropping it from the first floor and go up one by one until it breaks . then she 'd know that the floor below that is the one she needs to target for the real heist . but this could require as many as 100 tries . having an additional replica egg gives the thief a better option . she can drop the first egg from different floors at larger intervals in order to narrow down the range where the critical floor can be found . and once the first breaks , she can use the second egg to explore that interval floor by floor . large floor intervals do n't work great . in the worst case scenario , they require many tests with the second egg . smaller intervals work much better . for example , if she starts by dropping the first egg from every 10th floor , once it breaks , she 'll only have to test the nine floors below . that means it 'll take at most 19 tries to find the right floor . but can she do even better ? after all , there 's no reason every interval has to be the same size . let 's say there were only ten floors . the thief could test this whole building with just four total throws by dropping the first egg at floors four , seven , and nine . if it broke at floor four , it would take up to three throws of the second egg to find the exact floor . if it broke at seven , it would take up to two throws with the second egg . and if it broke at floor nine , it would take just one more throw of the second egg . intuitively , what we 're trying to do here is divide the building into sections where no matter which floor is correct , it takes up to the same number of throws to find it . we want each interval to be one floor smaller than the last . this equation can help us solve for the first floor we need to start with in the 100 floor building . there are several ways to solve this equation , including trial and error . if we plug in two for n , that equation would look like this . if we plug in three , we get this . so we can find the first n to pass 100 by adding more terms until we get to our answer , which is 14 . and so our thief starts on the 14th floor , moving up to the 27th , the 39th , and so on , for a maximum of 14 drops . like the old saying goes , you ca n't pull a heist without breaking a few eggs .
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and throwing souvenirs out the window too many times is probably going to draw the guards ' attention . what 's the least number of tries it would take to guarantee that she find the right floor ? pause here if you want to figure it out for yourself !
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what ’ s the least number of tries it would take to guarantee that the thief finds the right floor if she has only one egg to experiment with ?
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steel and plastic . these two materials are essential to so much of our infrastructure and technology , and they have a complementary set of strengths and weaknesses . steel is strong and hard , but difficult to shape intricately . while plastic can take on just about any form , it 's weak and soft . so would n't it be nice if there were one material as strong as the strongest steel and as shapeable as plastic ? well , a lot of scientists and technologists are getting excited about a relatively recent invention called metallic glass with both of those properties , and more . metallic glasses look shiny and opaque , like metals , and also like metals , they conduct heat and electricity . but they 're way stronger than most metals , which means they can withstand a lot of force without getting bent or dented , making ultrasharp scalpels , and ultrastrong electronics cases , hinges , screws ; the list goes on . metallic glasses also have an incredible ability to store and release elastic energy , which makes them perfect for sports equipment , like tennis racquets , golf clubs , and skis . they 're resistant to corrosion , and can be cast into complex shapes with mirror-like surfaces in a single molding step . despite their strength at room temperature , if you go up a few hundred degrees celsius , they soften significantly , and can be deformed into any shape you like . cool them back down , and they regain the strength . so where do all of these wondrous attributes come from ? in essence , they have to do with metallic glass ' unique atomic structure . most metals are crystalline as solids . that means that if you zoomed in close enough to see the individual atoms , they 'd be neatly lined up in an orderly , repeating pattern that extends throughout the whole material . ice is crystalline , and so are diamonds , and salt . if you heat these materials up enough and melt them , the atoms can jiggle freely and move randomly , but when you cool them back down , the atoms reorganize themselves , reestablishing the crystal . but what if you could cool a molten metal so fast that the atoms could n't find their places again , so that the material was solid , but with the chaotic , amorphous internal structure of a liquid ? that 's metallic glass . this structure has the added benefit of lacking the grain boundaries that most metals have . those are weak spots where the material is more susceptible to scratches or corrosion . the first metallic glass was made in 1960 from gold and silicon . it was n't easy to make . because metal atoms crystallize so rapidly , scientists had to cool the alloy down incredibly fast , a million degrees kelvin per second , by shooting tiny droplets at cold copper plates , or spinning ultrathin ribbons . at that time , metallic glasses could only be tens or hundreds of microns thick , which was too thin for most practical applications . but since then , scientists have figured out that if you blend several metals that mix with each other freely , but ca n't easily crystallize together , usually because they have very different atomic sizes , the mixture crystallizes much more slowly . that means you do n't have to cool it down as fast , so the material can be thicker , centimeters instead of micrometers . these materials are called bulk metallic glasses , or bmgs . now there are hundreds of different bmgs , so why are n't all of our bridges and cars made out of them ? many of the bmgs currently available are made from expensive metals , like palladium and zirconium , and they have to be really pure because any impurities can cause crystallization . so a bmg skyscraper or space shuttle would be astronomically expensive . and despite their strength , they 're not yet tough enough for load-bearing applications . when the stresses get high , they can fracture without warning , which is n't ideal for , say , a bridge . but when engineers figure out how to make bmgs from cheaper metals , and how to make them even tougher , for these super materials , the sky 's the limit .
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well , a lot of scientists and technologists are getting excited about a relatively recent invention called metallic glass with both of those properties , and more . metallic glasses look shiny and opaque , like metals , and also like metals , they conduct heat and electricity . but they 're way stronger than most metals , which means they can withstand a lot of force without getting bent or dented , making ultrasharp scalpels , and ultrastrong electronics cases , hinges , screws ; the list goes on .
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what is the key structural difference between metallic glasses and metals in general ?
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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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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 .
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which terrestrial organisms migrated first ?
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sugar is playing hide and seek with you . you 'd think it would be pretty easy for you to win , considering all the sugar in sodas , ice cream , candy , and big white bags labeled sugar . people get about half of their added sugars from those drinks and treats , so it might seem like sugar is hiding in plain sight , but like someone in the witness protection program , the other half is hidden in places you 'd least suspect . check the ingredients on ketchup , bologna , spaghetti sauce , soy milk , sports drinks , fish sticks , and peanut butter . you 'll find sugar hiding in most of those products . in fact , you 'll find added sugars in three-quarters of the more than 600,000 items available in grocery stores . but how is sugar hiding ? ca n't you just look on food labels ? it 's not that easy . just like your friend robert might go by bob , robby , rob , bobby , or roberto , added sugar has a lot of aliases . and by a lot , we do n't mean five or six , try fifty-six . there 's brown rice syrup , barley malt , demerara , florida crystals , muscovado , and , of course , high fructose corn syrup , sometimes called hfcs , or corn sugar . even sugar 's tricky nicknames have nicknames . grape or apple concentrate has the same effects on your body as its 55 sugary twins . and even though organic evaporated cane juice sounds healthy , when you evaporate it , you get sugar ! chemically speaking , it 's all the same . and even trickier , when multiple added types of sugars are used in one type of product , they get buried down in a long list of ingredients , so the sugar content might appear to be okay , but when you add them all together , sugar can be the single biggest ingredient . currently , the fda does n't suggest a recommended daily limit for sugar , so it 's hard to tell if this 65 grams in a bottle of soda is a little or a lot . but the world health organization recommends limiting sugar to just 5 % of your total calories , or about 25 grams per day . so , 65 grams is well over twice that amount . but just what is sugar ? what 's the difference between glucose and fructose ? well , both are carbohydrates with the same chemical composition of carbon , hydrogen , and oxygen . but they have very different structures and behave quite differently in our bodies . glucose is the best source of energy for nearly all organisms on earth . it can be metabolized by all organs in the body . fructose , on the other hand , is metabolized primarily in the liver , and when your liver gets overloaded with sweet , sweet fructose , the excess is metabolized to fat . fresh fruits actually contain fructose , but it 's naturally occurring and does n't cause an overload because the fiber in fruit slows its absorption . this gives your liver the time it needs to do its job . it 's sugar that makes cookies chewy and candy crunchy . it even turns bread crust a beautiful , golden brown . it 's also a great preservative ; it does n't spoil or evaporate , so the foods it 's added to are easier to store and ship long distances and tend to be cheaper . that 's why sugar is hiding everywhere . actually , it might be easier to list the foods that added sugar is n't hiding in , things like : vegetables , eggs , meats , fish , fruit , raw nuts , even your kitchen sink . simply choosing water over soda , juices , and sports drinks is a great way to avoid hidden added sugar . at the very least , try to pay attention to food labels , so you can keep your sugar intake at a healthy level . because in this game of hide and seek , every time you do n't find added sugar , you win !
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currently , the fda does n't suggest a recommended daily limit for sugar , so it 's hard to tell if this 65 grams in a bottle of soda is a little or a lot . but the world health organization recommends limiting sugar to just 5 % of your total calories , or about 25 grams per day . so , 65 grams is well over twice that amount .
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what is the world health organization limit for grams of sugar per day ?
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somewhere right now , people are lining up to scare themselves , maybe with a thrill ride or horror movie . in fact , in october of 2015 alone , about 28 million people visited a haunted house in the u.s . but many consider this behavior perplexing , asking the question , `` what could possibly be fun about being scared ? '' fear has a bad rap , but it 's not all bad . for starters , fear can actually feel pretty good . when a threat triggers our fight or flight response , our bodies prepare for danger by releasing chemicals that change how our brains and bodies function . this automatic response jumpstarts systems that can aid in survival . they do this by making sure we have enough energy and are protected from feeling pain , while shutting down nonessential systems , like critical thought . feeling pain-free and energized , while not getting caught up in worrisome thoughts that normally occupy our brains , that all sounds great , and it can be because this response is similar , though not exactly the same to what we experience in positive , high-arousal states , like excitement , happiness , and even during sex . the difference lays in the context . if we 're in real danger , we 're focused on survival , not fun . but when we trigger this high arousal response in a safe place , we can switch over to enjoying the natural high of being scared . it 's why people on roller coasters can go from screaming to laughing within moments . your body is already in a euphoric state . you 're just relabeling the experience . and though the threat response is universal , research shows differences between individuals in how the chemicals associated with the threat response work . this explains why some are more prone to thrill-seeking than others . other normal physical differences explain why some may love the dizziness associated with a loop-de-loop , while loathing the stomach-drop sensation of a steep roller coaster , or why some squeal with delight inside a haunted house , but retreat in terror if taken to an actual cemetery . fear brings more than just a fun , natural high . doing things that we 're afraid of can give us a nice boost of self-esteem . like any personal challenge , whether it 's running a race or finishing a long book , when we make it through to the end , we feel a sense of accomplishment . this is true even if we know we 're not really in any danger . our thinking brains may know the zombies are n't real , but our bodies tell us otherwise . the fear feels real , so when we make it through alive , the satisfaction and sense of accomplishment also feel real . this is a great evolutionary adaptation . those who had the right balance of bravery and wit to know when to push through the fear and when to retreat were rewarded with survival , new food , and new lands . finally , fear can bring people together . emotions can be contagious , and when you see your friend scream and laugh , you feel compelled to do the same . this is because we make sense of what our friends are experiencing by recreating the experience ourselves . in fact , the parts of the brain that are active when our friend screams are active in us when we watch them . this not only intensifies our own emotional experience , but makes us feel closer to those we 're with . the feeling of closeness during times of fear is aided by the hormone oxytocin released during fight or flight . fear is a powerful emotional experience , and anything that triggers a strong reaction is going to be stored in our memory really well . you do n't want to forget what can hurt you . so if your memory of watching a horror film with your friends is positive and left you with a sense of satisfaction , then you 'll want to do it over and over again .
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your body is already in a euphoric state . you 're just relabeling the experience . and though the threat response is universal , research shows differences between individuals in how the chemicals associated with the threat response work .
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individuals can experience the same situation very differently with some leaving with positive feelings , and others feeling negatively . what are some of the suggested causes for the difference in how people experience frightening things ?
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testing , testing , one , two , three . when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science , is a phenomenon called mutual causal interaction , where x affects y , y affects x , and so on , creating an ongoing process called a feedback loop . and the natural world is full of these mechanisms formed by the links between living and nonliving things that build resilience by governing the way populations and food webs respond to events . when plants die , the dead material enriches the soil with humus , a stable mass of organic matter , providing moisture and nutrients for other plants to grow . the more plants grow and die , the more humus is produced , allowing even more plants to grow , and so on . this is an example of positive feedback , an essential force in the buildup of ecosystems . but it 's not called positive feedback because it 's beneficial . rather , it is positive because it amplifies a particular effect or change from previous conditions . these positive , or amplifying , loops can also be harmful , like when removing a forest makes it vulnerable to erosion , which removes organic matter and nutrients from the earth , leaving less plants to anchor the soil , and leading to more erosion . in contrast , negative feedback diminishes or counteracts changes in an ecosystem to maintain a more stable balance . consider predators and their prey . when lynx eat snowshoe hares , they reduce their population , but this drop in the lynx 's food source will soon cause their own population to decline , reducing the predation rate and allowing the hare population to increase again . the ongoing cycle creates an up and down wavelike pattern , maintaining a long-term equilibrium and allowing a food chain to persist over time . feedback processes might seem counterintuitive because many of us are used to more predictable linear scenarios of cause and effect . for instance , it seems simple enough that spraying pesticides would help plants grow by killing pest insects , but it may trigger a host of other unexpected reactions . for example , if spraying pushes down the insect population , its predators will have less food . as their population dips , the reduced predation would allow the insect population to rise , counteracting the effects of our pesticides . note that each feedback is the product of the links in the loop . add one negative link and it will reverse the feedback force entirely , and one weak link will reduce the effect of the entire feedback considerably . lose a link , and the whole loop is broken . but this is only a simple example , since natural communities consist not of separate food chains , but networks of interactions . feedback loops will often be indirect , occurring through longer chains . a food web containing twenty populations can generate thousands of loops of up to twenty links in length . but instead of forming a disordered cacophany , feedback loops in ecological systems play together , creating regular patterns just like multiple instruments , coming together to create a complex but harmonious piece of music . wide-ranging negative feedbacks keep the positive feedbacks in check , like drums maintaining a rhythm . you can look at the way a particular ecosystem functions within its unique habitat as representing its trademark sound . ocean environments dominated by predator-prey interactions , and strong negative and positive loops stabilized by self-damping feedback , are powerful and loud , with many oscillations . desert ecosystems , where the turn over of biomass is slow , and the weak feedbacks loops through dead matter are more like a constant drone . and the tropical rainforest , with its great diversity of species , high nutrient turnover , and strong feedbacks among both living and dead matter , is like a lush panoply of sounds . despite their stabilizing effects , many of these habitats and their ecosystems develop and change over time , as do the harmonies they create . deforestation may turn lush tropics into a barren patch , like a successful ensemble breaking up after losing its star performers . but an abandoned patch of farmland may also become a forest over time , like a garage band growing into a magnificent orchestra .
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note that each feedback is the product of the links in the loop . add one negative link and it will reverse the feedback force entirely , and one weak link will reduce the effect of the entire feedback considerably . lose a link , and the whole loop is broken .
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the process of erosion on a landscape is an example of positive feedback . can you describe a feedback loop that explains this process in more detail , starting with the feedback between plant , humus , and at least one more node in the network ? hint : you will have to add more than one negative link .
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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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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 .
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`` any time someone puts a little more effort in the community , the community stands stronger , '' said the football coach in the film . what do you think he means by this ? include some examples from the film . describe a situation in your life where a community you are part of ( family , school , town , etc . ) has grown stronger due to a group effort . in a paragraph , describe the situation , the efforts that were taken , and the outcome .
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can you grow a human bone outside the human body ? the answer may soon be yes , but before we can understand how that 's possible , we need to look at how bones grow naturally inside the body . most bones start in a growing fetus as a soft , flexible cartilage . bone-forming cells replace the cartilage with a spongy mineral lattice made of elements like calcium and phosphate . this lattice gets harder , as osteoblasts , which are specialized bone-forming cells , deposit more mineral , giving bones their strength . while the lattice itself is not made of living cells , networks of blood vessels , nerves and other living tissues grow through special channels and passages . and over the course of development , a legion of osteoblasts reinforce the skeleton that protects our organs , allows us to move , produces blood cells and more . but this initial building process alone is not enough to make bones strong and functional . if you took a bone built this way , attached muscles to it , and tried to use it to lift a heavy weight , the bone would probably snap under the strain . this does n't usually happen to us because our cells are constantly reinforcing and building bone wherever they 're used , a principle we refer to as wolff 's law . however , bone materials are a limited resource and this new , reinforcing bone can be formed only if there is enough material present . fortunately , osteoblasts , the builders , have a counterpart called osteoclasts , the recyclers . osteoclasts break down the unneeded mineral lattice using acids and enzymes so that osteoblasts can then add more material . one of the main reasons astronauts must exercise constantly in orbit is due to the lack of skeletal strain in free fall . as projected by wolff 's law , that makes osteoclasts more active than osteoblasts , resulting in a loss of bone mass and strength . when bones do break , your body has an amazing ability to reconstruct the injured bone as if the break had never happened . certain situations , like cancer removal , traumatic accidents , and genetic defects exceed the body 's natural ability for repair . historical solutions have included filling in the resulting holes with metal , animal bones , or pieces of bone from human donors , but none of these are optimal as they can cause infections or be rejected by the immune system , and they ca n't carry out most of the functions of healthy bones . an ideal solution would be to grow a bone made from the patient 's own cells that 's customized to the exact shape of the hole , and that 's exactly what scientists are currently trying to do . here 's how it works . first , doctors extract stem cells from a patient 's fat tissue and take ct scans to determine the exact dimensions of the missing bone . they then model the exact shape of the hole , either with 3d printers , or by carving decellularized cow bones . those are the bones where all of the cells have been stripped away , leaving only the sponge-like mineral lattice . they then add the patient 's stem cells to this lattice and place it in a bioreactor , a device that will simulate all of the conditions found inside the body . temperature , humidity , acidity and nutrient composition all need to be just right for the stem cells to differentiate into osteoblasts and other cells , colonize the mineral lattice , and remodel it with living tissue . but there 's one thing missing . remember wolff 's law ? an artificial bone needs to experience real stress , or else it will come out weak and brittle , so the bioreactor constantly pumps fluids around the bone , and the pressure tells the osteoblasts to add bone density . put all of this together , and within three weeks , the now living bone is ready to come out of the bioreactor and to be implanted into the patient 's body . while it is n't yet certain that this method will work for humans , lab grown bones have already been successfully implanted in pigs and other animals , and human trials may begin as early as 2016 .
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can you grow a human bone outside the human body ? the answer may soon be yes , but before we can understand how that 's possible , we need to look at how bones grow naturally inside the body .
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how do we grow bones in the lab ? what are the key factors to help cells grow outside the body ?
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many of us have hundreds of things on our minds at any moment , often struggling to keep track of everything we need to do . but fortunately , there 's one important thing we do n't have to worry about remembering : breathing . when you breathe , you transport oxygen to the body 's cells to keep them working and clear your system of the carbon dioxide that this work generates . breathing , in other words , keeps the body alive . so , how do we accomplish this crucial and complex task without even thinking about it ? the answer lies in our body 's respiratory system . like any machinery , it consists of specialized components , and requires a trigger to start functioning . here , the components are the structures and tissues making up the lungs , as well as the various other respiratory organs connected to them . and to get this machine moving , we need the autonomic nervous system , our brain 's unconscious control center for the vital functions . as the body prepares to take in oxygen-rich air , this system sends a signal to the muscles around your lungs , flattening the diaphragm and contracting the intercostal muscles between your ribs to create more space for the lungs to expand . air then wooshes into your nose and mouth , through your trachea , and into the bronchi that split at the trachea 's base , with one entering each lung . like tree branches , these small tubes divide into thousands of tinier passages called bronchioles . it 's tempting to think of the lungs as huge balloons , but instead of being hollow , they 're actually spongy inside , with the bronchioles running throughout the parenchyma tissue . at the end of each bronchiole is a little air sack called an alveolus , wrapped in capillaries full of red blood cells containing special proteins called hemoglobin . the air you 've breathed in fills these sacks , causing the lungs to inflate . here is where the vital exchange occurs . at this point , the capillaries are packed with carbon dioxide , and the air sacks are full of oxygen . but due to the basic process of diffusion , the molecules of each gas want to move to a place where there 's a lower concentration of their kind . so as oxygen crosses over to the capillaries , the hemoglobin grabs it up , while the carbon dioxide is unloaded into the lungs . the oxygen-rich hemoglobin is then transported throughout the body via the bloodstream . but what do our lungs do with all that carbon dioxide ? exhale it , of course . the autonomic nervous system kicks in again , causing the diaphragm to ball up , and the intercostal muscles to relax , making the chest cavities smaller and forcing the lungs to compress . the carbon dioxide-rich air is expelled , and the cycle begins again . so that 's how these spongy organs keep our bodies efficiently supplied with air . lungs inhale and exhale between 15 and 25 times a minute , which amounts to an incredible 10,000 liters of air each day . that 's a lot of work , but do n't sweat it . your lungs and your autonomic nervous system have got it covered .
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many of us have hundreds of things on our minds at any moment , often struggling to keep track of everything we need to do . but fortunately , there 's one important thing we do n't have to worry about remembering : breathing .
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pick the true statement :
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[ ♪sustained note♪ ] [ flag flapping in breeze ] [ path of freedom ] [ ♪ music ♪ ] [ prisoners chattering ] [ ♪ music ♪ ] - this is a tough guy world , and we have to control all of their movement and their behavior [ roberta richman - rhode island dept . of corrections ] because that 's the way you keep an institution safe for everybody who lives in it . [ ♪ music ♪ ] we have everybody here— murderers and rapists , sex offenders , drug addicts— everybody . [ 1 out of every 100 americans is currently behind bars ] my name is dennis . i 'm 52 years old . i 'm serving a 15-year sentence for assaulting my wife . my name is louis , 35 . i sold narcotics [ clears throat ] since i was about 13 or so . my name is juan . i 'm 34 years old . i 'm here for second degree murder . yeah . sadly , this is my charge . my name is celine . i 'm 39 . i 'll be 40 soon . i was given a life term . [ ♪ music ♪ ] a lot of times what lands people in prison [ fleet maull - prison mindfulness institute ] and what brings them back is a lack of good problem-solving skills and good communication skills . [ ♪ music ♪ ] [ richman ] fleet approached us asking if he could do some work in here . we were challenged . our union wanted to know how we could possibly bring an ex-offender in . [ maull ] i served 14½ years on a 25-year , no parole sentence . hello . [ ♪ music ♪ ] having served 14 years boosts his credibility— boosts his credibility with inmates . how 's your week been ? - it 's good . [ maull ] yeah ? good . what 's up ? yeah . hey . welcome . when i got locked up , i really hit a wall of just seeing the craziness of my life path up until then and the incredible selfish decisions i 'd been making . my son was 9 years old . he was going to grow up without his dad . and i was just so deeply full of remorse and regret that i just literally started practicing meditation like my hair was on fire . so i became extremely motivated to turn my life around . [ ♪ music ♪ ] and so i was living the life of this prison monk . [ ♪ music ♪ ] i was sourcing a meditation group twice a week in the chapel . [ ♪ music ♪ ] i started receiving letters from prisoners while i was in prison . i had published some articles ; people knew about me out in the world a little bit , and they started sending some of these letters to me thinking i would know what to do with them . i worked in the education department , and i had access to a copy machine . i would copy articles out of books , and i 'd put together a little thing and i 'd send it off to a prisoner . so it started off that way , and i decided it was a much bigger deal than i could do from my prison cells . i think we have a co-creative relationship with our life . we ca n't control other people , we do n't control life , but is there some relationship between what we put out and what comes back ? freedom before i came here was just another word . i had never been to prison before . all you know is what the media and the movies say about prison— `` take care of yourself , man . '' `` somebody 's going to try to take your manhood or something . '' you know what i mean ? i 'm thinking i 'm going to come in here and fight the world . [ maull ] in a prison like moran , there 's a serious conflict waiting around any corner . it 's an environment where people 's worst behaviors are just right there just under the surface . [ ♪ music ♪ ] when i first came in , i fought with officers , would beat up anyone , would do the unthinkable just because . [ dennis ] it 's a vicious cycle because once you come to prison your life just keeps tumbling , tumbling , tumbling , and it 's like a never-ending wall that wo n't stop building unless you find some way to get over that wall or at least in front of it . [ richman ] what circumstances did they have to survive on the street to bring them to where they are now ? do we want to save those lives , or do we want to discard them ? the crimes i committed , i brought shame to not only myself but to those who i love . so i 'm just really trying to do something to get out of that cycle . somebody 's given us an opportunity just to meditate and connect ourselves , and that 's golden . so sit up with that good posture , just rest your hands on your legs , and just take a moment to just feel . [ ♪ music ♪ ] [ richman ] i 've always thought that the people who survive are so much stronger than i could ever be . i asked fleet how he survived and thrived the way he has . he credits meditation for having given him the strength to live his life in prison and come out not as much the worse for wear as most people do . i do n't have a release date . so i can only go home when they decide i can . so i learned to live day by day , and that helped me to deal with prison , and i could only do that being in the moment , being in the now . [ ♪ music ♪ ] it 's like if i do n't like what 's going on , what can i do to shift it ? if i do n't like the relationship i have with my boss or with one of the cos or something , could i approach that person in a different way ? can i get creative about what i 'm doing to bring about a shift in the way things are— in other words , owning my own situation . so how do you resolve that ? i take a breath and then [ chuckles ] i step back . really , you have to . [ maull ] then suddenly get that there 's this whole thing there that they thought was who they are . that 's the only reality they knew . suddenly they get to step outside of that a little bit . you just see the lights go on . it 's like this sudden illumination . it 's like a mini enlightenment of sorts . and that 's very powerful . that 's what keeps me coming . the reality of it is i 'm living life , and meditation it has brought a new perspective in the way that it gave me like a tool to really look inside myself and change the way i am . [ richman ] people do n't understand the value of what they call the soft stuff , and i sometimes think without the soft stuff , no matter how much hard stuff you have , you 're bound to fail . you can live your life . you can be yourself . you can show others that this is n't a place to breed a better criminal ; this could actually be a place to breed a better person . you 're here because the way that you were did n't work . so why not be better ? [ prisoners chattering ] [ richman ] the people in prison are us . they 're not monsters . and more importantly , whether we want them to or not , they 're getting out . so do you want them to come out angrier and meaner and more dangerous than they were when they came in , or do you want to do whatever you can to change their behavior while they 're here ? we need people to see and experience prisoners stepping out of that culture and doing something transformative with their lives , and then people will start to have faith , people will see people coming back to their community and they realize these are human beings and that human beings ' lives have value and they 're not expendable . [ ♪ music ♪ ] [ this year 700,000 people will return home from prison ] [ ♪ music ♪ ] [ directed by emmanuel vaughan-lee , produced by dorothee royal-hedinger ] [ cinematography by elias koch , edited by adam loften , sound recording by emmanuel vaughan-lee ] [ music by h. scott salinas , sound mix by d. chris smith ] [ www.globalonenessproject.org ]
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do we want to save those lives , or do we want to discard them ? the crimes i committed , i brought shame to not only myself but to those who i love . so i 'm just really trying to do something to get out of that cycle .
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how do the four prisoners introduce themselves in the beginning of the film ? what were the crimes they committed ?
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so the last time we tried to film chlorine experiments we found that the chlorine cylinder itself had a slight problem , it was seized here . but the stig has acquired another cylinder of chlorine . so you know what this means , it means that we feel duty-bound to increase the intensity of our chlorine video and show you some chemistry with chlorine . chlorine is an element that many people have heard of . it ’ s a greenish-yellow gas which consists of , the gas consists of two chlorine atoms bonded together so it ’ s cl2 and it ’ s much heavier than air . incredibly reactive , incredibly poisonous , not a very nice compound at all . ok so neil is about to open the cylinder of chlorine to allow some of the chlorine gas to leak through the pipe into the , to the flask in the fume hood . chlorine sits in the right-hand side of the periodic table in the halogens in group , well , some people say seven , some people say seventeen . really what that says is that chlorine wants another electron to get that noble gas configuration and it will move heaven and earth to get that electron ! so during the first world war it was used as a chemical weapon . the gas could spread across the battlefields and when it came to the trenches , which were holes in the ground , it would fall into the trenches and fill them up . you can see the yellow colour against the white background on the paper , so now we ’ re starting to fill that flask with chlorine ; it ’ s quite dense , so it will stick to the bottom of the flask it ’ s not like a light gas like hydrogen or helium , it won ’ t come upwards . so now you can see the colour in that chlorine is really quite intense . it wasn ’ t a terribly good weapon because it could quite easily , if the wind changed direction , it could blow the gas back to the people who were letting it out . so we ’ ll just put a stopper in to contain the gas while we prepare the rest of the experiment . chlorine is quite corrosive , it reacts with water to make an acid , hcl , hydrochloric acid which can attack people ’ s lungs . the lungs generate fluid , they fill up with fluid and quickly the person drowns in their own fluid . it also corrodes things very easily so all the metal fittings on people ’ s battle dress , the brass buttons , brass buckles , all went green as well . but it ’ s not a terribly effective weapon but when people weren ’ t expecting any sort of chemical weapon it must have been terrifying . ok so we have a small amount of aluminium here which we put on the end of a wire . we ’ re gon na heat the aluminium in that flame and then we ’ re gon na put the hot aluminium into the flask of chlorine , then hopefully we ’ ll see , the chlorine will react with the aluminium and we ’ ll get very rapid formation of aluminium trichloride , alcl3 . the british army created whole regiments of gas soldiers who were all trained chemists , who were sent out to handle these cylinders of gas . and on the german side in the first world war , fritz haber , the inventor of the haber process to make ammonia became very keen on chemical weapons and he was the chief proponent . his wife was really furious about this and in fact shot herself with his revolver , killed herself , the day before he was due to go back to the front . and he , it was said that this was because she objected to his work on chemical weapons . though at the same time there were rumours that he was having an affair with another woman , so there may have been other factors at play as well . so , let ’ s heat up our aluminium . ok , so it ’ s nice and warm , all over . and then we ’ ll drop it or add it into the chlorine glass . now instantly we are seeing aluminium trichloride coming out of the top and reacting with moisture in the air . so now you can see the reaction is getting very intense and we are seeing a flame in the bottom . so the aluminium is being consumed as it ’ s reacting , oxidising strongly in that chlorine-rich air . chlorine is found all over the world , the sea contains sodium chloride , and there are huge deposits of sodium chloride in salt lakes where lakes have dried out , such as in some parts of the states , where you , united states , where you have salt lakes where people can race cars and things across the flat surface and in other parts of the world . all of the aluminium has been consumed now by the chlorine : a very , very rapid reaction . there are many areas , such as in the north of england , in the county of cheshire and also in salzburg in austria , where there are prehistoric deposits of salt from prehistoric salt lakes , which can now be mined really quite easily , and there , so salt and chlorine is a very common element . it ’ s made from sodium chloride solution by electrolysis , by passing an electric current , and it ’ s a very energy intensive process . one percent of the uk ’ s electricity was used , at one time , for making chlorine from sodium chloride , and the chlorine is used particularly for making the plastic pvc . while we got chlorine here , we thought we ’ d do a couple of reactions . so we ’ ve got some chlorine in this flask and you can see the nice yellow colour and i thought what we ’ d try and do now is do a competition reaction again or a reaction with iron . so now the iron , we ’ re gon na heat the iron , this is iron wool which you might use for treating wood , and we ’ re gon na heat that until it ’ s warm and put it in the chlorine , the chlorine will oxidise it to iron chloride . chlorine will react with all sorts of metals . you can make salt by burning the metal sodium in chlorine , and if you put in other metals like aluminium or iron they will also react . aluminium reacts to form aluminium trichloride which is the salt of aluminium and iron will similarly react to form iron chloride , and most metals but not all of them will react with chlorine : lead will not for example . but it is really quite a reactive gas . so really rapid reaction there as the hot iron starts to react with the chlorine to form iron chloride . very , very exothermic again and i think , yes this is very hot , we might have to move it off the paper . so what happens in all of these reactions is that the chlorine removes an electron from the metal to make the chloride ion cl- , and the chloride ion is perfectly innocuous , you can drink , you can eat chloride , whereas chlorine itself is very poisonous . oh it ’ s warm , it ’ s not too hot to touch its like picking up a mug of warm tea or warm coffee . but you can see again the products of the chemical reaction have precipitated out across the flask , and now if i remove the…wire again i can see that all of the iron has been consumed again instantly . the moment that it got into that chlorine-rich flask ; very , very rapid reaction , very , very reactive with chlorine .
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so now the iron , we ’ re gon na heat the iron , this is iron wool which you might use for treating wood , and we ’ re gon na heat that until it ’ s warm and put it in the chlorine , the chlorine will oxidise it to iron chloride . chlorine will react with all sorts of metals . you can make salt by burning the metal sodium in chlorine , and if you put in other metals like aluminium or iron they will also react . aluminium reacts to form aluminium trichloride which is the salt of aluminium and iron will similarly react to form iron chloride , and most metals but not all of them will react with chlorine : lead will not for example .
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which common salt you will obtain in the reaction between metallic sodium and chlorine gas ?
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which of these entities has evolved the ability to manipulate an animal many times its size ? the answer is all of them . these are all parasites , organisms that live on or inside another host organism , which they harm and sometimes even kill . parasite survival depends on transmitting from one host to the next , sometimes through an intermediate species . our parasites elegantly achieve this by manipulating their host 's behavior , sometimes through direct brain hijacking . for example , this is the gordian worm . one of its hosts , this cricket . the gordian worm needs water to mate , but the cricket prefers dry land . so once it 's big enough to reproduce , the worm produces proteins that garble the cricket 's navigational system . the confused cricket jumps around erratically , moves closer to water , and eventually leaps in , often drowning in the process . the worm then wriggles out to mate and its eggs get eaten by little water insects that mature , colonize land , and are , in turn , eaten by new crickets . and thus , the gordian worm lives on . and here 's the rabies virus , another mind-altering parasite . this virus infects mammals , often dogs , and travels up the animal 's nerves to its brain where it causes inflammation that eventually kills the host . but before it does , it often increases its host 's aggressiveness and ramps up the production of rabies-transmitting saliva , while making it hard to swallow . these factors make the host more likely to bite another animal and more likely to pass the virus on when it does . and now , meet ophiocordyceps , also known as the zombie fungus . its host of choice is tropical ants that normally live in treetops . after ophiocordyceps spores pierce the ant 's exoskeleton , they set off convulsions that make the ant fall from the tree . the fungus changes the ant 's behavior , compelling it to wander mindlessly until it stumbles onto a plant leaf with the perfect fungal breeding conditions , which it latches onto . the ant then dies , and the fungus parasitizes its body to build a tall , thin stalk from its neck . within several weeks , the stalk shoots off spores , which turn more ants into six-legged leaf-seeking zombies . one of humanity 's most deadly assailants is a behavior-altering parasite , though if it 's any consolation , it 's not our brains that are being hijacked . i 'm talking about plasmodium , which causes malaria . this parasite needs mosquitoes to shuttle it between hosts , so it makes them bite more frequently and for longer . there 's also evidence that humans infected with malaria are more attractive to mosquitoes , which will bite them and transfer the parasite further . this multi-species system is so effective , that there are hundreds of millions of malaria cases every year . and finally , there are cats . do n't worry , there probably are n't any cats living in your body and controlling your thoughts . i mean , probably . but there is a microorganism called toxoplasma that needs both cats and rodents to complete its life cycle . when a rat gets infected by eating cat feces , the parasite changes chemical levels in the rat 's brain , making it less cautious around the hungry felines , maybe even attracted to them . this makes them easy prey , so these infected rodents get eaten and pass the parasite on . mind control successful . there 's even evidence that the parasite affects human behavior . in most cases , we do n't completely understand how these parasites manage their feats of behavior modification . but from what we do know , we can tell that they have a pretty diverse toolbox . gordian worms seem to affect crickets ' brains directly . the malaria parasite , on the other hand , blocks an enzyme that helps the mosquitoes feed , forcing them to bite over and over and over again . the rabies virus may cause that snarling , slobbering behavior by putting the immune system into overdrive . but whatever the method , when you think about how effectively these parasites control the behavior of their hosts , you may wonder how much of human behavior is actually parasites doing the talking . since more than half of the species on earth are parasites , it could be more than we think .
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these factors make the host more likely to bite another animal and more likely to pass the virus on when it does . and now , meet ophiocordyceps , also known as the zombie fungus . its host of choice is tropical ants that normally live in treetops .
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ants infected with ophiocordyceps are often called “ zombie ants. ” explain why .
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if you wake up one morning with 1,000 times the strength you had the night before , how will you handle delicate day-to-day tasks ? everything must seem so fragile to you since the scale of your strength has expanded one thousand times . you 'd have to be very careful when you 're shaking someone 's hand so you do n't end up breaking their bones or crushing everyone you hug . and using a fork to pick up a piece of broccoli from a styrofoam plate without driving the fork through the plate is going to be as difficult as brain surgery . say the day comes and you get the chance to save a damsel in distress falling from a helicopter . so , you hold out your arms , hoping to catch her . seconds later , you will find yourself holding her lifeless body . what happened ? well , pressure is force divided by area . the smaller the area , the bigger the pressure . this is why we can lift heavy objects without breaking our skin , but a tiny needle can make us bleed with just a little poke . the pressure that will be exerted on her body can be calculated by force divided by the area on the top of your arms that comes in contact with her . it does n't matter if your arms are strong enough to catch her body without breaking your bones . her spine is not strong enough to be caught by you without being damaged . even if you rip off the nearest door to provide a bigger area to catch her with , you still would n't be able to save her anyway . remember , it 's not the fall that kills her , but the sudden stop at the bottom . let 's say she 's falling from a 32 story building , about 300 feet , and you are 6 feet tall , maybe 10 feet on your tippy-toes , with your arms above your head holding a door , in hopes of distributing the pressure across a larger surface area , but all you 're doing is essentially moving the ground up by 10 feet . so , she 's now falling from 290 feet , instead of 300 feet , reaching the speed of 173 feet per second just before impact , not counting air resistance . it 's the equivalent of crashing at 94 miles per hour into a wall with a door in front of it . the only thing that could save her is flying . but that power comes with its own host of scientific issues . if you could fly , what you must do is fly up to her , start flying down at the speed she is falling , hold on to her , then gradually slow down until you come to a complete stop . this process requires a lot of cushion space between the point she starts falling and the ground . every second you waste on changing into your superhero costume and flying up to her height , her head is getting that much closer to the pavement ! if she 's falling from a high place , and you ca n't get to her until she 's only a few feet above the ground , there 's really nothing you can do other than magically turn the pavement into marshmellow to allow her enough time to slowly come to a stop . then , break out the chocolate and graham crackers and you 've got s'mores . mmmm , delicious ! 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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if you wake up one morning with 1,000 times the strength you had the night before , how will you handle delicate day-to-day tasks ? everything must seem so fragile to you since the scale of your strength has expanded one thousand times .
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if you wake up one morning with 1,000 times the strength you had the night before , you ’ d have to be careful when you are
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pumpkins are a mighty squash - and they 're actually the exact same species as a lot of other squash . acorn squash , yellow squash , spaghetti squash , and even zucchini . that means a zucchini and a pumpkin can breed and have little babies zumpkins or , maybe ... pumpkinis ? the latin name for pumpkins is cucurbita pepo , which just means gourd melon , a truly uninspired bit of naming . like all fruit , pumpkins are both a trick and a treat – the seeds are hidden inside a delicious , brightly covered package so animals to will eat them , and then spread them around . pumpkin seeds ( or pepitas ) have evolved tough shells that can survive the exciting journey through an animal 's digestive tract . in russia , some believe that eating pumpkin seeds can help get rid of parasitic worms . it 's not clear if that really works in humans but there is a real published study in which pumpkin seeds helped de-worm ostriches . pumpkins come from the americas - they were actually one of the first plants domesticated here 8-10 thousand years ago . when the pilgrims arrived in 1620 they ate a lot of pumpkins . they even wrote a poem about . that rhyme scheme was not great , but maybe that ’ s because the pilgrims were also making a lot of beer with their pumpkins . pumpkin beer was already a thing way back in the 17th century sorry hipsters ! people once thought they could get rid of freckles by putting mashed-up pumpkin on there faces . and in all fairness that probably did distract from the freckles . explorers soon brought pumpkins back to europe . it was only 1697 when a frenchman incorporated a pumpkin into the popular folktale we know as cinderella . that was actually a very specific variety of pumpkin - a red pumpkin – and there are lots of other colors . yellow , white , even blue . and all pumpkins start out green – their skin is full of green chlorophyll that photosynthesizes just like in a leaf . as the pumpkin ripens , the chlorophyll breaks down , and other pigments like orange carotene become visible . you know how they gas green tomatoes to turn them red ? it 's called ethylene - and its given off by a lot of ripening fruits . so if you have an unripe green pumpkin and you want to change its color , put it in a bag with some old apples and wait a few days . the jack-o-lantern has its roots in europe the story goes that a sinful man named stingy jack tricked the devil to get out of of hell but also was n't allowed into heaven so he was forced to wander the earth with only a single coal for a light . in the british isles , people used turnips to carve their own jack-o-lanterns , but when they got to the americas they must have realized : these will work waaaaay better .
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explorers soon brought pumpkins back to europe . it was only 1697 when a frenchman incorporated a pumpkin into the popular folktale we know as cinderella . that was actually a very specific variety of pumpkin - a red pumpkin – and there are lots of other colors .
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in 1697 a frenchman incorporated a pumpkin into what famous children 's folk tale ?
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austrian physicist erwin schrödinger is one of the founders of quantum mechanics , but he 's most famous for something he never actually did : a thought experiment involving a cat . he imagined taking a cat and placing it in a sealed box with a device that had a 50 % chance of killing the cat in the next hour . at the end of that hour , he asked , `` what is the state of the cat ? '' common sense suggests that the cat is either alive or dead , but schrödinger pointed out that according to quantum physics , at the instant before the box is opened , the cat is equal parts alive and dead , at the same time . it 's only when the box is opened that we see a single definite state . until then , the cat is a blur of probability , half one thing and half the other . this seems absurd , which was schrödinger 's point . he found quantum physics so philosophically disturbing , that he abandoned the theory he had helped make and turned to writing about biology . as absurd as it may seem , though , schrödinger 's cat is very real . in fact , it 's essential . if it were n't possible for quantum objects to be in two states at once , the computer you 're using to watch this could n't exist . the quantum phenomenon of superposition is a consequence of the dual particle and wave nature of everything . in order for an object to have a wavelength , it must extend over some region of space , which means it occupies many positions at the same time . the wavelength of an object limited to a small region of space ca n't be perfectly defined , though . so it exists in many different wavelengths at the same time . we do n't see these wave properties for everyday objects because the wavelength decreases as the momentum increases . and a cat is relatively big and heavy . if we took a single atom and blew it up to the size of the solar system , the wavelength of a cat running from a physicist would be as small as an atom within that solar system . that 's far too small to detect , so we 'll never see wave behavior from a cat . a tiny particle , like an electron , though , can show dramatic evidence of its dual nature . if we shoot electrons one at a time at a set of two narrow slits cut in a barrier , each electron on the far side is detected at a single place at a specific instant , like a particle . but if you repeat this experiment many times , keeping track of all the individual detections , you 'll see them trace out a pattern that 's characteristic of wave behavior : a set of stripes - regions with many electrons separated by regions where there are none at all . block one of the slits and the stripes go away . this shows that the pattern is a result of each electron going through both slits at the same time . a single electron is n't choosing to go left or right but left and right simultaneously . this superposition of states also leads to modern technology . an electron near the nucleus of an atom exists in a spread out , wave-like orbit . bring two atoms close together , and the electrons do n't need to choose just one atom but are shared between them . this is how some chemical bonds form . an electron in a molecule is n't on just atom a or atom b , but a+ b . as you add more atoms , the electrons spread out more , shared between vast numbers of atoms at the same time . the electrons in a solid are n't bound to a particular atom but shared among all of them , extending over a large range of space . this gigantic superposition of states determines the ways electrons move through the material , whether it 's a conductor or an insulator or a semiconductor . understanding how electrons are shared among atoms allows us to precisely control the properties of semiconductor materials , like silicon . combining different semiconductors in the right way allows us to make transistors on a tiny scale , millions on a single computer chip . those chips and their spread out electrons power the computer you 're using to watch this video . an old joke says that the internet exists to allow the sharing of cat videos . at a very deep level , though , the internet owes its existance to an austrian physicist and his imaginary cat .
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austrian physicist erwin schrödinger is one of the founders of quantum mechanics , but he 's most famous for something he never actually did : a thought experiment involving a cat . he imagined taking a cat and placing it in a sealed box with a device that had a 50 % chance of killing the cat in the next hour .
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schrödinger ’ s cat thought experiment raises deep philosophical issues about quantum mechanics , and physicists have been discussing it since 1935. discuss some ways this imaginary experiment runs into problems with our everyday intuition about how the world works .
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it should be alright ! there it goes ! aww , actually that ’ s quite spectacular at the end . and in my second-year , i think i love boron far too much i think , ‘ cause i talk about it too much . you love boron ? i love boron ! no , i used to do lots of chemistry with boron , i kind of moved away a little bit from boron now but i really like it . boron is an interesting element . it is one of the few that i have actually made myself when i was at school . boron sits on top of the group 13 . its atomic number is 5 , so it is a metalloid , so elemental boron is a metalloid which basically means that it has some of the properties of a non metal and some of the properties of a metal . i mixed an oxide of boron with magnesium , heated it up and then , it is a really dramatic reaction when you add water at the end to try and destroy the magnesium boride that has formed because you get puffs of gas coming off which burst into flames rather like little anti-aircraft guns . but boron itself was rather disappointing ; it ’ s a sort of brown powder . i mean there is a more of a powdery brown boron , there are several crystalline sort of types of alatropes of boron . there is one actually that is really , really hard , so the black crystalline boron is actually very , very hard . it ’ s just below diamond on mohs scale of hardness , so i believe . and actually in america , there is a town called boron . it ’ s in california , it ’ s got a population of around 2000 which actually was set up around the world ’ s biggest borax mine which is in california . well it used to be transported on trains of mules and the company that produced it used to have as their trademark a train of 20 mules sort of going along . of great interest to us chemists , well over the last sort of 50 , maybe sort of 60-70 years , have been the boron hydrides or borades . so boron hydrides are basically clusters of borons with hydrogens around them . and one of particular use and interest in the 50s was one called pentaborane , which basically : penta , five , it ’ s got five borons in it . and pentaborate was investigated during the cold war or in the early part of the cold war as being a rocket fuel . it actually burns with a green flame . they actually called it the ‘ green dragon ’ because it burns with a very , very hot green flame and also because it is pretty toxic , which i can actually show you if i … it is probably not going to be spectacular . and boron complexes or borax compounds are used in a variety of things . it is not a particularly expensive material . it is used in washing powder , particularly perborate which when you heat it up in the washing machine when the water gets to 60 degrees centigrade it turns into hydrogen peroxide which can then bleach the clothes and this is why the famous washing powder is called persil , because the ‘ per ’ stands for perborate and the ‘ sil ’ stands for silicate so it is really a mixture of perborate and silicate . ok so this isn ’ t pentaborane because pentaborane spontaneously combusts in the air . this is just benzene boronic acid . it ’ s an organic compound with some boron in it . so hopefully we can see , we should be able to see , if i can get some at the end of my spatula , that it should be able to burn with some sort of green flame . hey , there it is . you can also see a bit of yellow which is the organic bit going as well . it should be alright ! there it goes ! aww , actually that was quite spectacular at the end . ok .
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it is one of the few that i have actually made myself when i was at school . boron sits on top of the group 13 . its atomic number is 5 , so it is a metalloid , so elemental boron is a metalloid which basically means that it has some of the properties of a non metal and some of the properties of a metal . i mixed an oxide of boron with magnesium , heated it up and then , it is a really dramatic reaction when you add water at the end to try and destroy the magnesium boride that has formed because you get puffs of gas coming off which burst into flames rather like little anti-aircraft guns .
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is boron a metal or a non-metal ?
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before he turned physics upside down , a young albert einstein supposedly showed off his genius by devising a complex riddle involving this list of clues . can you resist tackling a brain teaser written by one of the smartest people in history ? let 's give it a shot . the world 's rarest fish has been stolen from the city aquarium . the police have followed the scent to a street with five identical looking houses . but they ca n't search all the houses at once , and if they pick the wrong one , the thief will know they 're on his trail . it 's up to you , the city 's best detective , to solve the case . when you arrive on the scene , the police tell you what they know . one : each house 's owner is of a different nationality , drinks a different beverage , and smokes a different type of cigar . two : each house 's interior walls are painted a different color . three : each house contains a different animal , one of which is the fish . after a few hours of expert sleuthing , you gather some clues . it may look like a lot of information , but there 's a clear logical path to the solution . solving the puzzle will be a lot like sudoku , so you may find it helpful to organize your information in a grid , like this . pause the video on the following screen to examine your clues and solve the riddle . answer in : 3 2 1 to start , you fill in the information from clues eight and nine . immediately , you also realize that since the norwegian is at the end of the street , there 's only one house next to him , which must be the one with the blue walls in clue fourteen . clue five says the green-walled house 's owner drinks coffee . it ca n't be the center house since you already know its owner drinks milk , but it also ca n't be the second house , which you know has blue walls . and since clue four says the green-walled house must be directly to the left of the white-walled one , it ca n't be the first or fifth house either . the only place left for the green-walled house with the coffee drinker is the fourth spot , meaning the white-walled house is the fifth . clue one gives you a nationality and a color . since the only column missing both these values is the center one , this must be the brit 's red-walled home . now that the only unassigned wall color is yellow , this must be applied to the first house , where clue seven says the dunhill smoker lives . and clue eleven tells you that the owner of the horse is next door , which can only be the second house . the next step is to figure out what the norwegian in the first house drinks . it ca n't be tea , clue three tells you that 's the dane . as per clue twelve , it ca n't be root beer since that person smokes bluemaster , and since you already assigned milk and coffee , it must be water . from clue fifteen , you know that the norwegian 's neighbor , who can only be in the second house , smokes blends . now that the only spot in the grid without a cigar and a drink is in the fifth column , that must be the home of the person in clue twelve . and since this leaves only the second house without a drink , the tea-drinking dane must live there . the fourth house is now the only one missing a nationality and a cigar brand , so the prince-smoking german from clue thirteen must live there . through elimination , you can conclude that the brit smokes pall mall and the swede lives in the fifth house , while clue six and clue two tell you that these two have a bird and a dog , respectively . clue ten tells you that the cat owner lives next to the blend-smoking dane , putting him in the first house . now with only one spot left on the grid , you know that the german in the green-walled house must be the culprit . you and the police burst into the house , catching the thief fish-handed . while that explanation was straightforward , solving puzzles like this often involves false starts and dead ends . part of the trick is to use the process of elimination and lots of trial and error to hone in on the right pieces , and the more logic puzzles you solve , the better your intuition will be for when and where there 's enough information to make your deductions . and did young einstein really write this puzzle ? probably not . there 's no evidence he did , and some of the brands mentioned are too recent . but the logic here is not so different from what you 'd use to solve equations with multiple variables , even those describing the nature of the universe .
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solving the puzzle will be a lot like sudoku , so you may find it helpful to organize your information in a grid , like this . pause the video on the following screen to examine your clues and solve the riddle . answer in : 3 2 1 to start , you fill in the information from clues eight and nine .
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which of the following clues does not help you figure out that the green house is in the 4th spot ( after entering clues 8 and 9 ) ?
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jean-paul sartre made thinking and philosophy glamorous . he was born in paris in 1905 . his father , a navy captain , died when he was a baby – and he grew up extremely close to his mother until she remarried , much to his regret , when he was twelve . sartre spent most of his life in paris , where he often went to cafes on the left bank . he had a strabismus , a wandering eye , and wore distinctive , heavy glasses . he was very short ( five feet three inches ) and frequently described himself as ugly . by the 60 ’ s sartre was a household name in both europe and the united states , and so was his chosen philosophy , existentialism . sartre is famous principally for his book being and nothingness ( 1943 ) , which enhanced his reputation not so much because people could understand his ideas but because they could n't quite . existentialism was built around a number of key insights : one : things are weirder than we think sartre is acutely attentive to moments when the world reveals itself as far stranger and more uncanny than we normally admit ; moments when the logic we ascribe to it day-to-day becomes unavailable , showing things to be highly contingent and even absurd and frightening . sartre ’ s first novel – nausea , published in 1938 – is full of evocations of such moments . at one point , the hero , roquentin , a 30-year-old writer living in a fictional french seaside town , is on a tram . he puts his hand on the seat , but then pulls it back rapidly . instead of being the most basic and obvious piece of design , scarcely worth a moment ’ s notice , the seat promptly strikes him as deeply strange ; the word ‘ seat ’ comes loose from its moorings , the object it refers to shines forth in all its primordial oddity , as if he ’ s never seen one before . roquentin has to force himself to remember that this thing beside him is something for people to sit on . for a terrifying moment , roquentin has peered into what sartre calls the ‘ absurdity of the world. ’ such a moment goes to the heart of sartre ’ s philosophy . to be sartrean is to be aware of existence as it is when it has been stripped of any of the prejudices and stabilising assumptions lent to us by our day-to-day routines . we can try out a sartrean perspective on many aspects of our own lives . think of what you know as ‘ the evening meal with your partner ’ . under such a description , it all seems fairly logical , but a sartrean would strip away the surface normality to show the radical strangeness lurking beneath . dinner really means that : when your part of the planet has spun away from the energy of a distant hydrogen and helium explosion , you slide your knees under strips of a chopped-up tree and put sections of dead animals and plants in your mouth and chew , while next to you , another mammal whose genitals you sometimes touch is doing the same . two : we are free such weird moments are certainly disorienting and rather scary , but sartre wants to draw our attention to them for one central reason : because of their liberating dimensions . life is a lot odder than we think , but it ’ s also as a consequence far richer in possibilities . things don ’ t have to be quite the way they are . in the course of fully realising our freedom , we will come up against what sartre calls the ‘ angoisse ’ or ‘ anguish ’ of existence . everything is ( terrifyingly ) possible because nothing has any pre-ordained , god-given sense or purpose . humans are just making it up as they go along , and are free to cast aside the shackles at any moment . three : we shouldn ’ t live in ‘ bad faith ’ sartre gave a term to the phenomenon of living without taking freedom properly on board . he called it bad faith . we are in bad faith whenever we tell ourselves that things have to be a certain way and shut our eyes to other options . it is bad faith to insist that we have to do a particular kind of work or live with a specific person or make our home in a given place . the most famous description of ‘ bad faith ’ comes in being and nothingness , when sartre notices a waiter who strikes him as overly devoted to his role , as if he were first and foremost a waiter rather than a free human being . his movement is quick and forward , a little too precise , a little too rapid . he comes towards the patrons with a step that is a little too quick . he bends forward a little too eagerly : his voice , his eyes express an interest a little too solicitous for the order of the customer… ’ the man ( he was probably modelled on someone in saint-germain ’ s café de flore ) has convinced himself that he is essentially , necessarily a waiter rather than a free creature who could be a jazz pianist or a fisherman on a north sea trawler . four : we 're free to dismantle capitalism . the one factor that most discourages people from experiencing themselves as free is money . most of us will shut down a range of possible options ( moving abroad , trying out a new career , leaving a partner ) by saying , ‘ that ’ s if i didn ’ t have to worry about money . ' this passivity in the face of money enraged sartre at a political level . he thought of capitalism as a giant machine designed to create a sense of necessity which doesn ’ t in fact exist in reality : it makes us tell ourselves we have to work a certain number of hours , buy a particular product or service , and so on . but in this , there is only the denial of freedom – and a refusal to take as seriously as we should the possibility of living in other ways . it was because of these views that sartre had a life long interest in marxism . marxism seemed in theory to allow people to explore their freedom , by reducing the role played in their lives by material considerations . sartre took part in many protests in the streets of paris in the 60s . arrested yet again in 1968 , president charles de gaulle had him pardoned , saying , “ you don ’ t arrest voltaire. ” sartre also visited fidel castro and che guevara and admired them both deeply . as a result of these connections and his radical politics , the fbi kept a large file on sartre trying to deduce what his suspicious philosophy might really mean . sartre is inspiring in his insistence that things do not have to be the way they are . he is hugely alive to our unfulfilled potential , as individuals and as a species . he urges us to accept the fluidity of existence and to create new institutions , habits , outlooks and ideas . the admission that life doesn ’ t have some preordained logic and is not inherently meaningful can be a source of immense relief when we feel oppressed by the weight of tradition and the status quo .
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things don ’ t have to be quite the way they are . in the course of fully realising our freedom , we will come up against what sartre calls the ‘ angoisse ’ or ‘ anguish ’ of existence . everything is ( terrifyingly ) possible because nothing has any pre-ordained , god-given sense or purpose .
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what is `` angoisse ? ''
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some of the issues that are important if you want to have people in space for long periods of time . one is that people will tend to lose bone and muscle mass . we know this . if you have to put a cast on your leg , and you take the cast off after a few weeks , you 'll see that your muscles have shrunk in size . and if you measured the bone strength , you 'd also see that might have gone down a little bit , too . and so , it 's very interesting that our body has that ability to adapt to the loads that are put on it , so that bones and muscles are n't static , they 're always changing . while we think of bone as being a solid thing that does n't change very much , it changes too . and it turns out that in weightlessness , you lose bone . and then you also cause the muscles that work against gravity , what are called the postural muscles , they 'll start to shrink and lose strength . there are other things in the cardiovascular system , the heart and blood vessels . and if you think about it , standing up in gravity means you have to work against gravity in order to keep blood pumping to your head . so , if you could n't keep blood pumping in the head , you 'd pass out every time you stood up because when you 're lying down , you do n't have to push against gravity . but when you stand up , you got to work against gravity to keep blood flowing to your head . and your heart and blood vessels have a really nicely worked-out system to make that happen every time . but that system can also change in weightlessness . and then the other area that changes is the system that has to do with balance . again , maintaining your balance is something that you 're doing against gravity , right ? if you did n't have gravity present , you would n't have to worry about falling . but you obviously do have to worry about falling , and we have a very highly developed sense of balance to keep us upright and to prevent us from falling . and when you see what skaters do , you realize just how exquisite a system it is . but when you go into weightlessness , your balance system changes . you do n't really notice it while you are in weightlessness , but when you come back , you do notice it , that your balance has changed and you have a little bit of trouble maintaining your balance . and what it shows is that while you 're in space , your brain is trying to allow you to function in weightlessness . and so , it re-adapts you to be weightless , which you do n't notice until you come back and find out that you 're now back on earth with a balance system that 's been adapted to space . you know , all life developed here on earth with gravity being present , so life evolved under the influence of gravity , and then we grow up with gravity being present , so we learn how to walk and catch a ball and ice skate or whatever , all with gravity being present . and what if you were to grow up without gravity ? what about the systems that depend on gravity , like your muscles or your balance system or the heart and blood vessels ? would they develop normally , or would they be different in some way ? one reason why you might think that it would go down a different pathway is from an experiment that was done some time ago by two neuroscientists called hubel and wiesel . and what they did is they had a kitten , and they put a patch over the eye of the kitten . and then the kitten grew up to be a cat , and they removed the patch . and so , the question is , can the cat see out of that eye ? now , there 's nothing wrong with the eye , right ? but it just has n't seen anything , there has n't been any light coming in . and the answer is that the cat ca n't see out of that eye because what happens is that the brain goes down a different pathway when it develops and the connections that would ordinarily develop to that eye do n't develop . and that ca n't be undone , that 's a permanent change . so , the brain of that cat is fundamentally different from the brain of a cat that grew up seeing out of that eye . that cat grew up with a different brain , in essence . so , then you wonder , well , what about gravity ? what if you do n't have the forces that gravity produces ? is your balance organ going to develop in the same way , or will it be different ? if somebody grew up in space , could they come back to earth and function , or would they really be a different person ?
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you know , all life developed here on earth with gravity being present , so life evolved under the influence of gravity , and then we grow up with gravity being present , so we learn how to walk and catch a ball and ice skate or whatever , all with gravity being present . and what if you were to grow up without gravity ? what about the systems that depend on gravity , like your muscles or your balance system or the heart and blood vessels ?
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you must worry about all of the following when considering an environment without gravity :
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mastering any physical skill , be it performing a pirouette , playing an instrument , or throwing a baseball , takes practice . practice is the repetition of an action with the goal of improvement , and it helps us perform with more ease , speed , and confidence . so what does practice do in our brains to make us better at things ? our brains have two kinds of neural tissue : grey matter and white matter . the grey matter processes information in the brain , directing signals and sensory stimuli to nerve cells , while white matter is mostly made up of fatty tissue and nerve fibers . in order for our bodies to move , information needs to travel from the brain 's grey matter , down the spinal cord , through a chain of nerve fibers called axons to our muscles . so how does practice or repetition affect the inner workings of our brains ? the axons that exist in the white matter are wrapped with a fatty substance called myelin . and it 's this myelin covering , or sheath , that seems to change with practice . myelin is similar to insulation on electrical cables . it prevents energy loss from electrical signals that the brain uses , moving them more efficiently along neural pathways . some recent studies in mice suggest that the repetition of a physical motion increases the layers of myelin sheath that insulates the axons . and the more layers , the greater the insulation around the axon chains , forming a sort of superhighway for information connecting your brain to your muscles . so while many athletes and performers attribute their successes to muscle memory , muscles themselves do n't really have memory . rather , it may be the myelination of neural pathways that gives these athletes and performers their edge with faster and more efficient neural pathways . there are many theories that attempt to quantify the number of hours , days , and even years of practice that it takes to master a skill . while we do n't yet have a magic number , we do know that mastery is n't simply about the amount of hours of practice . it 's also the quality and effectiveness of that practice . effective practice is consistent , intensely focused , and targets content or weaknesses that lie at the edge of one 's current abilities . so if effective practice is the key , how can we get the most out of our practice time ? try these tips . focus on the task at hand . minimize potential distractions by turning off the computer or tv and putting your cell phone on airplane mode . in one study , researchers observed 260 students studying . on average , those students were able to stay on task for only six minutes at a time . laptops , smartphones , and particularly facebook were the root of most distractions . start out slowly or in slow-motion . coordination is built with repetitions , whether correct or incorrect . if you gradually increase the speed of the quality repetitons , you have a better chance of doing them correctly . next , frequent repetitions with allotted breaks are common practice habits of elite performers . studies have shown that many top athletes , musicians , and dancers spend 50-60 hours per week on activities related to their craft . many divide their time used for effective practice into multiple daily practice sessions of limited duration . and finally , practice in your brain in vivid detail . it 's a bit surprising , but a number of studies suggest that once a physical motion has been established , it can be reinforced just by imagining it . in one study , 144 basketball players were divided into two groups . group a physically practiced one-handed free throws while group b only mentally practiced them . when they were tested at the end of the two week experiment , the intermediate and experienced players in both groups had improved by nearly the same amount . as scientists get closer to unraveling the secrets of our brains , our understanding of effective practice will only improve . in the meantime , effective practice is the best way we have of pushing our individual limits , achieving new heights , and maximizing our potential .
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and the more layers , the greater the insulation around the axon chains , forming a sort of superhighway for information connecting your brain to your muscles . so while many athletes and performers attribute their successes to muscle memory , muscles themselves do n't really have memory . rather , it may be the myelination of neural pathways that gives these athletes and performers their edge with faster and more efficient neural pathways .
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in actuality , muscle memory is :
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the area surrounding the north pole may seem like a frozen and desolate environment where nothing ever changes . but it is actually a complex and finely balanced natural system , and its extreme location makes it vulnerable to feedback processes that can magnify even tiny changes in the atmosphere . in fact , scientists often describe the arctic as the canary in the coal mine when it comes to predicting the impact of climate change . one major type of climate feedback involves reflectivity . white surfaces , like snow and ice , are very effective at reflecting the sun 's energy back into space , while darker land and water surfaces absorb much more incoming sunlight . when the arctic warms just a little , some of the snow and ice melts , exposing the ground and ocean underneath . the increased heat absorbed by these surfaces causes even more melting , and so on . and although the current situation in the arctic follows the warming pattern , the opposite is also possible . a small drop in temperatures would cause more freezing , increasing the amount of reflective snow and ice . this would result in less sunlight being absorbed , and lead to a cycle of cooling , as in previous ice ages . arctic sea ice is also responsible for another feedback mechanism through insulation . by forming a layer on the ocean 's surface , the ice acts as a buffer between the frigid arctic air and the relatively warmer water underneath . but when it thins , breaks , or melts in any spot , heat escapes from the ocean , warming the atmosphere and causing more ice to melt in turn . both of these are examples of positive feedback loops , not because they do something good , but because the initial change is amplified in the same direction . a negative feedback loop , on the other hand , is when the initial change leads to effects that work in the opposite direction . melting ice also causes a type of negative feedback by releasing moisture into the atmosphere . this increases the amount and thickness of clouds present , which can cool the atmosphere by blocking more sunlight . but this negative feedback loop is short-lived , due to the brief arctic summers . for the rest of the year , when sunlight is scarce , the increased moisture and clouds actually warm the surface by trapping the earth 's heat , turning the feedback loop positive for all but a couple of months . while negative feedback loops encourage stability by pushing a system towards equilibrium , positive feedback loops destabilize it by enabling larger and larger deviations . and the recently increased impact of positive feedbacks may have consequences far beyond the arctic . on a warming planet , these feedbacks ensure that the north pole warms at a faster rate than the equator . the reduced temperature differences between the two regions may lead to slower jet stream winds and less linear atmospheric circulation in the middle latitudes , where most of the world 's population lives . many scientists are concerned that shifts in weather patterns will last longer and be more extreme , with short term fluctuations becoming persistent cold snaps , heat waves , droughts and floods . so the arctic sensitivity does n't just serve as an early warning alarm for climate change for the rest of the planet . its feedback loops can affect us in much more direct and immediate ways . as climate scientists often warn , what happens in the arctic does n't always stay in the arctic .
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while negative feedback loops encourage stability by pushing a system towards equilibrium , positive feedback loops destabilize it by enabling larger and larger deviations . and the recently increased impact of positive feedbacks may have consequences far beyond the arctic . on a warming planet , these feedbacks ensure that the north pole warms at a faster rate than the equator .
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there is an old saying that goes : “ the rich get richer ” . give possible explanations for the popularity of this phrase , and note any places that feedbacks may contribute to the explanations .
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i 'm changing my tie to an alkali metal tie . you have an alkali metal tie ? it 's a new tie i just got . this one 's a dutch one . i was given it on saturday so here you can see we have the alkali metals ( and where are they ? ) here . and the alkali metals are very reactive . so , we 've seen that lithium does n't react very much but then as you go to sodium and then to potassium and rubidium the violence of the reaction gets more and more and more . in cesium it 's even greater . i do n't know wether the people making this tie were so frightened that they did n't put it on . but in each of these cases the reaction is removing one electron after another , one electron from the outer shell of the atom , and the bigger the atom , the easier it is to remove the electron . and as you go down the periodic table , the size of the atom increases so it 's easier to remove the electron . so francium would almost certainly be even bigger than cesium , because it 's a whole row lower down . and so , that should react with water with enormous violence . but , unfortunately , francium is very radioactive and you ca n't get a nice lump of francium the sort of size that you 'd like to throw in water to make the youtube video of the century . francium was named after france , was discovered by one of madame curie 's pupils in 1939 , five years after madame curie herself died . i always thought it was madame curie herself that discovered it but in fact it was discovered after her death . but its properties would probably be similar to those of cesium if it was not very radioactive . but radioactivity like that makes it very difficult for chemists to study the chemistry in enormous detail . chemical reactions are really quite sensitive to temperature and radioactive materials , as they decay , give out energy so the compounds themselves tend to heat up . a lump of plutonium , which is very radioactive , is really quite warm to touch . and francium , which i think is more radioactive , is probably very warm . so i think the melting point of francium will be lower than that of cesium because the melting points go down the group , and because it will be generating heat , almost certainly francium will be liquid at room temperature . but i 've never seen it . it might well be colored , as well , because cesium is golden colored so i would not be surprised if francium was red . but i have no idea . and i 'm not sure if anybody knows . . . . . . . . . . . . . captions by www.subply.com
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and as you go down the periodic table , the size of the atom increases so it 's easier to remove the electron . so francium would almost certainly be even bigger than cesium , because it 's a whole row lower down . and so , that should react with water with enormous violence . but , unfortunately , francium is very radioactive and you ca n't get a nice lump of francium the sort of size that you 'd like to throw in water to make the youtube video of the century . francium was named after france , was discovered by one of madame curie 's pupils in 1939 , five years after madame curie herself died .
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why didn ’ t we see pete throw a lump of francium in water , as we saw him do with the other alkaline metals ?
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denis diderot left a dungeon outside paris on november 3 , 1749 . he 'd had his writing burned in public before , but this time , he 'd gotten locked up under royal order for an essay about a philosopher 's death bed rejection of god . to free himself , denis promised never to write things like that again . so he got back to work on something a little like that , only way worse , and much bigger . in 1745 , publisher andré le breton had hired diderot to adapt the english cyclopedia , or a universal dictionary of arts and sciences for french subscribers . a broke writer , diderot survived by translating , tutoring , and authoring sermons for priests , and a pornographic novel once . le breton paired him with co-editor jean le rond d'alembert , a math genius found on a church doorstep as a baby . technical dictionaries , like the cyclopedia , were n't new , but no one had attempted one publication covering all knowledge , so they did . the two men organized the french enlightenment 's brightest stars to produce the first encyclopedia , or rational dictionary of the arts , sciences , and crafts . assembling every essential fact and principle in , as it turned out , over 70,000 entries , 20,000,000 words in 35 volumes of text and illustrations created over three decades of researching , writing , arguging , smuggling , backstabbing , law-breaking , and alphabetizing . to organize the work , diderot adapted francis bacon 's `` classification of knowledge '' into a three-part system based on the mind 's approaches to reality : memory , reason , and imagination . he also emphasized the importance of commerce , technology , and crafts , poking around shops to study the tools and techniques of parisian laborers . to spotlight a few of the nearly 150 philosoph contributers , jean jacques rousseau , diderot 's close friend , wrote much of the music section in three months , and was never reimbursed for copy fees . his entry on political economy holds ideas he 'd later develop further in `` the social contract . '' d'alembert wrote the famous preliminary discourse , a key statement of the french enlightenment , championing independent investigative reasoning as the path to progress . louis de jaucourt wrote a quarter of the encyclopedia , 18,000 articles , 5,000,000 words , unpaid . louis once spent 20 years writing a book on anatomy , shipped it to amsterdam to be published uncensored , and the ship sank . voltaire contributed entries , among them history , elegance , and fire . diderot 's entries sometimes exhibit slight bias . in `` political authority , '' he dismantled the divine right of kings . under `` citizen , '' he argued a state was strongest without great disparity in wealth . not surprising from the guy who wrote poetry about mankind strangling its kings with the entrails of a priest . so diderot 's masterpiece was n't a hit with the king or highest priest . upon release of the first two volumes , louie xv banned the whole thing but enjoyed his own copy . pope clement xiii ordered it burned . it was `` dangerous , '' `` reprehensible , '' as well as `` written in french , '' and in `` the most seductive style . '' he declared readers excommunicated and wanted diderot arrested on sight . but diderot kept a step ahead of being shut down , smuggling proofs outside france for publication , and getting help from allies in the french regime , including the king 's mistress , madame de pompadour , and the royal librarian and censor , malesherbes , who tipped diderot off to impending raids , and even hid diderot 's papers at his dad 's house . still , he faced years of difficulty . d'alembert dropped out . rousseau broke off his friendship over a line in a play . worse yet , his publisher secretly edited some proofs to read less radically . the uncensored pages reappeared in russia in 1933 , long after diderot had considered the work finished and died at lunch . the encyclopedia he left behind is many things : a cornerstone of the enlightenment , a testament to france 's crisis of authority , evidence of popular opinions migration from pulpit and pew to cafe , salon , and press . it even has recipes . it 's also irrepressibly human , as you can tell from diderot 's entry about a plant named aguaxima . read it yourself , preferably out loud in a french accent .
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d'alembert wrote the famous preliminary discourse , a key statement of the french enlightenment , championing independent investigative reasoning as the path to progress . louis de jaucourt wrote a quarter of the encyclopedia , 18,000 articles , 5,000,000 words , unpaid . louis once spent 20 years writing a book on anatomy , shipped it to amsterdam to be published uncensored , and the ship sank .
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how might an opponent of the encyclopedia argue against its publication ?
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there 's a man by the name of captain william swenson who recently was awarded the congressional medal of honor for his actions on september 8 , 2009 . on that day , a column of american and afghan troops were making their way through a part of afghanistan to help protect a group of government officials , a group of afghan government officials , who would be meeting with some local village elders . the column came under ambush , and was surrounded on three sides , and amongst many other things , captain swenson was recognized for running into live fire to rescue the wounded and pull out the dead . one of the people he rescued was a sergeant , and he and a comrade were making their way to a medevac helicopter . and what was remarkable about this day is , by sheer coincidence , one of the medevac medics happened to have a gopro camera on his helmet and captured the whole scene on camera . it shows captain swenson and his comrade bringing this wounded soldier who had received a gunshot to the neck . they put him in the helicopter , and then you see captain swenson bend over and give him a kiss before he turns around to rescue more . i saw this , and i thought to myself , where do people like that come from ? what is that ? that is some deep , deep emotion , when you would want to do that . there 's a love there , and i wanted to know why is it that i do n't have people that i work with like that ? you know , in the military , they give medals to people who are willing to sacrifice themselves so that others may gain . in business , we give bonuses to people who are willing to sacrifice others so that we may gain . we have it backwards . right ? so i asked myself , where do people like this come from ? and my initial conclusion was that they 're just better people . that 's why they 're attracted to the military . these better people are attracted to this concept of service . but that 's completely wrong . what i learned was that it 's the environment , and if you get the environment right , every single one of us has the capacity to do these remarkable things , and more importantly , others have that capacity too . i 've had the great honor of getting to meet some of these , who we would call heroes , who have put themselves and put their lives at risk to save others , and i asked them , `` why would you do it ? why did you do it ? '' and they all say the same thing : `` because they would have done it for me . '' it 's this deep sense of trust and cooperation . so trust and cooperation are really important here . the problem with concepts of trust and cooperation is that they are feelings , they are not instructions . i ca n't simply say to you , `` trust me , '' and you will . i ca n't simply instruct two people to cooperate , and they will . it 's not how it works . it 's a feeling . so where does that feeling come from ? if you go back 50,000 years to the paleolithic era , to the early days of homo sapiens , what we find is that the world was filled with danger , all of these forces working very , very hard to kill us . nothing personal . whether it was the weather , lack of resources , maybe a saber-toothed tiger , all of these things working to reduce our lifespan . and so we evolved into social animals , where we lived together and worked together in what i call a circle of safety , inside the tribe , where we felt like we belonged . and when we felt safe amongst our own , the natural reaction was trust and cooperation . there are inherent benefits to this . it means i can fall asleep at night and trust that someone from within my tribe will watch for danger . if we do n't trust each other , if i do n't trust you , that means you wo n't watch for danger . bad system of survival . the modern day is exactly the same thing . the world is filled with danger , things that are trying to frustrate our lives or reduce our success , reduce our opportunity for success . it could be the ups and downs in the economy , the uncertainty of the stock market . it could be a new technology that renders your business model obsolete overnight . or it could be your competition that is sometimes trying to kill you . it 's sometimes trying to put you out of business , but at the very minimum is working hard to frustrate your growth and steal your business from you . we have no control over these forces . these are a constant , and they 're not going away . the only variable are the conditions inside the organization , and that 's where leadership matters , because it 's the leader that sets the tone . when a leader makes the choice to put the safety and lives of the people inside the organization first , to sacrifice their comforts and sacrifice the tangible results , so that the people remain and feel safe and feel like they belong , remarkable things happen . i was flying on a trip , and i was witness to an incident where a passenger attempted to board before their number was called , and i watched the gate agent treat this man like he had broken the law , like a criminal . he was yelled at for attempting to board one group too soon . so i said something . i said , `` why do you have treat us like cattle ? why ca n't you treat us like human beings ? '' and this is exactly what she said to me . she said , `` sir , if i do n't follow the rules , i could get in trouble or lose my job . '' all she was telling me is that she does n't feel safe . all she was telling me is that she does n't trust her leaders . the reason we like flying southwest airlines is not because they necessarily hire better people . it 's because they do n't fear their leaders . you see , if the conditions are wrong , we are forced to expend our own time and energy to protect ourselves from each other , and that inherently weakens the organization . when we feel safe inside the organization , we will naturally combine our talents and our strengths and work tirelessly to face the dangers outside and seize the opportunities . the closest analogy i can give to what a great leader is , is like being a parent . if you think about what being a great parent is , what do you want ? what makes a great parent ? we want to give our child opportunities , education , discipline them when necessary , all so that they can grow up and achieve more than we could for ourselves . great leaders want exactly the same thing . they want to provide their people opportunity , education , discipline when necessary , build their self-confidence , give them the opportunity to try and fail , all so that they could achieve more than we could ever imagine for ourselves . charlie kim , who 's the ceo of a company called next jump in new york city , a tech company , he makes the point that if you had hard times in your family , would you ever consider laying off one of your children ? we would never do it . then why do we consider laying off people inside our organization ? charlie implemented a policy of lifetime employment . if you get a job at next jump , you can not get fired for performance issues . in fact , if you have issues , they will coach you and they will give you support , just like we would with one of our children who happens to come home with a c from school . it 's the complete opposite . this is the reason so many people have such a visceral hatred , anger , at some of these banking ceos with their disproportionate salaries and bonus structures . it 's not the numbers . it 's that they have violated the very definition of leadership . they have violated this deep-seated social contract . we know that they allowed their people to be sacrificed so they could protect their own interests , or worse , they sacrificed their people to protect their own interests . this is what so offends us , not the numbers . would anybody be offended if we gave a $ 150 million bonus to gandhi ? how about a $ 250 million bonus to mother teresa ? do we have an issue with that ? none at all . none at all . great leaders would never sacrifice the people to save the numbers . they would sooner sacrifice the numbers to save the people . bob chapman , who runs a large manufacturing company in the midwest called barry-wehmiller , in 2008 was hit very hard by the recession , and they lost 30 percent of their orders overnight . now in a large manufacturing company , this is a big deal , and they could no longer afford their labor pool . they needed to save 10 million dollars , so , like so many companies today , the board got together and discussed layoffs . and bob refused . you see , bob does n't believe in head counts . bob believes in heart counts , and it 's much more difficult to simply reduce the heart count . and so they came up with a furlough program . every employee , from secretary to ceo , was required to take four weeks of unpaid vacation . they could take it any time they wanted , and they did not have to take it consecutively . but it was how bob announced the program that mattered so much . he said , it 's better that we should all suffer a little than any of us should have to suffer a lot , and morale went up . they saved 20 million dollars , and most importantly , as would be expected , when the people feel safe and protected by the leadership in the organization , the natural reaction is to trust and cooperate . and quite spontaneously , nobody expected , people started trading with each other . those who could afford it more would trade with those who could afford it less . people would take five weeks so that somebody else only had to take three . leadership is a choice . it is not a rank . i know many people at the seniormost levels of organizations who are absolutely not leaders . they are authorities , and we do what they say because they have authority over us , but we would not follow them . and i know many people who are at the bottoms of organizations who have no authority and they are absolutely leaders , and this is because they have chosen to look after the person to the left of them , and they have chosen to look after the person to the right of them . this is what a leader is . i heard a story of some marines who were out in theater , and as is the marine custom , the officer ate last , and he let his men eat first , and when they were done , there was no food left for him . and when they went back out in the field , his men brought him some of their food so that he may eat , because that 's what happens . we call them leaders because they go first . we call them leaders because they take the risk before anybody else does . we call them leaders because they will choose to sacrifice so that their people may be safe and protected and so their people may gain , and when we do , the natural response is that our people will sacrifice for us . they will give us their blood and sweat and tears to see that their leader 's vision comes to life , and when we ask them , `` why would you do that ? why would you give your blood and sweat and tears for that person ? '' they all say the same thing : `` because they would have done it for me . '' and is n't that the organization we would all like to work in ? thank you very much . thank you . ( applause ) thank you . ( applause )
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we want to give our child opportunities , education , discipline them when necessary , all so that they can grow up and achieve more than we could for ourselves . great leaders want exactly the same thing . they want to provide their people opportunity , education , discipline when necessary , build their self-confidence , give them the opportunity to try and fail , all so that they could achieve more than we could ever imagine for ourselves . charlie kim , who 's the ceo of a company called next jump in new york city , a tech company , he makes the point that if you had hard times in your family , would you ever consider laying off one of your children ?
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have you ever had poor leaders in your life ? where do you think they could most improve ?
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in a time-lapse video , it looks like a monster coming alive . for a moment , it sits there innocuously . then , ripples move across its surface . it bulges outwards , bursting with weird boils . it triples in volume . its color darkens ominously , and its surface hardens into an alien topography of peaks and craters . then , the kitchen timer dings . your cookie is ready . what happened inside that oven ? do n't let the apron deceive you ! bakers are mad scientists . when you slide the pan into the oven , you 're setting off a series of chemical reactions that transform one substance , dough , into another , cookies . when the dough reaches 92 degrees fahrenheit , the butter inside melts , causing the dough to start spreading out . butter is an emulsion , or mixture of two substances that do n't want to stay together , in this case , water and fat , along with some dairy solids that help hold them together . as the butter melts , its trapped water is released . and as the cookie gets hotter , the water expands into steam . it pushes against the dough from the inside , trying to escape through the cookie walls like ridley scott 's chest-bursting alien . your eggs may have been home to squirming salmonella bacteria . an estimated 142,000 americans are infected this way each year . though salmonella can live for weeks outside a living body and even survive freezing , 136 degrees is too hot for them . when your dough reaches that temperature , they die off . you 'll live to test your fate with a bite of raw dough you sneak from your next batch . at 144 degrees , changes begin in the proteins , which come mostly from the eggs in your dough . eggs are composed of dozens of different kinds of proteins , each sensitive to a different temperature . in an egg fresh from the hen , these proteins look like coiled up balls of string . when they 're exposed to heat energy , the protein strings unfold and get tangled up with their neighbors . this linked structure makes the runny egg nearly solid , giving substance to squishy dough . water boils away at 212 degrees , so like mud baking in the sun , your cookie gets dried out and it stiffens . cracks spread across its surface . the steam that was bubbling inside evaporates , leaving behind airy pockets that make the cookie light and flaky . helping this along is your leavening agent , sodium bicarbonate , or baking soda . the sodium bicarbonate reacts with acids in the dough to create carbon dioxide gas , which makes airy pockets in your cookie . now , it 's nearly ready for a refreshing dunk in a cool glass of milk . one of science 's tastiest reactions occurs at 310 degrees . this is the temperature for maillard reactions . maillard reactions result when proteins and sugars break down and rearrange themselves , forming ring-like structures , which reflect light in a way that gives foods like thanksgiving turkey and hamburgers their distinctive , rich brown color . as this reaction occurs , it produces a range of flavor and aroma compounds , which also react with each other , forming even more complex tastes and smells . caramelization is the last reaction to take place inside your cookie . caramelization is what happens when sugar molecules break down under high heat , forming the sweet , nutty , and slightly bitter flavor compounds that define , well , caramel . and , in fact , if your recipe calls for a 350 degree oven , it 'll never happen , since caramelization starts at 356 degrees . if your ideal cookie is barely browned , like a northeasterner on a beach vacation , you could have set your oven to 310 degrees . if you like your cookies to have a nice tan , crank up the heat . caramelization continues up to 390 degrees . and here 's another trick : you do n't need that kitchen timer ; your nose is a sensitive scientific instrument . when you smell the nutty , toasty aromas of the maillard reaction and caramelization , your cookies are ready . grab your glass of milk , put your feet up , and reflect that science can be pretty sweet .
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you 'll live to test your fate with a bite of raw dough you sneak from your next batch . at 144 degrees , changes begin in the proteins , which come mostly from the eggs in your dough . eggs are composed of dozens of different kinds of proteins , each sensitive to a different temperature .
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where do most of the proteins in cookie dough come from ?
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element 113 is , again , labelled with this new systematic method for the artificial elements . so you have un-un-trium or it might be ununtrium , i don ’ t know , which stands for 113 . and you might actually ask , ‘ why should anybody want to make a few atoms of these artificial elements ? ’ and i think the answer , i don ’ t know definitely , is that there have been predictions that although the elements at this part of the periodic table are very unstable , that there may , at heavier elements , be one or two elements which are surprisingly stable , might last for very much longer . they are called ‘ islands of stability ’ that have been predicted , and so people are working systematically to see whether in fact there are one or two elements that are in fact really quite stable even though they are super heavy . and when i was a young researcher in the 1970s , somebody , i can ’ t remember who it was , got very excited because they thought in remnants of very ancient mineral mica , it ’ s a sort of mineral that comes in layers , that they found some strange patterns , which they thought was an indication of super heavy elements decaying , perhaps as heavy as element 164 . enormously heavier than anything anybody has been able to create in the lab . it turned out not to be as exciting as they thought and there was some other completely different explanation . but it is testing theories and things like that that really move science forward .
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so you have un-un-trium or it might be ununtrium , i don ’ t know , which stands for 113 . and you might actually ask , ‘ why should anybody want to make a few atoms of these artificial elements ? ’ and i think the answer , i don ’ t know definitely , is that there have been predictions that although the elements at this part of the periodic table are very unstable , that there may , at heavier elements , be one or two elements which are surprisingly stable , might last for very much longer . they are called ‘ islands of stability ’ that have been predicted , and so people are working systematically to see whether in fact there are one or two elements that are in fact really quite stable even though they are super heavy .
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what is the name for the concept that some superheavy elements might be more stable than lighter ones ?
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translator : andrea mcdonough reviewer : bedirhan cinar fourth and nineteen , folks , they 've got ta have a play as time 's ticking away because they 've got to stay in this ball game , they 've got to win . they come out lined up in the empty set , three receivers to the right , two to the left . defense looks like they 're gon na to man up with no safety . this is the exact offensive match-up that they want : the best receiver lined up against the linebacker . quarterback steps back to receive the ball , five yards deep in the gun . he takes a snap , drops three steps , he plants his back foot , he 's looking for an opening . there 's a blitz coming off the edge ! he steps up to avoid the rush . he 's looking down field . he 's got the inside receiver making a cut . he 's got a step on the linebacker . quarterback has a beat on it . he lets the ball go , it 's in the air ! receiver is out in front of the defender . he 's got it beat ! he 's out in front , racing for the ball ! it 's coming down ! he cradles it at the fifteen ! he 's at the ten , five ! touchdown ! unbelievable play ! now , wait a minute . of course , it 's believable , it 's physics , specifically the differences between scalars and vectors . so , let 's just see that replay . `` quarterback steps back to receive the ball , five yards deep in the gun . '' stop . see , measurements are defined as two different quantities . scalars are measurements with only numbers , and vectors are measurements with direction . for example , when that quarterback takes the snap , he 's five yards away , but from where ? back from the line of scrimmage , so the five yards by itself is a scalar quantity . when you add a direction , like five yards deep , it becomes a vector quantity . five yards - scalar , five yards deep - vector . ok , go ahead . `` he takes a snap , drops three steps . he plants his back foot , he 's looking for an opening . there 's a blitz coming off the edge ! he steps up to avoid the rush . '' whoa ! here 's a difference between distance and displacement . distance is a measurement without identifying where you moved . it 's a scalar quantity . when the quarterback makes a three-step drop , he moves about three yards back . when he moves about another three yards forward , when he steps up into the pocket , so that quarterback moves a total distance of six yards . that 's a distance , that 's a scalar . now , displacement is a vector quantity , describing about how far out of place the object is . so the quarterback dropped back three yards and then moved back forward three yards , he 's in the exact same place where he started . so , his displacement is zero yards . distance - six yards , displacement - zero yards . so , let 's look at what happened next . `` quarterback has a beat on it , he let 's the ball go ! it 's in the air ! receiver is out in front of the defender . '' stop . so , here 's speed and velocity , but let 's just do one thing at a time . so , speed is measurement without direction , it 's a scalar quantity . velocity is a vector quantity . it is that object 's speed , but with a direction of motion . so the receiver accelerates away , gaining both speed and distance . this takes the receiver 5 seconds to run those 50 yards . so his average speed , in any given time , is 10 yards/second . the linebacker tries to keep up , but his overall speed is slower , he only goes 35 yards in those 5 seconds , so his average speed is only 7 yards/second . they 're both traveling in a forward direction , so their velocity is also positive . you ca n't go from resting to your peak speed immediately . you 've got to build up to it . this is acceleration . at first the linebacker can keep up with that receiver , but eventually the faster receiver pulls away . that 's acceleration , the change in speed over time . acceleration is a vector quantity . it describes a rate at which an object changes velocity . like velocity , acceleration is a vector . it happens in a direction . so let 's just look at that play just one more time . `` quarterback steps back to receive the ball , five yards deep in the gun . '' vector ! `` he takes a snap , drops three steps , he plants his back foot . he 's looking for an opening . there 's a blitz coming off the edge ! he steps up to avoid the rush . '' displacement ! `` he 's got the inside receiver making a cut . he 's got a step on the linebacker . the quarterback has a beat on it . he let 's the ball go ! it 's in the air ! receiver is out in front of the defender ! '' velocity ! `` he 's got it beat ! he 's out in front , racing for the ball ! it 's coming down ! he cradles it at the fifteen , he 's at the ten , five ! '' acceleration ! `` touchdown ! unbelievable play ! that was a great play as time expired , resulting in the touchdown and ultimately the win and pure effort . '' and pure science .
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at first the linebacker can keep up with that receiver , but eventually the faster receiver pulls away . that 's acceleration , the change in speed over time . acceleration is a vector quantity .
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what type of line is always found on a graph of constant speed ?
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good evening ! what 's the matter ? are you afraid of vampires ? he he , no need to worry , i 'm not staying for dinner . ( laughter ) i 'm here to guide you through a brief history of vampires , illustrating how our image has changed from a shambling corpse to the dapper gentleman you see before you . vampires are nearly as old as you humans . stories about us , revenants , appear in cultures extending as far back as prehistoric times . but we were n't called vampires back then and most of us did not look the way we imagine vampires today . ha , far from it ! for example , the mesopotamian lamashtu was a creature with the head of a lion and the body of the donkey , and the ancient greek striges were simply described as bloodthirsty birds . others were even stranger . the philippine manananggal would sever her upper torso and sprout huge , bat-like wings to fly . the malaysian penanggalan was a flying female head with dangling entrails . ( laughter ) and the australian yara-ma-yha-who was a little red guy with a big head , a large mouth , and bloodsuckers on his hands and feet . oh , and let 's not forget the caribbean 's soucouyant , the west african obayifo , and the mexican tlahuelpuchi . ( laughter ) charming , are n't they ? though they may look vastly different , all of these beings have one common characteristic : they sustain themselves by consuming the life force of a living creature . this shared trait is what defines a vampire -- all the other attributes change with the tides . so , how do we arrive at the reanimated fellow you see before you ? our modern ideal emerges in 18th-century eastern europe . with the dramatic increase of vampire superstitions , stories of bloodsucking , shadowy creatures become nightly bedside terrors . and popular folklore , like the moroi among the romani people and the lugat in albania , provide the most common vampire traits known today , such as vampires being undead and nocturnal and shape-shifting . you see , eastern europe in the 18th century was a pretty grim place with many deaths occurring from unknown diseases and plagues . without medical explanations , people searched for supernatural causes and found what looked like evidence in the corpses of the victims . when villagers dug up bodies to discern the cause of the mysterious deaths , they would often find the cadavers looking very much alive -- longer hair and fingernails , bloated bellies , and blood at the corners of mouths . ( laughter ) clearly , these people were not really dead . heh , they were vampires ! and they had been leaving their graves to feast on the living . ( grunt ) the terrified villagers would quickly enact a ritual to kill the undead . the practices varied across the region , but usually included beheadings , burnings , and staking the body to the coffin to prevent it from getting up . ( laughter ) grizzly stuff ! but what the villagers interpreted as unholy reanimation were actually normal symptoms of death . when a body decomposes , the skin dehydrates , causing the hair and fingernails to extend . bacteria in the stomach creates gases that fill the belly , which force out blood and matter through the mouth . unfortunately , this science was not yet known , so the villagers kept digging . in fact , so many bodies were dug up that the empress of austria sent her physician around to disprove the vampire stories , and she even established a law prohibiting grave tampering . still , even after the vampire hunts had died down , the stories of legends survived in local superstition . this led to works of literature , such as polidori 's `` the vampyre , '' the gothic novel `` carmilla , '' and , most famously , bram stoker 's `` dracula . '' although stoker incorporated historical material , like elizabeth báthory 's virgin blood baths and the brutal executions of vlad dracul , it was these local myths that inspired the main elements of his story : the transylvanian setting , using garlic to defend oneself , and the staking of the heart . while these attributes are certainly familiar to us , elements he invented himself have also lasted over the years : fear of crucifixes , weakness in sunlight , and the vampire 's inability to see their reflection . by inventing new traits , stoker perfectly enacted the age-old tradition of elaborating upon and expanding the myth of vampires . as we saw , maybe you met my relatives , a huge of variety of creatures stalked the night before dracula , and many more will continue to creep through our nightmares . yet , so long as they subsist off a living being 's life force , they are part of my tribe . even sparkling vampires can be included . after all , it 's the continued storytelling and reimagining of the vampire legend that allows us to truly live forever . ( ominous laughter )
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( laughter ) clearly , these people were not really dead . heh , they were vampires ! and they had been leaving their graves to feast on the living .
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what is the one shared trait of all vampires ?
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calcium is the third element in group two on the periodic table . it ’ s really very common . we find it all over the world in all sorts of minerals . so for example you can have bones , this is a pelvis of a sheep , i found it when i was walking one day , you can see the legs go in there and there . in here we have some calcium turnings . we ’ re storing them in our glove box . this glove box here is a contraption full of nitrogen , it ’ s dry nitrogen so that we can keep our calcium away from oxygen and away from moisture as well , because obviously what we don ’ t want is when we get our nice very reactive calcium surface we don ’ t want it to tarnish from oxides too quickly before we can react it with things . so what we have here inside the bottle are turnings of calcium . calcium is quite hard compared to sort of the heavier group two elements , so strontium and barium , so it ’ s harder to file . bones are made from calcium phosphate mixed with some organic material as well and they ’ re very strong because of the structure within the bones . there are all sorts of shells of molluscs and the like where they use calcium carbonate from the sea water , getting the calcium out , reacting with carbon dioxide and making their shells . and because shells are made out of calcium carbonate , which dissolves in acid , people are quite worried about the effects of global warming . not the heating up but when the c02 dissolves into the sea it makes it more acid , so in principle shells could start dissolving and some molluscs may not be able to survive because they just can ’ t make their shells . if i just pour them out so you can see . calcium looks metallic than the calcium metal itself because of the way the electrons behave in the solid . in fact it is because it is a very good electrical conductor but the compounds are all white , because calcium has no free electrons that can go from one energy level to another in the way you can say with copper . so copper sulphate is a beautiful blue colour , calcium sulphate is white , and it ’ s actually colourless , so if you see a big crystal of calcium sulphate it just looks like glass . but the white is caused by very small crystals which scatter the light , just in the same way that any sort of white powder will scatter light , flour for example or talcum powder , anything like that . calcium compounds themselves are actually mostly white , but calcium metal itself , as you can see we ’ ve got tarnished parts but also there are some shiny bits where it ’ s untarnished . so you ’ re actually seeing the metal the lustre of the metal there as well . calcium carbonate dissolves in water saturated with c02 to make calcium bicarbonate which is more soluble . and so you can get water , so called hard water , that has quite high levels of calcium . and when this percolates through the ground and comes to a cave it can then crystallise out and you can get hanging down pillars of calcium carbonate , which are called stalactites . and you can have pillars growing from the floor called stalagmites . this is a stalagmite from turkey . one of my friends called hugh was really naughty . he knew i was interested in minerals and he broke this off from a cave in turkey about 45 years ago and brought it and gave it to me so i was really pleased . and you can see the outside looks quite blobby , and inside you can see there are nice crystals of calcium carbonate because it has grown very , very slowly and so it can crystalise . and sometimes these stalagmites and stalactites can grow really big . and more recently , in the last few years , people have found huge crystals of calcium sulphate under the ground . some of you may have seen pictures of caves in mexico where there are crystals big enough you can actually walk along them . so there is no danger that calcium will ever run out , it ’ s the basis of cements and concretes , or one of the bases because then you need other elements like iron and silica to make the concrete itself , but calcium is one of the principle components . we ’ re going to take calcium chloride , put it in a flame and do a flame test and see if we can see the colour of the calcium in the flame . so as i said before about calcium compounds , calcium compounds are often white , and here is a white calcium compound . so i ’ m going to put it in the flame and see if we get any colour . oh hello , that looks quite red doesn ’ t it ? brick red is the classic calcium colour . bit orangey to me , might be a bit of sodium in there , or something like that . that was our calcium flame test . the reason that you don ’ t find lumps of calcium metal lying around , the way you do with copper or gold , is that metallic calcium is very reactive , reacts with water very quickly . magnesium doesn ’ t react because it has a layer of oxide on the surface , so surprisingly magnesium is not nearly as reactive as calcium . you can use magnesium , or its alloys , for the wheels on your car , go round really fast because they ’ re light . you couldn ’ t have calcium wheels in your car , well you could , but the first time it rained your whole car would go up in flames . this again what we ’ ve got is our calcium chloride , hydrated calcium chloride . we ’ ve got a bunch of it on this spatula . i ’ ll put it in the flame so that you can see that it ’ s burning with a brick red flame which is characteristic of calcium . it ’ s kind of a bit orangey to me as well actually , might be a bit of sodium or something in there . got anymore in there ? a little bit . many people see calcium as a very english element , unlike strontium which was discovered in scotland , because of the white cliffs of dover , the gateway for many people when they first come to england . they ’ re made of calcium carbonate . and so this white colour of chalk is very characteristic and all over the southern part of england you find large amounts of chalk , which in the north of england they tend to be limestone , which is also calcium carbonate but a slightly different variety of calcium carbonate so it ’ s a yellow or honey colour because of the impurities of iron or some other element that ’ s in it . well you need calcium for all sorts of processes in the body and of course to build up your bones . particularly , say in the case of pregnant women , they need to have calcium for the bones of the developing baby . but as people get older the calcium can come out of their bones and make them very fragile , this is why elderly people sometimes break their hips and break their bones so easily . so drinking milk and eating other sources of calcium are good because it helps you replenish your bones and keep a reasonable level of calcium .
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and you can have pillars growing from the floor called stalagmites . this is a stalagmite from turkey . one of my friends called hugh was really naughty .
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what can be seen inside the blobby structure of the stalagmite that the professor has in his own minerals collection ?
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it 's a common saying that elephants never forget , but these magnificent animals are more than giant walking hard drives . the more we learn about elephants , the more it appears that their impressive memory is only one aspect of an incredible intelligence that makes them some of the most social , creative , and benevolent creatures on earth . unlike many proverbs , the one about elephant memory is scientifically accurate . elephants know every member in their herd , able to recognize as many as 30 companions by sight or smell . this is a great help when migrating or encountering other potentially hostile elephants . they also remember and distinguish particular cues that signal danger and can recall important locations long after their last visit . but it 's the memories unrelated to survival that are the most fascinating . elephants remember not only their herd companions but other creatures who have made a strong impression on them . in one case , two circus elephants that had briefly performed together rejoiced when crossing paths 23 years later . this recognition is n't limited to others of their species . elephants have also recognized humans they 've bonded with after decades apart . all of this shows that elephant memory goes beyond responses to stimuli . looking inside their heads , we can see why . the elephant boasts the largest brain of any land mammal , as well as an impressive encephalization quotient . this is the size of the brain relative to what we 'd expect for an animal 's body size , and the elephant 's eq is nearly as high as a chimpanzee 's . and despite the distant relation , convergent evolution has made it remarkably similar to the human brain , with as many neurons and synapses and a highly developed hippocampus and cerebral cortex . it is the hippocampus , strongly associated with emotion , that aids recollection by encoding important experiences into long-term memories . the ability to distinguish this importance makes elephant memory a complex and adaptable faculty beyond rote memorization . it 's what allows elephants who survived a drought in their youth to recognize its warning signs in adulthood , which is why clans with older matriarchs have higher survival rates . unfortunately , it 's also what makes elephants one of the few non-human animals to suffer from post-traumatic stress disorder . the cerebral cortex , on the other hand , enables problem solving , which elephants display in many creative ways . they also tackle problems cooperatively , sometimes even outwitting the researchers and manipulating their partners . and they 've grasped basic arithmetic , keeping track of the relative amounts of fruit in two baskets after multiple changes . the rare combination of memory and problem solving can explain some of elephants ' most clever behaviors , but it does n't explain some of the things we 're just beginning to learn about their mental lives . elephants communicate using everything from body signals and vocalizations , to infrasound rumbles that can be heard kilometers away . and their understanding of syntax suggests that they have their own language and grammar . this sense of language may even go beyond simple communication . elephants create art by carefully choosing and combining different colors and elements . they can also recognize twelve distinct tones of music and recreate melodies . and yes , there is an elephant band . but perhaps the most amazing thing about elephants is a capacity even more important than cleverness : their sense of empathy , altruism , and justice . elephants are the only non-human animals to mourn their dead , performing burial rituals and returning to visit graves . they have shown concern for other species , as well . one working elephant refused to set a log down into a hole where a dog was sleeping , while elephants encountering injured humans have sometimes stood guard and gently comforted them with their trunk . on the other hand , elephant attacks on human villages have usually occurred right after massive poachings or cullings , suggesting deliberate revenge . when we consider all this evidence , along with the fact that elephants are one of the few species who can recognize themselves in a mirror , it 's hard to escape the conclusion that they are conscious , intelligent , and emotional beings . unfortunately , humanity 's treatment of elephants does not reflect this , as they continue to suffer from habitat destruction in asia , ivory poaching in africa , and mistreatment in captivity worldwide . given what we now know about elephants and what they continue to teach us about animal intelligence , it is more important than ever to ensure that what the english poet john donne described as `` nature 's great masterpiece '' does not vanish from the world 's canvas .
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this recognition is n't limited to others of their species . elephants have also recognized humans they 've bonded with after decades apart . all of this shows that elephant memory goes beyond responses to stimuli .
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which of the following is something that no other animals besides elephants and humans do ?
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the biggest kidney stone on record weighed more than a kilogram and was 17 centimeters in diameter . the patient did n't actually swallow a stone the size of a coconut . kidney stones form inside the body , but unfortunately , they 're extremely painful to get out . a kidney stone is a hard mass of crystals that can form in the kidneys , ureters , bladder , or urethra . urine contains compounds that consist of calcium , sodium , potassium , oxalate , uric acid , and phosphate . if the levels of these particles get too high , or if urine becomes too acidic or basic , the particles can clump together and crystallize . unless the problem is addressed , the crystals will gradually grow over a few weeks , months , or even years , forming a detectable stone . calcium oxalate is the most common type of crystal to form this way , and accounts for about 80 % of kidney stones . less common kidney stones are made of calcium phosphate , or uric acid . a slightly different type of stone made of the minerals magnesium ammonium phosphate , or struvite , can be caused by bacterial infection . and even rarer stones can result from genetic disorders or certain medications . a kidney stone can go undetected until it starts to move . when a stone travels through the kidney and into the ureter , its sharp edges scratch the walls of the urinary tract . nerve endings embedded in this tissue transmit excruciating pain signals through the nervous system . and the scratches can send blood flowing into the urine . this can be accompanied by symptoms of nausea , vomiting , and a burning sensation while urinating . if a stone gets big enough to actually block the flow of urine , it can create an infection , or back flow , and damage the kidneys themselves . but most kidney stones do n't become this serious , or even require invasive treatment . masses less than five millimeters in diameter will usually pass out of the body on their own . a doctor will often simply recommend drinking large amounts of water to help speed the process along , and maybe taking some pain killers . if the stone is slightly larger , medications like alpha blockers can help by relaxing the muscles in the ureter and making it easier for the stone to get through . another medication called potassium citrate can help dissolve the stones by creating a less acidic urine . for medium-sized stones up to about ten millimeters , one option is pulverizing them with soundwaves . extracorporeal shock wave lithotripsy uses high-intensity pulses of focused ultrasonic energy aimed directly at the stone . the pulses create vibrations inside the stone itself and small bubbles jostle it . these combined forces crush the stone into smaller pieces that can pass out of the body more easily . but zapping a stone with sound does n't work as well if it 's simply too big . so sometimes , more invasive treatments are necessary . a rigid tube called a stent can be placed in the ureter to expand it . optical fibers can deliver laser pulses to break up the stone . stones can also be surgically removed through an incision in the patient 's back or groin . what about just avoiding kidney stones in the first place ? for people prone to them , their doctor may recommend drinking plenty of water , which dilutes the calcium oxalate and other compounds that eventually build up into painful stones . foods like potato chips , spinach , rhubarb , and beets are high in oxalate , so doctors might advise limiting them . even though calcium is often found in stones , calcium in foods and beverages can actually help by binding to oxalate in the digestive tract before it can be absorbed and reach the kidneys . if you do end up with a kidney stone , you 're not alone . data suggests that rates are rising , but that world record probably wo n't be broken any time soon .
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stones can also be surgically removed through an incision in the patient 's back or groin . what about just avoiding kidney stones in the first place ? for people prone to them , their doctor may recommend drinking plenty of water , which dilutes the calcium oxalate and other compounds that eventually build up into painful stones .
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what are some foods to avoid if you are prone to kidney stones ?
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what happens after death ? is there a restful paradise ? an eternal torment ? a rebirth ? or maybe just nothingness ? well , one chinese emperor thought that whatever the hereafter was , he better bring an army . we know that because in 1974 , farmers digging a well near their small village stumbled upon one of the most important finds in archeological history : vast underground chambers surrounding that emperor 's tomb , and containing more than 8,000 life-size clay soldiers ready for battle . the story of the subterranean army begins with ying zheng , who came to power as the king of the qin state at the age of 13 in 246 bce . ambitious and ruthless , he would go on to become qin shi huangdi , the first emperor of china after uniting its seven warring kingdoms . his 36 year reign saw many historic accomplishments , including a universal system of weights and measures , a single standardized writing script for all of china , and a defensive barrier that would later come to be known as the great wall . but perhaps qin shi huangdi dedicated so much effort to securing his historical legacy because he was obsessed with his mortality . he spent his last years desperately employing alchemists and deploying expeditions in search of elixirs of life that would help him achieve immortality . and as early as the first year of his reign , he began the construction of a massive underground necropolis filled with monuments , artifacts , and an army to accompany him into the next world and continue his rule . this magnificent army is still standing in precise battle formation and is split across several pits . one contains a main force of 6,000 soldiers , each weighing several hundred pounds , a second has more than 130 war chariots and over 600 horses , and a third houses the high command . an empty fourth pit suggests that the grand project could not be finished before the emperor 's death . in addition , nearby chambers contain figures of musicians and acrobats , workers and government officials , and various exotic animals , indicating that emperor qin had more plans for the afterlife than simply waging war . all the figurines are sculpted from terracotta , or baked earth , a type of reddish brown clay . to construct them , multiple workshops and reportedly over 720,000 laborers were commandeered by the emperor , including groups of artisans who molded each body part separately to construct statues as individual as the real warriors in the emperor 's army . they stand according to rank and feature different weapons and uniforms , distinct hairstyles and expressions , and even unique ears . originally , each warrior was painted in bright colors , but their exposure to air caused the paint to dry and flake , leaving only the terracotta base . it is for this very reason that another chamber less than a mile away has not been excavated . this is the actual tomb of qin shi huangdi , reported to contain palaces , precious stones and artifacts , and even rivers of mercury flowing through mountains of bronze . but until a way can be found to expose it without damaging the treasures inside , the tomb remains sealed . emperor qin was not alone in wanting company for his final destination . ancient egyptian tombs contain clay models representing the ideal afterlife , the dead of japan 's kofun period were buried with sculptures of horses and houses , and the graves of the jaina island off the mexican coast are full of ceramic figurines . fortunately , as ruthless as he was , emperor qin chose to have servants and soldiers built for this purpose , rather than sacrificing living ones to accompany him , as had been practiced in egypt , west africa , anatolia , parts of north america and even china during the previous shang and zhou dynasties . and today , people travel from all over the world to see these stoic soldiers silently awaiting their battle orders for centuries to come .
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in addition , nearby chambers contain figures of musicians and acrobats , workers and government officials , and various exotic animals , indicating that emperor qin had more plans for the afterlife than simply waging war . all the figurines are sculpted from terracotta , or baked earth , a type of reddish brown clay . to construct them , multiple workshops and reportedly over 720,000 laborers were commandeered by the emperor , including groups of artisans who molded each body part separately to construct statues as individual as the real warriors in the emperor 's army .
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the terracotta warriors were discovered in __________ by ____________ who were digging a ________ .
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translator : andrea mcdonough reviewer : jessica ruby mysteries of vernacular : bewilder , to confuse or puzzle completely . the root of the word bewilder can be traced back to the old english word wilde , which was used to refer to something that was in a natural state , uncultivated , or undomesticated . over time , the word wild was often linked to the old english word deor . deor , which was derived from an early indo-european root that meant breathe , was initially used to describe any untamed animal or beast . this eventually morphed into the modern word deer , meaning a ruminant of the family cervidae . the two old english words , when mashed together , became wilderness , meaning a tract of uncultivated land , primarily inhabited by undomesticated beasts . from the word wilderness , the word wilder was born . to wilder someone was to lead him astray or lure him into the woods . in the 1600 's , the prefix be , meaning thoroughly , was compounded with wilder as a way of tacking on a little extra punch . someone who was bewildered was thoroughly lost in the wild . from this winding background , bewilder eventually evolved into our current definition , to be completely confused .
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translator : andrea mcdonough reviewer : jessica ruby mysteries of vernacular : bewilder , to confuse or puzzle completely . the root of the word bewilder can be traced back to the old english word wilde , which was used to refer to something that was in a natural state , uncultivated , or undomesticated . over time , the word wild was often linked to the old english word deor .
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what is back-formation ?
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which of these entities has evolved the ability to manipulate an animal many times its size ? the answer is all of them . these are all parasites , organisms that live on or inside another host organism , which they harm and sometimes even kill . parasite survival depends on transmitting from one host to the next , sometimes through an intermediate species . our parasites elegantly achieve this by manipulating their host 's behavior , sometimes through direct brain hijacking . for example , this is the gordian worm . one of its hosts , this cricket . the gordian worm needs water to mate , but the cricket prefers dry land . so once it 's big enough to reproduce , the worm produces proteins that garble the cricket 's navigational system . the confused cricket jumps around erratically , moves closer to water , and eventually leaps in , often drowning in the process . the worm then wriggles out to mate and its eggs get eaten by little water insects that mature , colonize land , and are , in turn , eaten by new crickets . and thus , the gordian worm lives on . and here 's the rabies virus , another mind-altering parasite . this virus infects mammals , often dogs , and travels up the animal 's nerves to its brain where it causes inflammation that eventually kills the host . but before it does , it often increases its host 's aggressiveness and ramps up the production of rabies-transmitting saliva , while making it hard to swallow . these factors make the host more likely to bite another animal and more likely to pass the virus on when it does . and now , meet ophiocordyceps , also known as the zombie fungus . its host of choice is tropical ants that normally live in treetops . after ophiocordyceps spores pierce the ant 's exoskeleton , they set off convulsions that make the ant fall from the tree . the fungus changes the ant 's behavior , compelling it to wander mindlessly until it stumbles onto a plant leaf with the perfect fungal breeding conditions , which it latches onto . the ant then dies , and the fungus parasitizes its body to build a tall , thin stalk from its neck . within several weeks , the stalk shoots off spores , which turn more ants into six-legged leaf-seeking zombies . one of humanity 's most deadly assailants is a behavior-altering parasite , though if it 's any consolation , it 's not our brains that are being hijacked . i 'm talking about plasmodium , which causes malaria . this parasite needs mosquitoes to shuttle it between hosts , so it makes them bite more frequently and for longer . there 's also evidence that humans infected with malaria are more attractive to mosquitoes , which will bite them and transfer the parasite further . this multi-species system is so effective , that there are hundreds of millions of malaria cases every year . and finally , there are cats . do n't worry , there probably are n't any cats living in your body and controlling your thoughts . i mean , probably . but there is a microorganism called toxoplasma that needs both cats and rodents to complete its life cycle . when a rat gets infected by eating cat feces , the parasite changes chemical levels in the rat 's brain , making it less cautious around the hungry felines , maybe even attracted to them . this makes them easy prey , so these infected rodents get eaten and pass the parasite on . mind control successful . there 's even evidence that the parasite affects human behavior . in most cases , we do n't completely understand how these parasites manage their feats of behavior modification . but from what we do know , we can tell that they have a pretty diverse toolbox . gordian worms seem to affect crickets ' brains directly . the malaria parasite , on the other hand , blocks an enzyme that helps the mosquitoes feed , forcing them to bite over and over and over again . the rabies virus may cause that snarling , slobbering behavior by putting the immune system into overdrive . but whatever the method , when you think about how effectively these parasites control the behavior of their hosts , you may wonder how much of human behavior is actually parasites doing the talking . since more than half of the species on earth are parasites , it could be more than we think .
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i mean , probably . but there is a microorganism called toxoplasma that needs both cats and rodents to complete its life cycle . when a rat gets infected by eating cat feces , the parasite changes chemical levels in the rat 's brain , making it less cautious around the hungry felines , maybe even attracted to them . this makes them easy prey , so these infected rodents get eaten and pass the parasite on .
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some researchers have suggested that toxoplasma makes rats attracted to cats by increasing dopamine levels in the rat brain . design an experiment to test this hypothesis .
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translator : andrea mcdonough reviewer : bedirhan cinar ever see a medieval painting of baby jesus sitting or standing on his mother 's lap and wonder why she 's so large ? paintings like cimabue 's enthroned madonna with angels or duccio 's maesta also appear out of proportion . if mary were to stand up , it seems , the angels in the picture would be as tall as her shin bone , and her torso would be disproportionately small when compared to her legs . maybe you thought the artist simply was n't skilled enough to paint realistically or lacked the mathematical skill of perspective . but that 's not the full story . to understand why , we need to go back to the late fifth century when the city of rome was attacked by the goths . rome was built in marble and meant to last forever . it represented , for many years , the pinnacle of human civilization , so its destruction left a huge void . theologians , who preached about a world beyond the physical , began attracting an audience as rome crumbled , and christianity started to fill the void left by the empire . as a replacement for the physical beauty of rome , christianity offered a metaphysical beauty of virtue and an eternal heaven that could not be destroyed as rome had . after the fall of rome , early medieval theologians turned away from physical beauty , rejecting it in favor of inner-beauty . they maintained that while the physical world was temporary , virtue and religion were permanent . beautiful objects could lead to a misguided worship of the object rather than the worship of goodness . it is said that the early sixth century preacher , st. benedict , upon thinking of a beautiful woman , threw himself into a thorn patch , and through his suffering , regained his focus on spiritual beauty . he feared his desire for the beautiful woman would distract him from his desire to love god . as european civilization transitioned away from empires and towards religion , monasteries became the gatekeepers of knowledge , which meant that classical books that praised physical pleasures were not copied or protected . without protection , they became the victims of natural decay , fire , flooding , or pests . and without the help of monks transcribing new copies , these texts and the philosophies they carried disappeared in western europe and were replaced by the works of people like st. benedict , which brings us back to these depictions of jesus and mary . because christianity had so fervently rejected physical beauty , these medieval artists purposefully avoided aesthetically pleasing forms . at first , decorations for churches or palaces were limited to interesting geometric patterns , which could be pleasing without inspiring sinful thoughts of physical pleasure . as the medieval period progressed , depictions of jesus and mary were tolerated , but the artist clearly made an effort to veil mary and give her disproportionately large legs , with those enormous shin bones . the fear remained that a beautiful illustration of mary might inspire the viewer to love the painting or the physical form of mary , rather than the virtue she 's meant to represent . so even though it may be fun to think we can paint more realistically than cimabuey or duccio , we need to remember that they had different goals when picking up a paintbrush .
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it represented , for many years , the pinnacle of human civilization , so its destruction left a huge void . theologians , who preached about a world beyond the physical , began attracting an audience as rome crumbled , and christianity started to fill the void left by the empire . as a replacement for the physical beauty of rome , christianity offered a metaphysical beauty of virtue and an eternal heaven that could not be destroyed as rome had .
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what did christianity offer in place of the crumbling roman empire ?
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have you experienced déjà vu ? it 's that shadowy feeling you get when a situation seems familiar . a scene in a restaurant plays out exactly as you remember . the world moves like a ballet you 've choreographed , but the sequence ca n't be based on a past experience because you 've never eaten here before . this is the first time you 've had clams , so what 's going on ? unfortunately , there is n't one single explanation for déjà vu . the experience is brief and occurs without notice , making it nearly impossible for scientists to record and study it . scientists ca n't simply sit around and wait for it to happen to them -- this could take years . it has no physical manifestations and in studies , it 's described by the subject as a sensation or feeling . because of this lack of hard evidence , there 's been a surplus of speculation over the years . since emile boirac introduced déjà vu as a french term meaning `` already seen , '' more than 40 theories attempt to explain this phenomenon . still , recent advancements in neuroimaging and cognitive psychology narrow down the field of prospects . let 's walk through three of today 's more prevalent theories , using the same restaurant setting for each . first up is dual processing . we 'll need an action . let 's go with a waiter dropping a tray of dishes . as the scene unfolds , your brain 's hemispheres process a flurry of information : the waiter 's flailing arms , his cry for help , the smell of pasta . within milliseconds , this information zips through pathways and is processed into a single moment . most of the time , everything is recorded in-sync . however , this theory asserts that déjà vu occurs when there 's a slight delay in information from one of these pathways . the difference in arrival times causes the brain to interpret the late information as a separate event . when it plays over the already-recorded moment , it feels as if it 's happened before because , in a sense , it has . our next theory deals with a confusion of the past rather than a mistake in the present . this is the hologram theory , and we 'll use that tablecloth to examine it . as you scan its squares , a distant memory swims up from deep within your brain . according to the theory , this is because memories are stored in the form of holograms , and in holograms , you only need one fragment to see the whole picture . your brain has identified the tablecloth with one from the past , maybe from your grandmother 's house . however , instead of remembering that you 've seen it at your grandmother 's , your brain has summoned up the old memory without identifying it . this leaves you stuck with familiarity , but no recollection . although you 've never been in this restaurant , you 've seen that tablecloth but are just failing to identify it . now , look at this fork . are you paying attention ? our last theory is divided attention , and it states that déjà vu occurs when our brain subliminally takes in an environment while we 're distracted by one particular object . when our attention returns , we feel as if we 've been here before . for example , just now you focused on the fork and did n't observe the tablecloth or the falling waiter . although your brain has been recording everything in your peripheral vision , it 's been doing so below conscious awareness . when you finally pull yourself away from the fork , you think you 've been here before because you have , you just were n't paying attention . while all three of these theories share the common features of déjà vu , none of them propose to be the conclusive source of the phenomenon . still , while we wait for researchers and inventers to come up with new ways to capture this fleeting moment , we can study the moment ourselves . after all , most studies of déjà vu are based on first-hand accounts , so why ca n't one be yours ? the next time you get déjà vu , take a moment to think about it . have you been distracted ? is there a familiar object somewhere ? is your brain just acting slow ? or is it something else ?
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most of the time , everything is recorded in-sync . however , this theory asserts that déjà vu occurs when there 's a slight delay in information from one of these pathways . the difference in arrival times causes the brain to interpret the late information as a separate event .
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which theory asserts that déjà vu occurs when there is a delay in information to your brian ?
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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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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 .
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as the spinning cloud of dust and gas that formed the sun and the planets collapsed :
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the earliest known pregnancy test dates back to 1350 bc in ancient egypt . according to the egyptians , all you have to do is urinate on wheat and barley seeds , and wait . if either sprouts , congratulations , you 're pregnant ! and if wheat sprouts faster , it 's a girl , but if barley , it 's a boy . in 1963 , a small study reproduced this test and found that it predicted pregnancy with a respectable 70 % accuracy , though it could n't reliably tell the sex of the baby . scientists hypothesized that the test worked because pregnant women 's urine contains more estrogen , which can promote seed growth . now it 's easy to take this ancient method for granted because modern pregnancy tests give highly accurate results within minutes . so how do they work ? over-the-counter pregnancy tests are all designed to detect one thing : a hormone called hcg . hcg is produced in the earliest stages of pregnancy and starts a game of telephone that tells the body not to shed the inner lining of the uterus that month . as the pregnancy progresses , hcg supports the formation of the placenta , which transfers nutrients from mother to fetus . the test starts when urine is applied to the exposed end of the strip . as the fluid travels up the absorbent fibers , it will cross three separate zones , each with an important task . when the wave hits the first zone , the reaction zone , y-shaped proteins called antibodies will grab onto any hcg . attached to these antibodies is a handy enzyme with the ability to turn on dye molecules , which will be crucial later down the road . then the urine picks up all the ab1 enzymes and carries them to the test zone , which is where the results show up . secured to this zone are more y-shaped antibodies that will also stick to hcg on one of its five binding sites . scientists call this type of test a sandwich assay . if hcg is present , it gets sandwiched between the ab1 enzyme and ab2 , and sticks to the test zone , allowing the attached dye-activating enzyme to do its job and create a visible pattern . if there 's no hcg , the wave of urine and enzymes just passes on by . finally , there 's one last stop to make , the control zone . as in any good experiment , this step confirms that the test is working properly . whether the ab1 enzymes never saw hcg , or they 're extras because zone 1 is overstocked with them , all the unbound ab1 enzymes picked up in zone 1 should end up here and activate more dye . so if no pattern appears , that indicates that the test was faulty . these tests are pretty reliable , but they 're not failproof . for instance , false negatives can occur if concentrations of hcg are n't high enough for detection . after implantation , hcg levels double every two to three days , so it may just be too early to tell . and beverages can dilute the urine sample , which is why doctors recommend taking the test first thing in the morning . on the other hand , false positives can come from other sources of hcg , like ivf injections , ectopic pregnancies , or certain cancers such as uterine cancer or testicular cancer , making it possible for one of these tests to tell a man he 's pregnant . the best way for a woman to find out for sure is at the doctor 's office . the doctors are also looking for hcg , but with tests that are more sensitive and quantitative , which means they can determine the exact level of hcg in your blood . a few minutes can feel like forever when you 're waiting on the results of a pregnancy test . but in that brief time , you 're witnessing the power of the scientific method . that one little stick lets you ask a question , perform a controlled experiment , and then analyze the results to check your original hypothesis . and the best part is you wo n't even have to wait until the next harvest .
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the best way for a woman to find out for sure is at the doctor 's office . the doctors are also looking for hcg , but with tests that are more sensitive and quantitative , which means they can determine the exact level of hcg in your blood . a few minutes can feel like forever when you 're waiting on the results of a pregnancy test .
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which of the following is not true about human chorionic gonadotropin ( hcg ) ?
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while touring the remains of ancient alexandria , egypt , there are a few things that present-day explorers should look for . first , as you travel along the great harbor , keep your eyes open for large columns and statues . across the bay to your left is the island where the great lighthouse once stood . and as you make your way through the palaces of the royal quarter and reach the area where the library of alexandria once stood , keep your eyes open for sharks . because if you visit this section of alexandria , you 'll be fifteen feet deep in the mediterranean sea . though people are most familiar with plato 's fictional atlantis , many real underwater cities actually exist . places like alexandria , port royal , jamaica , and pavlopetri , greece . sunken cities are studied by scientists to help us understand the lives of our ancestors , the dynamic nature of our planet , and the impact of each on the other . water is essential for life , food sources , and transport , so many cities have been built along coast lines and river banks . however , these benefits also come with risks because natural forces that can sink a city are at their doorstep . take , for instance , an earthquake . june 7 , 1692 seemed like a normal morning in port royal , jamaica , then one of the richest ports in the world , but when a massive earthquake struck , two-thirds of port royal immediately sank to its rooftops . today , many buildings and elements of everyday life remain surprisingly intact on the sea floor , frozen in time . that includes a 300-year-old pocket watch that stopped at 11:43 , the moment port royal slipped beneath the carribean . and during the winter of 373 bce , the greek city of helike was struck by an earthquake so strong that it liquefied the sandy ground upon which the city was built . minutes later , a tsunami struck the city , and helike and its inhabitants sunk downwards into the mediterranean sea . centuries later , roman tourists would sail on the lagoon that formed and peer down at the city 's remains . earthquakes are sudden , unpredictable disasters that have drowned cities in an instant . luckily , however , throughout history , the majority of sunken cities were not submerged by a single cataclysmic event , but by a combination of more gradual processes . for instance , pavlopetri , the oldest known sunken city , was built on the southern coastline of greece 5,000 years ago . it 's an example of a city that was submerged due to what is called isostatic sea level change . 18,000 years ago when the ice age ended , glaciers began melting and the sea level rose globally until about 5,000 years ago . isostatic sea level change is n't caused by that melt water , but rather the earth 's crust slowly springing back from the released weight of the glaciers , making some places rise , and others sink . the ground around pavlopetri is still sinking at an average rate of a millimeter per year . but the ancient inhabitants were able to move gradually inland over several generations before they finally abandoned the city about 3,000 years ago . today , divers swim over the streets of pavlopetri and peer through ancient door jams into the foundations of houses and community buildings . they learn about the people who lived there by observing what they left behind . natural geological events , such as earthquakes and tsunamis , will continue to shape our continents , just as they have for millions of years . as increased global warming melts our polar ice caps at accelerated rates and sea levels rise , we will be forced to adapt , like pavlopetri 's inhabitants . undoubtedly , over the coming centuries , some of the coastal areas that we live in today will eventually be claimed by the water , too - cities like venice , new orleans , amsterdam , miami , and tokyo . imagine what future civilizations will learn about us as they swim around the ancient ruins of the cities that we live in today .
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water is essential for life , food sources , and transport , so many cities have been built along coast lines and river banks . however , these benefits also come with risks because natural forces that can sink a city are at their doorstep . take , for instance , an earthquake .
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which natural phenomena can contribute to sinking a city ?
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translator : tom carter reviewer : bedirhan cinar this is the story of an invention that changed the world . imagine a machine that could cut 10 hours of work down to one . a machine so efficient that it would free up people to do other things , kind of like the personal computer . but the machine i 'm going to tell you about did none of this . in fact , it accomplished just the opposite . in the late 1700s , just as america was getting on its feet as a republic under the new u.s constitution , slavery was a tragic american fact of life . george washington and thomas jefferson both became president while owning slaves , knowing that this peculiar institution contradicted the ideals and principles for which they fought a revolution . but both men believed that slavery was going to die out as the 19th century dawned , they were , of course , tragically mistaken . the reason was an invention , a machine they probably told you about in elementary school : mr. eli whitney 's cotton gin . a yale graduate , 28-year-old whitney had come to south carolina to work as a tutor in 1793 . supposedly he was told by some local planters about the difficulty of cleaning cotton . separating the seeds from the cotton lint was tedious and time consuming . working by hand , a slave could clean about a pound of cotton a day . but the industrial revolution was underway , and the demand was increasing . large mills in great britain and new england were hungry for cotton to mass produce cloth . as the story was told , whitney had a `` eureka moment '' and invented the gin , short for engine . the truth is that the cotton gin already existed for centuries in small but inefficient forms . in 1794 , whitney simply improved upon the existing gins and then patented his `` invention '' : a small machine that employed a set of cones that could separate seeds from lint mechanically , as a crank was turned . with it , a single worker could eventually clean from 300 to one thousand pounds of cotton a day . in 1790 , about 3,000 bales of cotton were produced in america each year . a bale was equal to about 500 pounds . by 1801 , with the spread of the cotton gin , cotton production grew to 100 thousand bales a year . after the destructions of the war of 1812 , production reached 400 thousand bales a year . as america was expanding through the land acquired in the louisiana purchase of 1803 , yearly production exploded to four million bales . cotton was king . it exceeded the value of all other american products combined , about three fifths of america 's economic output . but instead of reducing the need for labor , the cotton gin propelled it , as more slaves were needed to plant and harvest king cotton . the cotton gin and the demand of northern and english factories re-charted the course of american slavery . in 1790 , america 's first official census counted nearly 700 thousand slaves . by 1810 , two years after the slave trade was banned in america , the number had shot up to more than one million . during the next 50 years , that number exploded to nearly four million slaves in 1860 , the eve of the civil war . as for whitney , he suffered the fate of many an inventor . despite his patent , other planters easily built copies of his machine , or made improvements of their own . you might say his design was pirated . whitney made very little money from the device that transformed america . but to the bigger picture , and the larger questions . what should we make of the cotton gin ? history has proven that inventions can be double-edged swords . they often carry unintended consequences . the factories of the industrial revolution spurred innovation and an economic boom in america . but they also depended on child labor , and led to tragedies like the triangle shirtwaist fire that killed more than 100 women in 1911 . disposable diapers made life easy for parents , but they killed off diaper delivery services . and do we want landfills overwhelmed by dirty diapers ? and of course , einstein 's extraordinary equation opened a world of possibilities . but what if one of them is hiroshima ?
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but both men believed that slavery was going to die out as the 19th century dawned , they were , of course , tragically mistaken . the reason was an invention , a machine they probably told you about in elementary school : mr. eli whitney 's cotton gin . a yale graduate , 28-year-old whitney had come to south carolina to work as a tutor in 1793 . supposedly he was told by some local planters about the difficulty of cleaning cotton .
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eli whitney moved to south carolina to become
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you are the cargo director on the maiden voyage of the s.s . buoyant , and you 've agreed to transport several tanks containing the last specimens of a critically endangered fish species to their new aquarium . unfortunately , as you 're passing through shark-infested waters , the boat is battered by a fierce storm , throwing your precious cargo overboard . and to make matters worse , no one seems certain just how many fish tanks are missing . fortunately , you have a rescue sub at your disposal , but only enough fuel for one trip to the ocean floor . you need to know where the tanks are so you can gather them all in one quick pass . not a single fish can be lost . you decide to scan the three sectors of the ocean floor where the cargo could have landed . thermal imaging shows 50 organisms in the area , and you quickly realize that that number includes both your fish and some ravenous sharks . you flip on the sonar to get a better look . the image for sector alpha shows four tanks and two sharks , the image for sector beta shows two tanks and four sharks , and the image for sector gamma is blank . your sonar has malfunctioned , and you 're going to have to go with the info you have . you check the shipping notes , but all you learn is that each tank had the same number of fish inside . the cargo hold had space for anywhere from 1 to 13 total tanks . and finally , the old captain tells you that this area has the odd property that no two sectors can have the same number of sharks , but every sector will have at least one , and no more than seven . there 's no time to waste . the tanks wo n't withstand the pressure much longer . as you descend in the sub , you review everything you know . how many fish tanks do you need to find in sector gamma ? hurry , the fate of an entire species depends on you . pause here if you want to figure it out for yourself . answer in : 3 answer in : 2 answer in : 1 at first , it seems like there are just too many missing pieces of information . after all , you do n't know how many fish or how many tanks there are , let alone how many fish are in each one . but then you remember the best way to compare multiple pieces of partial information - a table . since we know there are thirteen tanks at most , and we already see six tanks in sectors alpha and beta , we know the total number of tanks must be between 6 and 13 . we also know that each sector has a different amount of sharks with no more than seven in each one . since there are two in sector alpha and four in sector beta , sector gamma can have 1 , 3 , 5 , 6 , or 7 sharks . what about the number of endangered fish ? out of the 50 total organisms in all three sectors , we know at least seven are sharks , leaving a maximum of 43 fish inside all the tanks . and the more sharks we find in sector 3 , the fewer fish there are to save . now , remember that the fish are equally distributed across all the tanks . why is that important ? because it means that one of the possible values for the total amount of fish must be divisible by one of the possible values for the total amount of tanks . and looking at the table , we can see that the only combination that works is 39 fish divided between 13 tanks with three fish in each . with sharks swarming around , you quickly pilot the sub through the first two sectors before retrieving the remaining seven tanks in sector gamma . you 've saved the species and taken an impromptu dive . all in all , not a bad day , unless you happen to be a hungry shark .
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after all , you do n't know how many fish or how many tanks there are , let alone how many fish are in each one . but then you remember the best way to compare multiple pieces of partial information - a table . since we know there are thirteen tanks at most , and we already see six tanks in sectors alpha and beta , we know the total number of tanks must be between 6 and 13 .
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can you think of any real life problems involving partial information that a table might help you solve ?
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it 's not hard to imagine a world where at any given moment , you and everyone you know could be wiped out without warning at the push of a button . this was the reality for millions of people during the 45-year period after world war ii , now known as the cold war . as the united states and soviet union faced off across the globe , each knew that the other had nuclear weapons capable of destroying it . and destruction never loomed closer than during the 13 days of the cuban missile crisis . in 1961 , the u.s. unsuccessfully tried to overthrow cuba 's new communist government . that failed attempt was known as the bay of pigs , and it convinced cuba to seek help from the u.s.s.r. soviet premier nikita khrushchev was happy to comply by secretly deploying nuclear missiles to cuba , not only to protect the island , but to counteract the threat from u.s. missiles in italy and turkey . by the time u.s. intelligence discovered the plan , the materials to create the missiles were already in place . at an emergency meeting on october 16 , 1962 , military advisors urged an airstrike on missile sites and invasion of the island . but president john f. kennedy chose a more careful approach . on october 22 , he announced that the the u.s. navy would intercept all shipments to cuba . there was just one problem : a naval blockade was considered an act of war . although the president called it a quarantine that did not block basic necessities , the soviets did n't appreciate the distinction . in an outraged letter to kennedy , khrushchev wrote , `` the violation of freedom to use international waters and international airspace is an act of aggression which pushes mankind toward the abyss of world nuclear missile war . '' thus ensued the most intense six days of the cold war . while the u.s. demanded the removal of the missiles , cuba and the u.s.s.r insisted they were only defensive . and as the weapons continued to be armed , the u.s. prepared for a possible invasion . on october 27 , a spy plane piloted by major rudolph anderson was shot down by a soviet missile . the same day , a nuclear-armed soviet submarine was hit by a small-depth charge from a u.s. navy vessel trying to signal it to come up . the commanders on the sub , too deep to communicate with the surface , thought war had begun and prepared to launch a nuclear torpedo . that decision had to be made unanimously by three officers . the captain and political officer both authorized the launch , but vasili arkhipov , second in command , refused . his decision saved the day and perhaps the world . but the crisis was n't over . for the first time in history , the u.s. military set itself to defcon 2 , the defense readiness one step away from nuclear war . with hundreds of nuclear missiles ready to launch , the metaphorical doomsday clock stood at one minute to midnight . but diplomacy carried on . in washington , d.c. , attorney general robert kennedy secretly met with soviet ambassador anatoly dobrynin . after intense negotiation , they reached the following proposal . the u.s. would remove their missiles from turkey and italy and promise to never invade cuba in exchange for the soviet withdrawal from cuba under u.n. inspection . once the meeting had concluded , dobrynin cabled moscow saying time is of the essence and we should n't miss the chance . and at 9 a.m. the next day , a message arrived from khrushchev announcing the soviet missiles would be removed from cuba . the crisis was now over . while criticized at the time by their respective governments for bargaining with the enemy , contemporary historical analysis shows great admiration for kennedy 's and khrushchev 's ability to diplomatically solve the crisis . but the disturbing lesson was that a slight communication error , or split-second decision by a commander , could have thwarted all their efforts , as it nearly did if not for vasili arkhipov 's courageous choice . the cuban missile crisis revealed just how fragile human politics are compared to the terrifying power they can unleash .
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as the united states and soviet union faced off across the globe , each knew that the other had nuclear weapons capable of destroying it . and destruction never loomed closer than during the 13 days of the cuban missile crisis . in 1961 , the u.s. unsuccessfully tried to overthrow cuba 's new communist government .
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the cuban missile crisis is when the us reached which defcon level ?
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translator : andrea mcdonough reviewer : jessica ruby in the 11th and 12th centuries , most english commoners were illiterate . since they had no way to learn the bible , the clergy came up with an inventive solution : they 'd create plays out of certain bible stories so even people who could n't read could learn them . these were called mystery plays because they revealed the mystery of god 's word . at about the same time , the clergy also developed plays about the saints of the church , called miracle plays . in the beginning , the clergy members acted out bible stories on the steps outside the cathedral . the audience reacted so well that soon they needed to move out to the street around the town square . by building moving carts to put on each play and by lining up one after the other , they could put on cycles of stories , which would take the viewer from genesis to revelation . these movable carts , called pageants , looked like huge boxes on wheels . each was two stories tall . the bottom story was curtained off and was used for costumes , props , and dressing . the top platform was the stage for the performance . spectators assembled in various corners of the town , and the pageant would move around in the cycle until the villagers had seen the entire series . soon , the plays required more actors than the clergy could supply . so , by the 13th century , different guilds were asked to be responsible for acting out different parts of the cycle . the assignments were meant to reflect the guilds ' professions . for example , the carpenter 's guild might put on the story of noah 's ark , and the baker 's guild might put on the last supper . can you imagine what might happen to the story if the butcher 's guild put on the crucifixion of christ ? yes , without the clergy , the plays soon started changing from their true bible stories . by the end of the 14th century , a new form of drama , called the morality play , had evolved . faith , truth , charity , and good deeds all became characters on the stage . and , at the same time , the opposite virtues of falsehood , covetousness , worldly flesh , and the devil became the antagonists . the morality plays were allegorical stories in which these characters battled for the control of the soul . audiences loved the immoral characters , and spectators were encouraged to interact with the actors . throwing rotten food and even getting into scuffles with other spectators became very common . the character of the devil often would roam through the crowds and pull unsuspecting watchers into a hell that was depicted as a dragon 's mouth . the virtuous biblical stories had morphed into crude and sometimes comic stories . the clergy intended to teach against immorality . how ironic , then , that the morality plays actually encouraged vices as more popular than virtues . by the mid-15th century , the church started to outlaw these performances . town charters required that any theater must be built outside the city wall . one of the first theaters was built like a larger version of a pageant , with tiers of gallery seating encircling a grassy area in front of the stage . sound familiar ? a young william shakespeare developed his craft here at the theater that was eventually renamed the globe . the medieval morality play had led to renaissance playwrights who were inspired by the inner struggles and the conscience of man . and that , in essence , is how drama emerged as a literary art form .
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the virtuous biblical stories had morphed into crude and sometimes comic stories . the clergy intended to teach against immorality . how ironic , then , that the morality plays actually encouraged vices as more popular than virtues .
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are there different options the clergy could have used to teach the bible effectively ? explain .
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it 's often said that despite humanity 's many conflicts , we all bleed the same blood . it 's a nice thought but not quite accurate . in fact , our blood comes in a few different varieties . our red blood cells contain a protein called hemoglobin that binds to oxygen , allowing the cells to transport it throughout the body . but they also have another kind of complex protein on the outside of the cell membrane . these proteins , known as antigens , communicate with white blood cells , immune cells that protect against infection . antigens serve as identifying markers , allowing the immune system to recognize your body 's own cells without attacking them as foreign bodies . the two main kinds of antigens , a and b , determine your blood type . but how do we get four blood types from only two antigens ? well , the antigens are coded for by three different alleles , varieties of a particular gene . while the a and b alleles code for a and b antigens , the o allele codes for neither , and because we inherit one copy of each gene from each parent , every individual has two alleles determining blood type . when these happen to be different , one overrides the other depending on their relative dominance . for blood types , the a and b alleles are both dominant , while o is recessive . so a and a gives you type a blood , while b and b gives you type b . if you inherit one of each , the resulting codominance will produce both a and b antigens , which is type ab . the o allele is recessive , so either of the others will override it when they 're paired , resulting in either type a or type b . but if you happen to inherit two os , instructions will be expressed that make blood cells without the a or the b antigen . because of these interactions , knowing both parents ' blood types lets us predict the relative probability of their children 's blood types . why do blood types matter ? for blood transfusions , finding the correct one is a matter of life and death . if someone with type a blood is given type b blood , or vice versa , their antibodies will reject the foreign antigens and attack them , potentially causing the transfused blood to clot . but because people with type ab blood produce both a and b antigens , they do n't make antibodies against them , so they will recognize either as safe , making them universal recipients . on the other hand , people with blood type o do not produce either antigen , which makes them universal donors , but will cause their immune system to make antibodies that reject any other blood type . unfortunately , matching donors and recipients is a bit more complicated due to additional antigen systems , particular the rh factor , named after the rhesus monkeys in which it was first isolated . rh+ or rh- refers to the presence or absence of the d antigen of the rh blood group system . and in addition to impeding some blood transfusions , it can cause severe complications in pregnancy . if an rh- mother is carrying an rh+ child , her body will produce rh antibodies that may cross the placenta and attack the fetus , a condition known as hemolytic disease of the newborn . some cultures believe blood type to be associated with personality , though this is not supported by science . and though the proportions of different blood types vary between human populations , scientists are n't sure why they evolved ; perhaps as protection against blood born diseases , or due to random genetic drift . finally , different species have different sets of antigens . in fact , the four main blood types shared by us apes seem paltry in comparison to the thirteen types found in dogs .
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on the other hand , people with blood type o do not produce either antigen , which makes them universal donors , but will cause their immune system to make antibodies that reject any other blood type . unfortunately , matching donors and recipients is a bit more complicated due to additional antigen systems , particular the rh factor , named after the rhesus monkeys in which it was first isolated . rh+ or rh- refers to the presence or absence of the d antigen of the rh blood group system . and in addition to impeding some blood transfusions , it can cause severe complications in pregnancy .
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what is rh factor ?
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before he turned physics upside down , a young albert einstein supposedly showed off his genius by devising a complex riddle involving this list of clues . can you resist tackling a brain teaser written by one of the smartest people in history ? let 's give it a shot . the world 's rarest fish has been stolen from the city aquarium . the police have followed the scent to a street with five identical looking houses . but they ca n't search all the houses at once , and if they pick the wrong one , the thief will know they 're on his trail . it 's up to you , the city 's best detective , to solve the case . when you arrive on the scene , the police tell you what they know . one : each house 's owner is of a different nationality , drinks a different beverage , and smokes a different type of cigar . two : each house 's interior walls are painted a different color . three : each house contains a different animal , one of which is the fish . after a few hours of expert sleuthing , you gather some clues . it may look like a lot of information , but there 's a clear logical path to the solution . solving the puzzle will be a lot like sudoku , so you may find it helpful to organize your information in a grid , like this . pause the video on the following screen to examine your clues and solve the riddle . answer in : 3 2 1 to start , you fill in the information from clues eight and nine . immediately , you also realize that since the norwegian is at the end of the street , there 's only one house next to him , which must be the one with the blue walls in clue fourteen . clue five says the green-walled house 's owner drinks coffee . it ca n't be the center house since you already know its owner drinks milk , but it also ca n't be the second house , which you know has blue walls . and since clue four says the green-walled house must be directly to the left of the white-walled one , it ca n't be the first or fifth house either . the only place left for the green-walled house with the coffee drinker is the fourth spot , meaning the white-walled house is the fifth . clue one gives you a nationality and a color . since the only column missing both these values is the center one , this must be the brit 's red-walled home . now that the only unassigned wall color is yellow , this must be applied to the first house , where clue seven says the dunhill smoker lives . and clue eleven tells you that the owner of the horse is next door , which can only be the second house . the next step is to figure out what the norwegian in the first house drinks . it ca n't be tea , clue three tells you that 's the dane . as per clue twelve , it ca n't be root beer since that person smokes bluemaster , and since you already assigned milk and coffee , it must be water . from clue fifteen , you know that the norwegian 's neighbor , who can only be in the second house , smokes blends . now that the only spot in the grid without a cigar and a drink is in the fifth column , that must be the home of the person in clue twelve . and since this leaves only the second house without a drink , the tea-drinking dane must live there . the fourth house is now the only one missing a nationality and a cigar brand , so the prince-smoking german from clue thirteen must live there . through elimination , you can conclude that the brit smokes pall mall and the swede lives in the fifth house , while clue six and clue two tell you that these two have a bird and a dog , respectively . clue ten tells you that the cat owner lives next to the blend-smoking dane , putting him in the first house . now with only one spot left on the grid , you know that the german in the green-walled house must be the culprit . you and the police burst into the house , catching the thief fish-handed . while that explanation was straightforward , solving puzzles like this often involves false starts and dead ends . part of the trick is to use the process of elimination and lots of trial and error to hone in on the right pieces , and the more logic puzzles you solve , the better your intuition will be for when and where there 's enough information to make your deductions . and did young einstein really write this puzzle ? probably not . there 's no evidence he did , and some of the brands mentioned are too recent . but the logic here is not so different from what you 'd use to solve equations with multiple variables , even those describing the nature of the universe .
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two : each house 's interior walls are painted a different color . three : each house contains a different animal , one of which is the fish . after a few hours of expert sleuthing , you gather some clues .
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who stole the fish ?
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have you ever noticed that it 's harder to start pedaling your bicycle than it is to ride at a constant speed ? or wondered what causes your bicycle to move ? or thought about why it goes forward instead of backwards or sideways ? perhaps not , and you would n't be alone . it was n't until the 17th century that isaac newton described the fundamental laws of motion and we understood the answer to these three questions . what newton recognized was that things tend to keep on doing what they are already doing . so when your bicycle is stopped , it stays stopped , and when it is going , it stays going . objects in motion tend to stay in motion and objects at rest tend to stay at rest . that 's newton 's first law . physicists call it the law of inertia , which is a fancy way of saying that moving objects do n't spontaneously speed up , slow down , or change direction . it is this inertia that you must overcome to get your bicycle moving . now you know that you have to overcome inertia to get your bicycle moving , but what is it that allows you to overcome it ? well , the answer is explained by newton 's second law . in mathematical terms , newton 's second law says that force is the product of mass times acceleration . to cause an object to accelerate , or speed up , a force must be applied . the more force you apply , the quicker you accelerate . and the more mass your bicycle has , and the more mass you have too , the more force you have to use to accelerate at the same rate . this is why it would be really difficult to pedal a 10,000 pound bicycle . and it is this force , which is applied by your legs pushing down on the pedals , that allows you to overcome newton 's law of inertia . the harder you push down on the pedals , the bigger the force and the quicker you accelerate . now on to the final question : when you do get your bike moving , why does it go forward ? according to newton 's third law , for every action , there is an equal and opposite reaction . to understand this , think about what happens when you drop a bouncy ball . as the bouncy ball hits the floor , it causes a downward force on the floor . this is the action . the floor reacts by pushing on the ball with the same force , but in the opposite direction , upward , causing it to bounce back up to you . together , the floor and the ball form what 's called the action/reaction pair . when it comes to your bicycle , it is a little more complicated . as your bicycle wheels spin clockwise , the parts of each tire touching the ground push backwards against the earth : the actions . the ground pushes forward with the same force against each of your tires : the reactions . since you have two bicycle tires , each one forms an action/reaction pair with the ground . and since the earth is really , really , really big compared to your bicycle , it barely moves from the force caused by your bicycle tires pushing backwards , but you are propelled forward .
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and the more mass your bicycle has , and the more mass you have too , the more force you have to use to accelerate at the same rate . this is why it would be really difficult to pedal a 10,000 pound bicycle . and it is this force , which is applied by your legs pushing down on the pedals , that allows you to overcome newton 's law of inertia .
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according to the video , why would it be really difficult to pedal a 10,000 pound bicycle ?
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translation - marie de hert in j.r.r . 's world , gandalf is one of five wizards sent by the valar to guide the inhabitants of middle earth in their struggles against the dark force of sauron . gandalf 's body was mortal , subject to the physical rules of middle earth , but his spirit was immortal , as seen when he died as gandalf the grey and resurrected as gandalf the white . according to the wachowski 's script , an awakened human only has to link up and hack the neon binary code of the matrix to learn how to fly a helicopter in a matter of seconds . or if you are the one , or one of the ones , you do n't even need a helicopter , you just need a cool pair of shades . cheshire cats can juggle their own heads . ipads are rudimentary . no quidditch match ends until the golden snitch is caught . and the answer to the ultimate question of life , the universe , and everything is most certainly 42 . just like real life , fictional worlds operate consistently within a spectrum of physical and societal rules . that 's what makes these intricate worlds believable , comprehensible , and worth exploring . in real life , the law of gravity holds seven book sets of `` harry potter '' to millions of bookshelves around the world . we know this to be true , but we also know that ever since j.k. typed the words wizard , wand , and `` wingardium leviosa , '' that law of gravity has ceased to exist on the trillions of pages resting between those bookends . authors of science fiction and fantasy literally build worlds . they make rules , maps , lineages , languages , cultures , universes , alternate universes within universes , and from those worlds sprout story , after story , after story . when it 's done well , readers can understand fictional worlds and their rules just as well as the characters that live in them do and sometimes , just as well or even better than the reader understands the world outside of the book . but how ? how can human-made squiggles on a page reflect lights into our eyes that send signals to our brains that we logically and emotionally decode as complex narratives that move us to fight , cry , sing , and think , that are strong enough not only to hold up a world that is completely invented by the author , but also to change the reader 's perspective on the real world that resumes only when the final squiggle is reached ? i 'm not sure anyone knows the answer to that question , yet fantastical , fictional worlds are created everyday in our minds , on computers , even on napkins at the restaurant down the street . the truth is your imagination and a willingness to , figuratively , live in your own world are all you need to get started writing a novel . i did n't dream up hogwarts or the star wars ' cantina , but i have written some science thrillers for kids and young adults . here are some questions and methods i 've used to help build the worlds in which those books take place . i start with a basic place and time . whether that 's a fantasy world or a futuristic setting in the real world , it 's important to know where you are and whether you 're working in the past , present , or future . i like to create a timeline showing how the world came to be . what past events have shaped the way it is now ? then i brainstorm answers to questions that draw out the details of my fictional world . what rules are in place here ? this covers everything from laws of gravity , or not , to the rules of society and the punishments for individuals who break them . what kind of government does this world have ? who has power , and who does n't ? what do people believe in here ? and what does this society value most ? then it 's time to think about day-to-day life . what 's the weather like in this world ? where do the inhabitants live and work and go to school ? what do they eat and how do they play ? how do they treat their young and their old ? what relationships do they have with the animals and plants of the world ? and what do those animals and plants look like ? what kind of technology exists ? transportation ? communication ? access to information ? there 's so much to think about ! so , spend some time living in those tasks and the answers to those questions , and you 're well on your way to building your own fictional world . once you know your world as well as you hope your reader will , set your characters free in it and see what happens . and ask yourself , `` how does this world you created shape the individuals who live in it ? and what kind of conflict is likely to emerge ? '' answer those questions , and you have your story . good luck , future world-builder !
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answer those questions , and you have your story . good luck , future world-builder !
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which of the following is not an important aspect to consider in world building ?
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so radium was the element that was discovered by madam curie and its chemistry is very similar to that of barium , except that it is radioactive and it was used quite widely for treatment of cancer in the days when radiation was used , radioactivity was used , for treating cancer . the idea is that cancer cells , well all cells are liable to be killed by radiation , by radioactivity when they are dividing so cancer cells are cells in the body which are dividing much faster , out-of-control compared to other cells , so if you radiate a patient , the cancer cells , because they are dividing faster , die quicker , so overall although a lot of cells die , the cancer cells die further . the people , who discovered radium , were really excited about it and they were mad with hindsight in the way they treated it . they carried sort of little glass tubes of radium in their pockets and were then surprised when they found burns on their flesh the next day and it ’ s thought that the reason why many of these researchers like madam curie ’ s husband and madam curie died rather young was the effect of the radioactivity of the elements that they handled . well in general as you go down the periodic table , heavier elements tend to be more dangerous . but even the very reactive ones like fluorine are usually not very dangerous because they react with something long before they get into the body . the radioactive elements tend to be dangerous because they can get into the body and then when they decay , they kill cells or even worse than killing the cells is that they change the dna so that the cells mutate into some more aggressive form of cancer .
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so radium was the element that was discovered by madam curie and its chemistry is very similar to that of barium , except that it is radioactive and it was used quite widely for treatment of cancer in the days when radiation was used , radioactivity was used , for treating cancer . the idea is that cancer cells , well all cells are liable to be killed by radiation , by radioactivity when they are dividing so cancer cells are cells in the body which are dividing much faster , out-of-control compared to other cells , so if you radiate a patient , the cancer cells , because they are dividing faster , die quicker , so overall although a lot of cells die , the cancer cells die further .
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radium was the second element to be discovered by marie and pierre curie . which element was their first discovery ?
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many of us have hundreds of things on our minds at any moment , often struggling to keep track of everything we need to do . but fortunately , there 's one important thing we do n't have to worry about remembering : breathing . when you breathe , you transport oxygen to the body 's cells to keep them working and clear your system of the carbon dioxide that this work generates . breathing , in other words , keeps the body alive . so , how do we accomplish this crucial and complex task without even thinking about it ? the answer lies in our body 's respiratory system . like any machinery , it consists of specialized components , and requires a trigger to start functioning . here , the components are the structures and tissues making up the lungs , as well as the various other respiratory organs connected to them . and to get this machine moving , we need the autonomic nervous system , our brain 's unconscious control center for the vital functions . as the body prepares to take in oxygen-rich air , this system sends a signal to the muscles around your lungs , flattening the diaphragm and contracting the intercostal muscles between your ribs to create more space for the lungs to expand . air then wooshes into your nose and mouth , through your trachea , and into the bronchi that split at the trachea 's base , with one entering each lung . like tree branches , these small tubes divide into thousands of tinier passages called bronchioles . it 's tempting to think of the lungs as huge balloons , but instead of being hollow , they 're actually spongy inside , with the bronchioles running throughout the parenchyma tissue . at the end of each bronchiole is a little air sack called an alveolus , wrapped in capillaries full of red blood cells containing special proteins called hemoglobin . the air you 've breathed in fills these sacks , causing the lungs to inflate . here is where the vital exchange occurs . at this point , the capillaries are packed with carbon dioxide , and the air sacks are full of oxygen . but due to the basic process of diffusion , the molecules of each gas want to move to a place where there 's a lower concentration of their kind . so as oxygen crosses over to the capillaries , the hemoglobin grabs it up , while the carbon dioxide is unloaded into the lungs . the oxygen-rich hemoglobin is then transported throughout the body via the bloodstream . but what do our lungs do with all that carbon dioxide ? exhale it , of course . the autonomic nervous system kicks in again , causing the diaphragm to ball up , and the intercostal muscles to relax , making the chest cavities smaller and forcing the lungs to compress . the carbon dioxide-rich air is expelled , and the cycle begins again . so that 's how these spongy organs keep our bodies efficiently supplied with air . lungs inhale and exhale between 15 and 25 times a minute , which amounts to an incredible 10,000 liters of air each day . that 's a lot of work , but do n't sweat it . your lungs and your autonomic nervous system have got it covered .
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air then wooshes into your nose and mouth , through your trachea , and into the bronchi that split at the trachea 's base , with one entering each lung . like tree branches , these small tubes divide into thousands of tinier passages called bronchioles . it 's tempting to think of the lungs as huge balloons , but instead of being hollow , they 're actually spongy inside , with the bronchioles running throughout the parenchyma tissue . at the end of each bronchiole is a little air sack called an alveolus , wrapped in capillaries full of red blood cells containing special proteins called hemoglobin .
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why is it better that the lungs are spongy rather than empty like a balloon ?
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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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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 .
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understanding geologic time is significant because it helps us
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are you familiar with the word symbiosis ? it 's a fancy term for a partnership between two different species , such as bees and flowers . in a symbiosis , both species depend on each other . i want to tell you about a remarkable symbiosis between a little bird , the clark 's nutcracker , and a big tree , the whitebark pine . whitebark grow in the mountains of wyoming , montana and other western states . they have huge canopies and lots of needles , which provide cover and shelter for other plants and animals , and whitebark feed the forest . their cones are packed with protein . squirrels gnaw the cones from the upper branches so they fall to the ground , and then race down to bury them in piles , or middens . but they do n't get to keep all of them ; grizzlies and black bears love finding middens . but there 's more to a symbiosis than one species feeding another . in the case of the clark 's nutcracker , this bird gives back . while gathering its seeds , it also replants the trees . here 's how it works : using her powerful beak , the nutcracker picks apart a cone in a treetop , pulling out the seeds . she can store up to 80 of them in a pouch in her throat . then she flies through the forest looking for a place to cache the seeds an inch under the soil in piles of up to eight seeds . nutcrackers can gather up to 90,000 seeds in the autumn , which they return for in the winter and spring . and these birds are smart . they remember where all those seeds are . they even use landmarks on the landscape -- trees , stumps , rocks -- to triangulate to caches buried deep under the snow . what they do n't go back and get , those seeds become whitebark . this symbiosis is so important to both species that they 've changed , or evolved , to suit each other . nutcrackers have developed long , tough beaks for extracting seeds from cones , and whitebarks ' branches all sweep upwards with the cones at the very ends , so they can offer them to the nutcrackers as they fly by . that 's a symbiosis : two species cooperating to help each other for the benefit of all .
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in a symbiosis , both species depend on each other . i want to tell you about a remarkable symbiosis between a little bird , the clark 's nutcracker , and a big tree , the whitebark pine . whitebark grow in the mountains of wyoming , montana and other western states .
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how does the whitebark pine benefit from its association with the clark ’ s nutcracker ?
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translator : tom carter reviewer : bedirhan cinar carbon dioxide , or co2 , is the main greenhouse gas in climate change . so how does co2 get into our atmosphere ? well , carbon is part of a cycle . it starts with the sun , which heats the earth 's surface with more energy in one hour than the whole world uses in a year . plants , which are kind of like biological chefs , take that sunlight , and then suck in some co2 from the air , mix them together , and bam ! they create a stored form of energy , in the form of carbohydrates such as glucose and sucrose . the process is called photosynthesis . when animals like us eat those plants our stomachs convert that food back into energy for our own growth . greenhouse gases are a byproduct of this process , and are released through waste . if those plants die , they decompose , and tiny microorganisms break down those carbohydrates and again , release greenhouse gases as a byproduct . as you see , energy originates from the sun . it is then transferred as it moves through the food chain . but sometimes , carbon based organisms like plants or animals get stuck in the earth . when this happens , they 're compressed under tons of pressure , and turned into carbon-based fossil fuels like oil , coal or natural gas . since the industrial revolution , humans have been pulling those fossil fuels out of the ground and burning them , activating the stored energy to make electricity and power engines . but the thing is it also releases millions of years worth of stored co2 back into the air . in addition , humans breathe in oxygen and breathe out co2 . but plants do the opposite . trees suck up huge amounts of co2 , which balances the cycle . thus , deforestation reduces the plants that store co2 . we 're attacking the cycle from both sides . think of it like a computer . a computer can operate a few programs at a time , right ? normally , when you 've finished with a document , you save , and you close it , so as not to overwork the computer . then , imagine you stopped closing your documents . so they were all open at once . your computer would n't be able to process it all . it would start to slow down , and then to freeze , and eventually it would crash . which might be where our environment is heading if we keep overloading the carbon cycle . so is there any way to rebalance the ecosystem ? what about technology ? technology is defined as a technique to solve a problem . and so , sustainable technologies are those whose output is equal to their input . they do not create negative externalities , such as co2 , in the present or the future . they sort of cancel themselves out to solve the problem . to achieve this , we need to invent sustainable technologies . if we put all the ideas and technologies ever created into one circle , then invention is the pushing of the boundaries of that circle . and the area outside of the circle is infinite , meaning the potential for invention is limitless . think about some of the incredible clean technologies we have today . [ wind ; electric & amp ; amp ; solar cars ; biogas ] [ biofuels ; photosynthetic algae ; compost ] all those ideas have one thing in common . they all came from people . people innovate . people create . it 's the limitless potential of creative people to build unimagined technologies that is going to stop climate change and rebalance the ecosystem . and that is something to be hopeful about .
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translator : tom carter reviewer : bedirhan cinar carbon dioxide , or co2 , is the main greenhouse gas in climate change . so how does co2 get into our atmosphere ?
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do you think that having to limit emissions would hamper the ability to increase the living standards of people ? why is affluence not an acceptable variable to reduce impact ? is it fair that developed nations have historically created lots of co2 while becoming wealthy , but now developing nations can not do the same without exacerbating climate change and putting everyone at risk ? what is a fair way for developing nations to grow and continue to move out of poverty but also keep carbon emissions from growing globally and causing climate change ?
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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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as the professor explained , it can not currently be measured , but it could be that hassium has the highest…
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depression is the leading cause of disability in the world . in the united states , close to 10 % of adults struggle with depression . but because it 's a mental illness , it can be a lot harder to understand than , say , high cholesterol . one major source of confusion is the difference between having depression and just feeling depressed . almost everyone feels down from time to time . getting a bad grade , losing a job , having an argument , even a rainy day can bring on feelings of sadness . sometimes there 's no trigger at all . it just pops up out of the blue . then circumstances change , and those sad feelings disappear . clinical depression is different . it 's a medical disorder , and it wo n't go away just because you want it to . it lingers for at least two consecutive weeks , and significantly interferes with one 's ability to work , play , or love . depression can have a lot of different symptoms : a low mood , loss of interest in things you 'd normally enjoy , changes in appetite , feeling worthless or excessively guilty , sleeping either too much or too little , poor concentration , restlessness or slowness , loss of energy , or recurrent thoughts of suicide . if you have at least five of those symptoms , according to psychiatric guidelines , you qualify for a diagnosis of depression . and it 's not just behavioral symptoms . depression has physical manifestations inside the brain . first of all , there are changes that could be seen with the naked eye and x-ray vision . these include smaller frontal lobes and hippocampal volumes . on a more microscale , depression is associated with a few things : the abnormal transmission or depletion of certain neurotransmitters , especially serotonin , norepinephrine , and dopamine , blunted circadian rhythms , or specific changes in the rem and slow-wave parts of your sleep cycle , and hormone abnormalities , such as high cortisol and deregulation of thyroid hormones . but neuroscientists still do n't have a complete picture of what causes depression . it seems to have to do with a complex interaction between genes and environment , but we do n't have a diagnostic tool that can accurately predict where or when it will show up . and because depression symptoms are intangible , it 's hard to know who might look fine but is actually struggling . according to the national institute of mental health , it takes the average person suffering with a mental illness over ten years to ask for help . but there are very effective treatments . medications and therapy complement each other to boost brain chemicals . in extreme cases , electroconvulsive therapy , which is like a controlled seizure in the patient 's brain , is also very helpful . other promising treatments , like transcranial magnetic stimulation , are being investigated , too . so , if you know someone struggling with depression , encourage them , gently , to seek out some of these options . you might even offer to help with specific tasks , like looking up therapists in the area , or making a list of questions to ask a doctor . to someone with depression , these first steps can seem insurmountable . if they feel guilty or ashamed , point out that depression is a medical condition , just like asthma or diabetes . it 's not a weakness or a personality trait , and they should n't expect themselves to just get over it anymore than they could will themselves to get over a broken arm . if you have n't experienced depression yourself , avoid comparing it to times you 've felt down . comparing what they 're experiencing to normal , temporary feelings of sadness can make them feel guilty for struggling . even just talking about depression openly can help . for example , research shows that asking someone about suicidal thoughts actually reduces their suicide risk . open conversations about mental illness help erode stigma and make it easier for people to ask for help . and the more patients seek treatment , the more scientists will learn about depression , and the better the treatments will get .
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but because it 's a mental illness , it can be a lot harder to understand than , say , high cholesterol . one major source of confusion is the difference between having depression and just feeling depressed . almost everyone feels down from time to time .
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involuntary hospitalization , a last resort for the treatment of major depression , is reserved for individuals whose safety is immediately at risk . how can society balance respect for personal freedom with mandatory hospitalization ?
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translator : andrea mcdonough reviewer : bedirhan cinar blue whales are the largest animals that have ever roamed the planet . they 're at least two times as big as the biggest dinosaurs , `` that 's big ! '' the length of a basketball court , and as heavy as 40 african elephants . if that 's not enough to make you marvel , here 's something that will . they 're grown to this enormous size by feeding exclusively on tiny shrimp-like creatures called krill that are no bigger than your little finger . in many ways , the sheer size of krill seems to have driven the evolution of the blue whale . see , krill are so small but are found in dense patches . for increased efficiency , blue whales have evolved to use a feeding strategy called lunge feeding . basically , the whale accelerates towards a prey patch and opens its mouth wide . to increase the capacity , its mouth expands . the special , accordion-like blubber layer that extends from its snout to its belly button enables the whale to engulf large quantities of prey-laden water . with each giant gulp , the whale takes in 125 % of its body weight in water and krill . the whale must then expel the water while retaining the yummy krill . to do this , it uses its baleen , the comb-like structure made of the same stuff our nails and hair are made of , and its tongue . it 's pretty crazy that the blue whale 's heart is as big as a small car , a child could crawl through its arteries , its tongue weighs as much as an elephant , but its esophagus is so small , the whale could choke on a loaf of bread . these whales are really not designed to feed on anything larger than krill . it 's estimated that blue whales eat four tons of krill per day . because of the incredible design , each dive provides the blue whale with 90 times as much energy as is used . every mouthful of krill provides almost 480,000 calories , the same amount you get from eating 1,900 hamburgers . but , why are blue whales so big ? blue whales are considerably larger than the largest living land animal , the elephant . the heavier an animal is , the greater its relative surface area . as weight increases , there 's a point at which the legs of that animal would simply collapse . that explains why elephants do n't stand on the delicate legs of a horse . they need legs shaped like stout pedestals to hold their bodies up against gravity . in water , the situation is quite different . buoyancy counteracts the gravitational pull on the body and their great bulk is therefore partially supported by the water . so , the ocean is a great place for species that want to grow bigger . the other secret to their size is their diet . by evolving such a huge mouth , the whale 's have specialized to catch enormous quantities of highly abundant and nutritious prey , which provides the energy needed to grow so big . but , now maybe you 're wondering why blue whales are n't any bigger ? after all , the ocean sounds like nirvana for any growing beast . well , while lunge feeding may have allowed blue whales to become the biggest animal to have ever roamed the planet , by enabling them to feed efficiently in dense prey patches , it is n't cost free . scientists compared all the costs involved with lunge feeding to the energy gained from the krill they eat . what they found is that when the whale 's body increases in size , the energy that body demands rises faster than the extra energy they get from their food . feeding whales needs 15 times the energy required to remain still and 5 times more energy than used when swimming . calculations show that the largest a lunge feeder can grow is 33 meters , pretty much blue whale size . turns out blue whales have a lot to thank krill for : neat , evolutionary adaptations that would not have been possible if krill were not so small . it 's incredible that these tiny creatures have allowed blue whales to really push the limits of size on our planet . makes you wonder if that old adage , `` you are what you eat , '' really does apply in blue whale world .
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it 's estimated that blue whales eat four tons of krill per day . because of the incredible design , each dive provides the blue whale with 90 times as much energy as is used . every mouthful of krill provides almost 480,000 calories , the same amount you get from eating 1,900 hamburgers .
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do some research . explain why it requires more energy for a whale to feed than it does for a whale to swim .
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translator : andrea mcdonough reviewer : jessica ruby big data is an elusive concept . it represents an amount of digital information , which is uncomfortable to store , transport , or analyze . big data is so voluminous that it overwhelms the technologies of the day and challenges us to create the next generation of data storage tools and techniques . so , big data is n't new . in fact , physicists at cern have been rangling with the challenge of their ever-expanding big data for decades . fifty years ago , cern 's data could be stored in a single computer . ok , so it was n't your usual computer , this was a mainframe computer that filled an entire building . to analyze the data , physicists from around the world traveled to cern to connect to the enormous machine . in the 1970 's , our ever-growing big data was distributed across different sets of computers , which mushroomed at cern . each set was joined together in dedicated , homegrown networks . but physicists collaborated without regard for the boundaries between sets , hence needed to access data on all of these . so , we bridged the independent networks together in our own cernet . in the 1980 's , islands of similar networks speaking different dialects sprung up all over europe and the states , making remote access possible but torturous . to make it easy for our physicists across the world to access the ever-expanding big data stored at cern without traveling , the networks needed to be talking with the same language . we adopted the fledgling internet working standard from the states , followed by the rest of europe , and we established the principal link at cern between europe and the states in 1989 , and the truly global internet took off ! physicists could easily then access the terabytes of big data remotely from around the world , generate results , and write papers in their home institutes . then , they wanted to share their findings with all their colleagues . to make this information sharing easy , we created the web in the early 1990 's . physicists no longer needed to know where the information was stored in order to find it and access it on the web , an idea which caught on across the world and has transformed the way we communicate in our daily lives . during the early 2000 's , the continued growth of our big data outstripped our capability to analyze it at cern , despite having buildings full of computers . we had to start distributing the petabytes of data to our collaborating partners in order to employ local computing and storage at hundreds of different institutes . in order to orchestrate these interconnected resources with their diverse technologies , we developed a computing grid , enabling the seamless sharing of computing resources around the globe . this relies on trust relationships and mutual exchange . but this grid model could not be transferred out of our community so easily , where not everyone has resources to share nor could companies be expected to have the same level of trust . instead , an alternative , more business-like approach for accessing on-demand resources has been flourishing recently , called cloud computing , which other communities are now exploiting to analyzing their big data . it might seem paradoxical for a place like cern , a lab focused on the study of the unimaginably small building blocks of matter , to be the source of something as big as big data . but the way we study the fundamental particles , as well as the forces by which they interact , involves creating them fleetingly , colliding protons in our accelerators and capturing a trace of them as they zoom off near light speed . to see those traces , our detector , with 150 million sensors , acts like a really massive 3-d camera , taking a picture of each collision event - that 's up to 14 millions times per second . that makes a lot of data . but if big data has been around for so long , why do we suddenly keep hearing about it now ? well , as the old metaphor explains , the whole is greater than the sum of its parts , and this is no longer just science that is exploiting this . the fact that we can derive more knowledge by joining related information together and spotting correlations can inform and enrich numerous aspects of everyday life , either in real time , such as traffic or financial conditions , in short-term evolutions , such as medical or meteorological , or in predictive situations , such as business , crime , or disease trends . virtually every field is turning to gathering big data , with mobile sensor networks spanning the globe , cameras on the ground and in the air , archives storing information published on the web , and loggers capturing the activities of internet citizens the world over . the challenge is on to invent new tools and techniques to mine these vast stores , to inform decision making , to improve medical diagnosis , and otherwise to answer needs and desires of tomorrow 's society in ways that are unimagined today .
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big data is so voluminous that it overwhelms the technologies of the day and challenges us to create the next generation of data storage tools and techniques . so , big data is n't new . in fact , physicists at cern have been rangling with the challenge of their ever-expanding big data for decades .
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the key characteristics of big data are often called the 3vs : volume , velocity , and variety . explain the role each one of these plays in making big data hard to handle . the complexity of some data sets leads people to add extra dimensions such as veracity and variability to this list . in what ways do these complicate things further ?
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translator : tom carter reviewer : bedirhan cinar in society , we have to follow laws that maintain order . did you know all chemical matter follows certain laws as well ? in fact , we can describe those laws by looking at relationships . some easy laws to begin with are the ones that govern the gases . back in 1662 , robert boyle realized that gases had an interesting response when he put them into containers and changed their volume . take an empty bottle and put the cap on it , closing that container . now squeeze your bottle , and what happens ? the pressure inside the bottle increases when the size of the container decreases . you can only crush that container so much until the gases inside push back on your hand . this is called an inverse proportion , and it changes at the same rate for every gas . boyle 's law allows chemists to predict the volume of any gas at any given pressure because the relationship is always the same . in 1780 , jacques charles noticed a different relationship between gases and their temperature . if you 've ever seen a hot-air balloon , you 've seen this law in action . when the ballons are laid out , they 're totally flat . instead of blowing the balloon up like a party balloon , they use a giant flame to heat the air inside that envelope . as the air is heated up , the balloon begins to inflate as the gas volume increases . the hotter the gas becomes , the larger the volume , and that 's charles ' law . notice this law is different from boyle 's . charles ' law is a direct relationship . as the temperature increases , the volume increases as well . the third law is also easily demonstrated . when you 're blowing up party balloons , the volume increases . as you are blowing , you 're forcing more and more gas particles into the balloon from your lungs . this causes the balloon volume to increase . this is avogadro 's law in action . as the number of particles of gas added to a container are increased , the volume will increase as well . if you add too many particles , well , you know what happens next . laws are everywhere , even in the tiniest particles of gas . if you squeeze them , the pressure will increase as the particles are pushed together . low volume means a high pressure because those particles push back . as the temperature increases , gases move away from one another , and the volume increases as well . finally , if you add gas to a closed container , that container 's volume will expand . but be careful not to add too much , because otherwise you could end up with a burst balloon .
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in 1780 , jacques charles noticed a different relationship between gases and their temperature . if you 've ever seen a hot-air balloon , you 've seen this law in action . when the ballons are laid out , they 're totally flat .
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which of the following explains why a hot air balloon inflates when it is heated ?
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if someone asked you who the richest people in history were , who would you name ? perhaps a billionaire banker or corporate mogul , like bill gates or john d. rockefeller . how about african king musa keita i ? ruling the mali empire in the 14th century ce , mansa musa , or the king of kings , amassed a fortune that possibly made him one of the wealthiest people who ever lived . but his vast wealth was only one piece of his rich legacy . when mansa musa came to power in 1312 , much of europe was racked by famine and civil wars . but many african kingdoms and the islamic world were flourishing , and mansa musa played a great role in bringing the fruits of this flourishing to his own realm . by strategically annexing the city of timbuktu , and reestablishing power over the city of gao , he gained control over important trade routes between the mediterranean and the west african coast , continuing a period of expansion , which dramatically increased mali 's size . the territory of the mali empire was rich in natural resources , such as gold and salt . the world first witnessed the extent of mansa musa 's wealth in 1324 when he took his pilgrimage to mecca . not one to travel on a budget , he brought a caravan stretching as far as the eye could see . accounts of this journey are mostly based on an oral testimony and differing written records , so it 's difficult to determine the exact details . but what most agree on is the extravagant scale of the excursion . chroniclers describe an entourage of tens of thousands of soldiers , civilians , and slaves , 500 heralds bearing gold staffs and dressed in fine silks , and many camels and horses bearing an abundance of gold bars . stopping in cities such as cairo , mansa musa is said to have spent massive quantities of gold , giving to the poor , buying souvenirs , and even having mosques built along the way . in fact , his spending may have destabilized the regional economy , causing mass inflation . this journey reportedly took over a year , and by the time mansa musa returned , tales of his amazing wealth had spread to the ports of the mediterranean . mali and its king were elevated to near legendary status , cemented by their inclusion on the 1375 catalan atlas . one of the most important world maps of medieval europe , it depicted the king holding a scepter and a gleaming gold nugget . mansa musa had literally put his empire and himself on the map . but material riches were n't the king 's only concern . as a devout muslim , he took a particular interest in timbuktu , already a center of religion and learning prior to its annexation . upon returning from his pilgrimage , he had the great djinguereber mosque built there with the help of an andalusian architect . he also established a major university , further elevating the city 's reputation , and attracting scholars and students from all over the islamic world . under mansa musa , the empire became urbanized , with schools and mosques in hundreds of densely populated towns . the king 's rich legacy persisted for generations and to this day , there are mausoleums , libraries and mosques that stand as a testament to this golden age of mali 's history .
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one of the most important world maps of medieval europe , it depicted the king holding a scepter and a gleaming gold nugget . mansa musa had literally put his empire and himself on the map . but material riches were n't the king 's only concern .
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mansa musa was a devout _____ .
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immortality . in movies , kings are always searching for the secret to immortality . but is immortality really a good thing ? to a ten-year-old boy , one year is the same as 10 % of his life . to his forty-year-old mother , one year is merely 2.5 % of her life . the same year , 365 days , can feel differently to different people . if we live until we 're 82 , that 's about 30,000 days . if this boy lives for 30,000 years , a year to him could feel like a day . and if this boy 's emotions sustain through the potential boredom of living for millions of years , he might become extremely lonely and sad , knowing he has and always will outlive everyone he has ever loved . but what if everyone were immortal ? well , first off , earth is only so big . so , where would we all live ? ( grunts ) `` excuse me ! '' `` that 's my face ! '' `` stop it ! '' `` pardon me . '' `` tight in here ! '' do you remember what you did last year or when you were five ? how much of your past have you forgotten ? if you have trouble remembering what you did when you were five , how will you remember what happened if you were alive a thousand years ago ? a million years ago ? we do n't remember every single detail of our past because our brains have a limited capacity and we replace useless memories , like middle school locker combinations , with relevant information . if this immortal boy finds a companion to fall in love with once every hundred years , he would have ten thousand girlfriends in a million years . and how many of those ten thousand girls ' names will he be able to remember ? this changes what a meaningful relationship means , does n't it ? another tricky thing about immortality : human beings have not always looked the same . this can be explained by darwin 's theory of evolution . for instance , if women find taller men more attractive , then more tall men would mate and have children , putting more tall genes in the gene pool . that means , in the next generation , more children will have the genes to be taller . repeat that process for a million years and the average height will be a lot taller than the average height today , assuming there 's no natural disaster that wipes out all the tall people . our ancestors were short , hairy apes . we still have body hair , but we do n't look like apes any more . if you 're the only person who is immortal , while everyone else keeps evolving , generation after generation , you will eventually look quite different than the people who surround you . `` hi , how you doing ? '' if one of our ancestors , apes , is still alive today , how many people will make friends with it instead of calling the museum of natural history ? and one more physical consideration for immortality : scars . after all , immortality does n't automatically translate to invincibility , it just means you can not die . but it does n't guarantee what condition you 'll be alive in . look at your body and count how many scars you have . if you have made this many permanent scars within your life , imagine how much damage you would have if you were one thousand years old ! now , there are approximately 185,000 amputation-related hospital discharges every year in the u.s . these injuries are due to accidents or illnesses . certainly the percentage is low comparing to the total population if you only live for a hundred years . however , if you 've been alive for over one million years , the odds of still having all your limbs are pretty slim . what about little accessories , like your eyes , your nose , your ears , fingers or toes ? what about your teeth ? what are the odds of you keeping your dental health for a hundred years ? a thousand years ? one million years ? you might end up looking like a horribly scuffed-up mr . potato head with missing pieces and dentures . so , are you sure you want to live forever ? 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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but is immortality really a good thing ? to a ten-year-old boy , one year is the same as 10 % of his life . to his forty-year-old mother , one year is merely 2.5 % of her life . the same year , 365 days , can feel differently to different people . if we live until we 're 82 , that 's about 30,000 days . if this boy lives for 30,000 years , a year to him could feel like a day .
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an 82-year-old man has lived approximately how many days ?
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hello , everyone . let 's begin our guided tour . welcome to the museum of museums . museums have been a part of human history for over 2000 years . but they were n't always like the ones we visit today . the history of museums is far older and much stranger than you might imagine . we 'll start over here in the greek wing . our word museum comes from the greek mouseion , temples built for the muses , the goddesses of the arts and the sciences . supplicants asked the muses to keep watch over academics and grant ingenuity to those they deemed worthy . the temples were filled with offerings of sculptures , mosaics , complex scientific apparatuses , poetic and literary inscriptions , and any other tribute that would demonstrate a mortal 's worthiness for divine inspiration . we have arrived at the mesopotamian wing . the first museum was created in 530 b.c . in what is now iraq . and the first curator was actually a princess . ennigaldi-nanna started to collect and house mesopotamian antiquities in e-gig-par , her house . when archeologists excavated the area , they discovered dozens of artifacts neatly arranged in rows , with clay labels written in three languages . she must have had interesting parties . the tradition of collecting and displaying intriguing items began to be mimicked , as you can see here in the roman empire wing . treasure houses of politicians and generals were filled with the spoils of war , and royal menageries displayed exotic animals to the public on special occasions , like gladiator tournaments . as you can see , we have a lion here and a gladiator , and , well , the janitor ought to be in this wing clearly . moving on , hurry along . the next step in the evolution of museums occurred in the renaissance , when the study of the natural world was once again encouraged after almost a millennium of western ignorance . curiosity cabinets , also referred to as wunderkammers , were collections of objects that acted as a kind of physical encyclopedia , showcasing artifacts . just step into the wardrobe here . there you go . mind the coats . and we 'll tour ole worm 's cabinet , one of the most notable wunderkammers belonged to a wealthy 17th-century naturalist , antiquarian , and physician ole worm . ole worm collected natural specimens , human skeletons , ancient runic texts , and artifacts from the new world . in other curiosity cabinets , you could find genetic anomalies , precious stones , works of art , and religious and historic relics . oh my . you might not want to touch that . these cabinets were private , again , often in residencies , curated by their owners , rulers and aristocrats , as well as merchants and early scientists . now , who hears a circus organ ? in the 1840s , an enterprising young showman named phineas t. barnum purchased some of the more famous cabinets of curiosity from europe and started barnum 's american museum in new york city . a spectacular hodgepodge of zoo , lecture hall , wax museum , theater , and freak show that was known for its eclectic residents , such as bears , elephants , acrobats , giants , siamese twins , a fiji mermaid , and a bearded lady , along with a host of modern machinery and scientific instruments . museums open to the public are a relatively new phenomenon . before barnum , the first public museums were only accessible by the upper and middle classes , and only on certain days . visitors would have to apply to visit the museum in writing prior to admision , and only small groups could visit the museum each day . the louvre famously allowed all members of the public into the museum but only three days a week . in the 19th century , the museum as we know it began to take shape . institutions like the smithsonian were started so that objects could be seen and studied , not just locked away . american museums , in particular , commissioned experiments and hired explorers to seek out and retrieve natural samples . museums became centers for scholarship and artistic and scientific discovery . this is often called the museum age . nowadays , museums are open to everybody , are centers of learning and research , and are turning into more hands-on institutions . but the question of who gets to go is still relevant as ticket prices can sometimes bar admission to those future scholars , artists and targets of divine inspiration who ca n't afford to satisfy their curiosity . thank you all for coming , and please , feel free to stop by the gift shop of gift shops on your way out .
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we have arrived at the mesopotamian wing . the first museum was created in 530 b.c . in what is now iraq .
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where was the first museum ?
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on july 26 , 1943 , los angeles was blanketed by a thick gas that stung people 's eyes and blocked out the sun . panicked residents believed their city had been attacked using chemical warfare . but the cloud was n't an act of war . it was smog . a portmanteau of smoke and fog , the word smog was coined at the beginning of the 20th century to describe the thick gray haze that covered cities such as london , glasgow , and edinburgh . this industrial smog was known to form when smoke from coal-burning home stoves and factories combined with moisture in the air . but the smog behind the la panic was different . it was yellowish with a chemical odor . since the city did n't burn much coal , its cause would remain a mystery until a chemist named arie haagen-smit identified two culprits , volatile organic compounds , or vocs , and nitrous oxides . vocs are compounds that easily become vapors and may contain elements , such as carbon , oxygen , hydrogen , chlorine , and sulfur . some are naturally produced by plants and animals , but others come from manmade sources , like solvents , paints , glues , and petroleum . meanwhile , the incomplete combustion of gas in motor vehicles releases nitrous oxide . that 's what gives this type of smog its yellowish color . vocs and nitrous oxide react with sunlight to produce secondary pollutants called pans and tropospheric , or ground level , ozone . pans and ozone cause eye irritation and damage lung tissue . both are key ingredients in photochemical smog , which is what had been plaguing la . so why does smog affect some cities but not others ? both industrial and photochemical smog combine manmade pollution with local weather and geography . london 's high humidity made it a prime location for industrial smog . photochemical smog is strongest in urban areas with calm winds and dry , warm , sunny weather . the ultraviolet radiation from sunlight provides the energy necessary to breakdown molecules that contribute to smog formation . cities surrounded by mountains , like la , or lying in a basin , like beijing , are also especially vulnerable to smog since there 's nowhere for it to dissipate . that 's also partially due to a phenomenon known as temperature inversion , where instead of warm air continuously rising upward , a pollution-filled layer of air remains trapped near the earth 's surface by a slightly warmer layer above . smog is n't just an aesthetic eyesore . both forms of smog irritate the eyes , nose , and throat , exacerbate conditions like asthma and emphysema , and increase the risk of respiratory infections like bronchitis . smog can be especially harmful to young children and older people and exposure in pregnant women has been linked to low birth weight and potential birth defects . secondary pollutants found in photochemical smog can damage and weaken crops and decrease yield , making them more susceptible to insects . yet for decades , smog was seen as the inevitable price of civilization . londoners had become accustomed to the notorious pea soup fog swirling over their streets until 1952 , when the great smog of london shut down all transportation in the city for days and caused more than 4,000 respiratory deaths . as a result , the clean air act of 1956 banned burning coal in certain areas of the city , leading to a massive reduction in smog . similarly , regulations on vehicle emissions and gas content in the us reduced the volatile compounds in the air and smog levels along with them . smog remains a major problem around the world . countries like china and poland that depend on coal for energy experience high levels of industrial smog . photochemical smog and airborne particles from vehicle emissions affect many rapidly developing cities , from mexico city and santiago to new delhi and tehran . governments have tried many methods to tackle it , such as banning cars from driving for days at a time . as more than half of the world 's population crowds into cities , considering a shift to mass transit and away from fossil fuels may allow us to breathe easier .
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but the cloud was n't an act of war . it was smog . a portmanteau of smoke and fog , the word smog was coined at the beginning of the 20th century to describe the thick gray haze that covered cities such as london , glasgow , and edinburgh .
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which groups of people are more prone to the breathing difficulties that are associated with smog ?
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dear mr. president , do you know much about physics ? i mean , you 're the president of the united states : a country with five thousand nuclear weapons , birthplace of the world 's computing and telecommunications industry , home of the first atomic clock and creator of the global positioning system . but chances are , if you just took regular american high school physics , you do n't know one iota about the science behind these things ( no offense ) . that 's because high school physics students across most of america are not required to learn about pretty much any physical phenomena discovered or explained more recently than 1865 . yes , 1865 . that 's the year the civil war ended and well over a decade before albert einstein was even born ! you know what can happen in 150 years , mr. president ? a lot . velcro , for one . but let me list some useful and important ideas of the last 150 years of physics that are n't a required part of most standard us high school physics courses : photons . the structure of atoms . the existence of antimatter . gps . lasers . transistors . diodes and leds . quarks . chaos theory . electron microscopy . mri scanning . the big bang . black holes . star formation . the fact that gravity bends light . the fact that the universe is expanding . the higgs boson and the weak and strong nuclear forces and all the rest of quantum mechanics and relativity and the topic of every single nobel prize in physics since… always . basically , most of the important stuff . i mean , mr. president , imagine if history classes did n't talk about the abolition of slavery , world wars i or ii , the great depression , the rise of the us as a global superpower , the cold war or the civil rights movement or heaven forbid the first african american president . or imagine if biology classes did n't talk about dna , or hormones , or cell reproduction or the modern germ theory of disease or ecology . or if geologists did n't talk about plate tectonics . and computer scientists… well… in 1865 a computer was a person who computed your taxes . now , if you were lucky enough to have an ambitious teacher or take advanced placement physics , then you might have learned about some of einstein 's discoveries of 1905 ! yes ! current events ! but learning about how einstein 's work helped set the stage for a century of amazing developments in our understanding of the universe is not a part of the standard curriculum . so why , mr. president , am i addressing this letter to you ? well , you appoint the secretary of education , for one - and i do believe that high school physics is somewhat related to education . now , maybe your education secretary says , `` ancient physics is already hard to teach to high schoolers . and you want us to teach them modern physics which is even harder ? ! students ca n't really appreciate the beauty of modern physics without fancy college level mathematics . '' rubbish . ever heard of carl sagan ? richard feynman ? or neil degrasse tyson ? these great men have been 100 % committed to the appreciation and dissemination of the awesomeness of the universe . and we should be too . how else are we supposed to foster and find our future brilliant innovators , inventors , and explorers ? how can we expect to educate our citizens for the next century if we do n't teach about the last ? and that 's not to say that we should ignore math , either - on the contrary , math is one of the most beautiful and awesome things in the universe , especially because it allows us to understand the universe . in particular , the last 150 years have borne fruit to perhaps the most drastic changes in our understanding of the universe , ever , and these new ways of thinking and solving problems should be the centerpiece of an education in physics . between you and me , mr. president , i think we 'd better start making physics education more awesome here in the us , otherwise the next carl sagan or richard feynman will come from somewhere with more educational foresight - maybe even , the internet . sincerely , a collection of atoms known as henry ps you 're probably super busy , but if you 'd like to hear about physics education across the atlantic , i highly recommend heading over to brady 's channel , sixty symbols , for a perspective from the uk . i bet you 'll enjoy it .
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i mean , you 're the president of the united states : a country with five thousand nuclear weapons , birthplace of the world 's computing and telecommunications industry , home of the first atomic clock and creator of the global positioning system . but chances are , if you just took regular american high school physics , you do n't know one iota about the science behind these things ( no offense ) . that 's because high school physics students across most of america are not required to learn about pretty much any physical phenomena discovered or explained more recently than 1865 . yes , 1865 .
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read the `` dig deeper '' section before responding to this question : do you think a high school student would find the topic you researched interesting/valuable to learn about ? why or why not ?
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this is ytterbium . again , a lanthanide . stored in a very old glass bowl . ytterbium is one of three lanthanides , which was named after a swedish town called ytterby which is where they were all discovered . ytterbium , terbium and erbium were all derivatives of that town name . the town 's done well out of it , has n't it ? -the town 's did very well out of it , yeah . have you ever been there ? no , not personally . -you should go ! yeah , i should . it 's quite moving , and quite ... quite stirring to be here in this place because this is where science and industry came together , for one of the earliest times i suppose . and quite a significant place of discovery and economic vibrancy for the local area . it 's almost spiritual , it 's really quite , quite different . what does it look like ? ytterbium , it depends on whether talk about metal or as an element . often , ytterbium 2 compounds as sort of yellows and oranges . where did i get it from ? from a catalogue . so ytterbium , it 's a rare earth element , it 's a metal . it 's a silvery lustrous metal . it 's very soft and it reacts very readily with oxygen to form a very nice protective oxide layer which sits over the metal . so it preserves itself after a reaction with oxygen . it was first identified or first isolated from a sample of a mineral which was recovered from this very quarry , where were in ytterby near stockholm in sweden . but it took a very long time to make that extraction and to purify the metal . it 's a rare earth element , it 's one of 15 . and it 's actually the least abandoned of the rare earths . but the name `` rare earth '' makes you think that it 's really rare . but if you look at its occurrence in the earth 's crust , it was a surprise to find that actually it 's twice as abundant as tin . but that said , total production of ytterbium is only 50 tons per year . so it 's still very little utilized , and that 's probably because its chemistry is least understood . and it 's least understood because we really are n't able to isolate significant meant of ytterbium in the late 1950s . like many other rare earth elements , it 's main applications lie in electronics industry . it 's used as a dopant for phosphorus , it 's used as a dopant for ceramic capacitors , and other electronic devices . so really niche applications , but research is broadening these applications day on day . the metal itself is really quite unusual because its properties change as a function of pressure . so it 's a metal , so it 's a conductor . but when you push it under extreme pressure , say 14,000 atmospheres of pressure , it becomes a semiconductor . and that semi conductor ability changes as a function of temperature so it 's used as a pressure sensor in extreme environments . and in fact , one of the major applications as an electronic devices for the monitoring sort of measurement of pressure especially within nuclear explosions . so quite a significant element , and quite a recent discovery . . . . . . . . . . . . . captions by www.subply.com
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so it 's a metal , so it 's a conductor . but when you push it under extreme pressure , say 14,000 atmospheres of pressure , it becomes a semiconductor . and that semi conductor ability changes as a function of temperature so it 's used as a pressure sensor in extreme environments .
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ytterbium properties change as a function of pressure . under extreme pressure , about 14000 atm , it becomes a …
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there was a time before our ancestors smashed flint and steel together , when they felt the cold lack of fire in their lives . but anthropologists theorize that early hominids relied on lightning to cause forest fires , from which they could collect coals and burning sticks . fire gave them the ability to cook food and clear land , and became central in many rituals and traditions . so instead of seeing forest fires as an exclusively bad thing , ancient humans may have learned to appreciate them . yet , it was n't just humans who benefitted from these natural phenomena . even as they destroy trees , fires also help the forest themselves , however counterintuitive that seems . in fact , several forest species , such as select conifers , need fire to survive . but how can fire possibly create life in addition to destroying it ? the answer lies in the way that certain forests grow . in the conifer-rich forests of western north america , lodgepole pines constantly seek the sun . their seeds prefer to grow on open sunny ground , which pits saplings against each other as each tries to get more light by growing straighter and faster than its neighbors . over time , generations of slender , lofty lodgepoles form an umbrella-like canopy that shades the forest floor below . but as the trees ' pine cones mature to release their twirling seeds , this signals a problem for the lodgepoles ' future . very few of these seeds will germintate in the cool , sunless shade created by their towering parents . these trees have adapted to this problem by growing two types of cones . there are the regular annual cones that release seeds spontaneously , and another type called serotinous cones , which need an environmental trigger to free their seeds . serotinous cones are produced in thousands , and are like waterproofed time capsules sealed with resinous pitch . many are able to stay undamaged on the tree for decades . cones that fall to the ground can be viable for several years , as well . but when temperatures get high enough , the cones pop open . let 's see that in action . once it 's gotten started , a coniferous forest fire typically spreads something like this . flames ravage the thick understory provided by species like douglas fir , a shade-tolerant tree that 's able to thrive under the canopy of lodgepole pines . the fire uses these smaller trees as a step ladder to reach the higher canopy of old lodgepole pines . that ignites a tremendous crown fire reaching temperatures of up to 2400 degrees fahrenheit . that 's well more than the 115-140 degrees that signal the moment when serotinous seeds can be freed . at those temperatures , the cones burst open , releasing millions of seeds , which are carried by the hot air to form new forests . after the fire , carbon-rich soils and an open sunlit landscape help lodgepole seeds germinate quickly and sprout in abundance . from the death of the old forest comes the birth of the new . fires are also important for the wider ecosystem as a whole . without wildfires to rejuvenate trees , key forest species would disappear , and so would the many creatures that depend on them . and if a fire-dependent forest goes too long without burning , that raises the risk of a catastrophic blaze , which could destroy a forest completely , not to mention people 's homes and lives . that 's why forest rangers sometimes intentionally start controlled burns to reduce fuels in order to keep the more dangerous wildfires at bay . they may be frightening and destructive forces of nature , but wildfires are also vital to the existence of healthy boreal forest ecosystems . by coming to terms with that , we can protect ourselves from their more damaging effects while enabling the forests , like the legendary phoenix , to rise reborn from their own ashes .
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very few of these seeds will germintate in the cool , sunless shade created by their towering parents . these trees have adapted to this problem by growing two types of cones . there are the regular annual cones that release seeds spontaneously , and another type called serotinous cones , which need an environmental trigger to free their seeds .
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lodgepole pine trees develop two types of cones : an annual cone and a ( n ) ___________ cone .
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translator : andrea mcdonough reviewer : bedirhan cinar you look down and see a yellow pencil lying on your desk . your eyes , and then your brain , are collecting all sorts of information about the pencil : its size , color , shape , distance , and more . but , how exactly does this happen ? the ancient greeks were the first to think more or less scientifically about what light is and how vision works . some greek philosophers , including plato and pythagoras , thought that light originated in our eyes and that vision happened when little , invisible probes were sent to gather information about far-away objects . it took over a thousand years before the arab scientist , alhazen , figured out that the old , greek theory of light could n't be right . in alhazen 's picture , your eyes do n't send out invisible , intelligence-gathering probes , they simply collect the light that falls into them . alhazen 's theory accounts for a fact that the greek 's could n't easily explain : why it gets dark sometimes . the idea is that very few objects actually emit their own light . the special , light-emitting objects , like the sun or a lightbulb , are known as sources of light . most of the things we see , like that pencil on your desk , are simply reflecting light from a source rather than producing their own . so , when you look at your pencil , the light that hits your eye actually originated at the sun and has traveled millions of miles across empty space before bouncing off the pencil and into your eye , which is pretty cool when you think about it . but , what exactly is the stuff that is emitted from the sun and how do we see it ? is it a particle , like atoms , or is it a wave , like ripples on the surface of a pond ? scientists in the modern era would spend a couple of hundred years figuring out the answer to this question . isaac newton was one of the earliest . newton believed that light is made up of tiny , atom-like particles , which he called corpuscles . using this assumption , he was able to explain some properties of light . for example , refraction , which is how a beam of light appears to bend as it passes from air into water . but , in science , even geniuses sometimes get things wrong . in the 19th century , long after newton died , scientists did a series of experiments that clearly showed that light ca n't be made up of tiny , atom-like particles . for one thing , two beams of light that cross paths do n't interact with each other at all . if light were made of tiny , solid balls , then you would expect that some of the particles from beam a would crash into some of the particles from beam b . if that happened , the two particles involved in the collision would bounce off in random directions . but , that does n't happen . the beams of light pass right through each other as you can check for yourself with two laser pointers and some chalk dust . for another thing , light makes interference patterns . interference patterns are the complicated undulations that happen when two wave patterns occupy the same space . they can be seen when two objects disturb the surface of a still pond , and also when two point-like sources of light are placed near each other . only waves make interference patterns , particles do n't . and , as a bonus , understanding that light acts like a wave leads naturally to an explanation of what color is and why that pencil looks yellow . so , it 's settled then , light is a wave , right ? not so fast ! in the 20th century , scientists did experiments that appear to show light acting like a particle . for instance , when you shine light on a metal , the light transfers its energy to the atoms in the metal in discrete packets called quanta . but , we ca n't just forget about properties like interference , either . so these quanta of light are n't at all like the tiny , hard spheres newton imagined . this result , that light sometimes behaves like a particle and sometimes behaves like a wave , led to a revolutionary new physics theory called quantum mechanics . so , after all that , let 's go back to the question , `` what is light ? '' well , light is n't really like anything we 're used to dealing with in our everyday lives . sometimes it behaves like a particle and other times it behaves like a wave , but it is n't exactly like either .
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the beams of light pass right through each other as you can check for yourself with two laser pointers and some chalk dust . for another thing , light makes interference patterns . interference patterns are the complicated undulations that happen when two wave patterns occupy the same space .
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what are interference patterns ?
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i must look rather strange to you , all covered in spines , without even a face . but i 've taken many forms during my life . i started out just like you : a tiny egg in a watery world . my parents never knew each other . one moonlit night before a storm , thousands of urchins , clams and corals released trillions of sperm and eggs into the open sea . my father 's sperm somehow met my mother 's egg , and they fused . fertilization . instantly , i became an embryo the size of a speck of dust . after a few hours of drifting , i cleaved in two , then four , then eight cells . then so many , i lost count . in less than a day , i developed a gut and a skeleton . i became a rocket ship , a pluteus larva . i floated through the world of plankton , searching for tiny algae to eat . for weeks , i was surrounded by all kinds of organisms , larvae of all sorts . most are so different from their adult form that biologists have a tough time figuring out who they are . try matching these youngsters to their parents . this veliger larvae will turn into a snail ; this zoea , into a crab ; and this planula , into a clytia jelly . some of my young companions are easier to picture as grown-ups . these baby jellies , known as ephyrae , already resemble their beautiful but deadly parents . here in the plankton , there 's more than one way to get your genes into the next generation . most medusa jellies make special structures called polyps , that simply bud off babies with no need for sex . salps are similar . when food is abundant , they just clone themselves into long chains . the plankton is full of surprises when it comes to sex . meet the hermaphrodites . these comb jellies and arrow worms produce , store and release both sperm and eggs . they can fertilize themselves , or another . when you 're floating in a vast sea , with little control over who you may meet , it can pay to play both sides of the field . the majority of species here , however , never mate , nor form any sort of lasting bonds . that was my parents ' strategy . there were so many of us pluteus larvae , i just hid in the crowd , while most of my kin were devoured . not all parents leave the survival of their offspring to chance . some have far fewer young and take much better care of them , brooding their precious cargo for days , even months . this speedy copepod totes her beautifully packaged eggs for days . this phronima crustacean carries her babies on her chest , then carefully places them in a gelatinous barrel . but the black-eyed squid takes the prize . she cradles her eggs in long arms for nine months , the same time it takes to gestate a human infant . eventually , all youngsters have to make it on their own in this drifting world . some will spend their whole lives in the plankton , but others , like me , move on . a few weeks after i was conceived , i decided to settle down , and metamorphosed into a recognizable urchin . so now you know a bit of my story . i may just be a slow-moving ball of spines , but do n't let my calm adult exterior fool you . i was a rocket ship . i was a wild child .
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some have far fewer young and take much better care of them , brooding their precious cargo for days , even months . this speedy copepod totes her beautifully packaged eggs for days . this phronima crustacean carries her babies on her chest , then carefully places them in a gelatinous barrel .
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where does a phronema crustacean carry its eggs ?
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sharks have been celebrated as powerful gods by some native cultures . for example , fijians believe the shark god dakuwaqa , could protect fisherman from the dangers at sea . and today , sharks are recognized as apex predators of the world 's ocean and include some of the earth 's longest living vertebrates . what is it that makes these fish worthy of our ancient legends and so successful in the seas ? much of their hunting prowess stems from a unique set of biological traits honed for more than 400 million years . their cartilaginous skeletons are less dense than bony ones and require less energy to move . large oily livers lend buoyancy to their streamlined bodies , and while trunk muscles of bony fishes attach directly to their skeletons , those of sharks also join to their skin . this special design transforms them into pressurized tubes whose springy skin can efficiently transmit muscular forces to the tail . shark skin has additional remarkable features . despite its smooth external appearance , at the micro level , it has a coarse texture thanks to thousands of tiny teeth-like scales called dermal denticles . each denticle is coated in a substance called enameloid , which turns the skin into a tough shield . plus the structure of denticles varies across the body in such a way as to reduce noise and drag when the shark moves through water . as for the teeth in their mouths , sharks can produce up to 50,000 in a lifetime . on average , they can lose one tooth a week , and each time that happens , it 's rapidly replaced . thanks to a layer of fluoride coating their teeth , sharks also avoid cavities . but teeth are n't the same in all sharks . they can vary across species and by diet . some are dense and flattened , useful for crushing mollusks . others are needle-like for gripping fish . the mouths of great whites contain pointy lower teeth for holding prey and triangular serrated upper teeth for slicing . this variety enables sharks to target prey in a diversity of ocean environments . many species also have another peculiar trait - the ability to launch their jaws out of their mouths , open them extra wide , and grab prey by surprise . over the course of evolution , shark brains have expanded , coupled with the growth of their sensory organs . modern-day sharks can smell a few drops of blood and hear sounds underwater from 800 meters away . they 're particularly well-tuned to low frequencies , including those emitted by dying fish . and like cats , they have reflective membranes called tapeta lucida at the backs of their eyes that dramatically improve their vision in low light . as if these heightened abilities were n't enough , sharks have even honed a sixth sense . they 're able to hunt using a network of electrosensory cells called ampullae of lorenzini . these cells are filled with hypersensitive jelly which allows them to detect electrical signals from prey , including the slightest twitch of a muscle . some of the most iconic shark species , like great whites , makos , porbeagles , and salmon sharks owe their success to another surprising trait : warm blood inside a cold-blooded creature . inside their bodies , they have bundles of arteries and veins called rete mirabile . here , venous blood warmed up by the shark 's working muscles passes right next to arteries carrying cold , oxygen-rich blood from the gills . this arrangement transfers heat to the blood that gets cycled back to the body 's vital organs . warmer muscles enable faster , more powerful swimming , while warmer bellies aid digestion , and the more rapid development of young in utero . and warmer eyes and brains keep the sharks alert in cold waters . with these amazing adaptations , there 's more to revere than fear from the 500 shark species roaming our oceans . unfortunately , one-third of these species are threatened due to overfishing . after millions of years in the making , these apex predators may be meeting their greatest challenge yet .
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some of the most iconic shark species , like great whites , makos , porbeagles , and salmon sharks owe their success to another surprising trait : warm blood inside a cold-blooded creature . inside their bodies , they have bundles of arteries and veins called rete mirabile . here , venous blood warmed up by the shark 's working muscles passes right next to arteries carrying cold , oxygen-rich blood from the gills .
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the rete mirabile is a :
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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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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 .
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the slits in the side of the dog 's nose are essential because _____ .
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hello , everyone . let 's begin our guided tour . welcome to the museum of museums . museums have been a part of human history for over 2000 years . but they were n't always like the ones we visit today . the history of museums is far older and much stranger than you might imagine . we 'll start over here in the greek wing . our word museum comes from the greek mouseion , temples built for the muses , the goddesses of the arts and the sciences . supplicants asked the muses to keep watch over academics and grant ingenuity to those they deemed worthy . the temples were filled with offerings of sculptures , mosaics , complex scientific apparatuses , poetic and literary inscriptions , and any other tribute that would demonstrate a mortal 's worthiness for divine inspiration . we have arrived at the mesopotamian wing . the first museum was created in 530 b.c . in what is now iraq . and the first curator was actually a princess . ennigaldi-nanna started to collect and house mesopotamian antiquities in e-gig-par , her house . when archeologists excavated the area , they discovered dozens of artifacts neatly arranged in rows , with clay labels written in three languages . she must have had interesting parties . the tradition of collecting and displaying intriguing items began to be mimicked , as you can see here in the roman empire wing . treasure houses of politicians and generals were filled with the spoils of war , and royal menageries displayed exotic animals to the public on special occasions , like gladiator tournaments . as you can see , we have a lion here and a gladiator , and , well , the janitor ought to be in this wing clearly . moving on , hurry along . the next step in the evolution of museums occurred in the renaissance , when the study of the natural world was once again encouraged after almost a millennium of western ignorance . curiosity cabinets , also referred to as wunderkammers , were collections of objects that acted as a kind of physical encyclopedia , showcasing artifacts . just step into the wardrobe here . there you go . mind the coats . and we 'll tour ole worm 's cabinet , one of the most notable wunderkammers belonged to a wealthy 17th-century naturalist , antiquarian , and physician ole worm . ole worm collected natural specimens , human skeletons , ancient runic texts , and artifacts from the new world . in other curiosity cabinets , you could find genetic anomalies , precious stones , works of art , and religious and historic relics . oh my . you might not want to touch that . these cabinets were private , again , often in residencies , curated by their owners , rulers and aristocrats , as well as merchants and early scientists . now , who hears a circus organ ? in the 1840s , an enterprising young showman named phineas t. barnum purchased some of the more famous cabinets of curiosity from europe and started barnum 's american museum in new york city . a spectacular hodgepodge of zoo , lecture hall , wax museum , theater , and freak show that was known for its eclectic residents , such as bears , elephants , acrobats , giants , siamese twins , a fiji mermaid , and a bearded lady , along with a host of modern machinery and scientific instruments . museums open to the public are a relatively new phenomenon . before barnum , the first public museums were only accessible by the upper and middle classes , and only on certain days . visitors would have to apply to visit the museum in writing prior to admision , and only small groups could visit the museum each day . the louvre famously allowed all members of the public into the museum but only three days a week . in the 19th century , the museum as we know it began to take shape . institutions like the smithsonian were started so that objects could be seen and studied , not just locked away . american museums , in particular , commissioned experiments and hired explorers to seek out and retrieve natural samples . museums became centers for scholarship and artistic and scientific discovery . this is often called the museum age . nowadays , museums are open to everybody , are centers of learning and research , and are turning into more hands-on institutions . but the question of who gets to go is still relevant as ticket prices can sometimes bar admission to those future scholars , artists and targets of divine inspiration who ca n't afford to satisfy their curiosity . thank you all for coming , and please , feel free to stop by the gift shop of gift shops on your way out .
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ole worm collected natural specimens , human skeletons , ancient runic texts , and artifacts from the new world . in other curiosity cabinets , you could find genetic anomalies , precious stones , works of art , and religious and historic relics . oh my .
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what 's another word for a curiosity cabinet ?
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imagine something small enough to float on a particle of dust that holds the keys to understanding cancer , virology , and genetics . luckily for us , such a thing exists in the form of trillions upon trillions of human lab-grown cells called hela . let 's take a step back for a second . scientists grow human cells in the lab to study how they function , understand how diseases develop , and test new treatments without endangering patients . to make sure that they can repeat these experiments over and over , and compare the results with other scientists , they need huge populations of identical cells that can duplicate themselves faithfully for years , but until 1951 , all human cell lines that researchers tried to grow had died after a few days . then a john hopkins scientist named george gey received a sample of a strange looking tumor : dark purple , shiny , jelly-like . this sample was special . some of its cells just kept dividing , and dividing , and dividing . when individual cells died , generations of copies took their place and thrived . the result was an endless source of identical cells that 's still around today . the very first immortal human cell line . gey labeled it `` hela '' after the patient with the unusual tumor , henrietta lacks . born on a tobacco farm in virginia , she lived in baltimore with her husband and five children . she died of aggressive cervical cancer a few months after her tumorous cells were harvested , and she never knew about them . so what 's so special about the cells from henrietta lacks that lets them survive when other cell lines die ? the short answer is we do n't entirely know . normal human cells have built-in control mechanisms . they can divide about 50 times before they self destruct in a process called apoptosis . this prevents the propagation of genetic errors that creep in after repeated rounds of division . but cancer cells ignore these signals , dividing indefinitely and crowding out normal cells . still , most cell lines eventually die off , especially outside the human body . not hela , though , and that 's the part we ca n't yet explain . regardless , when dr. gey realized he had the first immortal line of human cells , he sent samples to labs all over the world . soon the world 's first cell production facility was churning out 6 trillion hela cells a week , and scientists put them to work in an ethically problematic way , building careers and fortunes off of henrietta 's cells without her or her family 's consent , or even knowledge until decades later . the polio epidemic was at its peak in the early 50s . hela cells , which easily took up and replicated the virus , allowed jonas salk to test his vaccine . they 've been used to study diseases , including measles , mumps , hiv , and ebola . we know that human cells have 46 chromosomes because a scientist working with hela discovered a chemcial that makes chromosomes visible . hela cells themselves actually have around 80 highly mutated chromosomes . hela cells were the first to be cloned . they 've traveled to outer space . telomerase , an enzyme that helps cancer cells evade destruction by repairing their dna , was discovered first in hela cells . in an interesting turn of fate , thanks to hela , we know that cervical cancer can be caused by a virus called hpv and now there 's a vaccine . hela-fueled discoveries have filled thousands of scientific papers , and that number is probably even higher than anyone knows . hela cells are so resilient that they can travel on almost any surface : a lab worker 's hand , a piece of dust , invading cultures of other cells and taking over like weeds , countless cures , patents and discoveries all made thanks to henrieta lacks .
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the very first immortal human cell line . gey labeled it `` hela '' after the patient with the unusual tumor , henrietta lacks . born on a tobacco farm in virginia , she lived in baltimore with her husband and five children .
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what type of cancer killed henrietta lacks ?
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translator : andrea mcdonough reviewer : bedirhan cinar you might have heard that light is a kind of wave and that the color of an object is related to the frequency of light waves it reflects . high-frequency light waves look violet , low-frequency light waves look red , and in-between frequencies look yellow , green , orange , and so on . you might call this idea physical color because it says that color is a physical property of light itself . it 's not dependent on human perception . and , while this is n't wrong , it is n't quite the whole story either . for instance , you might have seen this picture before . as you can see , the region where the red and green lights overlap is yellow . when you think about it , this is pretty weird . because light is a wave , two different frequencies should n't interact with each other at all , they should just co-exist like singers singing in harmony . so , in this yellow looking region , two different kinds of light waves are present : one with a red frequency , and one with a green frequency . there is no yellow light present at all . so , how come this region , where the red and green lights mix , looks yellow to us ? to understand this , you have to understand a little bit about biology , in particular , about how humans see color . light perception happens in a paper-thin layer of cells , called the retina , that covers the back of your eyeball . in the retina , there are two different types of light-detecting cells : rods and cones . the rods are used for seeing in low-light conditions , and there is only one kind of those . the cones , however , are a different story . there three kinds of cone cells that roughly correspond to the colors red , green , and blue . when you see a color , each cone sends its own distinct signal to your brain . for example , suppose that yellow light , that is real yellow light , with a yellow frequency , is shining on your eye . you do n't have a cone specifically for detecting yellow , but yellow is kind of close to green and also kind of close to red , so both the red and green cones get activated , and each sends a signal to your brain saying so . of course , there is another way to activate the red cones and the green cones simultaneously : if both red light and green light are present at the same time . the point is , your brain receives the same signal , regardless of whether you see light that has the yellow frequency or light that is a mixture of the green and red frequencies . that 's why , for light , red plus green equals yellow . and , how come you ca n't detect colors when it 's dark ? well , the rod cells in your retina take over in low-light conditions . you only have one kind of rod cell , and so there is one type of signal that can get sent to your brain : light or no light . having only one kind of light detector does n't leave any room for seeing color . there are infinitely many different physical colors , but , because we only have three kinds of cones , the brain can be tricked into thinking it 's seeing any color by carefully adding together the right combination of just three colors : red , green , and blue . this property of human vision is really useful in the real world . for example , tv manufacturing . instead of having to put infinitely many colors in your tv set to simulate the real world , tv manufacturers only have to put three : red , green , and blue , which is lucky for them , really .
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there three kinds of cone cells that roughly correspond to the colors red , green , and blue . when you see a color , each cone sends its own distinct signal to your brain . for example , suppose that yellow light , that is real yellow light , with a yellow frequency , is shining on your eye .
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explain what happens when someone is color blind . does this alter his or her ability to see in the dark ?
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ani stands before a large golden scale where the jackal-headed god anubis is weighing his heart against a pure ostrich feather . ani was a real person , a scribe from the egyptian city of thebes who lived in the 13th century bce . and depicted here is a scene from his book of the dead , a 78-foot papyrus scroll designed to help him attain immortality . such funerary texts were originally written only for pharaohs , but with time , the egyptians came to believe regular people could also reach the afterlife if they succeeded in the passage . ani 's epic journey begins with his death . his body is mummified by a team of priests who remove every organ except the heart , the seat of emotion , memory , and intelligence . it 's then stuffed with a salt called natron and wrapped in resin-soaked linen . in addition , the wrappings are woven with charms for protection and topped with a heart scarab amulet that will prove important later on . the goal of the two-month process is to preserve ani 's body as an ideal form with which his spirit can eventually reunite . but first , that spirit must pass through the duat , or underworld . this is a realm of vast caverns , lakes of fire , and magical gates , all guarded by fearsome beasts - snakes , crocodiles , and half-human monstrosities with names like `` he who dances in blood . '' to make things worse , apep , the serpent god of destruction , lurks in the shadows waiting to swallow ani 's soul . fortunately , ani is prepared with the magic contained within his book of the dead . like other egyptians who could afford it , ani customized his scroll to include the particular spells , prayers , and codes he thought his spirit might need . equipped with this arsenal , our hero traverses the obstacles , repels the monsters ' acts , and stealthily avoids apep to reach the hall of ma'at , goddess of truth and justice . here , ani faces his final challenge . he is judged by 42 assessor gods who must be convinced that he has lived a righteous life . ani approaches each one , addressing them by name , and declaring a sin he has not committed . among these negative confessions , or declarations of innocence , he proclaims that he has not made anyone cry , is not an eavesdropper , and has not polluted the water . but did ani really live such a perfect life ? not quite , but that 's where the heart scarab amulet comes in . it 's inscribed with the words , `` do not stand as a witness against me , '' precisely so ani 's heart does n't betray him by recalling the time he listened to his neighbors fight or washed his feet in the nile . now , it 's ani 's moment of truth , the weighing of the heart . if his heart is heavier than the feather , weighed down by ani 's wrongdoings , it 'll be devoured by the monstrous ammit , part crocodile , part leopard , part hippopotamus , and ani will cease to exist forever . but ani is in luck . his heart is judged pure . ra , the sun god , takes him to osiris , god of the underworld , who gives him final approval to enter the afterlife . in the endless and lush field of reeds , ani meets his deceased parents . here , there is no sadness , pain , or anger , but there is work to be done . like everyone else , ani must cultivate a plot of land , which he does with the help of a shabti doll that had been placed in his tomb . today , the papyrus of ani resides in the british museum , where it has been since 1888 . only ani , if anyone , knows what really happened after his death . but thanks to his book of the dead , we can imagine him happily tending his crops for all eternity .
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but ani is in luck . his heart is judged pure . ra , the sun god , takes him to osiris , god of the underworld , who gives him final approval to enter the afterlife .
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during the weighing of the heart ceremony , the heart is weighed against
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the dead coming back to life sounds scary . but for scientists , it can be a wonderful opportunity . of course , we 're not talking about zombies . rather , this particular opportunity came in the unlikely form of large , slow-moving fish called the coelacanth . this oddity dates back 360 million years , and was believed to have died out during the same mass extinction event that wiped out the dinosaurs 65 million years ago . to biologists and paleontologists , this creature was a very old and fascinating but entirely extinct fish , forever fossilized . that is , until 1938 when marjorie courtenay-latimer , a curator at a south african museum , came across a prehistoric looking , gleaming blue fish hauled up at the nearby docks . she had a hunch that this strange , 1.5 meter long specimen was important but could n't preserve it in time to be studied and had it taxidermied . when she finally was able to reach j.l.b . smith , a local fish expert , he was able to confirm , at first site , that the creature was indeed a coelacanth . but it was another 14 years before a live specimen was found in the comoros islands , allowing scientists to closely study a creature that had barely evolved in 300 million years . a living fossil . decades later , a second species was found near indonesia . the survival of creatures thought extinct for so long proved to be one of the biggest discoveries of the century . but the fact that the coelacanth came back from the dead is n't all that makes this fish so astounding . even more intriguing is the fact that genetically and morphologically , the coelacanth has more in common with four-limbed vertebrates than almost any other fish , and its smaller genome is ideal for study . this makes the coelacanth a powerful link between aquatic and land vertebrates , a living record of their transition from water to land millions of years ago . the secret to this transition is in the fins . while the majority of ocean fish fall into the category of ray-finned fishes , coelacanths are part of a much smaller , evolutionarily distinct group with thicker fins known as lobe-finned fish . six of the coelacanth 's fins contain bones organized much like our limbs , with one bone connecting the fin to the body , another two connecting the bone to the tip of the fin , and several small , finger-like bones at the tip . not only are those fins structured in pairs to move in a synchronized way , the coelacanth even shares the same genetic sequence that promotes limb development in land vertebrates . so although the coelacanth itself is n't a land-walker , its fins do resemble those of its close relatives who first hauled their bodies onto land with the help of these sturdy , flexible appendages , acting as an evolutionary bridge to the land lovers that followed . so that 's how this prehistoric fish helps explain the evolutionary movement of vertebrates from water to land . over millions of years , that transition led to the spread of all four-limbed animals , called tetrapods , like amphibians , birds , and even the mammals that are our ancestors . there 's even another powerful clue in that unlike most fish , coelacanths do n't lay eggs , instead giving birth to live , young pups , just like mammals . and this prehistoric fish will continue to provide us with fascinating information about the migration of vertebrates out of the ocean over 300 million years ago . a journey that ultimately drove our own evolution , survival and existence . today the coelacanth remains the symbol of the wondrous mysteries that remain to be uncovered by science . with so much left to learn about this fish , the ocean depths and evolution itself , who knows what other well-kept secrets our future discoveries may bring to life !
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to biologists and paleontologists , this creature was a very old and fascinating but entirely extinct fish , forever fossilized . that is , until 1938 when marjorie courtenay-latimer , a curator at a south african museum , came across a prehistoric looking , gleaming blue fish hauled up at the nearby docks . she had a hunch that this strange , 1.5 meter long specimen was important but could n't preserve it in time to be studied and had it taxidermied .
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what happened in 1938 ?
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[ go project films ] [ wind sounds ] [ a film by emmanuel vaughan-lee ] [ wind sounds ] [ engine sounds ] [ yukon river , alaska ] [ engine sounds ] [ engine sounds continue ] [ i 'm hungry . where 's the fish ? ] [ the yup'ik peoples have lived off king salmon for centuries . ] [ since 1998 the king salmon have been disappearing . ] [ ♪ music ♪ ] [ male speaker ] i 've been fishing all my life . in fact i used to fish with my dad . [ scraping sounds ] [ ♪ music ♪ ] i do n't know . [ ♪ music ♪ ] [ ♪ music continues ♪ ] [ ♪ music continues ♪ ] we have nine kids , thirty-three grandchildren . we 've been blessed by our children . they help us out . warm gear , life jackets , do n't forget . [ footsteps sounds ] every one of my grandkids , since they were small , they 've been with me in the camp . do n't forget your rubber gloves . but they all work , even the littlest ones . [ rustling sounds ] [ boat horn sounds ] [ ♪ music ♪ ] [ water and engine sounds ] when i was young , average fish was like thirty pounds . [ ♪ music ♪ ] but now you 're lucky if you get eighteen pounder , fifteen pound king . nobody can explain that . but they can guess . they can talk . [ ♪ music ♪ ] [ ♪ music continues ♪ ] [ fire crackling sounds ] right now for subsistence , average person can take maybe ten kings and they 're satisfied . [ fire crackling sounds ] salmon is a way of our life . i hope it does n't go away . [ ♪ music ♪ ] i remember when i was growing up , i used to hear— elders will talk . they said , `` people will change , the weather will change . '' it 's true , i see it now . there 's no stopping it . [ ♪ music ♪ ] [ ♪ music continues ♪ ] [ seagull sounds ] it 's hard . for our younger people , it 's very hard . they got ta have that money to pay for the gas . got ta have gas to go out and try to get your subsistence . if there 's no more salmon , there will be no more work , i know . [ ♪ music ♪ ] [ seagull sounds ] [ ♪ music continues ♪ ] [ seagull sounds continue ] [ ♪ music ♪ ] [ water sounds ] yeah , i take my grandchildren out fishing . i teach them how to check net and how to set net and how to use the current . [ ♪ music ♪ ] [ ♪ music continues ♪ ] [ ♪ music continues ♪ ] [ ♪ music continues ♪ ] [ ♪ music continues ♪ ] i feel good when i teach them something they can remember . [ ♪ music ♪ ] [ ♪ music continues ♪ ] because we 're not going to be around forever . we 'll be gone . [ rustling and rattling sounds ] this is how they used , long time ago , no cooking pot , they cooked it out on open fire . it sure beats cup of noodles . so far they 're okay , the grandchildren . [ ♪ music ♪ ] but we 're not there all the time to watch them . [ ♪ music ♪ ] [ ♪ music continues ♪ ] i know my grandchildren will teach their kids how to fish . they will . i know they will . [ ♪ music ♪ ] [ ♪ music continues ♪ ] [ ♪ music continues ♪ ] [ yukon kings ] [ kuigpiim taryaquii ] [ ♪ music ♪ ] [ directed by emmanuel vaughan-lee ] [ produced by dorothée royal-hedinger ] [ emmanuel vaughan-lee ] [ edited by adam loften ] [ director of photography ] [ andrew david watson ] [ music by h. scott salinas ] [ guitars : h. scott salinas ] [ matthew atticus berger ] [ cello : artyom manukyan ] [ sound design/mix by d. chris smith ] [ assistant camera : elias koch ] [ color grading : leo hallal ] [ special thanks : the waska family ] [ kwik'pak fisheries ] [ ©2012 goprojectfilms.com ]
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[ the yup'ik peoples have lived off king salmon for centuries . ] [ since 1998 the king salmon have been disappearing . ] [ ♪ music ♪ ] [ male speaker ] i 've been fishing all my life .
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is there a tradition in your family that is lost or dying ? what are the reasons for its disappearing , and what , if anything , could you do to bring it back ?
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have you ever noticed something swimming in your field of vision ? it may look like a tiny worm or a transparent blob , and whenever you try to get a closer look , it disappears , only to reappear as soon as you shift your glance . but do n't go rinsing out your eyes ! what you are seeing is a common phenomenon known as a floater . the scientific name for these objects is muscae volitantes , latin for `` flying flies , '' and true to their name , they can be somewhat annoying . but they 're not actually bugs or any kind of external objects at all . rather , they exist inside your eyeball . floaters may seem to be alive , since they move and change shape , but they are not alive . floaters are tiny objects that cast shadows on the retina , the light-sensitive tissue at the back of your eye . they might be bits of tissue , red blood cells , or clumps of protein . and because they 're suspended within the vitreous humor , the gel-like liquid that fills the inside of your eye , floaters drift along with your eye movements , and seem to bounce a little when your eye stops . floaters may be only barely distinguishable most of the time . they become more visible the closer they are to the retina , just as holding your hand closer to a table with an overhead light will result in a more sharply defined shadow . and floaters are particularly noticeable when you are looking at a uniform bright surface , like a blank computer screen , snow , or a clear sky , where the consistency of the background makes them easier to distinguish . the brighter the light is , the more your pupil contracts . this has an effect similar to replacing a large diffuse light fixture with a single overhead light bulb , which also makes the shadow appear clearer . there is another visual phenomenon that looks similar to floaters but is in fact unrelated . if you 've seen tiny dots of light darting about when looking at a bright blue sky , you 've experienced what is known as the blue field entoptic phenomenon . in some ways , this is the opposite of seeing floaters . here , you are not seeing shadows but little moving windows letting light through to your retina . the windows are actually caused by white blood cells moving through the capillaries along your retina 's surface . these leukocytes can be so large that they nearly fill a capillary causing a plasma space to open up in front of them . because the space and the white blood cells are both more transparent to blue light than the red blood cells normally present in capillaries , we see a moving dot of light wherever this happens , following the paths of your capillaries and moving in time with your pulse . under ideal viewing conditions , you might even see what looks like a dark tail following the dot . this is the red blood cells that have bunched up behind the leukocyte . some science museums have an exhibit which consists of a screen of blue light , allowing you to see these blue sky sprites much more clearly than you normally would . while everybody 's eyes experience these sort of effects , the number and type vary greatly . in the case of floaters , they often go unnoticed , as our brain learns to ignore them . however , abnormally numerous or large floaters that interfere with vision may be a sign of a more serious condition , requiring immediate medical treatment . but the majority of the time entoptic phenomena , such as floaters and blue sky sprites , are just a gentle reminder that what we think we see depends just as much on our biology and minds as it does on the external world .
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in some ways , this is the opposite of seeing floaters . here , you are not seeing shadows but little moving windows letting light through to your retina . the windows are actually caused by white blood cells moving through the capillaries along your retina 's surface . these leukocytes can be so large that they nearly fill a capillary causing a plasma space to open up in front of them .
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the astronomer johannes kepler was the first scientist to explain that the eye works by focusing an image of the outside world onto the retina . however , we can see floaters just in front of the retina and white blood cells moving in the capillaries on the retina because of the shadows they cast and the light they let through . no focusing of an image is involved . can you think of any other things and ways we might see that also do not rely on the focusing of an image on the retina ?
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oh , excuse me ! have you ever yawned because somebody else yawned ? you are n't especially tired , yet suddenly your mouth opens wide and a big yawn comes out . this phenomenon is known as contagious yawning . and while scientists still do n't fully understand why it happens , there are many hypotheses currently being researched . let 's take a look at a few of the most prevalent ones , beginning with two physiological hypotheses before moving to a psychological one . our first physiological hypothesis states that contagious yawning is triggered by a specific stimulus , an initial yawn . this is called fixed action pattern . think of fixed action pattern like a reflex . your yawn makes me yawn . similar to a domino effect , one person 's yawn triggers a yawn in a person nearby that has observed the act . once this reflex is triggered , it must run its course . have you ever tried to stop a yawn once it has begun ? basically impossible ! another physiological hypothesis is known as non-conscious mimicry , or the chameleon effect . this occurs when you imitate someone 's behavior without knowing it , a subtle and unintentional copycat maneuver . people tend to mimic each other 's postures . if you are seated across from someone that has their legs crossed , you might cross your own legs . this hypothesis suggests that we yawn when we see someone else yawn because we are unconsciously copying his or her behavior . scientists believe that this chameleon effect is possible because of a special set of neurons known as mirror neurons . mirror neurons are a type of brain cell that responds equally when we perform an action as when we see someone else perform the same action . these neurons are important for learning and self-awareness . for example , watching someone do something physical , like knitting or putting on lipstick , can help you do those same actions more accurately . neuroimaging studies using fmri , functional magnetic resonance imaging , show us that when we seem someone yawn or even hear their yawn , a specific area of the brain housing these mirror neurons tends to light up , which , in turn , causes us to respond with the same action : a yawn ! our psychological hypothesis also involves the work of these mirror neurons . we will call it the empathy yawn . empathy is the ability to understand what someone else is feeling and partake in their emotion , a crucial ability for social animals like us . recently , neuroscientists have found that a subset of mirror neurons allows us to empathize with others ' feelings at a deeper level . ( yawn ) scientists discovered this empathetic response to yawning while testing the first hypothesis we mentioned , fixed action pattern . this study was set up to show that dogs would enact a yawn reflex at the mere sound of a human yawn . while their study showed this to be true , they found something else interesting . dogs yawned more frequently at familiar yawns , such as from their owners , than at unfamiliar yawns from strangers . following this research , other studies on humans and primates have also shown that contagious yawning occurs more frequently among friends than strangers . in fact , contagious yawning starts occurring when we are about four or five years old , at the point when children develop the ability to identify others ' emotions properly . still , while newer scientific studies aim to prove that contagious yawning is based on this capacity for empathy , more research is needed to shed light on what exactly is going on . it 's possible that the answer lies in another hypothesis altogether . the next time you get caught in a yawn , take a second to think about what just happened . were you thinking about a yawn ? did someone near you yawn ? was that person a stranger or someone close ? and are you yawning right now ? ( yawn ) ( lip smacking )
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basically impossible ! another physiological hypothesis is known as non-conscious mimicry , or the chameleon effect . this occurs when you imitate someone 's behavior without knowing it , a subtle and unintentional copycat maneuver .
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the physiological hypothesis known as non-conscious mimicry is also referred to as :
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