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the human eye is an amazing mechanism , able to detect anywhere from a few photons to direct sunlight , or switch focus from the screen in front of you to the distant horizon in a third of a second . in fact , the structures required for such incredible flexibility were once considered so complex that charles darwin himself acknowledged that the idea of there having evolved seemed absurd in the highest possible degree . and yet , that is exactly what happened , starting more than 500 million years ago . the story of the human eye begins with a simple light spot , such as the one found in single-celled organisms , like euglena . this is a cluster of light-sensitive proteins linked to the organism 's flagellum , activating when it finds light and , therefore , food . a more complex version of this light spot can be found in the flat worm , planaria . being cupped , rather than flat , enables it to better sense the direction of the incoming light . among its other uses , this ability allows an organism to seek out shade and hide from predators . over the millenia , as such light cups grew deeper in some organisms , the opening at the front grew smaller . the result was a pinhole effect , which increased resolution dramatically , reducing distortion by only allowing a thin beam of light into the eye . the nautilus , an ancestor of the octopus , uses this pinhole eye for improved resolution and directional sensing . although the pinhole eye allows for simple images , the key step towards the eye as we know it is a lens . this is thought to have evolved through transparent cells covering the opening to prevent infection , allowing the inside of the eye to fill with fluid that optimizes light sensitivity and processing . crystalline proteins forming at the surface created a structure that proved useful in focusing light at a single point on the retina . it is this lens that is the key to the eye 's adaptability , changing its curvature to adapt to near and far vision . this structure of the pinhole camera with a lens served as the basis for what would eventually evolve into the human eye . further refinements would include a colored ring , called the iris , that controls the amount of light entering the eye , a tough white outer layer , known as the sclera , to maintain its structure , and tear glands that secrete a protective film . but equally important was the accompanying evolution of the brain , with its expansion of the visual cortex to process the sharper and more colorful images it was receiving . we now know that far from being an ideal masterpiece of design , our eye bares traces of its step by step evolution . for example , the human retina is inverted , with light-detecting cells facing away from the eye opening . this results in a blind spot , where the optic nerve must pierce the retina to reach the photosensitive layer in the back . the similar looking eyes of cephalopods , which evolved independently , have a front-facing retina , allowing them to see without a blind spot . other creatures ' eyes display different adaptations . anableps , the so called four-eyed fish , have eyes divided in two sections for looking above and under water , perfect for spotting both predators and prey . cats , classically nighttime hunters , have evolved with a reflective layer maximizing the amount of light the eye can detect , granting them excellent night vision , as well as their signature glow . these are just a few examples of the huge diversity of eyes in the animal kingdom . so if you could design an eye , would you do it any differently ? this question is n't as strange as it might sound . today , doctors and scientists are looking at different eye structures to help design biomechanical implants for the vision impaired . and in the not so distant future , the machines built with the precision and flexibilty of the human eye may even enable it to surpass its own evolution .
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the similar looking eyes of cephalopods , which evolved independently , have a front-facing retina , allowing them to see without a blind spot . other creatures ' eyes display different adaptations . anableps , the so called four-eyed fish , have eyes divided in two sections for looking above and under water , perfect for spotting both predators and prey .
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which one of these eyes is the most `` advanced '' ?
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during a long day spent roaming the forest in search of edible grains and herbs , the weary divine farmer shennong accidentally poisoned himself 72 times . but before the poisons could end his life , a leaf drifted into his mouth . he chewed on it and it revived him , and that is how we discovered tea . or so an ancient legend goes at least . tea does n't actually cure poisonings , but the story of shennong , the mythical chinese inventor of agriculture , highlights tea 's importance to ancient china . archaeological evidence suggests tea was first cultivated there as early as 6,000 years ago , or 1,500 years before the pharaohs built the great pyramids of giza . that original chinese tea plant is the same type that 's grown around the world today , yet it was originally consumed very differently . it was eaten as a vegetable or cooked with grain porridge . tea only shifted from food to drink 1,500 years ago when people realized that a combination of heat and moisture could create a complex and varied taste out of the leafy green . after hundreds of years of variations to the preparation method , the standard became to heat tea , pack it into portable cakes , grind it into powder , mix with hot water , and create a beverage called muo cha , or matcha . matcha became so popular that a distinct chinese tea culture emerged . tea was the subject of books and poetry , the favorite drink of emperors , and a medium for artists . they would draw extravagant pictures in the foam of the tea , very much like the espresso art you might see in coffee shops today . in the 9th century during the tang dynasty , a japanese monk brought the first tea plant to japan . the japanese eventually developed their own unique rituals around tea , leading to the creation of the japanese tea ceremony . and in the 14th century during the ming dynasty , the chinese emperor shifted the standard from tea pressed into cakes to loose leaf tea . at that point , china still held a virtual monopoly on the world 's tea trees , making tea one of three essential chinese export goods , along with porcelain and silk . this gave china a great deal of power and economic influence as tea drinking spread around the world . that spread began in earnest around the early 1600s when dutch traders brought tea to europe in large quantities . many credit queen catherine of braganza , a portuguese noble woman , for making tea popular with the english aristocracy when she married king charles ii in 1661 . at the time , great britain was in the midst of expanding its colonial influence and becoming the new dominant world power . and as great britain grew , interest in tea spread around the world . by 1700 , tea in europe sold for ten times the price of coffee and the plant was still only grown in china . the tea trade was so lucrative that the world 's fastest sailboat , the clipper ship , was born out of intense competition between western trading companies . all were racing to bring their tea back to europe first to maximize their profits . at first , britain paid for all this chinese tea with silver . when that proved too expensive , they suggested trading tea for another substance , opium . this triggered a public health problem within china as people became addicted to the drug . then in 1839 , a chinese official ordered his men to destroy massive british shipments of opium as a statement against britain 's influence over china . this act triggered the first opium war between the two nations . fighting raged up and down the chinese coast until 1842 when the defeated qing dynasty ceded the port of hong kong to the british and resumed trading on unfavorable terms . the war weakened china 's global standing for over a century . the british east india company also wanted to be able to grow tea themselves and further control the market . so they commissioned botanist robert fortune to steal tea from china in a covert operation . he disguised himself and took a perilous journey through china 's mountainous tea regions , eventually smuggling tea trees and experienced tea workers into darjeeling , india . from there , the plant spread further still , helping drive tea 's rapid growth as an everyday commodity . today , tea is the second most consumed beverage in the world after water , and from sugary turkish rize tea , to salty tibetan butter tea , there are almost as many ways of preparing the beverage as there are cultures on the globe .
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from there , the plant spread further still , helping drive tea 's rapid growth as an everyday commodity . today , tea is the second most consumed beverage in the world after water , and from sugary turkish rize tea , to salty tibetan butter tea , there are almost as many ways of preparing the beverage as there are cultures on the globe .
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when was tea first consumed as a beverage ?
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translator : andrea mcdonough reviewer : jessica ruby today , we 're going to look at the world of rome through the eyes of a young girl . here she is , drawing a picture of herself in the atrium of her father 's enormous house . her name is domitia , and she is just 5 years old . she has an older brother who is fourteen , lucius domitius ahenobarbus , named after her dad . girls do n't get these long names that boys have . what is worse is that dad insists on calling all his daughters domitia . `` domitia ! '' his call to domitia drawing on the column , domitia iii . she has an older sister , domitia ii , who is 7 years old . and then there 's domitia i , who is ten . there would have been a domitia iv , but mom died trying to give birth to her three years ago . confused ? the romans were too . they could work out ancestry through the male line with the nice , tripartite names such as lucius domitius ahenobarbus . but they got in a real mess over which domitia was married to whom and was either the great aunt or the great stepmother and so on to whom when they came to write it down . domitia iii is not just drawing on the pillar , she 's also watching the action . you see , it 's early , in the time of day when all her dad 's clients and friends come to see him at home to pay their respects . lucius popidius secundus , a 17 year old , he wants to marry domitia ii within the next five to seven years , has come as well . he seems to be wooing not his future wife , but her dad . poor lucius , he does not know that domitia 's dad thinks he and his family are wealthy but still scumbags from the subura . afterall , it is the part of rome full of barbers and prostitutes . suddenly , all the men are leaving with dad . it 's the second hour and time for him to be in court with a sturdy audience of clients to applaud his rhetoric and hiss at his opponent . the house is now quieter . the men wo n't return for seven hours , not until dinner time . but what happens in the house for those seven hours ? what do domitia , domitia , and domitia do all day ? not an easy question ! everything written down by the romans that we have today was written by men . this makes constructing the lives of women difficult . however , we ca n't have a history of just roman men , so here it goes . we can begin in the atrium . there is a massive loom , on which dad 's latest wife is working on a new toga . domitia , domitia , and domitia are tasked with spinning the wool that will be used to weave this mighty garment , 30 or more feet long and elliptical in shape . romans loved the idea that their wives work wool . we know that because it 's written on the gravestones of so many roman women . unlike women in greece , roman women go out the house and move about the city . they go to the baths in the morning to avoid the men or to separate baths that are for women only . some do go in for the latest fad of the ad 70s : nude bathing with men present . where they have no place is where the men are : in the forum , in the law court , or in the senate house . their place in public is in the porticos with gardens , with sculpture , and with pathways for walking in . when domitia , domitia , and domitia want to leave the house to go somewhere , like the portico of livia , they must get ready . domitia ii and domitia iii are ready , but domitia i , who is betrothed to be married in two years to darling philatus , is n't ready . she 's not slow , she just has more to do . being betrothed means she wears the insignia of betrothal : engagement rings and all the gifts pilatus has given her - jewels , earrings , necklaces , and the pendants . she may even wear her myrtle crown . all this bling shouts , `` i 'm getting married to that 19 year old who gave me all this stuff i 'm wearing ! '' while as they wait , domitia ii and domitia iii play with their dolls that mirror the image of their sister decked out to be married . one day , these dolls will be dedicated to the household gods on the day of their wedding . okay , we 're ready . the girls step into litters carried by some burly slaves . they also have a chaperone with them and will be meeting an aunt at the porticus of livia . carried high on the shoulders of these slaves , the girls look out through the curtains to see the crowded streets below them . they traverse the city , pass the coliseum , but then turn off to climb up the hill to the porticus of livia . it was built by livia , the wife of the first emperor augustus , on the site of the house of vedius pollio . he was n't such a great guy . he once tried to feed a slave to the eels in his fish pond for simply dropping a dish . luckily , the emperor was at the dinner and tamed his temper . the litters are placed on the ground and the girls get out and arm in arm , two by two , they ascend the steps into the enclosed garden with many columns . domitia iii shot off and is drawing on a column . domitia ii joins her but seeks to read the graffiti higher up on the column . she spots a drawing of gladiators and tries to imagine seeing them fighting , something she will never be permitted to do , except from the very rear of the coliseum . from there , she will have a good view of the 50,000 spectators but will see little by way of blood and gore . if she really wanted a decent view , she could become a vestal virgin and would sit right down the front . but a career tending the sacred flame of vesta is not to everybody 's taste . domitia i has met another ten year old also decked out in the insignia of betrothal . home time . when they get there after the eighth hour , something is up . a smashed dish lies on the floor . all the slaves are being gathered together in the atrium and await the arrival of their master . dad is going to go mad . he will not hit his children , but like many other romans , he believes that slaves have to be punished . the whip lies ready for his arrival . no one knows who smashed the dish , but dad will call the undertaker to torture it out of them , if he must . the doorkeeper opens the front door to the house . a hush comes over the anxious slaves . in walks not their master but , instead , a pregnant teenager . it is the master 's eldest daughter , age 15 , who is already a veteran of marriage and child birth . guess what her name is . there is a five to ten percent chance she wo n't survive giving birth to her child , but , for now , she has come to dinner with her family . as a teenage mother , she has proved that she is a successful wife by bringing children and descendants for her husband , who will carry on his name in the future . the family head off to the dining room and are served dinner . it would seem dad has had an invite to dinner elsewhere . with dinner concluded , the girls crossed the atrium to bid farewell to their older sister who is carried home in a litter , escorted by some of dad 's bodyguards . returning to the house , the girls cross the atrium . the slaves , young and old , male and female , await the return of their owner . when he returns , he may exact vengeance , ensuring his power over the slaves is maintained through violence and terror , to which any slave could be subjected . but , for the girls , they head upstairs for the night , ready for bed .
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when domitia , domitia , and domitia want to leave the house to go somewhere , like the portico of livia , they must get ready . domitia ii and domitia iii are ready , but domitia i , who is betrothed to be married in two years to darling philatus , is n't ready . she 's not slow , she just has more to do .
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how does the public know that a woman is betrothed to be married ?
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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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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 .
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briefly describe your favorite period of art history . why do you enjoy it as much as you do ?
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some of the world 's most recognizable symbols exist to sell products , others to steer traffic or advance political causes . but there 's one whose main purpose is to help people . you may know it as the wheelchair symbol , or a sign for people with disabilities , but its formal title as maintained by the iso is the international symbol of access . but despite its familiarity , many people are unclear as to what the symbol actually means , which has a lot to do with the symbol itself and the way it came about . in 1968 , the international commission on technology and accessibility held a design contest . they were looking for a symbol that would be readily identifiable from a reasonable distance , self-descriptive , simple , practical , and could n't be confused with existing signage . the winning design , which did n't have a head , was created by a danish designer named susanne koefed . the addition of a head a year later gave it a more human form , and within ten years , it was endorsed by both the united nations and the iso . with minimal cost and minimal fuss , a global icon was born . there have been a few tweaks over the decades . the graphic artists guild added more rounded , human-like features , and in 2012 , the accessible icon project produced a more dynamic version . but what does it really represent ? what 's its purpose ? put simply , it 's a sign to identify where there are accessible facilities . the strength of such an internationally recognized image is that wherever you travel , you do n't need to speak the language or have in-depth cultural knowledge . if you require an accessible toilet , the sign shows the way . but the confusion comes from the term accessibility and what that actually means . many people assume that because the symbol depicts a wheelchair , that accessible facilities are meant only for people who use wheelchairs , or those , at the very least , who have a visible physical condition . but accessibility is a broad concept that applies to many , many different conditions . that includes people with autism , visual impairments , and autoimmune diseases , like lupus , which can cause pain and fatigue , along with many other conditions . in fact , the world health organization estimates that there are approximately 1 billion people who experience some form of disability , which means that this group is very likely to include yourself , or a family member , a classmate , a friend , or a work colleague . and people who use wheelchairs only make up about 65 million , or 15 % of the total . the vast majority have non-visible disabilities . accessible parking spaces , facilities , and entrances are designed with that entire group in mind . so it 's easy to see why in recent years people have begun to raise questions about whether the symbol is really appropriate for what it 's meant to do . and it 's not just about accuracy . it 's common for people to become indignant , sometimes abusive , when they see people without visible disabilities using accessible facilities . the symbol is unfortunately creating widespread issues for the very people and families it 's meant to help . the recent redesigns have attempted with some success to acknowledge concerns over the current symbol . but some think that a complete redesign is in order . it 's a difficult task , though . how do you replace a symbol that 's familiar the world over ? and what do you replace it with ?
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many people assume that because the symbol depicts a wheelchair , that accessible facilities are meant only for people who use wheelchairs , or those , at the very least , who have a visible physical condition . but accessibility is a broad concept that applies to many , many different conditions . that includes people with autism , visual impairments , and autoimmune diseases , like lupus , which can cause pain and fatigue , along with many other conditions . in fact , the world health organization estimates that there are approximately 1 billion people who experience some form of disability , which means that this group is very likely to include yourself , or a family member , a classmate , a friend , or a work colleague . and people who use wheelchairs only make up about 65 million , or 15 % of the total .
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how many people across the globe does the world health organization estimate are living with some type of disability ?
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vatican city : capitol of the catholic church , home to the pope , owner of impressive collections of art and history all contained within the borders of the world 's smallest country : conveniently circumnavigateable on foot in only 40 minutes . just how did the world end up with this tiny nation ? the short answer is : because mussolini and the long answer is fiendishly complicated so here 's a simplified medium version : the popes used to rule a country called the papal states that covered much of modern day italy . it was during this 1,000+ year reign that the popes constructed st. peter 's basilica the largest church in the world -- and also built a wall around the base of a hill known as vatican upon which st. peter 's stood . but the kingdom of italy next door thought rome would be an awesome capital for their country and so conquered the papal states . his nation destroyed the pope hid behind the walls of vatican and conflictingly refused to acknowledge that the kingdom of italy existed , while simultaneously complaining about being a prisoner of the kingdom of italy -- which according to him did n't exist . rather than risk religious civil war by getting rid of the pope the kingdom of italy decided to wait him out assuming he 'd eventually give up -- but religion is nothing if not obstinate -- and 1 , 2 , 3 , 4 , 5 popes and sixty years later nothing had changed . which brings us to benito mussolini the then prime minister of italy who was tired of listing to the pope complain to italian catholics about his self-imposed imprisonment so mussolini thought he could score some political points by striking a deal which looked like this : 1 ) italy gave the land of vatican to the pope . and… 2 ) italy gave the pope a bunch of apology money in return 1 ) the pope acknowledged that italy existed and and… 2 ) the pope promised to remain neutral in politics and wars . on the off chance that , you know , mussolini thought this might be a thing . the deal was signed and a new country , vatican city was born . and today the tiny nation on a hill has all the things you 'd expect of a country : its own government that makes its own laws that are enforced by its own police , who put people who break them in its own jail . it also has its own bank and prints its own stamps and issues its own license plates , though only its citizens can drive within its borders presumably because of terrible , terrible parking -- and as the true mark of any self-respecting nation : it has its own top-level domain : .va but , despite all these national trappings vatican city is not really like any other country . hold on to your fancy hat , because it 's about to get weird : to understand the vatican : there are two people and two things that you need to know about : the famous pope , the incredibly confusing holy see , the country of vatican city and along with that the almost completely unknown king of vatican city . but first the pope : who gets a throne to sit upon and from which he acts as the bishop for all the catholics in rome . actually all bishops in the catholic church get their own thrones but because the bishop of rome is also the pope his thrown is special and has it 's own special name : the holy see . every time a pope dies or retires there is a sort of game of thrones to see which of the bishops will next get to occupy the holy see . so while popes come and go the throne is eternal . as such the name the holy see not only refers to the throne but also all the rules that make the catholic church the catholic church . when mussolini crafted that aforementioned deal , technically he gave the land of vatican city to the holy see -- which , believe it or not , is a legal corporate person in international law . basically every time you hear the words the holy see think catholic church , inc of which the pope is the ceo . now back to the king . the king of vatican city has absolute , unchecked power within the country 's borders and his presence makes vatican city one of only six remanning absolute monarchies in the world , including brunei , oman , qatar , saudi arabia , and swaziland . the king 's absolute power is why vatican city ca n't join the european union because only democracies are allowed . through vatican city does , strictly speaking , have a legislative brach of government -- staffed by cardinals , appointed by the pope -- the king of vatican city can overrule their decisions and at any time for any reason . so why do you never hear about the king of vatican city ? because though king and pope are two different roles , they just happen to be occupied by the same person at the same time -- which has the funny consequence that , because the pope is elected and the king is all-powerful but they 're the same guy it makes vatican city the world 's only elected , non-hereditary absolute monarchy . it 's this dual-role that makes untangling vatican city so difficult because the pope , depending on the situation either acts as the king of the country of vatican city or the pope of the holy see . got it ? no ? ok , here 's an analogy : imagine if a powerful international company , say grey industries , had a ceo who convinced the united states to give one of its islands to the company which then made the island into a new country -- greytropolis -- with an absolute monarchy as its government and the law that the king of greytropolis is , by definition , the ceo of grey industries . it 's pretty obvious at that point that the ceo should move his corporate headquarters to the new nation -- so that the laws of the country can benefit the company and the company 's global reach can benefit the country . as for the man in the middle sometimes it 's good to the the ceo and sometimes it 's good to be the king . that is essentially vatican city . but if you 're still confused , do n't worry even other countries ca n't keep it straight . for example the united nations has the holy see the corporation as a member but not vatican city the actual country . and the holy see gives passports to vatican city citizens that other countries accept even though those passports come from a company , not a country . and speaking of vatican city citizens , they are perhaps the strangest consequence of the pope 's dual role as religious leader and monarch . while other countries mint new citizens with the ever popular process of human reproduction vatican city does not . no one in vatican city is born a citizen -- and that 's not just because , within a rounding error , there are no female vaticans . the only way to become a citizen is for the king of vatican city to appoint you as one . and the king only appoints you a citizen if you work for the pope -- who is also the king . and because the king is all-powerful your citizenship is at his whim . if you quit your job for the pope , the king -- who is also the pope -- will revoke your citizenship . these rules mean that vatican city does n't have a real permanent population to speak of : there are only about 500 full citizens -- which is fewer people that live in single skyscrapers in many countries -- and all these citizens work for the holy see as either cardinals or diplomats or the pope 's bodyguards or other catholic-related jobs . so it 's best to think of vatican city as a kind of sovereign corporate headquarters that grants temporary citizenship to its managers rather than a real city-state like singapore : which has a self-reproducing population of citizens engaged in a variety of economic activities both of which vatican city lacks . but in the end , the reason the world cares about vatican city is not because of the citizens within its walls but because of the billion members of its church outside those walls .
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as for the man in the middle sometimes it 's good to the the ceo and sometimes it 's good to be the king . that is essentially vatican city . but if you 're still confused , do n't worry even other countries ca n't keep it straight .
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what were the parameters for the agreement between mussolini and the catholic church to create vatican city ?
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today when people complain about the state of american politics , they often mention the dominance of the democratic and republican parties , or the sharp split between red and blue states . but while it may seem like both of these things have been around forever , the situation looked quite different in 1850 , with the republican party not yet existing , and support for the dominant democrats and whigs cutting across geographic divides . the collapse of this second party system was at the center of increasing regional tensions that would lead to the birth of the republican party , the rise of abraham lincoln as its leader , and a civil war that would claim over half a million lives . and if this collapse could be blamed on a single event , it would be the kansas-nebraska act of 1854 . the story starts with the missouri compromise of 1820 . to balance the number of slave states and free states in the union , it allowed slavery in the newly admitted state of missouri , while making it off limits in the remaining federally administered louisiana territory . but compromises tend to last only as long as they 're convenient , and by the early 1850s , a tenacious democratic senator from illionis named stephen a. douglas found its terms very inconvenient . as an advocate of western expansion , he promoted constructing a transcontinental railroad across the northern plains with an eastern terminus in chicago , where he happened to own real estate . for his proposal to succeed , douglas felt that the territories through which the railroad passed , would have to be formally organized , which required the support of southern politicians . he was also a believer in popular sovereignty , arguing that the status of slavery in a territory should be decided by its residents rather than congress . so douglas introduced a bill designed to kill two birds with one stone . it would divide the large chunk of incorporated land into two new organized territories : nebraska and kansas , each of which would be open to slavery if the population voted to allow it . while douglas and his southern supporters tried to frame the bill as protecting the political rights of settlers , horrified northerners recognized it as repealing the 34-year-old missouri compromise and feared that its supporters ' ultimate goal was to extend slavery to the entire nation . congress was able to pass the kansas-nebraska act , but at the huge cost of bitterly dividing the nation , with 91 % of the opposition coming from northerners . in the house of representatives , politicians traded insults and brandished weapons until a sargent at arms restored order . president pierce signed the bill into law amidst a storm of protest , while georgia 's alexander stephens , future confederate vice president , hailed the act 's passage as , `` glory enough for one day . '' the new york tribune reported , `` the unanimous sentiment of the north is indignant resistance . '' douglas even admitted that he could travel from washington d.c. to chicago by the light of his own burning effigies . the political consequences of the kansas-nebraska act were stunning . previously , both whigs and democrats had included northern and southern lawmakers united around various issues , but now slavery became a dividing factor that could not be ignored . congressmen from both parties spoke out against the act , including an illinois whig named abraham lincoln , denouncing `` the monstrous injustice of slavery '' in an 1854 speech . by this time the whigs had all but ceased to exist , irreparably split between their northern and southern factions . in the same year , the new republican party was founded by the anti-slavery elements from both existing parties . although lincoln still ran for senate as a whig in 1854 , he was an early supporter of the new party , and helped to recruit others to its cause . meanwhile the democratic party was shaken when events in the newly formed kansas territory revealed the violent consequences of popular sovereignty . advertisements appeared across the north imploring people to emigrate to kansas to stem the advance of slavery . the south answered with border ruffians , pro-slavery missourians who crossed state lines to vote in fraudulent elections and raid anti-slavery settlements . one northern abolitionist , john brown , became notorious following the pottawatomie massacre of 1856 when he and his sons hacked to death five pro-slavery farmers with broad swords . in the end , more than 50 people died in bleeding kansas . while nominally still a national party , douglas 's democrats were increasingly divided along sectional lines , and many northern members left to join the republicans . abraham lincoln finally took up the republican party banner in 1856 and never looked back . that year , john c. fremont , the first republican presidential candidate , lost to democrat , james buchanan , but garnered 33 % of the popular vote all from northern states . two years later , lincoln challenged douglas for his illinois senate seat , and although he lost that contest , it elevated his status among republicans . lincoln would finally be vindicated in 1860 , when he was elected president of the united states , defeating in his own home state , a certain northern democrat , who was finally undone by the disastrous aftermath of the law he had masterminded . americans today continue to debate whether the civil war was inevitable , but there is no doubt that the kansas-nebraska act made the ghastly conflict much more likely . and for that reason , it should be remembered as one of the most consequential pieces of legislation in american history .
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in the end , more than 50 people died in bleeding kansas . while nominally still a national party , douglas 's democrats were increasingly divided along sectional lines , and many northern members left to join the republicans . abraham lincoln finally took up the republican party banner in 1856 and never looked back .
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many northerners opposed passage of douglas ' proposal because ________ .
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around the globe , there are approximately 60 million people who have been forced to leave their homes to escape war , violence , and persecution . the majority of them have become internally displaced persons , which means they have fled their homes but are still within their own countries . others have crossed a border and sought shelter outside of their own countries . they are commonly referred to as refugees . but what exactly does that term mean ? the world has known refugees for millennia , but the modern definition was drafted in the un 's 1951 convention relating to the status of refugees in response to mass persecutions and displacements of the second world war . it defines a refugee as someone who is outside their country of nationality , and is unable to return to their home country because of well-founded fears of being persecuted . that persecution may be due to their race , religion , nationality , membership in a particular social group , or political opinion , and is often related to war and violence . today , roughly half the world 's refugees are children , some of them unaccompanied by an adult , a situation that makes them especially vulnerable to child labor or sexual exploitation . each refugee 's story is different , and many must undergo dangerous journeys with uncertain outcomes . but before we get to what their journeys involve , let 's clear one thing up . there 's a lot of confusion regarding the difference between the terms `` migrant '' and `` refugee . '' `` migrants '' usually refers to people who leave their country for reasons not related to persecution , such as searching for better economic opportunities or leaving drought-stricken areas in search of better circumstances . there are many people around the world who have been displaced because of natural disasters , food insecurities , and other hardships , but international law , rightly or wrongly , only recognizes those fleeing conflict and violence as refugees . so what happens when someone flees their country ? most refugee journeys are long and perilous with limited access to shelter , water , or food . since the departure can be sudden and unexpected , belongings might be left behind , and people who are evading conflict often do not have the required documents , like visas , to board airplanes and legally enter other countries . financial and political factors can also prevent them from traveling by standard routes . this means they can usually only travel by land or sea , and may need to entrust their lives to smugglers to help them cross borders . whereas some people seek safety with their families , others attempt passage alone and leave their loved ones behind with the hopes of being reunited later . this separation can be traumatic and unbearably long . while more than half the world 's refugees are in cities , sometimes the first stop for a person fleeing conflict is a refugee camp , usually run by the united nations refugee agency or local governments . refugee camps are intended to be temporary structures , offering short-term shelter until inhabitants can safely return home , be integrated to the host country , or resettle in another country . but resettlement and long-term integration options are often limited . so many refugees are left with no choice but to remain in camps for years and sometimes even decades . once in a new country , the first legal step for a displaced person is to apply for asylum . at this point , they are an asylum seeker and not officially recognized as a refugee until the application has been accepted . while countries by and large agree on one definition of refugee , every host country is responsible for examining all requests for asylum and deciding whether applicants can be granted the status of refugee . different countries guidelines can vary substantially . host countries have several duties towards people they have recognized as refugees , like the guarantee of a minimum standard of treatment and non-discrimination . the most basic obligation towards refugees is non-refoulement , a principle preventing a nation from sending an individual to a country where their life and freedom are threatened . in reality , however , refugees are frequently the victims of inconsistent and discriminatory treatment . they 're increasingly obliged to rebuild their lives in the face of xenophobia and racism . and all too often , they are n't permitted to enter the work force and are fully dependent on humanitarian aid . in addition , far too many refugee children are out of school due to lack of funding for education programs . if you go back in your own family history , chances are you will discover that at a certain point , your ancestors were forced from their homes , either escaping a war or fleeing discrimination and persecution . it would be good of us to remember their stories when we hear of refugees currently displaced , searching for a new home .
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around the globe , there are approximately 60 million people who have been forced to leave their homes to escape war , violence , and persecution . the majority of them have become internally displaced persons , which means they have fled their homes but are still within their own countries .
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think about a family forced to leave their country to flee war . explain the main obstacles and challenges they may face along the way .
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thinking of getting a tattoo ? decorating your birthday suit would add another personal story to a history of tattoos stretching back at least 8000 years . tattooed mummies from around the world attest to the universality of body modification across the millennia , and to the fact that you really were stuck with it forever if your civilization never got around to inventing laser removal . a mummy from the chinchorro culture in pre-incan peru has a mustache tattooed on his upper lip . ötzi , mummified iceman of the alps , has patterned charcoal tats along his spine , behind his knee and around his ankles , which might be from an early sort of acupuncture . the mummy of amunet , a priestess in middle kingdom egypt , features tattoos thought to symbolize sexuality and fertility . even older than the mummies , figurines of seemingly tattooed people , and tools possibly used for tattooing date back tens of thousands of years . tattoos do n't have one historical origin point that we know of , but why do we english speakers call them all tattoos ? the word is an anglophonic modification of `` tatao , '' a polynesian word used in tahiti , where english captain james cook landed in 1769 and encountered heavily tattooed men and women . stories of cook 's findings and the tattoos his crew acquired cemented our usage of `` tattoo '' over previous words like `` scarring , '' `` painting , '' and `` staining , '' and sparked a craze in victorian english high society . we might think of victorians having victorian attitudes about such a risque thing , and you can find such sentiments , and even bans , on tattooing throughout history . but while publicly some brits looked down their noses at tattoos , behind closed doors and away from their noses , lots of people had them . reputedly , queen victoria had a tiger fighting a python , and tattoos became very popular among cook 's fellow soldiers , who used them to note their travels . you crossed the atlantic ? get an anchor . been south of the equator ? time for your turtle tat . but westerners sported tattoos long before meeting the samoans and maori of the south pacific . crusaders got the jerusalem cross so if they died in battle , they 'd get a christian burial . roman soldiers on hadrian 's wall had military tattoos and called the picts beyond it `` picts , '' for the pictures painted on them . there 's also a long tradition of people being tattooed unwillingly . greeks and romans tattooed slaves and mercenaries to discourage escape and desertion . criminals in japan were tattooed as such as far back as the 7th century . most infamously , the nazis tattooed numbers on the chest or arms of jews and other prisoners at the auschwitz concentration camp in order to identify stripped corpses . but tattoos forced on prisoners and outcasts can be redefined as people take ownership of that status or history . primo levi survived auschwitz and wore short sleeves to germany after the war to remind people of the crime his number represented . today , some holocaust survivors ' descendants have their relatives numbers ' tattooed on their arms . the torah has rules against tattoos , but what if you want to make indelible what you feel should never be forgotten ? and those criminals and outcasts of japan , where tattooing was eventually outlawed from the mid-19th century to just after world war ii , added decoration to their penal tattoos , with designs borrowed from woodblock prints , popular literature and mythical spirtual iconography . yakuza gangs viewed their outsider tattoos as signs of lifelong loyalty and courage . after all , they lasted forever and it really hurt to get them . for the maori , those tattoos were an accepted mainstream tradition . if you shied away from the excruciating chiseling in of your moko design , your unfinished tattoo marked your cowardice . today , unless you go the traditional route , your tattoo artist will probably use a tattoo machine based on the one patented by samuel o'reilly in 1891 , itself based on thomas edison 's stencil machine from 1876 . but with the incredibly broad history of tattoos giving you so many options , what are you going to get ? this is a bold-lined expression of who you are , or you want to appear to be . as the naturalist aboard cook 's ship said of the tataoed tahitians , `` everyone is marked , thus in different parts of his body , according maybe to his humor or different circumstances of his life . '' maybe your particular humor and circumstances suggest getting a symbol of cultural heritage , a sign of spirituality , sexual energy , or good old-fashioned avant-garde defiance . a reminder of a great accomplishment , or of how you think it would look cool if hulk hogan rode a rhino . it 's your expression , your body , so it 's your call . just two rules : you have to find a tattooist who wo n't be ashamed to draw your idea , and when in doubt , you can never go wrong with `` mom . ''
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thinking of getting a tattoo ? decorating your birthday suit would add another personal story to a history of tattoos stretching back at least 8000 years .
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what does a tattoo tell you about a person ’ s place in his/her culture ?
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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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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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what are some practical applications for archimedes ' principle . why do you think it 's so important ?
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ladies and gentlemen , at ted we talk a lot about leadership and how to make a movement . so let 's watch a movement happen , start to finish , in under three minutes and dissect some lessons from it . first , of course you know , a leader needs the guts to stand out and be ridiculed . what he 's doing is so easy to follow . here 's his first follower with a crucial role ; he 's going to show everyone else how to follow . now , notice that the leader embraces him as an equal . now it 's not about the leader anymore ; it 's about them , plural . now , there he is calling to his friends . now , if you notice that the first follower is actually an underestimated form of leadership in itself . it takes guts to stand out like that . the first follower is what transforms a lone nut into a leader . ( laughter ) ( applause ) and here comes a second follower . now it 's not a lone nut , it 's not two nuts -- three is a crowd , and a crowd is news . so a movement must be public . it 's important to show not just the leader , but the followers , because you find that new followers emulate the followers , not the leader . now , here come two more people , and immediately after , three more people . now we 've got momentum . this is the tipping point . now we 've got a movement . ( laughter ) so , notice that , as more people join in , it 's less risky . so those that were sitting on the fence before now have no reason not to . they wo n't stand out , they wo n't be ridiculed , but they will be part of the in-crowd if they hurry . ( laughter ) so , over the next minute , you 'll see all of those that prefer to stick with the crowd because eventually they would be ridiculed for not joining in . and that 's how you make a movement . but let 's recap some lessons from this . so first , if you are the type , like the shirtless dancing guy that is standing alone , remember the importance of nurturing your first few followers as equals so it 's clearly about the movement , not you . ( laughter ) okay , but we might have missed the real lesson here . the biggest lesson , if you noticed -- did you catch it ? -- is that leadership is over-glorified . yes , it was the shirtless guy who was first , and he 'll get all the credit , but it was really the first follower that transformed the lone nut into a leader . so , as we 're told that we should all be leaders , that would be really ineffective . if you really care about starting a movement , have the courage to follow and show others how to follow . and when you find a lone nut doing something great , have the guts to be the first one to stand up and join in . and what a perfect place to do that , at ted . thanks . ( applause )
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so a movement must be public . it 's important to show not just the leader , but the followers , because you find that new followers emulate the followers , not the leader . now , here come two more people , and immediately after , three more people .
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who do new followers emulate ?
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what would you do if you thought your country was on the path to tyranny ? if you saw one man gaining too much power , would you try to stop him ? even if that man was one of your closest friends and allies ? these were the questions haunting roman senator marcus junius brutus in 44 bce , the year julius caesar would be assassinated . opposing unchecked power was n't just a political matter for brutus ; it was a personal one . he claimed descent from lucius junius brutus , who had helped overthrow the tyrannical king known as tarquin the proud . instead of seizing power himself , the elder brutus led the people in a rousing oath to never again allow a king to rule . rome became a republic based on the principle that no one man should hold too much power . now , four and a half centuries later , this principle was threatened . julius ceasar 's rise to the powerful position of consul had been dramatic . years of military triumphs had made him the wealthiest man in rome . and after defeating his rival pompey the great in a bitter civil war , his power was at its peak . his victories and initiatives , such as distributing lands to the poor , had made him popular with the public , and many senators vied for his favor by showering him with honors . statues were built , temples were dedicated , and a whole month was renamed , still called july today . more importantly , the title of dictator , meant to grant temporary emergency powers in wartime , had been bestowed upon caesar several times in succession . and in 44 bce , he was made dictator perpetuo , dictator for a potentially unlimited term . all of this was too much for the senators who feared a return to the monarchy their ancestors had fought to abolish , as well as those whose own power and ambition were impeded by caesar 's rule . a group of conspirators calling themselves the liberators began to secretly discuss plans for assassination . leading them were the senator gaius cassius longinus and his friend and brother-in-law , brutus . joining the conspiracy was not an easy choice for brutus . even though brutus had sided with pompey in the ill-fated civil war , caesar had personally intervened to save his life , not only pardoning him but even accepting him as a close advisor and elevating him to important posts . brutus was hesitant to conspire against the man who had treated him like a son , but in the end , cassius 's insistence and brutus 's own fear of caesar 's ambitions won out . the moment they had been waiting for came on march 15 . at a senate meeting held shortly before caesar was to depart on his next military campaign , as many as 60 conspirators surrounded him , unsheathing daggers from their togas and stabbing at him from all sides . as the story goes , caesar struggled fiercely until he saw brutus . despite the famous line , `` et tu , brute ? '' written by shakespeare , we do n't know caesar 's actual dying words . some ancient sources claim he said nothing , while others record the phrase , `` and you , child ? `` , fueling speculation that brutus may have actually been caesar 's illegitimate son . but all agree that when caesar saw brutus among his attackers , he covered his face and gave up the fight , falling to the ground after being stabbed 23 times . unfortunately for brutus , he and the other conspirators had underestimated caesar 's popularity among the roman public , many of whom saw him as an effective leader , and the senate as a corrupt aristocracy . within moments of caesar 's assassination , rome was in a state of panic . most of the other senators had fled , while the assassins barricaded themselves on the capitoline hill . mark antony , caesar 's friend and co-consul , was swift to seize the upper hand , delivering a passionate speech at caesar 's funeral days later that whipped the crowd into a frenzy of grief and anger . as a result , the liberators were forced out of rome . the ensuing power vacuum led to a series of civil wars , during which brutus , facing certain defeat , took his own life . ironically , the ultimate result would be the opposite of what the conspirators had hoped to accomplish : the end of the republic and the concentration of power under the office of emperor . opinions over the assassination of caesar were divided from the start and have remained so . as for brutus himself , few historical figures have inspired such a conflicting legacy . in dante 's `` inferno , '' he was placed in the very center of hell and eternally chewed by satan himself for his crime of betrayal . but swift 's `` gulliver 's travels '' described him as one of the most virtuous and benevolent people to have lived . the interpretation of brutus as either a selfless fighter against dictatorship or an opportunistic traitor has shifted with the tides of history and politics . but even today , over 2000 years later , questions about the price of liberty , the conflict between personal loyalties and universal ideals , and unintended consequences remain more relevant than ever .
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but swift 's `` gulliver 's travels '' described him as one of the most virtuous and benevolent people to have lived . the interpretation of brutus as either a selfless fighter against dictatorship or an opportunistic traitor has shifted with the tides of history and politics . but even today , over 2000 years later , questions about the price of liberty , the conflict between personal loyalties and universal ideals , and unintended consequences remain more relevant than ever .
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was brutus a true patriot or an opportunistic traitor ?
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so , we ’ re braving the elements brady , to repeat the experiment that we did quite some time ago , so you will remember that we had a very small balloon of hydrogen match on a stick to hydrogen , big bang coming ! are you ready ? yep ! here we go ! and the fact that we ’ ve come outside , might actually give you an idea of what we are going to do , cause we are going to make it a little bit bigger , so let ’ s go and fill a balloon . alright , cool . well , hydrogen , i think is very important because , it is the simplest atom , it ’ s the atom , consists of a positively charged proton which is relatively large and a negatively charged electron , that goes round it . electric match ? i think an electric match will go well on that . yep . oh , look at the tension on the balloon ! hold it , i ’ ve really gone for it and blown that one up . the tension ! what happens is that hydrogen is reacting with oxygen and h2 plus o2 reacts to form h2o and an oxygen atom and then that oxygen atom goes on to react with another hydrogen molecule to make more water and the reaction generates a lot of heat and that heat , heats up more gas to make it react faster , so you generate more and more heat , so the reaction that begins quite slowly with the first few molecules , runs away and that is why you get the explosion . so here we have a rather large balloon of hydrogen , neil is just preparing our electric match which we are going to attach to the side of this balloon . and some of the biggest explosions in the 20th century , the chernobyl reactor , the space shuttle that blew up when it was taking off , were in fact explosions caused by hydrogen and oxygen . so we ’ ve filled up a balloon of hydrogen , and i think if you look at the hydrogen balloon you will see that it is slightly larger than those we have attempted before . now we are going to try to detonate it or burn the hydrogen , in the air by giving it a match and the match we are going to use is again an electric match , which is connected to our detonator box . if you stick a pin in the balloon , the balloon will burst because the rubber will break , but the hydrogen will come out and it won ’ t react with the oxygen because the hydrogen is cool , it ’ s at the same temperature as the air , but the reaction of hydrogen and oxygen like many reactions involves so called activation energy , you have to put in a certain amount of energy to get it going . but once you get it going , you get more heat coming out , than you put in to start it off . so , let ’ s arm the circuit , 5-4-3-2-1 . that was more like it . lovely ! when pete puts the match to the balloon , first of all the match burns a hole in the balloon , and then the heat gets the hydrogen and oxygen near the outside of the balloon and they start reacting and the heat then spreads through the volume of the hydrogen and oxygen , faster probably than the balloon is bursting and as it spreads through the temperature builds up and up and up because you are generating so much heat . the reason that you hear a noise , is because , it causes a rise in pressure which sends a pressure wave out through the air and it hits your ears or the microphone on your camera . i honestly don ’ t know why you see any colour . i suspect that the colour may actually be caused by the burning balloon which contains carbon and is really like the flame on a candle . because normally when you have a hydrogen/oxygen flame you don ’ t see any colour at all . alternatively , it may be some impurities in the gas , but i suspect that what you are seeing in the fire ball is just the burning of the balloon . the other thing which is really quite exciting about hydrogen is that in principle if you heat hydrogen to really high temperatures , you can get two hydrogen atoms to fuse together , or rather , it will not work with hydrogen , but it will work with a heavier form of hydrogen which is know as deuterium where instead of a proton and an electron , you have a proton and a neutron , which is a neutral particle , and an electron , and two molecules of deuterium can fuse together to make one atom of helium which has two protons , two neutrons , and two electrons and this produces a lot of energy . it is the basis of the so-called hydrogen bombs , which are like super atomic bombs , but which require an enormously high temperature to get the reaction to go . you can probably hear it hitting and fizzing into the bottle there . there is great hope that in the end much of the world ’ s energy crisis can be solved by doing this so called nuclear fusion of deuterium to make helium which would produce energy extremely cleanly . so here , we ’ ll just tie it off , if my welsh hands can actually tie a knot on a balloon , ‘ cause , you know we are all a little bit bizarre . deuterium gas , in all its properties , will be very similar to that of hydrogen , of course it is denser , because it has a neutron as well as a proton but it is still much lighter than air so a deuterium balloon will still float up to the ceiling and make pete look just as stupid as the hydrogen one . you ’ ve got to keep hold of it . or you lose it or you lose it , you know ! i was thinking more of fusing it , that sounds like a really big explosion we could do out the back . no ! fusing reactors are way beyond what pete can do unless he is a lot cleverer than i think . i got a balloon ! i had a balloon of hydrogen ! that is the second time you have done that ! now it ’ s going to go up there eventually anyway !
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now we are going to try to detonate it or burn the hydrogen , in the air by giving it a match and the match we are going to use is again an electric match , which is connected to our detonator box . if you stick a pin in the balloon , the balloon will burst because the rubber will break , but the hydrogen will come out and it won ’ t react with the oxygen because the hydrogen is cool , it ’ s at the same temperature as the air , but the reaction of hydrogen and oxygen like many reactions involves so called activation energy , you have to put in a certain amount of energy to get it going . but once you get it going , you get more heat coming out , than you put in to start it off .
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in the sun , which isotopes of hydrogen react to generate helium and a large amount of energy ?
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food does n't last . in days , sometimes hours , bread goes moldy , apple slices turn brown , and bacteria multiply in mayonnaise . but you can find all of these foods out on the shelf at the grocery store , hopefully unspoiled , thanks to preservatives . but what exactly are preservatives ? how do they help keep food edible and are they safe ? there are two major factors that cause food to go bad : microbes and oxidation . microbes like bacteria and fungi invade food and feed off its nutrients . some of these can cause diseases , like listeria and botulism . others just turn edibles into a smelly , slimy , moldy mess . meanwhile , oxidation is a chemical change in the food 's molecules caused by enzymes or free radicals which turn fats rancid and brown produce , like apples and potatoes . preservatives can prevent both types of deterioration . before the invention of artificial refrigeration , fungi and bacteria could run rampant in food . so we found ways to create an inhospitable environment for microbes . for example , making the food more acidic unravels enzymes that microbes need to survive . and some types of bacteria can actually help . for thousands of years , people preserved food using bacteria that produce lactic acid . the acid turns perishable vegetables and milk into longer lasting foods , like sauerkraut in europe , kimchi in korea , and yogurt in the middle east . these cultured foods also populate your digestive track with beneficial microbes . many synthetic preservatives are also acids . benzoic acid in salad dressing , sorbic acid in cheese , and propionic acid in baked goods . are they safe ? some studies suggest that benzoates , related to benzoic acid , contribute to hyperactive behavior . but the results are n't conclusive . otherwise , these acids seem to be perfectly safe . another antimicrobial strategy is to add a lot of sugar , like in jam , or salt , like in salted meats . sugar and salt hold on to water that microbes need to grow and actually suck moisture out of any cells that may be hanging around , thus destroying them . of course , too much sugar and salt can increase your risk of heart disease , diabetes , and high blood pressure , so these preservatives are best in moderation . antimicrobial nitrates and nitrites , often found in cured meats , ward off the bacteria that cause botulism , but they may cause other health problems . some studies linking cured meats to cancer have suggested that these preservatives may be the culprit . meanwhile , antioxidant preservatives prevent the chemical changes that can give food an off-flavor or color . smoke has been used to preserve food for millennia because some of the aromatic compounds in wood smoke are antioxidants . combining smoking with salting was an effective way of preserving meat before refrigeration . for antioxidant activity without a smoky flavor , there are compounds like bht and tocopherol , better known as vitamin e. like the compounds in smoke , these sop up free radicals and stave off rancid flavors that can develop in foods like oils , cheese , and cereal . other antioxidants like citric acid and ascorbic acid help cut produce keep its color by thwarting the enzyme that causes browning . some compounds like sulfites can multitask . they 're both antimicrobials and antioxidants . sulfites may cause allergy symptoms in some people , but most antioxidant preservatives are generally recognized as safe . so should you be worried about preservatives ? well , they 're usually near the end of the ingredients list because they 're used in very small amounts determined by the fda to be safe . nevertheless , some consumers and companies are trying to find alternatives . packaging tricks , like reducing the oxygen around the food can help , but without some kind of chemical assistance , there are very few foods that can stay shelf stable for long .
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sugar and salt hold on to water that microbes need to grow and actually suck moisture out of any cells that may be hanging around , thus destroying them . of course , too much sugar and salt can increase your risk of heart disease , diabetes , and high blood pressure , so these preservatives are best in moderation . antimicrobial nitrates and nitrites , often found in cured meats , ward off the bacteria that cause botulism , but they may cause other health problems . some studies linking cured meats to cancer have suggested that these preservatives may be the culprit .
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nitrates defend against _______ , but may increase your risk of _______ .
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global oneness project a game for life i do n't know how i can really put this , but my football is really something that is very powerful in my life , that gives me the drive to be who i am now , and have the goals i have now . i think if it was n't for football… i ca n't really imagine myself without football . certain things , certain principles in my life are based on my football . i do n't know if you understand what i mean . [ ♪ native music ♪ ] [ children playing ] [ ♪ native music ♪ ] this is my place . its a very small place . its just a four room house . this is where we sit as a family , watch tv , eat supper , and chat . just family chats . i 'll show you the kitchen where we cook our dinner . this is my kitchen . its not a very big place but it is where i live . this is my bedroom ; i share it with my aunt , but unfortunately now she is asleep because she was working night shift . this is my bed . i sleep here with my kitten . oh yes , this is my kitten . it is my friend . i sleep with her almost every night . this is my aunt . she stays here . she is selling veggies and fruit and her business is definitely going very well . in one week you find that you come and buy something and then its not there , its finished . so she 's got a business that is doing well . this road that we are walking on , this is where i started playing soccer when i got to port elizabeth . we put small stones , there would be goals on each side of the road , then we 'd be playing with the guys . that was before there was grass here . there was no grass here , so we would play from that wall to this side of the road . i grew up playing here and when i see this road or when i walk here i always remember where i started playing soccer . [ ♪ native music ♪ ] most of the time i was with my other two cousin-brothers , and they would spend most of their time playing soccer and that 's how i got on to the field and played as well . [ ♪ native music ♪ ] when i was growing up i was very , very poor . when i was still in primary school , i would wash with cold water . my school shoes , the sole was broken , so when it was raining , my socks would be so wet . and in terms of food , there was absolutely nothing to eat . [ ♪ native music ♪ ] for me to be able to eat at school i would have to wait until we are writing a test . then each pupil would put on 10 cents or 20 cents . then the whole amount would go to the person who was the highest on a test , and that is how i would manage to eat , because , if we were writing a test and put on some money , it was definitely my money because i was a very good student . [ ♪ native music ♪ ] i know their are many people out there who are going through what i went through . i know they wo n't deal with it the way i dealt with it , because i was taking everyday as it was coming . [ ♪ native music ♪ ] i never thought of going out and being a prostitute or something , and i know other people who are going through that thing . always , not always , but sometimes opt for that if they are girls , and if they are boys , they go to armed robbery , bad things like that . so the main reason i always tell the story is just to let them know that poverty can not conquer you for the rest of your life . you can conquer poverty as well . [ ♪ native music ♪ ] [ dog barking ] [ ♪ native music ♪ ] there is a way that you can go . there is a solution to poverty . they always do things that are unethical because they say they are going through poverty . [ ♪ native music ♪ ] i 've never done anything to anyone when i was very poor , but here i am today . i 'm not as poor as i was before and for me , now , i do n't feel like i 'm poor , even though i do n't have everything i want . i do n't have a big house , i do n't have a car , but i still feel that i am rich because i am rich inside . [ speaking in native language ] [ laughter ] this is a very good friend of mine . i grew up playing with him on the street . he was never a very good player , but a very good goal keeper . [ laughter ] come try it : [ gaming device sounds ] [ winning tune ] [ quarters hitting the metal return ] i 've won . it 's my lucky day . there you go , that 's all the money . [ ♪ native hip-hop music ♪ ] soccer helped me to stay away from the option of being a prostitute . i have always had love for my football and discipline . if you are going to be doing all the wrong things to try and get something to eat , or money , then those things wo n't be in-line with your football . if you look at soccer , the things you do that are in line with football , they are also in line with your own life . [ ♪ native hip-hop music ♪ ] people love soccer , and the young kids out there , they are interested in soccer . if you talk about soccer , they all know what you 're talking about , because everyone knows about soccer . so its easy to reach out to the people with soccer . [ ♪ native hip-hop music ♪ ] grassroots soccer we have the kids who know how to prevent themselves from getting hiv and also to teach them life skills . [ ♪ native hip-hop music ♪ ] the older guys have gone through things in their lives , but would like to teach the kids so that they could not go through those things . the way we would do is with interactive games . so we do n't really say , `` yeah , we 're going to talk about hiv now . '' some people might just lose interest in it , but simply because its interactive , we do the actual activities where they just learn from them . and its not as if we are telling them what to do , like to abstain . [ ♪ native hip-hop music ♪ ] so why was it not easy to find the ball ? because you could n't see the ball . so remember when we play that game , what did you say ? teacher > yes my girl , say it . student > someone who has the ball is going to be hiv positive . so what does that tell you about hiv ? you ca n't see someone who has hiv . [ clapping ] since we work with kids we use the power of soccer , and we use soccer balls because kids love to play . if you just make them play , especially with our street leagues , the way we do the teaching for hiv and aids gives them time to play soccer . [ ♪ native hip-hop music ♪ ] those are tools for them to be better people , to stay away from things that could destroy their lives . [ ♪ native hip-hop music ♪ ] after we 've done the program , we also assess the change in their attitudes . [ ♪ native hip-hop music ♪ ] [ clapping ] if there 's a big difference where their attitudes were before they went through the program , i would be very happy about that . [ ♪ native music ♪ ] when you 've got something in your heart and you also want someone else to have that same feeling , i do n't know how to say it ... but it 's always important to just share things with other people . it 's just important . if you know you can do something to help the next person , just do it with all your heart . and not expect to get a reward . it really makes more sense to be able to have others help because , really , we can not live in isolation . honestly , we could be a unity here , but what about the others that are not a unity ? we are going to say , yes we are a unity , that is fine for us . they are not a unity , that 's their own problem . it should n't be like that . [ ♪ native music ♪ ] if people could unite . i 'm telling you , i do n't see anything stopping the world from being a better place . i do n't see anything stopping it . [ ♪ native music ♪ ] it does n't take much for soccer to get people together . if there 's a soccer match somewhere , as long as they know that match is somewhere , they will definitely go . it 's really easy for it to unite people . [ ♪ native music ♪ ] for me its really about passion because i love soccer . i love soccer . it just really ... even if i can be stressed out about something , at my training session or at my game , i forget about it . i do n't know what to say about soccer , but that 's the thing about it . i just do n't know what it is . [ ♪ native music ♪ ] nolusindiso `` titie '' plaatjie is 22 years old and lives in port elizabeth south africa . she studied human movement science at nelson mandela metropolitan university and dreams of becoming an engineer . titie is a well-known soccer star , and in 2001 , she was named captain of the provincial team . she has been playing soccer since the age of five . currently working for grassroots soccer as the port elizabeth project coordinator , titie is a key facilitator in raising hiv ? aids awareness among youth and people of her community . she believes that this is a fight for the world . www.globalonenessproject.org
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currently working for grassroots soccer as the port elizabeth project coordinator , titie is a key facilitator in raising hiv ? aids awareness among youth and people of her community . she believes that this is a fight for the world . www.globalonenessproject.org
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in 2010 , which country hosted the world cup ?
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cancer is like a car crash . your body typically regulates the speed at which your cells divide , but sometimes , cancer cuts the brake lines , and your cells divide too quickly , accumulating mutations that cause them to veer away from their original function , form dangerous tumors , and land you in the hospital . cancer is basically an inability of the body to control the speed at which cells divide . when cells divide too quickly , they can often accumulate mutations that cause them to ignore their original function in the body , forming tumors . in turn , these tumors may interfere with the natural processes of the body , such as digestion and respiration , potentially leading to death . typically , your body has a number of genetic mechanisms to control how fast your cells divide . one of these genes is brca1 , which stands for breast cancer susceptibility gene 1 . brca1 belongs to a class of genes called tumor suppressor genes . tumor suppressor genes are involved in regulating how fast a cell divides . normally , cell division follows an orderly process called the cell cycle , which is basically the life cycle of a cell . within the cell cycle is a series of checkpoints , where proteins , such as the one produced by brca1 , regulate how fast the cell may proceed . how does it do this ? brca1 helps repair some forms of mutation in your dna . if your dna is damaged , brca1 keeps the cell from dividing until the mutation is repaired . you have two copies of the brca1 gene in every cell of your body . one copy you inherited from mom , the other from dad . this redundancy is a good a thing because you only need one functioning brca1 gene in a cell to regulate the cell cycle . but it 's important to note that while these copies have a similar function they 're not necessarily the same . in fact , there are hundreds of variations , or alleles , of brca1 . some regulate the cell cycle more effectively than others . in other words , some people are born with better regulating and repair mechanisms than others . and in some cases , mutations may render brca1 ineffective . when this happens , cells with damaged dna are allowed to divide . as they divide , these cells may accumulate additional mutations . these mutations may cause the cell to become less specialized and stop performing its original function in the tissue . if this occurs , then there 's a greater chance they 'll develop into cancer cells . while we all have the gene , such as brca1 , that can cause cancer , it 's only when these genes fail at their function that problems develop . having an ineffective or mutated version of brca1 can increase your susceptibility to cancer , much like driving with bad brakes increases the risk of an accident .
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in other words , some people are born with better regulating and repair mechanisms than others . and in some cases , mutations may render brca1 ineffective . when this happens , cells with damaged dna are allowed to divide .
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there may be hundreds of mutations in the brca1 gene that influence its ability to regulate cell division . why might some of these mutations be more likely to result in the formation of cancer than others ?
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if you visit a museum with a collection of modern and contemporary art , you 're likely to see works that sometimes elicit the response , `` my cat could make that , so how is it art ? '' a movement called abstract expressionism , also known as the new york school , gets this reaction particularly often . abstract expressionism started in 1943 and developed after the end of world war ii . it 's characterized by large , primarily abstract paintings , all-over compositions without clear focal points , and sweeping swaths of paint embodying and eliciting emotions . the group of artists who are considered abstract expressionists includes barnett newman with his existential zips , willem de kooning , famous for his travestied women , helen frankenthaler , who created soak-stains , and others . but perhaps the most famous , influential , and head-scratching one was jackson pollock . most of his paintings are immediately recognizable . they feature tangled messes of lines of paint bouncing around in every direction on the canvas . and sure , these fields of chaos are big and impressive , but what 's so great about them ? did n't he just drip the paint at random ? ca n't anyone do that ? well , the answer to these questions is both yes and no . while pollock implemented a technique anyone is technically capable of regardless of artistic training , only he could have made his paintings . this paradox relates to his work 's roots in the surrealist automatic drawings of andré masson and others . these surrealists supposedly drew directly from the unconscious to reveal truths hidden within their minds . occasionally , instead of picturing something and then drawing it , they let their hands move automatically and would later tease out familiar figures that appeared in the scribbles . and after pollock moved away from representation , he made drip , or action , paintings following a similar premise , though he developed a signature technique and never looked for images or messages hidden in the works . first , he took the canvas off of the easel and laid it on the floor , a subversive act in itself . then , in a controlled dance , he stepped all around the canvas , dripping industrial paint onto it from stirrers and other tools , changing speed and direction to control how the paint made contact with the surface . these movements , like the surrealist scribbles , were supposedly born out of pollock 's subconscious . but unlike the surrealists , whose pictures represented the mind 's hidden contents , pollock 's supposedly made physical manifestations of his psyche . his paintings are themselves signatures of his mind . in theory , anyone could make a painting that is an imprint of their mind . so why is pollock so special ? well , it 's important to remember that while anyone could have done what he did , he and the rest of the new york school were the ones who actually did it . they destroyed conventions of painting that had stood for centuries , forcing the art world to rethink them entirely . but one last reason why jackson pollock 's work has stayed prominent stems from the specific objects he made , which embody fascinating contradictions . for instance , while pollock 's process resulted in radically flat painted surfaces , the web of painted lines can create the illusion of an infinite layered depth when examined up close . and the chaos of this tangled mess seems to defy all control , but it 's actually the product of a deliberate , though not pre-planned , process . these characteristics made pollock into a celebrity , and within art history , they also elevated him to the mythified status of the genius artist as hero . so rather than evening the playing field for all creative minds , his work unfortunately reinforced a long-standing elitist aspect of art . elitist , innovative , whatever you choose to call it , the history embedded in abstract expressionism is one that no cat , however talented , can claim .
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if you visit a museum with a collection of modern and contemporary art , you 're likely to see works that sometimes elicit the response , `` my cat could make that , so how is it art ? '' a movement called abstract expressionism , also known as the new york school , gets this reaction particularly often . abstract expressionism started in 1943 and developed after the end of world war ii . it 's characterized by large , primarily abstract paintings , all-over compositions without clear focal points , and sweeping swaths of paint embodying and eliciting emotions .
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compare and contrast surrealism with abstract expressionism .
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hey , vsauce . michael here . when you call customer service and hear this `` to ensure quality service your call may be monitored or recorded '' , they 're not kidding . over the last year the marchex institute analysed more than 600,000 recorded phone conversations americans made to businesses in the united states . turns out , people from ohio were the most likely to use curse words - the 'a ' word , the 'f ' word and the 's ' word . washington state residents were the least likely to use bad words . but what makes a word bad ? oh , be careful because etymologically speaking even the word 'bad ' can be considered a bad word . it began in old english as a derogatory term for an effeminate man . eighty percent of swear words overheard in public in 1986 , 1997 and 2006 were essentially the same . one third of all counts included the top two - the 'f ' word and the 's ' word . slate 's brilliant lexicon valley podcast purported that these 10 words makeup about 0.7 % of the average english speakers daily vocabulary , which means socially unacceptable words are used almost as often as socially descriptive words . first person plural pronouns account for about 1 % of the words we say everyday . when a bad word is bleeped , it is covered with a 1 kilohertz sine wave , which sounds like this . son of a ... by the way , the symbols and squiggles that are used to represent a bad word have a name . they 're called grawlixes . they were named by mort walker in his seminal `` the lexicon of comicana . '' he names a lot of things but most of them show stuff , they do n't hide stuff . why the need to hide bad words , especially if we all pretty much know what 's being said ? well , there is no one single reason bad words are bad . steven pinker in his excellent lecture on the topic delineates five types of swearing . first of all , some words are bad on purpose . they are created and/or used with the intent to hurt others . he calls this `` abusive swearing . '' using words to insult , humiliate , objectify or marginalise disfavoured people . now , if that this disfavoured person is god , we 're talking about supernatural swearing , which was particularly taboo in victorian times . it was believed that casually or vainly referring to god would physically injure god himself , literally . so , at the time people were forced to come up with euphemisms , like `` zounds ! '' and `` gadzooks ! `` , which originally meant `` god 's wounds ! '' and `` god 's hooks ! `` , referring to the nails driven through the hands of jesus . historically , swear words often came from things we were afraid of , things we perceived as dangerous , stronger than us and mercurial . such as death , disease and infirmity , sex and sexually transmitted diseases , as well as body fluids , germy , gross effluvia . words for those gross things became gross and bad in and of themselves , uncouth to speak . but not all words for gross things are socially unacceptable , which brings us to pinker 's second type of swearing - emphatic swearing . emphatic swearing is where the taboo-ness of bad words becomes quite practical . you would n't usually use those words but when you really want to convey that your current emotions matter more to you than proper social conduct , you can use them . dysphemism . a euphemism is kind , acceptable word that allows you to talk about something unpleasant while simultaneously letting everyone know you totally get that it 's unpleasant and want to respect that . for instance , if you want to be professional , you would n't say s*** . you might say 'defecate ' . if , on the other hand , you really want to drive home just how unpleasant the experience was , dysphemisms can help out a lot . it was n't a bag of canine defecation you found on your front porch , it was a s*** bag of hot dog s*** . both of these words refer to pretty much the same thing but they have different levels of social acceptability and that 's very helpful . it means word choice allows us to not only refer to things in the real world but also to how we feel about them . if both these words had the same level of social acceptance we might even have to find new , badder words so as not to lose the power language currently has to express emotion , repulsion and disgust . but when it comes to two words referring to the same thing , but with different levels of social acceptance , who decides which one 's good and which one 's bad ? well , historically , many of the bad words we use today are the result of class differences . in medieval england , the lower-class saxons spoke a germanic tongue while the upper-class normans spoke a language related to french and latin . english , as we know it today , contains many consequences of their differences . the lower class worked with animals and from them we get animal names . the upper class only ate the animals , which is where the names of the meat come from . today 's swear words are similar . defecation stems from fancy pants latin , whereas the less classy s*** is germanic . there 's also idiomatic swearing , where nothing is being emphasized . no dysphemism is meant ; instead , it 's an easygoing type of swearing that shows an atmosphere is casual . bad words can be used , we 're all close here . it 's okay to swear , we 're all cool . cathartic swearing is a bit different . it gives us `` lalochezia , '' the medical term for the relief swearing provides when you 're in pain . in the brain , swearing seems to involve different regions than regular language , which may explain why people with aphasia caused by brain damage struggle to comprehend or construct spoken words but yet are fluent at swearing . or why people with coprolalia control normal language just fine , but involuntarily utter profanity , an obscene words . it turns out swearing may be centralized in the limbic system , along with the motions . many animals make automatic noises when in pain or threat to startle or intimidate attackers , or to let others know what 's going on . in humans , bad words are great for this purpose . their taboo-ness makes them special . people would n't use them otherwise , so they are great alarms . swearing is changing . some bad words are being used more and more frequently . of the seven words , george carlin said you could never say on television . today , every second 22 of them are sent out on twitter . so , what will swearing look like in the future ? it probably wo n't go away altogether , it 's too useful . but the words we do n't like will likely change . history has shown that as disease becomes less scary and sex and the supernatural more personal , words related to them become less taboo and more common ; whereas words that were common in the past are increasingly unpleasant . perhaps , in the future , spurt not by runaway political correctness but by wider knowledge , words like `` schizo '' , `` mental '' , `` aspy '' , or even `` depressed '' will take the square stage . or as john mcwhorter ventured , words centered around class and the gap between opportunity and disadvantage will become more taboo . salt of the earth , trash , chav , pikey , urban as a pejorative . when mckay hatch started a `` no cussing club '' at his school , his campaign became the target of so many online jokes and insults for being lame or anti-free speech . on his book , he literally subtitled his own name `` the most cyberbullied kid in the world . '' people care about this stuff . is it censorship to tell us what we can and can not say or is it a safety seal , ensuring certain dysphemisms do n't get worn down to a quotidian bluntness like every other word ? or is that badness of bad words a boundary , a moving boundary of we reject - sometimes arbitrary , sometimes irrational , but always moving in the direction of acceptance moving forward ? crime and inequality have existed ever since they could . but when n.w.a released a reaction , in the form of a song with bad word in the title , `` f*** the police '' , the federal bureau of investigations released a statement against the song . it was the only time , up until then and since , the fbi has ever issued an official statement about a work of art . bad words have power . if you wan na push for change you 'll need something to push . if everything 's fine , nothing 's cool . so , bad words are the precipitate of a larger reaction - the process of us slowly becoming what we want to become . that 's some deep s*** . and as always , thanks for watching .
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but when it comes to two words referring to the same thing , but with different levels of social acceptance , who decides which one 's good and which one 's bad ? well , historically , many of the bad words we use today are the result of class differences . in medieval england , the lower-class saxons spoke a germanic tongue while the upper-class normans spoke a language related to french and latin . english , as we know it today , contains many consequences of their differences .
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why do our english words for farm animals ( chicken , pig , etc . ) historically come from a lower class version of the english language , while our words for the meats they produce ( poultry , pork , etc . ) come from an upper class version of the english language ?
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he was one of the most influential figures of the 20th century , forever changing the course of one of the world 's largest countries . but was he a hero who toppled an oppressive tyranny or a villain who replaced it with another ? it 's time to put lenin on the stand in history vs. lenin . `` order , order , hmm . now , was n't it your fault that the band broke up ? '' `` your honor , this is vladimir ilyich ulyanov , aka lenin , the rabblerouser who helped overthrow the russian tsar nicholas ii in 1917 and founded the soviet union , one of the worst dictatorships of the 20th century . '' `` ohh . '' `` the tsar was a bloody tyrant under whom the masses toiled in slavery . '' `` this is rubbish . serfdom had already been abolished in 1861 . '' `` and replaced by something worse . the factory bosses treated the people far worse than their former feudal landlords . and unlike the landlords , they were always there . russian workers toiled for eleven hours a day and were the lowest paid in all of europe . '' `` but tsar nicholas made laws to protect the workers . '' `` he reluctantly did the bare minimum to avert revolution , and even there , he failed . remember what happened in 1905 after his troops fired on peaceful petitioners ? '' `` yes , and the tsar ended the rebellion by introducing a constitution and an elected parliament , the duma . '' `` while retaining absolute power and dissolving them whenever he wanted . '' `` perhaps there would 've been more reforms in due time if radicals , like lenin , were n't always stirring up trouble . '' `` your honor , lenin had seen his older brother aleksandr executed by the previous tsar for revolutionary activity , and even after the reforms , nicholas continued the same mass repression and executions , as well as the unpopular involvement in world war i , that cost russia so many lives and resources . '' `` hm , this tsar does n't sound like such a capital fellow . '' `` your honor , maybe nicholas ii did doom himself with bad decisions , but lenin deserves no credit for this . when the february 1917 uprisings finally forced the tsar to abdicate , lenin was still exiled in switzerland . '' `` hm , so who came to power ? '' `` the duma formed a provisional government , led by alexander kerensky , an incompetent bourgeois failure . he even launched another failed offensive in the war , where russia had already lost so much , instead of ending it like the people wanted . '' `` it was a constitutional social democratic government , the most progressive of its time . and it could have succeeded eventually if lenin had n't returned in april , sent by the germans to undermine the russian war effort and instigate riots . '' `` such slander ! the july days were a spontaneous and justified reaction against the government 's failures . and kerensky showed his true colors when he blamed lenin and arrested and outlawed his bolshevik party , forcing him to flee into exile again . some democracy ! it 's a good thing the government collapsed under their own incompetence and greed when they tried to stage a military coup then had to ask the bolsheviks for help when it backfired . after that , all lenin had to do was return in october and take charge . the government was peacefully overthrown overnight . '' `` but what the bolsheviks did after gaining power was n't very peaceful . how many people did they execute without trial ? and was it really necessary to murder the tsar 's entire family , even the children ? '' `` russia was being attacked by foreign imperialists , trying to restore the tsar . any royal heir that was rescued would be recognized as ruler by foreign governments . it would 've been the end of everything the people had fought so hard to achieve . besides , lenin may not have given the order . '' `` but it was not only imperialists that the bolsheviks killed . what about the purges and executions of other socialist and anarchist parties , their old allies ? what about the tambov rebellion , where peasants , resisting grain confiscation , were killed with poison gas ? or sending the army to crush the workers in kronstadt , who were demanding democratic self-management ? was this still fighting for the people ? '' `` yes ! the measures were difficult , but it was a difficult time . the new government needed to secure itself while being attacked from all sides , so that the socialist order could be established . '' `` and what good came of this socialist order ? even after the civil war was won , there were famines , repression and millions executed or sent to die in camps , while lenin 's successor stalin established a cult of personality and absolute power . '' `` that was n't the plan . lenin never cared for personal gains , even his enemies admitted that he fully believed in his cause , living modestly and working tirelessly from his student days until his too early death . he saw how power-hungry stalin was and tried to warn the party , but it was too late . '' `` and the decades of totalitarianism that followed after ? '' `` you could call it that , but it was lenin 's efforts that changed russia in a few decades from a backward and undeveloped monarchy full of illiterate peasants to a modern , industrial superpower , with one of the world 's best educated populations , unprecedented opportunities for women , and some of the most important scientific advancements of the century . life may not have been luxurious , but nearly everyone had a roof over their head and food on their plate , which few countries have achieved . '' `` but these advances could still have happened , even without lenin and the repressive regime he established . '' `` yes , and i could 've been a famous rock and roll singer . but how would i have sounded ? '' we can never be sure how things could 've unfolded if different people were in power or different decisions were made , but to avoid the mistakes of the past , we must always be willing to put historical figures on trial .
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`` he reluctantly did the bare minimum to avert revolution , and even there , he failed . remember what happened in 1905 after his troops fired on peaceful petitioners ? '' `` yes , and the tsar ended the rebellion by introducing a constitution and an elected parliament , the duma . ''
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what happened following the events of bloody sunday ? ( choose all that apply )
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( music ) aw , thank you , thank you . as you can probably tell , i 'm an astronaut . no , i 'm a dj/producer , as it says on the screen . i am also a high school student , just like many of you guys . how many high school students do we have out here ? ( cheers ) oh , okay ! a good amount . i 'm a proud member of my school 's marching band , and i run track , as well , so if any of you guys are into that , it 's one of my other passions . i have been djing and producing for a little over three years now , and i 've worked with artists that you may know , like avicii , skrillex , major lazer , krewella , porter robinsion , carnage , and many others . how many of you guys like dance music ? show off hands , dance music , oh okay . how many of you guys like rap or trap hip hop ? okay , good amount . jazz ? classical ? that 's good , you guys have smart minds , that 's good . what 's great about djing is that you can combine all these genres into one idea , and what i like to do is combine dance , hip hop , trap , dubstep , even movie samples , and kind of combine them into one set . djing creates this , sort of , combined culture that really unites many fans . a good example of this is skrillex and a $ ap rocky 's collaboration `` wild for the night '' or , most recently , avicii and ella black 's `` wake me up . '' how many of you guys know that song ? it 's a great track . now , what exactly does a dj do ? well , as you just saw earlier , they mix tracks . what i just did was mix a kanye west intro from `` black skinheads '' with a track called `` lrad . '' one of the main goals is to really trigger samples , tracks , or clips and kind of create this long journey . i 'm going to do another little example for you guys right now of what djs call a `` mashup , '' which is taking two or more tracks and combining them into one . this mashup was made famous by a hungarian duo myon & amp ; amp ; shane 54 , and it takes the vocals from krewella 's `` alive . '' how many of you guys know that song ? `` alive '' ? yeah , okay . i 'm going to take the vocals from that track and the song `` language '' by porter robinson . so , let me just play you the vocals first . ( music ) so , that 's the vocals , and here 's the actual track . ( music ) so , what i 'm going to do is i 'm going to fill these vocals on top of the track and create a new song , a kind of combined song , with the two vocals . ( music ) if you turn it down , you can just hear i 'm playing it a capella or just the song by itself . ( music ) now , what i 'm going to do after this drops is change it into another song . one of the most important things about dance music is really the drop , so i 'm going to change it into another song and really catch you by surprise . ( music ) and that 's one example right there . ( applause ) so , as you saw , i took three different songs and kind of combined them into one new idea , which is something plenty of djs do out there on the professional circuit . there are plenty of ways to get started djing . one of the main things i did was really take the time to study djs that inspired me . whether it was watching podcasts , watching live sets , or just really looking them up online . i really tried to take in what it meant to be a fantastic dj . one of the best ways to really learn is to ask a friend , you know , a friend who knows how to dj . just go over there , ask him a few questions . if no that , thankfully we have a lot of great online resources . one of the things you can do is check out youtube , check out some demonstrations . now , many djs , a high percentage of them , check out beatport or soundcloud to find a lot of the tracks . there are also many other blog sites , such as billboard 's code , edmtunes , edm sauce , or dancing astronaut . now , there are multiple ways to dj , and what could originally only be done on turntables and vinyl , by legends such as larry levan , grandmaster flash , and paul oakenfold , can now be done with many more pieces of equipment , such as cdjs , which are , sort of , digital turntables and what i learned on and what i still use to this day . there are many other amazing programs now , such as ableton , traktor pro , serato , or even apps for tablets and touchscreens . there are many hardware systems just like my apc40 here that can launch samples , clips and tracks . you can also just use turntables , cdjs , an s4 controller , or an novation launchpad . and all of these really kind of do the same thing , and that 's mix tracks . so , what i 'm going to do now is show you guys another mix demonstration . i 'm going to start with one of my own songs that i did with my friend matt dzyacky , and from there i 'm going to go in a sort of medley of different tracks and show you the different styles of mixing that you can do . ( music ) so i 'll show you guys when i start mixing the new track , so you can hear it coming in . ( music ) you can hear in the back , a new song is mixing in . ( music ) now , another thing that djs use is what 's called a mixer , and a mixer has many different effects , such as a beat roll , filter effects , and any other different ones . there 's plenty of effects to use . ( music ) so , now i 'm going into a new song , and after this drops , i 'm going to drop it in another song and kind of change it up . ( music ) and that 's a new song bite . ( music ) so i 'm just going to straight mash up another song right when this one breaks down . ( music ) now , if i want to change up the music , let 's say , throw in some new beats , i can just choose a trap beat i want to throw over the breakdown . ( music ) so , i get ready to throw in my new beats now . ( music ) and that is the end of that demo . ( applause ) thank you , thank you ! now , the great thing about technologies now is whether it 's a two dollar app or a couple hundred dollar equipment , which i 'm sure most parents wo n't want to buy for their child , is that almost anyone who has a passion for djing and a passion for the music and who might want to pursue a career in it really has the ability to , well , pursue it , such as myself . you can start with an app on a tablet or an app on your phone , even , an app on your ipad , and then move on to bigger equipment . the opportunities are endless , and , as you saw , you can mix many different styles of music . so , thank you !
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how many of you guys know that song ? it 's a great track . now , what exactly does a dj do ?
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plante says that the thing that 's great about djing is that you can ________ .
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translator : ido dekkers reviewer : ariana bleau lugo so what is gravity ? i bet most of you think it 's : `` what goes up , must come down ! '' is that right ? well , sorta , but not really . technically , the law of gravity is an equation . it is : f = g x m1 x m2 / r^2 , where g is the universal gravitational constant , m1 and m2 are the masses of the two objects , and r is the distance between them squared . that was easy , right ? probably not . what does this actually mean ? well it means that - well , everything is attracted to everything else . what i mean by that is if you have two objects , any two objects , they are attracted to each other . ok. let 's try and wrap our minds around this . what happens when you drop a rock off a cliff ? it falls to the earth . right ? well , yes , but something else happens . you see , the law of gravity says that both objects , the rock and the earth , are attracted to each other . this means that the rock falls towards the earth , and the earth falls towards the rock . wait a second - you mean to tell me that if - the earth falls up to meet the rock ? yes , that 's exactly what i 'm saying . and the reason you do n't see the earth fall up to meet the rock is because the objects move towards each other proportionate to their respective masses . the earth is much much much more massive than the rock , so it moves a very very small distance , and the rock is much less massive , so it moves farther with respect to the earth . maybe a better way to understand gravity is to take two teenagers in spacesuits , and place them far out in space - away from all the planets and the stars . it turns out they will be attracted to each other . i 'm not talking about that kind of attraction . see , they have mass , and since they have mass , they will move towards each other . they are attracted to each other . maybe one more thing might help . have you ever played with two magnets ? you know , the magnets with the north and the south poles ? when you take the magnets and put them closer to each other , they move together . they are attracted to each other . and the closer they are , the stronger the attraction . think of the mass of the object like the strength of a magnet and the distance between the objects like the distance between the two magnets . now understand , i 'm not saying that gravity and magnetism are the same , they just behave in a similar way . let 's think of one other thing - astronauts . you know , astronauts , they weigh less on the moon than on the earth . why is that ? well you see , the moon is less massive than the earth . therefore it has a smaller gravitational pull on the astronaut . it 's like the moon is a weaker magnet . they are n't as attracted to each other . distance also plays a role . think back to playing with a magnet . the pull of the magnets towards each other are stronger when they are closer together . the same is true of gravity . for example , the sun is the most massive object near the earth . it dictates most of the gravitational forces in our solar system . it is very very massive . but it is relatively far away , so even though the sun is a much stronger magnet , so to speak , it is a long ways away . therefore the attraction is n't as strong . so let 's look back at that law of gravity . the equation : f = g x m1 x m2 / r ^2 . you see the force of gravity is equal to a number . that 's that universal gravitational constant g times the mass of object one , times the mass of object two . think of m1 being the mass of the sun and m2 being the mass of the earth . and then we divide by the distance between them squared . this determines the force of attraction between the sun and earth . you could just as easily plug in your mass and the earth 's mass and the distance between you and the center of the earth , and find out how much you are attracted to the earth , and the earth attracted to you . so , what 's gravity ? everything is attracted to everything else . everything . oh , one last thing , just to make you wonder . what causes gravity ? why are two objects with mass attracted to each other ? well , the answer is - we do n't know . the cause of gravity remains a mystery to scientists . we do n't really know conclusively what causes gravity . it is one of the great mysteries of science .
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oh , one last thing , just to make you wonder . what causes gravity ? why are two objects with mass attracted to each other ?
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what causes gravity ?
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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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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 .
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a group can be made of anything as long as the elements follow _____ rules
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this is a thinker who helps us understand why our lives and relationships are full of so much confusion and pain . he tells us why life is hard , and how to cope . his own life incurred a lot of anxiety . sigmund schlomo freud was born to a middle-class jewish family in 1856 . his professional life was not an immediate success . as a medical student , he dissected hundreds of eels in an unsuccessful attempt to locate their reproductive organs . he promoted cocaine as a medical drug , but it turned out to be a dangerous and addictive idea . a few years later he founded the discipline that would ultimately make his name . a new psychological medicine he called psychoanalysis the landmark study was his 1900 book the interpretation of dreams . many others followed . despite his success , he was often unhappy . during some particularly strenuous research he recorded , “ the chief patient i am preoccupied with is myself… ” he was convinced he would die between 61 and 62 and had great phobias about those numbers . ( although he actually died much later , at age 83 . ) perhaps because of his frustrations , freud achieved a series of deep insights into the sources of human unhappiness . he proposed that we are all driven by the : pleasure principle which inclines us towards easy physical and emotional rewards : and away from unpleasant things like drudgery and discipline . as infants we are guided more or less solely according to the pleasure principle , freud argued . but it will , if adhered to without constraints , lead us to dangerous reckless things : like never doing any work eating too much or , most notoriously , sleeping with members of own family . we need to adjust to what freud called the reality principle though we all have to bow to this reality principle , freud believed that there were better and worse kinds of adaptations . he called the troublesome ones neuroses neuroses are the result of faulty negotiations with –or in freud ’ s language , repression of–the pleasure principle . freud described a conflict between three parts of our minds : the id driven by the pleasure principle , and the the superego driven by a desire to follow the rules and do the right thing according to society . and the ego which has to somehow accomodate the two . to understand more about these dynamics , freud urged us to think back to the origins of our neuroses in childhood . as we grow up , we go through what freud termed : the oral phase where we deal with all the feelings around ingestion and eating . if our parents aren ’ t careful we might pick up all kinds of neuroses here : we might take pleasure in refusing food , or turn to food to calm ourselves down , or hate the idea of depending on anyone else for food . then comes the anal phase which is closely aligned with what we now call “ potty-training ” . during this period , our parents tell us what to do -- and when to go . at this phase we begin to learn about testing the limits of authority . again , if things go wrong , if we don ’ t feel authority is benign enough , we might , for example , choose to withhold out of defiance . then , as adults , we might become “ anally retentive ” ; in other words , not able to give or surrender . next comes : the phallic phase which goes until about age 6 . freud shocked his contemporaries by insisting that little children have sexual feelings . moreover , in the phallic phase children direct their sexual impulses towards their parents , the most immediately available and gratifying people around . freud famously described what he called the oedipus complex where we are unconsciously predisposed towards “ being in love with the one parent and hating the other. ” what is complex is that no matter how much our parents love us , they can not extend this to sexual life and will always have another life with a partner . this makes our young selves feel dangerously jealous and angry – and also ashamed and guilty about this anger . the complex provides a huge amount of internalised worry for a small child . ultimately , most of us experience some form of confusion around our parents that later ties into our ideas of love . mum and dad may both give us love , but they often mix it in with disturbed behaviour . yet because we love them , we remain loyal to them and also to their bizarre , destructive patterns . for example , if our mother is cold , we will be apt nevertheless to long for her . and as a result , however , we may be prone to always associate love with a certain distance . naturally , the result is very difficult adult relationships . often the kind of love we ’ ve learned from mum and dad means we can ’ t fuse sex and love because the people we learnt about love from are also those we were blocked from having sex with . we might find that the more in love with someone we are , the harder it becomes to make love to them . this can reach a pitch of crisis after a few years of marriage and some kids . freud compared the issues we so often have with intimacy to hedgehogs in the winter : they need to cuddle for warmth , but they also can ’ t come too close because they ’ re prickly . there ’ s no easy solution . freud says we can ’ t make ourselves fully rational , and we can ’ t change society , either . in his 1930 book civilisation and its discontents , freud wrote that society provides us with many things , but it does this by imposing heavy dictates on us : insisting that we sleep with only a few ( usually one ) other , imposing the incest taboo , requiring us to put off our immediate desires , demanding that we follow authority and work to make money . societies themselves are neurotic–that is how they function - and it ’ s why there are constant wars and other troubles . freud attempted to invent a treatment for our many neuroses : psychoanalysis . he thought that with a little proper analysis , people could uncover what ails them and better adjust to the difficulties of reality . in his sessions he analysed a number of key things . he looked at people ’ s dreams , which he saw as expressions of wish fulfillments he also looked at parapraxes or slips of the tongue . we now call these revealing mistakes freudian slips like when we write ‘ thigh ’ when we wanted to write ‘ though ’ . he also liked to think about jokes . he believed that jokes often help us make fun of something symbolic like death or marriage , and thus relieve some of our anxiety about these topics . there ’ s a temptation to say freud just made everything up , and life isn ’ t quite so hard as he makes it out to be . but then one morning we find ourselves filled with inexplicable anger towards our partner , or running high with unrelenting anxiety on the train to work , and we ’ re reminded all over again just how elusive , difficult , and freudian our mental workings actually are . we could still reject his work , of course . but as freud said , “ no one who disdains the key will ever be able to unlock the door. ” we could all use a bit more of freud ’ s ideas to help us unpick ourselves .
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societies themselves are neurotic–that is how they function - and it ’ s why there are constant wars and other troubles . freud attempted to invent a treatment for our many neuroses : psychoanalysis . he thought that with a little proper analysis , people could uncover what ails them and better adjust to the difficulties of reality .
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freud believed that society put too many restrictions on people , which lead to large-scale societal neuroses . what are his examples of this ?
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translator : jennifer cody reviewer : jessica ruby when faced with a big challenge where potential failure seems to lurk at every corner , maybe you 've heard this advice before : `` be more confident . '' and most likely , this is what you think when you hear it : `` if only it were that simple . '' but what is confidence ? take the belief that you are valuable , worthwhile , and capable , also known as self-esteem , add in the optimism that comes when you are certain of your abilities , and then empowered by these , act courageously to face a challenge head-on . this is confidence . it turns thoughts into action . so where does confidence even come from ? there are several factors that impact confidence . one : what you 're born with , such as your genes , which will impact things like the balance of neurochemicals in your brain . two : how you 're treated . this includes the social pressures of your environment . and three : the part you have control over , the choices you make , the risks you take , and how you think about and respond to challenges and setbacks . it is n't possible to completely untangle these three factors , but the personal choices we make certainly play a major role in confidence development . so , by keeping in mind a few practical tips , we do actually have the power to cultivate our own confidence . tip 1 : a quick fix . there are a few tricks that can give you an immediate confidence boost in the short term . picture your success when you 're beginning a difficult task , something as simple as listening to music with deep bass ; it can promote feelings of power . you can even strike a powerful pose or give yourself a pep talk . tip two : believe in your ability to improve . if you 're looking for a long-term change , consider the way you think about your abilities and talents . do you think they are fixed at birth , or that they can be developed , like a muscle ? these beliefs matter because they can influence how you act when you 're faced with setbacks . if you have a fixed mindset , meaning that you think your talents are locked in place , you might give up , assuming you 've discovered something you 're not very good at . but if you have a growth mindset and think your abilities can improve , a challenge is an opportunity to learn and grow . neuroscience supports the growth mindset . the connections in your brain do get stronger and grow with study and practice . it also turns out , on average , people who have a growth mindset are more successful , getting better grades , and doing better in the face of challenges . tip three : practice failure . face it , you 're going to fail sometimes . everyone does . j.k. rowling was rejected by twelve different publishers before one picked up `` harry potter . '' the wright brothers built on history 's failed attempts at flight , including some of their own , before designing a successful airplane . studies show that those who fail regularly and keep trying anyway are better equipped to respond to challenges and setbacks in a constructive way . they learn how to try different strategies , ask others for advice , and perservere . so , think of a challenge you want to take on , realize it 's not going to be easy , accept that you 'll make mistakes , and be kind to yourself when you do . give yourself a pep talk , stand up , and go for it . the excitement you 'll feel knowing that whatever the result , you 'll have gained greater knowledge and understanding . this is confidence .
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take the belief that you are valuable , worthwhile , and capable , also known as self-esteem , add in the optimism that comes when you are certain of your abilities , and then empowered by these , act courageously to face a challenge head-on . this is confidence . it turns thoughts into action .
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the best way to increase your confidence after you have failed at something is to :
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why do we buy certain products or choose certain brands ? this is the sort of question advertisers have always asked , and there are no easy answers . however , there is a handy tool that helps companies explore this and similar questions , and it 's called the focus group . until the 1940s , market research was often quantitative using things like sales figures and customer polls to track consumption . but this changed during world war ii . sociologists robert merton and paul lazarsfeld set out to learn how unprecedented exposure to wartime propaganda was affecting the public . instead of polling large numbers of people with straightforward questions and quantifiable answers , the researchers conducted in-person interviews , sometimes with small groups , engaging them in more open discussions . later , this method was picked up by the advertising industry with the help of consultants , like austrian-born psychologist ernest dichter , who first coined the term focus group . this new technique was a type of qualitative research focused on the nature of people 's preferences and thoughts . it could n't tell marketers what percentage of people buy a certain product or brand , but it could tell them more about the people who do , their reasoning for doing so , and even the unconscious motivations behind those reasons . rather than providing definite conclusions for business and sales , focus groups would be used for exploratory research , generating new ideas for products and marketing based on deeper understanding of consumer habits . for example , early focus groups found that contrary to popular opinion at the time , wives often had more influence than their husbands when choosing which car to buy , so chrysler shifted gears by marketing cars directly to women . and dr. dichter himself conducted focus groups for mattel to learn what girls wanted in a doll . the result was the original barbie doll . so how does a focus group work ? first , companies recruit between six and ten participants according to specific criteria that meet their research objectives . they could be mothers of children between five and seven , or teenagers planning to buy a new phone in the next three months . this is often done through professional recruiters who manage lists of people who 've agreed to participate in focus groups for payment or other rewards . during a session , participants are asked to respond to various prompts from the group moderator , like sharing their opinions on a certain product , or their emotional reactions to an advertisement . they may even be asked to do seemingly unrelated tasks , like imagining brands as animals in a zoo . the idea is that this can reveal useful information about the participant 's feelings that traditional questions might not get to . beyond these basics , many variations are possible . a focus group may have two or more moderators perhaps taking opposite sides on a question , or a researcher might be hidden in the focus group unknown to other participants to see how their answers can be influenced . and the whole process may also be observed by researchers through a one-way mirror . but although they can provide valuable insight , focus groups do have their limitations , and one of the main ones is that the simple act of observing something can change it . this principle is called observer interference . the answers participants give are likely to be affected by the presence of the researchers , social pressure from the rest of the group , or simply knowing that they 're taking part in a focus group . and because researchers often use a small sample size in a specific setting , it 's hard to generalize their results . the findings that researchers do reach from focus groups are often tested through experiments and data gathering . those put numbers on questions like how many potential customers there are and what price they 'd be willing to pay . this part of the process changes as technology evolves . but focus groups have remained largely the same for decades . perhaps when it comes to the big , important questions , there 's no substitute for people genuinely interacting with each other .
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sociologists robert merton and paul lazarsfeld set out to learn how unprecedented exposure to wartime propaganda was affecting the public . instead of polling large numbers of people with straightforward questions and quantifiable answers , the researchers conducted in-person interviews , sometimes with small groups , engaging them in more open discussions . later , this method was picked up by the advertising industry with the help of consultants , like austrian-born psychologist ernest dichter , who first coined the term focus group .
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in a focus group , people are sometimes asked to do exercises like imagining that a product magically becomes a person in a party , and then asked to describe what this person does or says to the other people in the party . how do you think this type of exercise can provide us information about what people think about products ?
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translator : tom carter reviewer : bedirhan cinar optics , or the enhancement of our natural vision , has been one of the biggest catalysts for science over the past 500 years , interestingly , it was n't scientific interest , but more practical matters that led to the initial advancements in optics , starting around 1440 when johannes gutenberg invented his printing press . in short order , books , which had been a rarity , were now becoming a widespread phenomenon . all that new reading material meant more knowledge was circulating , but it also meant that more people were straining their eyes , likely as they read by candlelight . and while spectacles had been invented in italy around 1286 , the need for reading glasses increased substantially . now that people could use lenses to see things more clearly , they started wondering if vision could be enhanced to see things the human eye could n't perceive by its own devices . robert hooke pursued microscopy , and 1665 he published his findings of worlds inside worlds , which he called `` cells '' in the book `` micrographia . '' at the other end of the spectrum , galileo innovated with telescopic lenses , and in 1609 , he had refined a telescope until he had an instrument powerful enough to see distant objects in the sky with an accuracy no one had before him . he found that the moon had craters and mountains , that jupiter had moons of its own , and the whole system governing the earth and space was brought into question . not everyone was thrilled with all the things galileo saw though . for instance , it was taught at the time that the moon was a perfectly smooth sphere . yet here was visual proof that was awfully hard to discount . upon finding moons around jupiter , he also verified what johannes kepler had surmised : that the earth was not the center of the universe , dispelling another central dogma of galileo 's day . then almost exactly a year after galileo died , isaac newton was born . a lot that had been unknown was visible by now , but much of it was simply the foundation for further questions . what was light anyway ? and color , for that matter ? what were the laws that governed the earth , and the heavens ? and could we capture them through keen observation ? newton experimented extensively with optics , and came to understand light as something of substance , and colors as components of light at different frequencies . before newton , people widely believed that the color was due to different amounts of light , with red being lots of light , and blue being mostly dark . newton 's prism experiments showed that white light could not only be broken into its component colors with one prism , but that a second lens could recompose those colors back into white light again , thus showing that color was a matter of light 's refraction rather than how light or dark it was . newton 's studies of optics led to the development of the reflecting telescope . this , together with his study of planetary motion , led to his theory of gravitation , one of the world 's greatest examples of learning to see something invisible by observing its effect on things that are visible . so fast forward a few hundred years , and here we stand . we 've evolved from a single lens to optics that reveal the birth of a star in another galaxy , or a child developing in the womb , or an electron whirling around an atom . at a time when so much is visible , how we see the world around us matters even more than what we see . will we see a world where everything important has already been discovered ? or will we see one in which yesterday 's discoveries are but a doorway to the breakthroughs of tomorrow ?
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newton experimented extensively with optics , and came to understand light as something of substance , and colors as components of light at different frequencies . before newton , people widely believed that the color was due to different amounts of light , with red being lots of light , and blue being mostly dark . newton 's prism experiments showed that white light could not only be broken into its component colors with one prism , but that a second lens could recompose those colors back into white light again , thus showing that color was a matter of light 's refraction rather than how light or dark it was .
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people of newton 's time believed that color was simply a matter of how much light was present . newton discovered that :
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emily dickinson said over a century ago that `` there is no frigate like a book to take us lands away ... '' and it 's true . when we pick up a book , turn on the tv , or watch a movie , we 're carried away down the currents of story into a world of imagination . and when we land , on a shore that is both new and familiar , something strange happens . stepping onto the shore , we 're changed . we do n't retrace the footsteps of the authors or characters we followed here . no ; instead , we walk a mile in their shoes . researchers in psychology , neuroscience , child development and biology are finally starting to gain quantifiable scientific evidence , showing what writers and readers have always known : that stories have a unique ability to change a person 's point of view . scholars are discovering evidence that stories shape culture , and that much of what we believe about life comes not from fact , but from fiction - that our ideas of class , marriage and even gender are relatively new , and that many ideologies which held fast for centuries were revised within the 18th century , and redrafted in the pages of the early novel . imagine a world where class , and not hard work , decides a person 's worth ; a world where women are simply men 's more untamed copy ; a world where marriage for love is a novel notion . well , that was the world in which samuel richardson 's `` pamela '' first appeared . richardson 's love story starred a poor , serving-class heroine , who is both more superior and smarter than her upper-class suitor . the book , challenging a slew of traditions , caused quite a ruckus . there was more press for `` pamela '' than for parliament . it spawned intense debate and several counter-novels . still , for all those who could n't accept `` pamela , '' others were eager for this new fictional world . this best seller and all its literary heirs - `` pride and prejudice , '' `` jane eyre , '' and yes , even `` twilight '' - have continuously shared the same tale and taught similar lessons , which are now conventional and commonplace . similarly , novels have helped shape the minds of thought leaders across history . some scholars say that darwin 's theory of evolution is highly indebted to the plots he read and loved . his theory privileges intelligence , swiftness , and adaptability to change - all core characteristics in a hero . whether you 're reading `` harry potter '' or `` great expectations , '' you 're reading the kind of plot that inspired darwin . yet , recent studies show that his theory might not be the whole story . our sense of being a hero - one man or one woman or even one species taking on the challenges of the world - might be wrong . instead of being hardwired for competition for being the solitary heroes in our own story , we might instead be members of a shared quest . more hobbit than harry . sometimes , of course , the shoes we 've been walking in can get plain worn out . after all , we have n't walked just one mile in jane austen 's or mark twain 's shoes - we 've walked about 100 trillion miles in them . this is n't to say that we ca n't read and enjoy the classics ; we should travel with dickens , let pip teach us what to expect from ourselves , have a talk with austen and elizabeth about our prides and prejudices . we should float with twain down the mississippi , and have jim show us what it means to be good . but on our journey , we should also keep in mind that the terrain has changed . we 'll start shopping around for boots that were made for walking into a new era . take , for instance , katniss everdeen and her battle with the capitol . can `` hunger games '' lead us into thinking about capitalism in a new way ? can it teach us a lesson about why the individual should not put herself before the group ? will `` uglies '' reflect the dangers of pursuing a perfect body and letting the media define what is beautiful ? will `` seekers '' trod a path beyond global warming ? will the life-and-death struggles of toklo , kallik , lusa and the other bears chart a course for understanding animals and our place in their world ? only the future will tell which stories will engage our imagination , which tales of make-believe we 'll make tomorrow . but the good news is this : there are new stories to venture in every day , new tales that promise to influence , to create and to spark change - stories that you might even write yourself . so i guess the final question is this : what story will you try on next ?
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no ; instead , we walk a mile in their shoes . researchers in psychology , neuroscience , child development and biology are finally starting to gain quantifiable scientific evidence , showing what writers and readers have always known : that stories have a unique ability to change a person 's point of view . scholars are discovering evidence that stories shape culture , and that much of what we believe about life comes not from fact , but from fiction - that our ideas of class , marriage and even gender are relatively new , and that many ideologies which held fast for centuries were revised within the 18th century , and redrafted in the pages of the early novel .
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according to wise , what do researchers in a variety of fields say that stories have the ability to do ?
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you probably do n't need to be told how important your brain is . after all , every single thing you experience , your thoughts and your actions , your perceptions and your memories are processed here in your body 's control center . but if this already seems like a lot for a single organ to handle , it 's actually only a small part of what the brain does . most of its activities are ones you 'd never be aware of , unless they suddenly stopped . the brain is made up of billions of neurons , and trillions of connections . neurons can be activated by specific stimuli or thoughts , but they are also often spontaneously active . some fire cyclically in a set pattern . others fire rapidly in short bursts before switching off , or remain quiet for long periods until thousands of inputs from other neurons line up in just the right way . on a large scale , this results in elaborate rhythms of internally generated brain activity , humming quietly in the background whether we 're awake , asleep , or trying not to think about anything at all . and these spontaneously occurring brain functions form the foundation upon which all other brain functions rely . the most crucial of these automatically occurring activities are the ones that keep us alive . for example , while you 've been paying attention to this video spontaneous activity in your brain has been maintaining your breathing at 12 to 16 breaths a minute , making sure that you do n't suffocate . without any conscious effort , signals from parts of your brainstem are sent through the spinal cord to the muscles that inflate your lungs , making them expand and contract , whether or not you 're paying attention . the neuronal circuits underlying such rhythmic spontaneous activity are called central pattern generators , and control many simple repetitive behaviors , like breathing , walking , and swallowing . ongoing neural activity also underlies our sensory perception . it may seem that the neurons in your retina that translate light into neural signals would remain quiet in the dark , but in fact , the retinal ganglion cells that communicate with the brain are always active . and the signals they send are increases and decreases in the rate of activity , rather than separate bursts . so at every level , our nervous system is teeming with spontaneous activity that helps it interpret and respond to any signals it might receive . and our brain 's autopilot is n't just limited to our basic biological functions . have you ever been on the way home , started thinking about what 's for dinner , and then realized you do n't remember walking for the past five minutes ? while we do n't understand all the details , we do know that the ongoing activity in multiple parts of your brain is somehow able to coordinate what is actually a complex task involving both cognitive and motor functions , guiding you down the right path and moving your legs while you 're getting dinner figured out . but perhaps the most interesting thing about spontaneous brain function is its involvement in one of the most mysterious and poorly understood phenomena of our bodies : sleep . you may shut down and become inactive at night , but your brain does n't . while you sleep , ongoing spontaneous activity gradually becomes more and more synchronized , eventually developing into large , rhythmic neural oscillations that envelop your brain . this transition to the more organized rhythms of sleep starts with small clusters of neurons tucked in the hypothalamus . despite their small number , these neurons have a huge effect in turning off brainstem regions that normally keep you awake and alert , letting other parts , like the cortex and thalamus , slowly slip into their own default rhythms . the deeper we fall into sleep , the slower and more synchronized this rhythm becomes , with the deepest stages dominated by large amplitude , low frequency delta waves . but surprisingly , in the middle of this slow wave sleep , the brain 's synchronized spontaneous activity repeatedly transitions into the sort of varied bursts that occur when we 're wide awake . this is the sleep stage known as rem sleep , where our eyes move rapidly back and forth as we dream . neuroscientists are still trying to answer many fundamental questions about sleep , such as its role in rejuvenating cognitive capacity , cellular homeostasis , and strengthening memory . and more broadly , they are exploring how it is that brain can accomplish such important and complex tasks , such as driving , or even breathing , without our awareness . but for now , until we are better able to understand the inner workings of their spontaneous functioning , we need to give our brains credit for being much smarter than we ourselves are .
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on a large scale , this results in elaborate rhythms of internally generated brain activity , humming quietly in the background whether we 're awake , asleep , or trying not to think about anything at all . and these spontaneously occurring brain functions form the foundation upon which all other brain functions rely . the most crucial of these automatically occurring activities are the ones that keep us alive .
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an odd feature of the human sensory systems is that they often have to create or interpret the sensory signals picked up by our eyes , ears , and other sensory organs . for example , our visual system spontaneously “ fills in ” the two gaping holes in our visual field created by the optic nerve punching through the retina to make it ’ s way to the brain . do you think that our memory systems also spontaneously fill in missing information ? have you ever remembered being somewhere with someone , but later realized you were totally wrong and you were actually with someone else ? if this has happened to you , why do you think your brain spontaneously filled in this information ? why not just leave that part of the memory blank ?
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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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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 .
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food waste is a problem because it :
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some of the world 's most recognizable symbols exist to sell products , others to steer traffic or advance political causes . but there 's one whose main purpose is to help people . you may know it as the wheelchair symbol , or a sign for people with disabilities , but its formal title as maintained by the iso is the international symbol of access . but despite its familiarity , many people are unclear as to what the symbol actually means , which has a lot to do with the symbol itself and the way it came about . in 1968 , the international commission on technology and accessibility held a design contest . they were looking for a symbol that would be readily identifiable from a reasonable distance , self-descriptive , simple , practical , and could n't be confused with existing signage . the winning design , which did n't have a head , was created by a danish designer named susanne koefed . the addition of a head a year later gave it a more human form , and within ten years , it was endorsed by both the united nations and the iso . with minimal cost and minimal fuss , a global icon was born . there have been a few tweaks over the decades . the graphic artists guild added more rounded , human-like features , and in 2012 , the accessible icon project produced a more dynamic version . but what does it really represent ? what 's its purpose ? put simply , it 's a sign to identify where there are accessible facilities . the strength of such an internationally recognized image is that wherever you travel , you do n't need to speak the language or have in-depth cultural knowledge . if you require an accessible toilet , the sign shows the way . but the confusion comes from the term accessibility and what that actually means . many people assume that because the symbol depicts a wheelchair , that accessible facilities are meant only for people who use wheelchairs , or those , at the very least , who have a visible physical condition . but accessibility is a broad concept that applies to many , many different conditions . that includes people with autism , visual impairments , and autoimmune diseases , like lupus , which can cause pain and fatigue , along with many other conditions . in fact , the world health organization estimates that there are approximately 1 billion people who experience some form of disability , which means that this group is very likely to include yourself , or a family member , a classmate , a friend , or a work colleague . and people who use wheelchairs only make up about 65 million , or 15 % of the total . the vast majority have non-visible disabilities . accessible parking spaces , facilities , and entrances are designed with that entire group in mind . so it 's easy to see why in recent years people have begun to raise questions about whether the symbol is really appropriate for what it 's meant to do . and it 's not just about accuracy . it 's common for people to become indignant , sometimes abusive , when they see people without visible disabilities using accessible facilities . the symbol is unfortunately creating widespread issues for the very people and families it 's meant to help . the recent redesigns have attempted with some success to acknowledge concerns over the current symbol . but some think that a complete redesign is in order . it 's a difficult task , though . how do you replace a symbol that 's familiar the world over ? and what do you replace it with ?
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and people who use wheelchairs only make up about 65 million , or 15 % of the total . the vast majority have non-visible disabilities . accessible parking spaces , facilities , and entrances are designed with that entire group in mind .
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what types of non-visible disabilities can you think of ? how many of these might benefit from accessible facilities ? which facilities ? why ?
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hannah fry : so today we 're going to talk about rock-paper-scissors and i reckon everyone knows how to play it scissors beats paper , paper covers rock , rock blunts scissors , so three -- brady : wait , i always thought it smashed them ? dr. fry : oh , i thought it blunts them actually , if anything , it would probably sharpen them , right ? there are three strategies , each one of them loses once and wins once so it looks like there 's no strategy that you can play to win , but i 'm going to show you about a new paper that had just come out where it gives you some top tips of how to win so it 's a group of chinese scientists , where they run an experiment where they got 360 students to play games of rock-paper-scissors with one another 300 rounds in every game , which took up to 2 hours , which is astonishing , students playing rock-paper-scissors for 2 hours okay , so normally if you have rock-paper-scissors and some of you had rock ( r ) up there , and rock is beaten by paper ( p ) , which is then beaten by scissors ( s ) so none of these strategies dominate the other , so really all you can do is play each strategy with an equal probability : 1/3 , 1/3 , 1/3 , okay now , if you were playing against a computer , who was choosing these perfectly randomly , then that would be the best thing for you to do -- just to pick each strategy with equal probability but the thing is , humans are quite predictably irrational , so to say , in the way they choose their strategy so , in recording what one of these students did in playing rock-paper-scissors the scientists came up with two quite important findings of how people try to beat each other okay , so the first one is that people who win tend to repeat their strategy so , for example , if i beat you by playing rock , there is a very high chance , or high probability that i will play rock again the second time . if it worked once , it 's going to work again , right ? the second thing that they found out is that losers change brady : to anything in particular , or ... ? dr. fry : well , so this is a thing that you can exploit , essentially so if you know -- so this gives us , i suppose , two strategies that we can use so the first tip is that if you lose , that means the other person just won , right ? so let 's imagine that your opponent won by playing rock now , the chances are that they 're going to play rock again , you should then play paper so you just lost on scissors , so you should play paper which means that , basically , even though paper beats rock ( so the cycle goes around like this : paper beats rock and so on ) you should go the other way around the triangle let 's imagine that you played scissors , the other person played rock , what you should do is you should go backwards around this triangle and play paper the next time because of the high chance that they 're going to play rock again so that 's the first thing : go backwards , i guess or another way to say it is -- essentially , you 've just played scissors , they 've played rock so play the thing that did n't come up in that , if you lose now the second thing , is that if you 've just won now , they 're going to expect you to play the same thing again , right ? which means , that they 're going to play the thing that you would beat the thing that you just played so you need to play the thing that would beat that would beat the thing that you just played which is equivalent to saying , you need to play what they just played you want to [ laughs ] let 's go again [ both laugh ] brady : i like the easy way better , so you should play what they just played dr. fry : you should play what they just played , yes so let 's imagine , then , you just won -- you played rock , right ? -- and you just won on rock that means that they played scissors , now they 're going to think that you 're going to play rock again , which means that they 're going to play paper , which means that you should play scissors and so again , you basically end up going backwards around the triangle so play what they just played , and the game go backwards or an easier way to say it then is to play what they just played . so in general , if you 're cycling through rock-paper-scissors , your best strategy is to go backwards and go scissors-paper-rock , and cycle through that way brady : how much -- is this mathematics or is this psychology ? this is -- i ca n't tell if this is all to do with probability , or it 's just about knowing how humans think dr. fry : well , i think that a balance of the two , so it 's rooted in game theory which is the mathematics of looking at decisions and strategies , so in any situation where you 're competing against someone , and you best move is dependent on what the other person is playing , you can frame in game theory brady : numberphile is brought to you by the mathematical sciences research institute but this video has also been sponsored by squarespace squarespace is a great service for designing , hosting , creating your own websites and as probably mentioned before , i use it myself no matter what you want to do -- a blog , podcast , shop , portfolio , squarespace is as easy as 1-2-3 but it 's not just amateurs who benefit from squarespace and all its brilliant templates , their developer platform will also give you full control over all the code , letting you tweak the html , css and javascript into your heart 's content and if you like stats , and you 're watching numberphile , you 'll really like watching squarespace 's analytics , their 3rd party integrations , and their easy-to-use commerce if you 'd like to find out more , go to squarespace.com/numberphile you can try it all out , you can set up your own site , and you can do it all for free , no credit card required and then if you do like it , and decide to opt in , use the offer code numberphile and you get 10 % off so thank you very much to squarespace for supporting this video and thank you to you for watching it
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dr. fry : well , so this is a thing that you can exploit , essentially so if you know -- so this gives us , i suppose , two strategies that we can use so the first tip is that if you lose , that means the other person just won , right ? so let 's imagine that your opponent won by playing rock now , the chances are that they 're going to play rock again , you should then play paper so you just lost on scissors , so you should play paper which means that , basically , even though paper beats rock ( so the cycle goes around like this : paper beats rock and so on ) you should go the other way around the triangle let 's imagine that you played scissors , the other person played rock , what you should do is you should go backwards around this triangle and play paper the next time because of the high chance that they 're going to play rock again so that 's the first thing : go backwards , i guess or another way to say it is -- essentially , you 've just played scissors , they 've played rock so play the thing that did n't come up in that , if you lose now the second thing , is that if you 've just won now , they 're going to expect you to play the same thing again , right ? which means , that they 're going to play the thing that you would beat the thing that you just played so you need to play the thing that would beat that would beat the thing that you just played which is equivalent to saying , you need to play what they just played you want to [ laughs ] let 's go again [ both laugh ] brady : i like the easy way better , so you should play what they just played dr. fry : you should play what they just played , yes so let 's imagine , then , you just won -- you played rock , right ?
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according to this strategy , if you lose your first hand to someone who played rock , what should you play in your second hand ?
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in the 18th century , swedish botanist carolus linnaeus designed the flower clock , a timepiece made of flowering plants that bloom and close at specific times of day . linnaeus 's plan was n't perfect , but the idea behind it was correct . flowers can indeed sense time , after a fashion . mornings glories unfurl their petals like clockwork in the early morning . a closing white water lily signals that it 's late afternoon , and moon flowers , as the name suggests , only bloom under the night sky . but what gives plants this innate sense of time ? it 's not just plants , in fact . many organisms on earth have a seemingly inherent awareness of where they are in the day 's cycle . that 's because of circadian rhythms , the internal timekeepers that tick away inside many living things . these biological clocks allow organisms to keep track of time and pick up on environmental cues that help them adapt . that 's important , because the planet 's rotations and revolutions put us in a state of constant flux , although it plays out in a repetitive , predictable way . circadian rhythms incorporate various cues to regulate when an organism should wake and sleep , and perform certain activities . for plants , light and temperature are the cues which trigger reactions that play out at a molecular scale . the cells in stems , leaves , and flowers contain phytochromes , tiny molecules that detect light . when that happens , phytochromes initiate a chain of chemical reactions , passing the message down into the cellular nuclei . there , transcription factors trigger the manufacture of proteins required to carry out light-dependent processes , like photosynthesis . these phytochromes not only sense the amount of light the plant receives , but can also detect tiny differences in the distribution of wavelengths the plant takes in . with this fine-tuned sensing , phytochromes allow the plant to discern both time , the difference between the middle of the day and the evening , and place , whether it is in direct sunlight or shade , enabling the plant to match its chemical reactions to its environment . this makes for early risers . a few hours before sunrise , a typical plant is already active , creating mrna templates for its photosynthesizing machinery . as the phytochromes detect increasing sunlight , the plant readies its light-capturing molecules so it can photosynthesize and grow throughout the morning . after harvesting their morning light , plants use the rest of the day to build long chains of energy in the form of glucose polymers , like starch . the sun sets , and the day 's work is done , though a plant is anything but inactive at night . in the absence of sunlight , they metabolize and grow , breaking down the starch from the previous day 's energy harvest . many plants have seasonal rhythms as well . as spring melts the winter frost , phytochromes sense the longer days and increasing light , and a currently unknown mechanism detects the temperature change . these systems pass the news throughout the plant and make it produce blooming flowers in preparation for the pollinators brought out by warmer weather . circadian rhythms act as a link between a plant and its environment . these oscillations come from the plants themselves . each one has a default rhythm . even so , these clocks can adapt their oscillations to environmental changes and cues . on a planet that 's in constant flux , it 's the circadian rhythms that enable a plant to stay true to its schedule and to keep its own time .
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the sun sets , and the day 's work is done , though a plant is anything but inactive at night . in the absence of sunlight , they metabolize and grow , breaking down the starch from the previous day 's energy harvest . many plants have seasonal rhythms as well .
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what is starch ?
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when we hear the word radiation , it 's tempting to picture huge explosions and frightening mutations , but that 's not the full story . radiation also applies to rainbows and a doctor examining an x-ray . so what is radiation really , and how much should we worry about its effects ? the answer begins with understanding that the word radiation describes two very different scientific phenomena : electromagnetic radiation and nuclear radiation . electromagnetic radiation is pure energy consisting of interacting electrical and magnetic waves oscillating through space . as these waves oscillate faster , they scale up in energy . at the lower end of the spectrum , there 's radio , infrared , and visible light . at the higher end are ultraviolet , x-ray , and gamma rays . modern society is shaped by sending and detecting electromagnetic radiation . we might download an email to our phone via radio waves to open an image of an x-ray print , which we can see because our screen emits visible light . nuclear radiation , on the other hand , originates in the atomic nucleus , where protons repel each other due to their mutually positive charges . a phenomenon known as the strong nuclear force struggles to overcome this repulsion and keep the nucleus intact . however , some combinations of protons and neutrons , known as isotopes , remain unstable , or radioactive . they will randomly eject matter and/or energy , known as nuclear radiation , to achieve greater stability . nuclear radiation comes from natural sources , like radon , a gas which seeps up from the ground . we also refine naturally occurring radioactive ores to fuel nuclear power plants . even bananas contain trace amounts of a radioactive potassium isotope . so if we live in a world of radiation , how can we escape its dangerous effects ? to start , not all radiation is hazardous . radiation becomes risky when it rips atoms ' electrons away upon impact , a process that can damage dna . this is known as ionizing radiation because an atom that has lost or gained electrons is called an ion . all nuclear radiation is ionizing , while only the highest energy electromagnetic radiation is . that includes gamma rays , x-rays , and the high-energy end of ultraviolet . that 's why as an extra precaution during x-rays , doctors shield body parts they do n't need to examine , and why beach-goers use sunscreen . in comparison , cell phones and microwaves operate at the lower end of the spectrum , so there is no risk of ionizing radiation from their use . the biggest health risk occurs when lots of ionizing radiation hits us in a short time period , also known as an acute exposure . acute exposures overwhelm the body 's natural ability to repair the damage . this can trigger cancers , cellular dysfunction , and potentially even death . fortunately , acute exposures are rare , but we are exposed daily to lower levels of ionizing radiation from both natural and man-made sources . scientists have a harder time quantifying these risks . your body often repairs damage from small amounts ionizing radiation , and if it ca n't , the results of damage may not manifest for a decade or more . one way scientists compare ionizing radiation exposure is a unit called the sievert . an acute exposure to one sievert will probably cause nausea within hours , and four sieverts could be fatal . however , our normal daily exposures are far lower . the average person receives 6.2 millisieverts of radiation from all sources annually , around a third due to radon . at only five microsieverts each , you 'd need to get more than 1200 dental x-rays to rack up your annual dosage . and remember that banana ? if you could absorb all the banana 's radiation , you 'd need around 170 a day to hit your annual dosage . we live in a world of radiation . however , much of that radiation is non-ionizing . for the remainder that is ionizing , our exposures are usually low , and choices like getting your home tested for radon and wearing sunscreen can help reduce the associated health risks . marie curie , one of the early radiation pioneers , summed up the challenge as follows : `` nothing in life is to be feared , it is only to be understood . now is the time to understand more , so that we may fear less . ''
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a phenomenon known as the strong nuclear force struggles to overcome this repulsion and keep the nucleus intact . however , some combinations of protons and neutrons , known as isotopes , remain unstable , or radioactive . they will randomly eject matter and/or energy , known as nuclear radiation , to achieve greater stability .
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there are two isotopes of the same element in front of you . what is the difference between them ?
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europium is an element which , when you excite the atoms or excite the electrons in the atoms , gives out very nice red coloured light . ok , so europium is pretty much in the middle of the lanthanide series . perhaps its most famous use is in television screens . in fact , most or many of the rare earths can fluoresce in this way and give out light , but europium is particularly good at giving a very nice red colour , and so europium salts are used in television screens , not lcd screens like you have on the laptop , but the old-fashioned cathode ray televisions . so it ’ s very good at phosphorescence , for example , so we use it in the tubes in tv screens to get different colours . the screen on the inside of the screen you have dots of europium and when the electrons from the electron beam in the cathode ray tube hit the europium you get a very intense emission of red light which gives you the red colour to form the colour television pictures .
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europium is an element which , when you excite the atoms or excite the electrons in the atoms , gives out very nice red coloured light . ok , so europium is pretty much in the middle of the lanthanide series . perhaps its most famous use is in television screens .
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thanks to its chemistry , europium is easier to isolate than the other lanthanides , so investigators know a little more about it . which is the stable , low oxidation state that europium shares with samarium , but not the other lanthanides ?
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this is tungsten , i think . tungsten is a very hard and heavy element . it has a number of very important uses . it is used in the filament of light bulbs , the ordinary sort of light bulbs because it has more or less the highest boiling point of any element and therefore you can use it as the filament and it can get very hot without very much evaporation on to the walls . if you add iodine in the gas around the bulb you can run it at even higher temperatures , the so called quartz halogen lamps and sometimes you see these in up-market cars . yes , it ’ s tungsten . so this is tungsten . tungsten is used as an element material to form the very , very fine wire that we may have used in old-style electric light bulbs . it is a really quite wonderful metal and it is actually used in nature . but here we have a really quite beautiful sample . this is a single crystal of tungsten which is mounted . tungsten carbide , the compound of tungsten and carbon is used in the very tip , the balls in the tip of a biro pen or ball point pen . really quite amazing . i have got some other tungsten here somewhere and in fact here is a very fine wire of tungsten and this is precisely the material which was used in the formation of very early electric light bulbs . a really quite amazing metal . there is also quite a nice book by oliver sacks , who is an englishman who now lives in america , called uncle tungsten . there are not many books that have chemical names in the title and this is a story of his childhood and how chemistry really had a big effect on him . that ’ s lovely .
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if you add iodine in the gas around the bulb you can run it at even higher temperatures , the so called quartz halogen lamps and sometimes you see these in up-market cars . yes , it ’ s tungsten . so this is tungsten . tungsten is used as an element material to form the very , very fine wire that we may have used in old-style electric light bulbs . it is a really quite wonderful metal and it is actually used in nature .
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tungsten filaments are used in ordinary incandescent light bulbs . which gas fills the bulb to prevent the combustion of this filament ?
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have you ever tried to picture an ideal world ? one without war , poverty , or crime ? if so , you 're not alone . plato imagined an enlightened republic ruled by philosopher kings , many religions promise bliss in the afterlife , and throughout history , various groups have tried to build paradise on earth . thomas more 's 1516 book `` utopia '' gave this concept a name , greek for `` no place . '' though the name suggested impossibility , modern scientific and political progress raised hopes of these dreams finally becoming reality . but time and time again , they instead turned into nightmares of war , famine , and oppression . and as artists began to question utopian thinking , the genre of dystopia , the not good place , was born . one of the earliest dystopian works is jonathan swift 's `` gulliver 's travels . '' throughout his journey , gulliver encounters fictional societies , some of which at first seem impressive , but turn out to be seriously flawed . on the flying island of laputa , scientists and social planners pursue extravagant and useless schemes while neglecting the practical needs of the people below . and the houyhnhnm who live in perfectly logical harmony have no tolerance for the imperfections of actual human beings . with his novel , swift established a blueprint for dystopia , imagining a world where certain trends in contemporary society are taken to extremes , exposing their underlying flaws . and the next few centuries would provide plenty of material . industrial technology that promised to free laborers imprisoned them in slums and factories , instead , while tycoons grew richer than kings . by the late 1800 's , many feared where such conditions might lead . h. g. wells 's `` the time machine '' imagined upper classes and workers evolving into separate species , while jack london 's `` the iron heel '' portrayed a tyrannical oligarchy ruling over impoverished masses . the new century brought more exciting and terrifying changes . medical advances made it possible to transcend biological limits while mass media allowed instant communication between leaders and the public . in aldous huxley 's `` brave new world '' , citizens are genetically engineered and conditioned to perform their social roles . while propaganda and drugs keep the society happy , it 's clear some crucial human element is lost . but the best known dystopias were not imaginary at all . as europe suffered unprecedented industrial warfare , new political movements took power . some promised to erase all social distinctions , while others sought to unite people around a mythical heritage . the results were real-world dystopias where life passed under the watchful eye of the state and death came with ruthless efficiency to any who did n't belong . many writers of the time did n't just observe these horrors , but lived through them . in his novel `` we '' , soviet writer yevgeny zamyatin described a future where free will and individuality were eliminated . banned in the u.s.s.r. , the book inspired authors like george orwell who fought on the front lines against both fascism and communism . while his novel `` animal farm '' directly mocked the soviet regime , the classic `` 1984 '' was a broader critique of totalitarianism , media , and language . and in the u.s.a. , sinclair lewis 's `` it ca n't happen here '' envisioned how easily democracy gave way to fascism . in the decades after world war ii , writers wondered what new technologies like atomic energy , artificial intelligence , and space travel meant for humanity 's future . contrasting with popular visions of shining progress , dystopian science fiction expanded to films , comics , and games . robots turned against their creators while tv screens broadcast deadly mass entertainment . workers toiled in space colonies above an earth of depleted resources and overpopulated , crime-plagued cities . yet politics was never far away . works like `` dr. strangelove '' and `` watchmen '' explored the real threat of nuclear war , while `` v for vendetta '' and `` the handmaid 's tale '' warned how easily our rights could disappear in a crisis . and today 's dystopian fiction continues to reflect modern anxieties about inequality , climate change , government power , and global epidemics . so why bother with all this pessimism ? because at their heart , dystopias are cautionary tales , not about some particular government or technology , but the very idea that humanity can be molded into an ideal shape . think back to the perfect world you imagined . did you also imagine what it would take to achieve ? how would you make people cooperate ? and how would you make sure it lasted ? now take another look . does that world still seem perfect ?
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though the name suggested impossibility , modern scientific and political progress raised hopes of these dreams finally becoming reality . but time and time again , they instead turned into nightmares of war , famine , and oppression . and as artists began to question utopian thinking , the genre of dystopia , the not good place , was born .
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what was disturbing about the future world of `` the time machine '' ?
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have you ever daydreamed about traveling through time , perhaps fast forward in the centuries and seeing the distant future ? well , time travel is possible , and what 's more , it 's already been done . meet sergei krikalev , the greatest time traveler in human history . this russian cosmonaut holds the record for the most amount of time spent orbiting our planet , a total of 803 days , 9 hours , and 39 minutes . during his stay in space , he time traveled into his own future by 0.02 seconds . traveling at 17,500 miles an hour , he experienced an effect known as time dilation , and one day the same effect might make significant time travel to the future commonplace . to see why moving faster through space affects passage of time , we need to go back to the 1880s , when two american scientists , albert michelson and edward morley , were trying to measure the effect of the earth 's movement around the sun on the speed of light . when a beam of light was moving in the same direction as the earth , they expected the light to travel faster . and when the earth was moving in the opposite direction , they expected it to go slower . but they found something very curious . the speed of light remained the same no matter what the earth was doing . two decades later , albert einstein was thinking about the consequences of that never-changing speed of light . and it was his conclusions , formulated in the theory of special relativity , that opened the door into the world of time travel . imagine a man named jack , standing in the middle of a train carriage , traveling at a steady speed . jack 's bored and starts bouncing a ball up and down . what would jill , standing on the platform , see through the window as the train whistles through ? well , between jack dropping the ball and catching it again , jill would have seen him move slightly further down the track , resulting in her seeing the ball follow a triangular path . this means jill sees the ball travel further than jack does in the same time period . and because speed is distance divided by time , jill actually sees the ball move faster . but what if jack 's bouncing ball is replaced with two mirrors which bounce a beam of light between them ? jack still sees the beam dropping down and jill still sees the light beam travel a longer distance , except this time jack and jill can not disagree on the speed because the speed of light remains the same no matter what . and if the speed is the same while the distance is different , this means the time taken will be different as well . thus , time must tick at different rates for people moving relative to each other . imagine that jack and jill have highly accurate watches that they synchronize before jack boards the train . during the experiment , jack and jill would each see their own watch ticking normally . but if they meet up again later to compare watches , less time would have elapsed on jack 's watch , balancing the fact that jill saw the light move further . this idea may sound crazy , but like any good scientific theory , it can be tested . in the 1970s , scientists boarded a plane with some super-accurate atomic clocks that were synchronized with some others left on the ground . after the plane had flown around the world , the clocks on board showed a different time from those left behind . of course , at the speed of trains and planes , the effect is minuscule . but the faster you go , the more time dilates . for astronauts orbiting the earth for 800 days , it starts to add up . but what affects humans also affects machines . satellites of the global positioning system are also hurdling around the earth at thousands of miles an hour . so , time dilation kicks in here , too . in fact , their speed causes the atomic clocks on board to disagree with clocks on the ground by seven millionths of a second daily . left uncorrected , this would cause gps to lose accuracy by a few kilometers each day . so , what does all this have to do with time travel to the far , distant future ? well , the faster you go , the greater the effect of time dilation . if you could travel really close to the speed of light , say 99.9999 % , on a round-trip through space for what seemed to you like ten years , you 'd actually return to earth around the year 9000. who knows what you 'd see when you returned ? ! humanity merged with machines , extinct due to climate change or asteroid impact , or inhabiting a permanent colony on mars . but the trouble is , getting heavy things like people , not to mention space ships , up to such speeds requires unimaginable amounts of energy . it already takes enormous particle accelerators like the large hadron collider to accelerate tiny subatomic particles to close to light speed . but one day , if we can develop the tools to accelerate ourselves to similar speeds , then we may regularly send time travelers into the future , bringing with them tales of a long , forgotten past .
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well , the faster you go , the greater the effect of time dilation . if you could travel really close to the speed of light , say 99.9999 % , on a round-trip through space for what seemed to you like ten years , you 'd actually return to earth around the year 9000. who knows what you 'd see when you returned ? ! humanity merged with machines , extinct due to climate change or asteroid impact , or inhabiting a permanent colony on mars .
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think about what it might be like for someone from the 21st century arriving back to earth in the year 9000. can you see any problems they might encounter ? imagine if someone from 7000 years ago arrived now .
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how do you imagine the life of a scientist ? boring and monotonous , spending endless hours in the lab with no social interaction ? maybe for some but not tycho brahe . the 16th century scholar who accurately predicted planetary motion and cataloged hundreds of stars before the telescope had been invented also had a cosmic-sized personal life . tycho brahe was born in 1546 to danish nobles , but at age two was kidnapped to be raised by his uncle instead . his parents did n't seem to mind . tycho was supposed to have a career in law , but after witnessing a solar eclipse at thirteen , he began spending more time with mathematics and science professors , who taught him the art of celestial observation . by the time tycho 's uncle sent him off to germany a few years later , he had lost interest in his law studies , instead reading astronomy books , improving his instruments , and taking careful notes of the night skies . it was n't long before his own measurements were more accurate than those in his books . while in germany , tycho got into a bit of an argument with another student at a party over a mathematical formula , resulting in a sword duel and tycho losing a good-sized chunk of his nose . after that , he was said to have worn a realistic prosthetic of gold and silver that he would glue onto his face . fortunately , tycho did n't need his nose to continue his astronomical work . he kept studying the night sky and creating all sorts of instruments , including a building-sized quadrant for measuring the angles of stars . after months of careful observation , tycho discovered a new star in the constellation cassiopeia . the publication of this discovery granted him rock star status and offers of scientific positions all over europe . wanting to keep him at home , the king of denmark offered to give tycho his own personal island with a state of the art observatory . called uraniborg and costing about 1 % of denmark 's entire budget , this observatory was more of a castle , containing formal gardens , rooms for family , staff and visiting royalty , and an underground section just for all the giant instruments . tycho also built a papermill and printing press for publishing his papers , and a lab for studying alchemy . and since no castle would be complete without entertainment , tycho employed a clairvoyant dwarf named jep as court jester . tycho lived on his island , studying and partying for about 20 years . but after falling out with the new danish king , he took up an invitation from the holy roman emperor to become the official imperial astronomer in prague . there , he met another famous astronomer johannes kepler , who became his assistant . while kepler 's work interested him , tycho was protective of his data , and the two often got into heated arguments . in 1601 , tycho attended a formal banquet where he drank quite a lot but was too polite to leave the table to relieve himself , deciding to tough it out instead . this proved to be a bad idea , as he quickly developed a bladder infection and died a few days later . but over 400 years after his death , tycho still had a few surprises up his sleeve . when his body was exhumed and studied in 2010 , the legendary gold and silver nose was nowhere to be found , with chemical traces suggesting that he wore a more casual brass nose instead . tycho 's mustache hair was also found to contain unusually high levels of toxic mercury . was it from a medicine used to treat his bladder infection ? a residue from his alchemy experiments ? or did his quarrelsome coworker johannes kepler poison him to acquire his data ? we may never know , but the next time you think scientists lead boring lives , dig a little deeper . a fascinating story may be just beyond the tip of your nose .
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boring and monotonous , spending endless hours in the lab with no social interaction ? maybe for some but not tycho brahe . the 16th century scholar who accurately predicted planetary motion and cataloged hundreds of stars before the telescope had been invented also had a cosmic-sized personal life .
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besides astronomy , brahe pursued what other science-related interest ?
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you know , i had a real rough time in school with add , and i have a phd . i earned a phd , but ... tough to pay attention -- biology , geology , physics , chemistry -- really tough for me . only one thing grabbed my attention , and it 's that planet called earth . but in this picture here , you 'll see that earth is mostly water . that 's the pacific . seventy percent of earth is covered with water . you can say , `` hey , i know earth . i live here . '' you do n't know earth . you do n't know this planet , because most of it 's covered with that -- average depth , two miles . and when you go outside and look up at the empire state building , chrysler building , the average depth of the ocean is 15 of those on top of one another . we 've explored about five percent of what 's in that water . `` explored , '' meaning , for the first time , go peek and see what 's there . so what i want to do today is show you some things about this planet , about the oceans . i want to take you from shallow water down to the deep water , and hopefully , like me , you 'll see some things that get you hooked on exploring planet earth . you know things like corals ; you 've seen plenty of corals , those of you who 've been to the beach , snorkeling , know corals are an amazing place to go -- full of life , some big animals , small animals , some nice , some dangerous , sharks , whales , all that stuff . they need to be protected from humanity . they 're great places . but what you probably do n't know is in the very deep part of the ocean , we have volcanic eruptions . most volcanoes on earth are at the bottom of the sea -- more than 80 percent . and we actually have fire , fire deep inside the ocean , going on right now . all over the world -- in the pacific , the atlantic , the indian ocean . in this place , the ocean floor , the rocks actually turn to liquid . so you actually have waves on the ocean floor . you 'd say nothing could live there , but when we look in detail , even there , in the deepest , darkest places on earth , we find life , which tells us that life really wants to happen . so , pretty amazing stuff . every time we go to the bottom of the sea , we explore with our submarines , with our robots , we see something that 's usually surprising , sometimes it 's startling and sometimes revolutionary . you see that puddle of water sitting there . and all around the water there 's a little cliff , there 's a little white sandy beach . we 'll get closer , you 'll see the beach a little bit better , some of the waves in that water , down there . the thing that 's special about this water is that it 's at the bottom of the gulf of mexico . so you 're sitting inside a submarine , looking out the window at a little pond of water beneath the sea . we see ponds , we see lakes , we see rivers -- in fact , right here is a river at the bottom of the ocean going from the lower left to the upper right . water is actually flowing through there . this totally blew our minds . how can you have this at the bottom ? you 're in the ocean looking at more water . and there 's animals that only live in that water . so , the bottom of the ocean -- i love this map , because it shows in the middle of the ocean , there 's a mountain range . it 's the greatest mountain range on earth , called the mid-ocean ridge -- 50,000 miles long , and we 've hardly had a peek at it . hardly had a peek at it . we find valleys , many thousands of valleys , larger , wider , deeper than the grand canyon . we find , as i said , underwater lakes , rivers , waterfalls . the largest waterfall on the planet is actually under the ocean , up near iceland . all that stuff is in that five percent that we 've explored . so the deal about the ocean is that to explore it , you 've got to have technology . not only technology , but it 's not just dave gallo or one person exploring , it 's a team of people . you 've got to have the talent , the team . you 've got to have the technology . in this case , it 's our ship , atlantis , and the submarine , alvin . inside that submarine -- this is an alvin launch -- there 's three people . they 're being wheeled out onto deck . there 's 47 other people , the teamwork on that ship , making sure that these people are okay . everybody in that submarine is thinking one thing right now : should i have gone to the bathroom one more time ? because you 're in there for 10 hours -- 10 hours in that little sphere . three of you together and nobody is going to be around you . you go into the water and once you hit the water , it 's amazing . there 's a lovely color blue that penetrates right inside you . you do n't hear the surface ship anymore , you hear that pinging of a sonar . if you 've got an iphone you 've got sonar on there -- it 's that same pinging that goes down to the bottom and comes back up . divers check out the sub to make sure the outside is okay , and then they say `` go , '' and down you go to the bottom of the ocean and it 's an amazing trip . so for two and a half hours , you sink down to the bottom . and two hours of it is totally pitch black . we thought that nothing could live inside that world at the bottom of the ocean . and when we look , we find some amazing things . all the way down -- we call it the mid-water -- from the top of the ocean down to the bottom , we find life . whenever we stop and look , we find life . i 'm going to show you some jellies . they 're absolutely some of the coolest creatures on earth . look at that thing , just flailing his arms around . that 's like a little lobster . that one is like all these animals with their mouths hooked together , the colonial animals . some animals are tiny , some can be longer than this stage . just amazing animals . and you ca n't collect them with a net -- we have to go with our cameras and take a look at them . so every time we go , new species of life . the ocean is full of life . and yet the deepest part of the ocean -- when we go to that mountain range , we find hot springs . now we were sure -- because this is poisonous water , because it 's so deep it would crush the titanic the same way you crush an empty cup in your hand -- we were sure there would be no life there at all . instead , we find more life and diversity and density than in the tropical rainforest . so , in one instance , in one peek out the window of the sub , we discover something that revolutionizes the way we think about life on earth ; and that is , you do n't always have to have sunlight to get life going . there 's big animals down there too , some that look familiar . that guy 's called dumbo . i love him . dumbo 's great . this guy -- oh man , i wish i had more footage of this . we 're trying to get an expedition together to go look at this and maybe in a year we 'll have that . go online and look . vampyroteuthis infernalis . the vampire squid . incredibly cool . in the darkness of the deep sea , he 's got glowing tentacles , so if i 'm coming at you like him , i put my arms out in the darkness so all you see are little glowing things over here . meanwhile , i 'm coming at you . when he wants to escape , he 's got these glowing pods on his butt that look like eyes . glowing eyes on his butt . how cool is that ? just an amazing animal . ( laughter ) `` vampire '' squid , because when it gets protective , it pulls this black cape over its whole body , and curls up into a ball . outrageous animal . this ship , `` the ship of dreams '' -- a hundred years ago this coming april , this ship was supposed to show up in new york . it 's the titanic . i co-led an expedition out there last year . we are learning so much about that ship . the titanic is an interesting place for biology , because animals are moving in to live on the titanic . microbes are actually eating the hull of the titanic . that 's where jack was king of the world there on the bow of the titanic . so we 're doing real good . and what 's exciting to me is that we 're making a virtual titanic , so you can sit there at home with your joystick and your headset on , and you can actually explore the titanic for yourself . that 's what we want to do , make these virtual worlds , so it 's not dave gallo or someone else exploring the world ; it 's you . you explore it for yourself . so here 's the bottom line : the oceans are unexplored and i ca n't begin to tell you how important that is , because they 're important to us . seven billion people live on this planet and all of us are impacted by the sea , because the oceans control the air you breathe , the water you drink , the food you eat . all those are controlled in some way by the ocean , and this is a thing that we have n't even explored -- five percent . the thing i want to leave you with is , in that five percent , i showed you some cool stuff . there 's a lot more cool stuff -- every dive we go on in the ocean , we find something new about the sea . so what 's in that other 95 percent ? did we get the exciting stuff or is there more out there ? and i 'm here to tell you that the ocean is full of surprises . there 's a quote i love by marcel proust : `` the true voyage of exploration is not so much in seeking new landscapes , '' which we do , `` but in having new eyes . '' and so i hope today , by showing you some of this , it 's given you some new eyes about this planet , and for the first time , i want you to think about it differently . thank you very much . thank you . ( applause )
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you know , i had a real rough time in school with add , and i have a phd . i earned a phd , but ... tough to pay attention -- biology , geology , physics , chemistry -- really tough for me . only one thing grabbed my attention , and it 's that planet called earth . but in this picture here , you 'll see that earth is mostly water .
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gallo begins his talk by observing that in some ways , he ’ s an unlikely candidate to have earned a phd in science , because he had adhd and struggled in school . yet the ocean , he says , is the one thing that grabbed and held his attention . what grabs your attention in science class ( if anything ) ? what makes science an exciting topic to study , and/or how could science classes be improved , in your opinion ?
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hannah fry : so today we 're going to talk about rock-paper-scissors and i reckon everyone knows how to play it scissors beats paper , paper covers rock , rock blunts scissors , so three -- brady : wait , i always thought it smashed them ? dr. fry : oh , i thought it blunts them actually , if anything , it would probably sharpen them , right ? there are three strategies , each one of them loses once and wins once so it looks like there 's no strategy that you can play to win , but i 'm going to show you about a new paper that had just come out where it gives you some top tips of how to win so it 's a group of chinese scientists , where they run an experiment where they got 360 students to play games of rock-paper-scissors with one another 300 rounds in every game , which took up to 2 hours , which is astonishing , students playing rock-paper-scissors for 2 hours okay , so normally if you have rock-paper-scissors and some of you had rock ( r ) up there , and rock is beaten by paper ( p ) , which is then beaten by scissors ( s ) so none of these strategies dominate the other , so really all you can do is play each strategy with an equal probability : 1/3 , 1/3 , 1/3 , okay now , if you were playing against a computer , who was choosing these perfectly randomly , then that would be the best thing for you to do -- just to pick each strategy with equal probability but the thing is , humans are quite predictably irrational , so to say , in the way they choose their strategy so , in recording what one of these students did in playing rock-paper-scissors the scientists came up with two quite important findings of how people try to beat each other okay , so the first one is that people who win tend to repeat their strategy so , for example , if i beat you by playing rock , there is a very high chance , or high probability that i will play rock again the second time . if it worked once , it 's going to work again , right ? the second thing that they found out is that losers change brady : to anything in particular , or ... ? dr. fry : well , so this is a thing that you can exploit , essentially so if you know -- so this gives us , i suppose , two strategies that we can use so the first tip is that if you lose , that means the other person just won , right ? so let 's imagine that your opponent won by playing rock now , the chances are that they 're going to play rock again , you should then play paper so you just lost on scissors , so you should play paper which means that , basically , even though paper beats rock ( so the cycle goes around like this : paper beats rock and so on ) you should go the other way around the triangle let 's imagine that you played scissors , the other person played rock , what you should do is you should go backwards around this triangle and play paper the next time because of the high chance that they 're going to play rock again so that 's the first thing : go backwards , i guess or another way to say it is -- essentially , you 've just played scissors , they 've played rock so play the thing that did n't come up in that , if you lose now the second thing , is that if you 've just won now , they 're going to expect you to play the same thing again , right ? which means , that they 're going to play the thing that you would beat the thing that you just played so you need to play the thing that would beat that would beat the thing that you just played which is equivalent to saying , you need to play what they just played you want to [ laughs ] let 's go again [ both laugh ] brady : i like the easy way better , so you should play what they just played dr. fry : you should play what they just played , yes so let 's imagine , then , you just won -- you played rock , right ? -- and you just won on rock that means that they played scissors , now they 're going to think that you 're going to play rock again , which means that they 're going to play paper , which means that you should play scissors and so again , you basically end up going backwards around the triangle so play what they just played , and the game go backwards or an easier way to say it then is to play what they just played . so in general , if you 're cycling through rock-paper-scissors , your best strategy is to go backwards and go scissors-paper-rock , and cycle through that way brady : how much -- is this mathematics or is this psychology ? this is -- i ca n't tell if this is all to do with probability , or it 's just about knowing how humans think dr. fry : well , i think that a balance of the two , so it 's rooted in game theory which is the mathematics of looking at decisions and strategies , so in any situation where you 're competing against someone , and you best move is dependent on what the other person is playing , you can frame in game theory brady : numberphile is brought to you by the mathematical sciences research institute but this video has also been sponsored by squarespace squarespace is a great service for designing , hosting , creating your own websites and as probably mentioned before , i use it myself no matter what you want to do -- a blog , podcast , shop , portfolio , squarespace is as easy as 1-2-3 but it 's not just amateurs who benefit from squarespace and all its brilliant templates , their developer platform will also give you full control over all the code , letting you tweak the html , css and javascript into your heart 's content and if you like stats , and you 're watching numberphile , you 'll really like watching squarespace 's analytics , their 3rd party integrations , and their easy-to-use commerce if you 'd like to find out more , go to squarespace.com/numberphile you can try it all out , you can set up your own site , and you can do it all for free , no credit card required and then if you do like it , and decide to opt in , use the offer code numberphile and you get 10 % off so thank you very much to squarespace for supporting this video and thank you to you for watching it
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-- and you just won on rock that means that they played scissors , now they 're going to think that you 're going to play rock again , which means that they 're going to play paper , which means that you should play scissors and so again , you basically end up going backwards around the triangle so play what they just played , and the game go backwards or an easier way to say it then is to play what they just played . so in general , if you 're cycling through rock-paper-scissors , your best strategy is to go backwards and go scissors-paper-rock , and cycle through that way brady : how much -- is this mathematics or is this psychology ? this is -- i ca n't tell if this is all to do with probability , or it 's just about knowing how humans think dr. fry : well , i think that a balance of the two , so it 's rooted in game theory which is the mathematics of looking at decisions and strategies , so in any situation where you 're competing against someone , and you best move is dependent on what the other person is playing , you can frame in game theory brady : numberphile is brought to you by the mathematical sciences research institute but this video has also been sponsored by squarespace squarespace is a great service for designing , hosting , creating your own websites and as probably mentioned before , i use it myself no matter what you want to do -- a blog , podcast , shop , portfolio , squarespace is as easy as 1-2-3 but it 's not just amateurs who benefit from squarespace and all its brilliant templates , their developer platform will also give you full control over all the code , letting you tweak the html , css and javascript into your heart 's content and if you like stats , and you 're watching numberphile , you 'll really like watching squarespace 's analytics , their 3rd party integrations , and their easy-to-use commerce if you 'd like to find out more , go to squarespace.com/numberphile you can try it all out , you can set up your own site , and you can do it all for free , no credit card required and then if you do like it , and decide to opt in , use the offer code numberphile and you get 10 % off so thank you very much to squarespace for supporting this video and thank you to you for watching it
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is this strategy based on mathematics or psychology ?
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albert einstein . the icon of genius . why ? because he figured out e equals m c squared ? because he did n't like socks ? nope ! because he came up with the most powerful idea in science.. general relativity his masterpiece is now 100 years old . and while the physicists are partying , the rest of us are left wondering what the bleep it ’ s all about ! well here goes . at 26 he figured out nothing less than a new theory of space and time . it led to a nifty way of simplifying physics – by treating space and time as one thing ... spacetime ! but albert was just warming up . he wasn ’ t happy with isaac newton ’ s mysterious force of gravity . naturally , he started work on his own theory . and sure enough , he cracked it . mass causes spacetime to curve ! the natural motion of things is to follow the simplest path through spacetime . but since objects with mass curve spacetime , stuff moves towards the most massive objects . that ’ s what you feel as gravity . it ’ s warped space and time that ’ s keeping your feet on the ground . “ warped space ” might sound too sci-fi to be true . but we can measure the bending of starlight as is passes through the warped space around the sun . warped time sounds even more ridiculous . but take an accurate clock to the top of a building and you ’ ll see it runs slightly quicker than one on the ground ! that ’ s because as you move away from the centre of the planet space and time are less warped . most amazing of all , einstein ’ s theory told us that our universe has a beginning . everything is expanding out from a hot dense origin 13.8 billion years ago . but here ’ s the catch : we ’ ve spotted that the universe is expanding faster than albert ’ s theory predicts . could the old genius be wrong ? to stick with his idea we ’ ve had to invent a made up energy - ‘ dark energy ’ - to account for the speedy expansion . and we ’ ve had to assume there ’ s an exotic form of ‘ dark matter ' we haven ’ t detected yet either . these two unknowns should make up 95 % of the universe – yet we ’ ve never detected them . that ’ s the sort of thing that keeps physicists awake at night . so they ’ re plotting some seriously big experiments to put albert ’ s theory to the ultimate test . for the last 100 years , uncle albert ’ s great theory has passed every test possible . if it succeeds again physicists will party . if they find its limits and it finally fails they ’ ll party too . physicists are funny like that .
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and sure enough , he cracked it . mass causes spacetime to curve ! the natural motion of things is to follow the simplest path through spacetime .
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what does mass do to spacetime ?
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perfumers can learn to distinguish individual odors in a fragrance made of hundreds of scents . tea experts have been known to sniff out not just the location where a tea was from , but the season of harvest and whether it was planted by a plum tree . and the new york city transit authority once had an employee responsible only for sniffing out gas leaks in the subway system . can just anyone learn to smell with the sensitivity of those experts ? for most of us , what we smell is largely involuntary , whether it 's garbage behind a restaurant , the shampoo of the woman leaving an elevator as you enter , or a bakery 's fresh-made bread . with a few million olfactory receptors in our noses , we clearly do n't lack the ability to smell well . we just might not always pay close enough attention . that 's a shame because we may be missing opportunities to make strong emotional connections . smells are powerfully linked to emotions and can awaken memories of places we 've long ago left and people we 've loved . but fortunately , it is possible to train our brains to smell better . for example , helen keller was able to recognize a person 's work , and in her words , distinguish the carpenter from the iron worker , the artist from the mason or the chemist , by a simple inhale . follow these steps and you too can change the way the world smells to you . first , stick your nose in it . some animals that are known to be great smellers , like dogs who can sniff out explosives and pigs who can find truffles underground , put their noses right at the place they want to smell . human noses , meanwhile , are casting around in the middle of the air , giving us an anatomical disadvantage . so bring your nose close to the world around you . the ground , surfaces , objects , the food in your hand . get close to your dog , your partner , the book you 're reading . not only will your nose be closer to the odor source , but the warmth of your breath will make odors easier to smell . second , sniff like you mean it . smelling actually happens way up near the bridge of our noses in a postage stamp-sized square of tissue called the olfactory epithelium . when we sniff , odor molecules are sucked up into our nostrils until they hit this tissue where they combine to our olfactory , or scent , receptors . when we inhale normally , only a little air makes it there . but one or two solid sharp sniffs will ensure that more air gets to your smell receptors . after just a few more sniffs , the receptors , which are best at noticing new smells , turn off temporarily . so you can give your nose a rest and sniff again later . finally , dwell on the smell . most smells pass by us with little attention , but simply noticing what you 're smelling and by trying to describe it , name it , and locate its source , you can expand your vocabulary of smells . when an odor molecule binds to a scent receptor , it sends an electrical signal from the sensory neurons to our brain 's olfactory bulbs . the signal then continues to other areas of the brain , where it 's integrated with taste , memory , or emotional information before registering to us as a smell . fmri research shows that the extra time spent focusing on scent changes the brain of experienced smellers . for them , perceiving and imagining odors becomes more automatic than for non-experts . to get started yourself , take ingredients from your kitchen : spices , vanilla , or fruit , but never anything toxic . close your eyes and have someone bring them under your nose . sniff and try to name the source . over time , you 'll begin to appreciate nuances in familiar odors and recognize characteristics of new and unusual smells . the perfumer has practiced these steps enough to become an artist of odor , but even if you never pursue smelling to that degree , the spectacular result of an unspectacular action will change how you sense and experience your days .
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follow these steps and you too can change the way the world smells to you . first , stick your nose in it . some animals that are known to be great smellers , like dogs who can sniff out explosives and pigs who can find truffles underground , put their noses right at the place they want to smell .
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you really want to smell something . the best thing to do is “ stick your nose in it. ” why ?
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o polônio foi outro elemento descoberto por madame curie , a madame curie ela polonesa , mas fez boa parte da pesquisa , se não toda , em paris . polônio é um nome por causa da polônia polônio é um elemento que tem sido não muito importante , até a invenção da bomba atômica , e o polônio tornou-se um material absolutamente crucial pq é usado , ou foi usado , como um gatilho no centro da bomba atômica original . uma das dificuldades é que tem uma meia-vida muito curta . se vc tem um pedaço de polônio , metade dele decai em 138 dias se vc mantém por muito tempo , ele se vai , ou quase todo se vai , e portanto , no início da produção de bombas atômicas , das de hiroshima e nagasaki , o fator limitante na produção de bombas era a produção de polônio para o gatilho . em vez do enriquecimento de urânio ou plutônio , que eram usados para as bombas . bem recentemente o polônio teve uma nova notoriedade , pq foi usado neste caso trágico de envenenamento . no qual uma grande dose de polônio foi dado a um infeliz cidadão russo , que visitava a inglaterra . e ainda não está claro de onde veio o polônio . mas é um material bem pouco comum . e difícil para alguém comum encontrar . se for ingerido , pq decai muito rápido , a radioatividade pode causar todo tipo de efeitos desagradáveis . e , novamente , é provavelmente venenoso ele mesmo . traduzido por prof. dr. luís brudna
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o polônio foi outro elemento descoberto por madame curie , a madame curie ela polonesa , mas fez boa parte da pesquisa , se não toda , em paris . polônio é um nome por causa da polônia polônio é um elemento que tem sido não muito importante , até a invenção da bomba atômica , e o polônio tornou-se um material absolutamente crucial pq é usado , ou foi usado , como um gatilho no centro da bomba atômica original .
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what is the half-life of polonium ?
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this is the vhs for an extremely goofy movie . it ’ s the follow up to the cult classic a goofy movie and it ’ s one of my favorite animated films . now , there ’ s a moment in this movie where bobby zimmeruski , max ’ s stoner friend — you know , the one that chugs cheese wiz ? he says , “ do you ever wonder why we ’ re always like ... wearing gloves ? ” that ’ s a damn good question , bobby . let ’ s figure this out . does the question , `` why do animated characters wear gloves ? `` , come up a lot for you ? john : the question rarely comes up , but when it does , there are a number of answers to it . that ’ s john canemaker , he ’ s an animation historian and professor at nyu . the most basic theory is that gloves saved time . john : animation of any kind— even with computers— is a very work-intensive or labor intensive process . `` pardon me . i 've always wondered how they were made . '' at the dawn of animation , everything was hand-drawn over and over and over again . and certain techniques to make the process more efficient shaped the style of the cartoons . john : felix the cat , for example , was a very boxy-looking character . as felix was becoming more popular , the animator bill nolan decided to remove his snout and make him more circular overall . john : and that design—what they call the rubber hose and circle design , very spaghetti-like arms of the characters— continued to the design of mickey mouse as well . this rubber hose and circle aesthetic allowed animators to quickly draw arms , legs , and heads without spending too much time developing realistic details of the character ’ s body—like elbows and knees . a round edge was much faster to draw than an angle , and that certainly applied to hands , with all those fingers and knuckles . but hands posed another a problem for animators in the age of fuzzy black and white film . john : characters were in black and white films difficult to see against their black bodies . take a look at mickey mouse . in 1927 ’ s plane crazy he had black hands and feet , just like felix . he gained shoes by 1928 ’ s steamboat willie and in 1929 he ’ s wearing gloves in the opry house . the rubber hose style of animation is in full effect here . every character is exaggerated , round , and simple . and like many of the glove-wearing cartoon characters of his time , mickey mouse is a non-human doing very human things . in his 1968 biography , `` the disney version '' , walt disney addresses this very issue . he says , `` we did n't want him to have mouse hands , because he was supposed to be more human . so we gave him gloves. ” so in addition to saving time and providing color contrast , gloves bring non-human things to life , making their grand gestures stand out . these 1935 tea kettles from van beuren studio have them . this movie camera does too . when pinocchio is a puppet , he wears gloves . but when he becomes a boy , they disappear . they ’ re no longer needed . but there ’ s another , less practical influence behind cartoon characters ’ white gloves . the opry house is a film about mickey putting on a big vaudeville show . that film and many of the animations that predated it were inextricably linked to vaudeville performance and the blackface minstrel shows of the time . in fact , early animators often performed on vaudeville stages . nicholas sammond writes in birth of an industry that early animated characters like felix the cat , bimbo , bosko , and mickey mouse “ weren ’ t just like minstrels , they were minstrels. ” both the cartoons and the stage characters were portrayed as mischievous and rebellious yet good natured . they wore loose clothes , had painted faces , and … they wore white gloves . in the 1930s vaudeville and blackface minstrelsy declined . white gloves were no longer associated with vaudeville to a new generation of viewers . instead , they were just part of the cartoon style people came to expect . john : there ’ s also the band concert , do you know that film ? it ’ s from 1935 . john : one of the characters is clarabelle cow and she plays the flute and her glove gets stuck in the flute [ chiuckles ] so , really strange without the glove on it . sixty years later goofy takes off his gloves before getting in a pool and it ’ s quite frankly , really disturbing . now what ’ s really bothering me is why daffy duck and many other animated birds don ’ t wear gloves . we might never know . daffy : look , let ’ s not split hairs . why do you even wear gloves ? bugs bunny : because , i ’ ve always worn them . it ’ s who i am . why do you wear that thing around your neck ? touché bugs bunny . touché .
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let ’ s figure this out . does the question , `` why do animated characters wear gloves ? `` , come up a lot for you ?
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what is the most basic theory as to why cartoon characters wear gloves ?
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every four seconds , someone is diagnosed with alzheimer 's disease . it 's the most common cause of dementia , affecting over 40 million people worldwide , and yet finding a cure is something that still eludes researchers today . dr. alois alzheimer , a german psychiatrist , first described the symptoms in 1901 when he noticed that a particular hospital patient had some peculiar problems , including difficulty sleeping , disturbed memory , drastic mood changes , and increasing confusion . when the patient passed away , alzheimer was able to do an autopsy and test his idea that perhaps her symptoms were caused by irregularities in the brain 's structure . what he found beneath the microscope were visible differences in brain tissue in the form of misfolded proteins called plaques , and neurofibrillary tangles . those plaques and tangles work together to break down the brain 's structure . plaques arise when another protein in the fatty membrane surrounding nerve cells gets sliced up by a particular enzyme , resulting in beta-amyloid proteins , which are sticky and have a tendency to clump together . that clumping is what forms the things we know as plaques . these clumps block signaling and , therefore , communication between cells , and also seem to trigger immune reactions that cause the destruction of disabled nerve cells . in alzheimer 's disease , neurofibrillary tangles are built from a protein known as tau . the brain 's nerve cells contain a network of tubes that act like a highway for food molecules among other things . usually , the tau protein ensures that these tubes are straight , allowing molecules to pass through freely . but in alzheimer 's disease , the protein collapses into twisted strands or tangles , making the tubes disintegrate , obstructing nutrients from reaching the nerve cell and leading to cell death . the destructive pairing of plaques and tangles starts in a region called the hippocampus , which is responsible for forming memories . that 's why short-term memory loss is usually the first symptom of alzheimer 's . the proteins then progressively invade other parts of the brain , creating unique changes that signal various stages of the disease . at the front of the brain , the proteins destroy the ability to process logical thoughts . next , they shift to the region that controls emotions , resulting in erratic mood changes . at the top of the brain , they cause paranoia and hallucinations , and once they reach the brain 's rear , the plaques and tangles work together to erase the mind 's deepest memories . eventually the control centers governing heart rate and breathing are overpowered as well resulting in death . the immensely destructive nature of this disease has inspired many researchers to look for a cure but currently they 're focused on slowing its progression . one temporary treatment helps reduce the break down of acetylcholine , an important chemical messenger in the brain which is decreased in alzheimer 's patients due to the death of the nerve cells that make it . another possible solution is a vaccine that trains the body 's immune system to attack beta-amyloid plaques before they can form clumps . but we still need to find an actual cure . alzheimer 's disease was discovered more than a century ago , and yet still it is not well understood . perhaps one day we 'll grasp the exact mechanisms at work behind this threat and a solution will be unearthed .
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every four seconds , someone is diagnosed with alzheimer 's disease . it 's the most common cause of dementia , affecting over 40 million people worldwide , and yet finding a cure is something that still eludes researchers today .
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which part of the brain does alzheimer ’ s disease first affect ?
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anyone who has played a claw machine can relate to the experience of having the claw perfectly positioned only to see it weakly graze the prize before pulling back up . `` no man ! '' it may seem like the machine is n't even trying . and well ... `` it is not your imagination , those claw machines are rigged ! '' there are a couple of beloved stuffed animals that i have that are from a claw machine , a koala and a bear . that is vox.com writer , phil edwards . `` i looked at the instruction guides for a few of the biggest claw games out there . take for example , the manual for black tie toys advanced crane machine . if you look at page 8 , section subheading claw strength you will see a horrifying piece of information . `` managing profit is made easy . simply input the coin value , the average value of the merchandise , and the profit level . the machine will automatically calculate when to send full strength to the claw . '' alright , so if it cost 50 cents to play the game , and the prize inside cost 7 dollars . to make a profit of 50 % full power will be sent to the claw only about once every 21 games or so . that sucks . they also randomize that winning game within a range so that players ca n't predict when exactly it will happen . and you might notice a subheading that says `` dropping skill '' they can program the machine to make you think you almost won . they taunt you with it . you see the stuffed animal flying in the air . and then it drops it . and that just ruins everything . so , most of the time claw machines are more like slot machines , than like skeeball or wack-a-mole . `` who 's in charge here ! '' `` the claw ! '' the question of whether claw machines are a game of skill or chance goes back decades . the earlier versions back in the 1930s had very little element of skill and were marketed as highly profitable for their owners . this was the depression era and people were desperate for ways to get money moving . during a crackdown on organzied crime in the 1950s federal law classified claw machines as gambling devices and prohibited the transporation of them across state lines . after those laws were relaxed in the 1970s newer claw machines from europe and asia spread throughout the united states . they actually started calling them `` skill cranes '' because the joystick gave players more precise control . but owners had increasing control over profits as well . and they 've been met with a patchwork of state and local laws and regulations . if machine operators want to make that claw really really unfair against the players , there 's not a lot stopping them . most of the regulations focus on the prize size , not the strength of the claw . that 's a reason that you might see fewer of the `` win a free ipad '' claw machines or `` win a free iphone '' claw machines around . and more of just old fashioned stuffed animals . it 's great if players know what they are up against . especially since sites like youtube have enabled claw machine enthusiast to broadcast their victories . like this guy . `` i 'm matt magnone . join me as i venture out and win as much crap as i can from claw machines ! '' my best outcome of this is not that all the claw machines go away . since i first wrote this article , i 've spent a dollar on claw machines ... and i 've lost . all i want for people to know is that they are not the problem . the claw machine is the problem . `` ah , you piece of crap ! ''
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this was the depression era and people were desperate for ways to get money moving . during a crackdown on organzied crime in the 1950s federal law classified claw machines as gambling devices and prohibited the transporation of them across state lines . after those laws were relaxed in the 1970s newer claw machines from europe and asia spread throughout the united states .
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the 1950s saw a crackdown on organized crime in america , and claw machines were outlawed because they were considered ...
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translator : jessica ruby reviewer : caroline cristal russia , with the largest territory in the world , has roughly the same total population as nigeria , a country 1/16 its size . but this similarity wo n't last long . one of the populations is rapidly growing , while the other is slowly declining . what can this tell us about the two countries ? population statistics are some of the most important data social scientists and policy experts have to work with . but understanding a country 's situation and making accurate predictions requires knowing not just the total size of the population but its internal characteristics , such as age and gender distribution . so , how can we keep track of all that data in a way that makes it easy to comprehend ? complex data is more easily interpreted through visualization , and one of the ways that demographers represent the internal distribution of a population is the population pyramid . here , the data is divided by gender with females on one side and males on the other . the population numbers are shown for each five-year age interval , starting from 0-4 and continuing up to 100 and up . these intervals are grouped together into pre-reproductive ( 0-14 ) , reproductive ( 15-44 ) , and post-reproductive years ( 45 and up ) . such a population pyramid can be a powerful predictor of future population trends . for example , rwanda 's population pyramid shows it to be a fast-growing country , with most of the population being in the youngest age groups at the bottom of the pyramid . the number will grow rapidly in the coming years . as today 's children reach their reproductive years and have children of their own , the total population is almost certain to double within the next few decades . for our second example , let 's look at canada , where most of the population is clustered around the middle of the graph . because there are less people in the pre-reproductive age groups than there are in the reproductive ones , the population will grow more slowly , as the number of people reaching their reproductive years decreases . finally , let 's look at japan . because the majority of its population is in its post-reproductive years and the number of people is smaller at each younger interval , this means that at current rates of reproduction the population will begin to decline as fewer and fewer people reach reproductive age . comparing these three population pyramids side by side shows us three different stages in a demographic transition , as a country moves from a pre-industrial society to one with an industrial or post-industrial economy . countries that have only recently begun the process of industrialization typically see an increase in life expectancy and a fall in child mortality rates as a result of improvements in medicine , sanitation , and food supply . while birth rates remain constant , leading to a population boom . developing countries that are farther along in the industrialization process begin to see a fall in birth rates , due to factors such as increased education and opportunities for women outside of child-rearing and a move from rural to urban living that makes having large families less economically advantageous . finally , countries in advanced stages of industrialization reach a point where both birth and death rates are low , and the population remains stable or even begins to decline . now , let 's take a look at the projected population pyramids for the same three countries in 2050 . what do these tell us about the expected changes in each country 's population , and what kinds of factors can alter the shape of these future pyramids ? a population pyramid can be useful not only as a predictor of a country 's future but as a record of its past . russia 's population pyramid still bears the scars of world war ii , which explains both the fewer numbers of elderly men compared to elderly women and the relatively sudden population increase as soldiers returned from the war and normal life resumed . china 's population pyramid reflects the establishment of the one child policy 35 years before , which prevented a population boom such as that of rwanda but also led to sex-selective abortions , resulting in more male children than female children . finally , the pyramid for the united states shows the baby boom that followed world war ii . as you can see , population pyramids tell us far more about a country than just a set of numbers , by showing both where it 's been and where it 's headed within a single image . and in today 's increasingly interconnected world , facing issues such as food shortages , ecological threats , and economic disparities , it is increasingly important for both scientists and policy makers to have a rich and complex understanding of populations and the factors affecting them .
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developing countries that are farther along in the industrialization process begin to see a fall in birth rates , due to factors such as increased education and opportunities for women outside of child-rearing and a move from rural to urban living that makes having large families less economically advantageous . finally , countries in advanced stages of industrialization reach a point where both birth and death rates are low , and the population remains stable or even begins to decline . now , let 's take a look at the projected population pyramids for the same three countries in 2050 .
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in an advanced stage of industrialization , a country will exhibit which set of characteristics ?
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♪♪ when he was nine years old , ron , without my parents or myself knowing his whereabouts , decided to take a mile walk from our home down to the library , which was , of course , a public library , but not so public for black folks when you 're talking about 1959 . so as he was walking in there , all these folks were staring at him because it was white folk only and they were looking at him saying , you know , `` who is this negro ? '' so he politely positioned himself in line to check out his books . well , this old librarian , she says , `` this library 's not for coloreds . '' he said , `` well , i would like to check out these books . '' she says , `` young man , if you do n't leave this library right now , i 'm gon na call the police . '' so he just propped himself up on the counter ... ( laughs ) and sat there and said , `` i 'll wait . '' so , she called the police and subsequently called my mother . the police came down , two burly guys , come in and say , `` well , where 's the disturbance ? '' she pointed to the little nine year old boy sitting up on the counter . he says , `` ma'am , what 's the problem ? '' so my mother , in the meanwhile , she was called and she comes down there praying the whole way there , `` lordy , jesus , please do n't let them put my child in jail . '' and my mother asked the librarian , `` what 's the problem ? '' `` he wanted to check out the book . you know your son should n't be down here . '' and the police officer said , `` why do n't you just give the kid the books ? '' and my mother said , `` he 'll take good care of them . '' and reluctantly , the librarian gave ron the books . and my mother said , `` what do you say ? '' he said , `` thank you , ma'am . '' ( laughs ) later on , as youngsters , a show came on tv called , `` star trek . '' now , star trek showed the future where there were black folk and white folk working together , and i just looked at it as science-fiction , because that was n't gon na happen , really . but ronald saw it as science-possibility , you know . he came up during a time when there was neil armstrong and all of those guys . so how was a colored boy from south carolina , wearing glasses , who never flew a plane , how was he gon na become an astronaut ? but ron was the one who did n't accept societal norms as being his norm . that was for other people . and uh , he got to be aboard his own starship enterprise . ♪♪ closed captions by captionlink www.captionlink.com
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now , star trek showed the future where there were black folk and white folk working together , and i just looked at it as science-fiction , because that was n't gon na happen , really . but ronald saw it as science-possibility , you know . he came up during a time when there was neil armstrong and all of those guys .
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which mission did ronald fly in ?
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translator : tom carter reviewer : bedirhan cinar it is the spring of 1787 . the revolutionary war has been over for only six years , and the young united states is still struggling in its infancy . uprisings , boundary disputes and the lack of a common vision all plague the newborn country . in an effort to steady this precarious ship , the confederation congress calls on states to send delegates to the grand convention , to begin on may 14 in philadelphia . the delegates must draft revisions to the articles of confederation , which would then be considered by the congress and approved by the states . under the terms of the articles , all 13 states had to agree to any changes . since the purpose of the convention is just to make recommendations , not everyone is excited about attending , and frankly , some think it 's a waste of time . as men from different parts of the country began to travel down dusty , rugged roads on the way to philadelphia , not all states send delegates . in fact , rhode island never even shows up . on may 14th , only 8 delegates -- not states , but individual delegates -- are present , so they wait . finally , on may 25th , the necessary quorum of seven states is acheived . in all , 55 delegates arrive in philadelphia over the course of the convention . they are all white males , property owners , and the average age is about 44 . some are slaveholders , some had signed the declaration of independence , [ james madison , roger sherman ] and almost all are well-educated . [ benjamin franklin ] picture the delegates , james madison and george washington among them , sitting in independence hall in hot , humid philadelphia . they 're all wearing the dress of the day : frock coats , high collars and thick pants . they vote to keep their discussions secret to encourage honest debate . but that means the windows are closed , and there is no air conditioning in 1787 , not even an electric fan . and they 'll sit in that sweltering heat , in those heavy clothes , for three months . shockingly , they all keep their vow of secrecy . that could never happen today , not even for an hour-long meeting . someone would share `` james madison thinks he 's so smart . keyword : articles are dead '' via social media , and the whole thing would be a disaster . but in 1787 , there are no leaks . not even a drip that hints at what they are doing . and what they are doing is nothing short of overthrowing the very government that sent them there . within a few days , with only a seven-state quorum , and only six of those states agreeing , a handful of men change the course of history . they vote to get rid of the articles of confederation , and write a new , more nationalistic document that becomes our constitution . the risk is immense . everyone on the outside assumes they were working on recommended revisions to the articles . it 's an incredible gamble , and even when the convention presents the signed constitution on september 17th , not all delegates endorse it . the country will argue and debate for two more years before the document is adopted by the required nine out of 13 states . but instead of punishing them for their deception , today we celebrate the wisdom and vision of those men in philadelphia .
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everyone on the outside assumes they were working on recommended revisions to the articles . it 's an incredible gamble , and even when the convention presents the signed constitution on september 17th , not all delegates endorse it . the country will argue and debate for two more years before the document is adopted by the required nine out of 13 states .
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assume today ’ s congress called for a national meeting of delegates from each state to discuss proposed amendments to the constitution . what do you think some of the significant differences would be between the grand convention and this hypothetical convention ?
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what is reality , knowledge , the meaning of life ? big topics you might tackle figuratively explaining existence as a journey down a road or across an ocean , a climb , a war , a book , a thread , a game , a window of opportunity , or an all-too-short-lived flicker of flame . 2,400 years ago , one of history 's famous thinkers said life is like being chained up in a cave , forced to watch shadows flitting across a stone wall . pretty cheery , right ? that 's actually what plato suggested in his allegory of the cave , found in book vii of `` the republic , '' in which the greek philosopher envisioned the ideal society by examining concepts like justice , truth and beauty . in the allegory , a group of prisoners have been confined in a cavern since birth , with no knowledge of the outside world . they are chained , facing a wall , unable to turn their heads , while a fire behind them gives off a faint light . occasionally , people pass by the fire , carrying figures of animals and other objects that cast shadows on the wall . the prisoners name and classify these illusions , believing they 're perceiving actual entities . suddenly , one prisoner is freed and brought outside for the first time . the sunlight hurts his eyes and he finds the new environment disorienting . when told that the things around him are real , ` while the shadows were mere reflections , he can not believe it . the shadows appeared much clearer to him . but gradually , his eyes adjust until he can look at reflections in the water , at objects directly , and finally at the sun , whose light is the ultimate source of everything he has seen . the prisoner returns to the cave to share his discovery , but he is no longer used to the darkness , and has a hard time seeing the shadows on the wall . the other prisoners think the journey has made him stupid and blind , and violently resist any attempts to free them . plato introduces this passage as an analogy of what it 's like to be a philosopher trying to educate the public . most people are not just comfortable in their ignorance but hostile to anyone who points it out . in fact , the real life socrates was sentenced to death by the athenian government for disrupting the social order , and his student plato spends much of `` the republic '' disparaging athenian democracy , while promoting rule by philosopher kings . with the cave parable , plato may be arguing that the masses are too stubborn and ignorant to govern themselves . but the allegory has captured imaginations for 2,400 years because it can be read in far more ways . importantly , the allegory is connected to the theory of forms , developed in plato 's other dialogues , which holds that like the shadows on the wall , things in the physical world are flawed reflections of ideal forms , such as roundness , or beauty . in this way , the cave leads to many fundamental questions , including the origin of knowledge , the problem of representation , and the nature of reality itself . for theologians , the ideal forms exist in the mind of a creator . for philosophers of language viewing the forms as linguistic concepts , the theory illustrates the problem of grouping concrete things under abstract terms . and others still wonder whether we can really know that the things outside the cave are any more real than the shadows . as we go about our lives , can we be confident in what we think we know ? perhaps one day , a glimmer of light may punch a hole in your most basic assumptions . will you break free to struggle towards the light , even if it costs you your friends and family , or stick with comfortable and familiar illusions ? truth or habit ? light or shadow ? hard choices , but if it 's any consolation , you 're not alone . there are lots of us down here .
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most people are not just comfortable in their ignorance but hostile to anyone who points it out . in fact , the real life socrates was sentenced to death by the athenian government for disrupting the social order , and his student plato spends much of `` the republic '' disparaging athenian democracy , while promoting rule by philosopher kings . with the cave parable , plato may be arguing that the masses are too stubborn and ignorant to govern themselves .
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how does this imaginary dialogue relate to what actually happened to the historical socrates ?
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there 's a factory inside you that weighs about 1.4 kilograms and runs for 24 hours a day . this is your liver , the heaviest organ in your body , and one of the most crucial . this industrious structure simultaneously acts as a storehouse , a manufacturing hub , and a processing plant . and each of these functions involve so many important subtasks that without the liver , our bodies would simply stop working . one of the liver 's main functions is to filter the body 's blood , which it receives in regular shipments from two sources : the hepatic artery delivers blood from the heart , while the hepatic portal vein brings it from the intestine . this double delivery fills the liver with nutrients , that it then sorts , processes and stores with the help of thousands of tiny internal processing plants , known as lobules . both blood flows also deliver the oxygen that the liver needs to function . the blood that is received from the intestine contains carbohydrates , fats , and vitamins and other nutrients dissolved in it from the food you 've consumed . these must be processed in different ways . in the case of carbohydrates , the liver breaks them down and converts them into sugars for the body to use as energy when the filtered blood is sent back out . sometimes the body has leftovers of nutrients that it does n't immediately require . when that happens , the liver holds some back , and stacks them in its storage facility . this facility works like a pantry for future cases when the body might be in need of nutrients . but the blood flowing into the liver is n't always full of good things . it also contains toxins and byproducts that the body ca n't use . and the liver monitors these strictly . when it spots a useless or toxic substance , it either converts it into a product that ca n't hurt the body or isolates it and whisks it away , channeling it through the kidneys and intestine to be excreted . of course , we would n't consider the liver a factory if it did n't also manufacture things . this organ makes everything from various blood plasma proteins that transport fatty acids and help form blood clots , to the cholesterol that helps the body create hormones . it also makes vitamin d and substances that help digestion . but one of its most vital products is bile . like an eco-friendly treatment plant , the liver uses cells called hepatocytes to convert toxic waste products into this bitter greenish liquid . as it 's produced , bile is funneled into a small container below the liver , called the gallbladder , before being trickled into the intestine to help break down fats , destroy microbes , and neutralize extra stomach acid . bile also helps carry other toxins and byproducts from the liver out of the body . so as you can see , the liver is an extremely efficient industrial site , performing multiple tasks that support each other . but such a complex system needs to be kept running smoothly by keeping it healthy and not overloading it with more toxins than it can handle . this is one factory we simply ca n't afford to shut down .
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this double delivery fills the liver with nutrients , that it then sorts , processes and stores with the help of thousands of tiny internal processing plants , known as lobules . both blood flows also deliver the oxygen that the liver needs to function . the blood that is received from the intestine contains carbohydrates , fats , and vitamins and other nutrients dissolved in it from the food you 've consumed .
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what is in the blood when it enters the liver ?
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what would you say is the most important discovery made in the past few centuries ? is it the computer ? the car ? electricity ? or maybe the discovery of the atom ? i would argue that it is this chemical reaction : a nitrogen gas molecule plus three hydrogen gas molecules gets you two ammonia gas molecules . this is the haber process of binding nitrogen molecules in the air to hydrogen molecules , or turning air into fertilizer . without this reaction , farmers would be capable of producing enough food for only 4 billion people ; our current population is just over 7 billion people . so , without the haber process , over 3 billion people would be without food . you see , nitrogen in the form of nitrate , no3 , is an essential nutrient for plants to survive . as crops grow , they consume the nitrogen , removing it from the soil . the nitrogen can be replenished through long , natural fertilization processes like decaying animals , but humans want to grow food much faster than that . now , here 's the frustrating part : 78 % of the air is composed of nitrogen , but crops ca n't just take nitrogen from the air because it contains very strong triple bonds , which crops can not break . what haber did basically was figure out a way to take this nitrogen in the air and put it into the ground . in 1908 , the german chemist fritz haber developed a chemical method for utilizing the vast supply of nitrogen in the air . haber found a method which took the nitrogen in the air and bonded it to hydrogen to form ammonia . ammonia can then be injected into the soil , where it is quickly converted into nitrate . but if haber 's process was going to be used to feed the world , he would need to find a way to create a lot of this ammonia quickly and easily . in order to understand how haber accomplished this feat , we need to know something about chemical equilibrium . chemical equilibrium can be achieved when you have a reaction in a closed container . for example , let 's say you put hydrogen and nitrogen into a closed container and allow them to react . in the beginning of the experiment , we have a lot of nitrogen and hydrogen , so the formation of ammonia proceeds at a high speed . but as the hydrogen and nitrogen react and get used up , the reaction slows down because there is less nitrogen and hydrogen in the container . eventually , the ammonia molecules reach a point where they start to decompose back into the nitrogen and hydrogen . after a while , the two reactions , creating and breaking down ammonia , will reach the same speed . when these speeds are equal , we say the reaction has reached equilibrium . this might sound good , but it 's not when what you want is to just create a ton of ammonia . haber does n't want the ammonia to break down at all , but if you simply leave the reaction in a closed container , that 's what will happen . here 's where henry le chatelier , a french chemist , can help . what he found was that if you take a system in equilibrium and you add something to it , like , say , nitrogen , the system will work to get back to equilibrium again . le chatelier also found that if you increase the amount of pressure on a system , the system tries to work to return to the pressure it had . it 's like being in a crowded room . the more molecules there are , the more pressure there is . if we look back at our equation , we see that on the left-hand side , there are four molecules on the left and just two on the right . so , if we want the room to be less crowded , and therefore have less pressure , the system will start combining nitrogen and hydrogen to make the more compact ammonia molecules . haber realized that in order to make large amounts of ammonia , he would have to create a machine that would continually add nitrogen and hydrogen while also increasing the pressure on the equilibrium system , which is exactly what he did . today , ammonia is one of the most produced chemical compounds in the world . roughly 131 million metric tons are produced a year , which is about 290 billion pounds of ammonia . that 's about the mass of 30 million african elephants , weighing roughly 10,000 pounds each . 80 % of this ammonia is used in fertilizer production , while the rest is used in industrial and household cleaners and to produce other nitrogen compounds , such as nitric acid . recent studies have found that half of the nitrogen from these fertilizers is not assimilated by plants . consequently , the nitrogen is found as a volatile chemical compound in the earth 's water supplies and atmosphere , severely damaging our environment . of course , haber did not foresee this problem when he introduced his invention . following his pioneering vision , scientists today are looking for a new haber process of the 21st century , which will reach the same level of aid without the dangerous consequences .
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without this reaction , farmers would be capable of producing enough food for only 4 billion people ; our current population is just over 7 billion people . so , without the haber process , over 3 billion people would be without food . you see , nitrogen in the form of nitrate , no3 , is an essential nutrient for plants to survive .
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what impact has haber ’ s process had on the world ? should we continue to use the haber process , or should we replace it ?
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the evolutionary tango of animal genitalia . can you guess what you 're looking at ? if you answered `` duck vagina , '' you 'd be right . although the bird 's outward appearance may not strike you as especially odd , it uses this strange , intricate , cork-screw shaped contraption to reproduce . we see similarly unbelievable genitalia in insects , mammals , reptiles , fish , spiders , and even snails . apparently , no organs evolve faster and into more variable shapes than those involved in procreation . superficially , it makes sense because evolution works via reproduction . when an animal leaves more offspring , its genes will spread . and since genitalia are an animal 's tools for reproduction , any improvement there will have immediate effect . and yet , what 's the point of having such decorative nether regions ? after all , the function of genitalia seems simple . a penis deposits a bit of sperm and a vagina receives it and delivers it to the egg . a pipette-like thingy on the male and a funnel-like gizmo on the female should do just fine for any animal . and yet , that 's not what we see . the penis of a chicken flea , for example , looks nothing like a pipette , more like an exploded grandfather clock . and the vagina of a featherwing beetle resembles something you 'd find in a dr. seuss book . throughout the animal kingdom , genitalia are very complex things , much more complicated than seems necessary for what they 're meant to do . that 's because genitalia do more than just deposit and receive sperm . many male animals also use the penis as courtship device , like crane flies . in some south american species , males have a tiny washboard and scraper on their penis , which produces a song that reverberates throughout the female 's body when they mate . it 's thought that if female crane flies enjoy this unusual serenade , they 'll allow the male to father their offspring . this way , the genes of the most musical penises spread , leading to rapid evolution of insects ' phalluses . similarly , some beetles have two little drumsticks on either side of the penis . during mating , they 'll rub , slap , or tap the female with these . and some hoofed mammals , like rams and bulls , use a whip-like extension on the penis 's left side to create a sensation during mating . but how can females really choose between males if she can only assess them after mating ? this is where the power of female adaptation comes into play . in fact , insemination is different to conception , and the female genitalia exploit this distinction . for instance , in some dung flies , the vagina contains pockets for separating sperm from different males depending on how appealing they were . males using their penises for courtship and females controlling their own sperm management are two reasons why genitalia evolve into such complex shapes . but there are others because genitalia are also where a sexual conflict is played out . a female 's interests are best served if she fertilizes her eggs with the sperm of the best fathers and creates genetic variability amongst her offspring . for a male , on the other hand , this is bad news . for him , it would be best if a female used his sperm to fertilize all of her eggs . so we see cycles of adaptation in an evolutionary arms race to retain control . black widow spiders have a disposable penis tip that breaks off inside the vagina blocking the attempts of his rivals , and bed bug males bypass a female 's genitalia altogether using a syringe-like penis to inject sperm cells directly into her belly . not to be outdone , females have evolved their own countermeasures . in some bed bug species , the females have evolved an entirely new set of genitalia on their right hand flanks where the males usually pierce them . that allows them to maintain the power to filter out unwanted sperm with their genitalia . and duck vaginas are shaped like a clockwise spiral so that when the male inflates his long , counterclockwise coiled penis into her , and she disapproves , all she needs to do is flex her vaginal muscles and the penis just flubs out . so , genitalia differs so much , not just to fascinate us , but because in every species , they 're the result of a furious evolutionary tango of sex that has been going on for millions of years and will continue for millions of years to come .
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the evolutionary tango of animal genitalia . can you guess what you 're looking at ?
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what is meant when we say that genitalia are involved in `` an evolutionary arms race '' ?
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consider the classic white t-shirt . annually , we sell and buy two billion t-shirts globally , making it one of the most common garments in the world . but how and where is the average t-shirt made , and what 's its environmental impact ? clothing items can vary a lot , but a typical t-shirt begins its life on a farm in america , china , or india where cotton seeds are sown , irrigated and grown for the fluffy bolls they produce . self-driving machines carefully harvest these puffs , an industrial cotton gin mechanically separates the fluffy bolls from the seeds , and the cotton lint is pressed into 225-kilogram bales . the cotton plants require a huge quantity of water and pesticides . 2,700 liters of water are needed to produce the average t-shirt , enough to fill more than 30 bathtubs . meanwhile , cotton uses more insecticides and pesticides than any other crop in the world . these pollutants can be carcinogenic , harm the health of field workers , and damage surrounding ecosystems . some t-shirts are made of organic cotton grown without pesticides and insecticides , but organic cotton makes up less than 1 % of the 22.7 million metric tons of cotton produced worldwide . once the cotton bales leave the farm , textile mills ship them to a spinning facility , usually in china or india , where high-tech machines blend , card , comb , pull , stretch , and , finally , twist the cotton into snowy ropes of yarn called slivers . then , yarns are sent to the mill , where huge circular knitting machines weave them into sheets of rough grayish fabric treated with heat and chemicals until they turn soft and white . here , the fabric is dipped into commercial bleaches and azo dyes , which make up the vivid coloring in about 70 % of textiles . unfortunately , some of these contain cancer-causing cadmium , lead , chromium , and mercury . other harmful compounds and chemicals can cause widespread contamination when released as toxic waste water in rivers and oceans . technologies are now so advanced in some countries that the entire process of growing and producing fabric barely touches a human hand . but only up until this point . after the finished cloth travels to factories , often in bangladesh , china , india , or turkey , human labor is still required to stitch them up into t-shirts , intricate work that machines just ca n't do . this process has its own problems . bangladesh , for example , which has surpassed china as the world 's biggest exporter of cotton t-shirts , employs 4.5 million people in the t-shirt industry , but they typically face poor conditions and low wages . after manufacture , all those t-shirts travel by ship , train , and truck to be sold in high-income countries , a process that gives cotton an enormous carbon footprint . some countries produce their own clothing domestically , which cuts out this polluting stage , but generally , apparel production accounts for 10 % of global carbon emissions . and it 's escalating . cheaper garments and the public 's willingness to buy boosted global production from 1994 to 2014 by 400 % to around 80 billion garments each year . finally , in a consumer 's home , the t-shirt goes through one of the most resource-intensive phases of its lifetime . in america , for instance , the average household does nearly 400 loads of laundry per year each using about 40 gallons of water . washing machines and dryers both use energy , with dryers requiring five to six times more than washers . this dramatic shift in clothing consumption over the last 20 years , driven by large corporations and the trend of fast fashion has cost the environment , the health of farmers , and driven questionable human labor practices . it 's also turned fashion into the second largest polluter in the world after oil . but there are things we can do . consider shopping secondhand . try to look for textiles made from recycled or organic fabrics . wash clothes less and line dry to save resources . instead of throwing them away at the end of their life , donate , recycle , or reuse them as cleaning rags . and , finally , you might ask yourself , how many t-shirts and articles of clothing will you consume over your lifetime , and what will be their combined impact on the world ?
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and it 's escalating . cheaper garments and the public 's willingness to buy boosted global production from 1994 to 2014 by 400 % to around 80 billion garments each year . finally , in a consumer 's home , the t-shirt goes through one of the most resource-intensive phases of its lifetime .
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the environment has been affected by the creation of cheaper garments and the willingness of the public to buy them . how ?
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today lots of girls play sports . but , for a long time , girls were not encouraged to kick , throw , run , jump , shoot , slide , or hit like boys . so , why did things change ? and how much have they changed ? are girls and boys treated equally when it comes to sports ? to begin to answer these questions , we have to look back . in 1972 , congress passed a law called title ix , which protected girls and women from discrimination in schools , colleges , and universities . this included discrimination in school-sponsored sports . at that time , only 15 % of college athletes were women , and in high schools , only 7 % of athletes were girls . female athletes did n't get a lot of support either and often had to provide their own uniforms and equipment . it was title ix that forced school administrators to make sports more equal . but what does equal mean in sports ? the government developed rules to measure equality under two general categories : participation and treatment . in the early days of title ix , the number of girls playing sports was so low that it would have been very difficult for schools to suddenly provide exactly the same number of opportunities for girls and boys . instead , the government wrote rules that gave schools three options , or tests , to demonstrate fairness in opportunities for girls . the three tests are proportionality , progress , and satisfied interests . a school can pick which test to follow . proportionality means that girls should receive the same percentage of athletic opportunities as the percentage of girls in the student body . so , if 51 % of students are girls , then girls should have approximately 51 % of the opportunities to play sports . the second test , progress , requires schools to make up for the days when girls had fewer opportunities by adding new sports for girls on a regular basis . the third test asks if girls interested in athletics are satisfied . under this test , a school must regularly ask female students what sports they are interested in and also take into consideration the popularity of certain sports in the area where the school is located . it must , then , add teams according to the girls ' interests . another important part of title ix is that it does n't just look at how many athletic opportunities are available to each sex but whether those opportunities are of equal quality . specifically , title ix requires equality between boys and girls teams for things like equipment and supplies , publicity , the scheduling of games and practice times , and the quality and number of coaches . girls should also have equal access to locker rooms , practice spaces , and competitive facilities , as well as medical services . so , if the best time to play basketball is on friday nights because that 's when most parents and fans can come , then the girls and boys teams should take turns playing on friday night . if boys teams play in a stadium with lights , scoreboards , and concession stands , then girls teams must have the same opportunity , either by sharing those facilities or getting their own of equal quality . but , as we all know , just because a law exists does n't mean that everybody follows it . school officials are responsible for making sure there is fairness in sports , but you can help , too , by keeping an eye on your own school . look around . are there a lot more boys than girls who play sports ? is the boys ' soccer field better than the girls ' ? are athletic trainers available to all teams equally ? does the baseball team get new uniforms every year , while the softball team gets them every three years ? if you think there might be inequality in your schools , you can approach a school administrator , a parent , or the office of civil rights , a government agency that makes sure schools comply with title ix because equality is important for everyone , both on the field and off .
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female athletes did n't get a lot of support either and often had to provide their own uniforms and equipment . it was title ix that forced school administrators to make sports more equal . but what does equal mean in sports ?
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which of the following situations might indicate that a school is violating title ix ?
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for most jobs , it 's understood that you can be fired , whether for crime , incompetence , or just poor performance . but what if your job happens to be the most powerful position in the country , or the world ? that 's where impeachment comes in . impeachment is n't the same as actually removing someone from office . like an indictment in criminal court , it 's only the formal accusation that launches a trial , which could end in conviction or acquittal . originating in the united kingdom , impeachment allowed parliament to vote for removing a government official from office even without the king 's consent . although this was an important check on royal power , the king could n't be impeached because the monarch was considered the source of all government power . but for the founders of the american republic , there was no higher authority beyond the people themselves . and so impeachment was adopted in the united states as a power of congress applying to any civil officers , up to and including the president . although demands for impeachment can come from any members of the public , only the house of representatives has the power to actually initiate the process . it begins by referring the matter to a committee , usually the house committee on rules and the house committee on the judiciary . these committees review the accusations , examine the evidence , and issue a recommendation . if they find sufficient grounds to proceed , the house holds a separate vote on each of the specific charges , known as articles of impeachment . if one or more passes by a simple majority , the official is impeached and the stage is set for trial . the actual trial that follows impeachment is held in the senate . selected members of the house , known as managers , act as the prosecution , while the impeached official and their lawyers present their defense . the senate acts as both judge and jury , conducting the trial and deliberating after hearing all the arguments . if it 's the president or vice president being impeached , the chief justice of the supreme court presides . a conviction requires a supermajority of two-thirds and results in automatic removal from power . depending on the original charges , it can also disqualify them from holding office in the future and open them to standard criminal prosecution . so what exactly can get someone impeached ? that 's a bit more complicated . unlike in the united kingdom , impeachment in the u.s. pits an elected legislature against other democratically elected members of government . therefore , to prevent the process from being used as a political weapon , the constitution specifies that an official can only be impeached for treason , bribery , or other high crimes and misdemeanors . that still leaves a lot of room for interpretation , not to mention politics , and many impeachment trials have split along partisan lines . but the process is generally understood to be reserved for serious abuses of power . the first official to be impeached was tennesse senator william blount in 1797 for conspiring with britain to cease the spanish colony of louisiana . since then , the house has launched impeachment investigations about 60 times , but only 19 have led to actual impeachment proceedings . the eight cases that ended in a conviction and removal from office were all federal judges . and impeachment of a sitting president is even more rare . andrew johnson was impeached in 1868 for attempting to replace secretary of war edwin stanton without consulting the senate . over a century later , bill clinton was impeached for making false statements under oath during a sexual harassment trial . both were ultimately acquitted when the senate 's votes to convict fell short of the required two-thirds majority . and contrary to popular belief , richard nixon was never actually impeached for the watergate scandal . he resigned before it could happen knowing he would almost certainly be convicted . theoretically , the u.s. government is already designed to prevent abuses of power , limiting different branches through a system of checks and balances , term limits , and free elections . but impeachment can be seen as an emergency brake for when these safeguards fail .
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the senate acts as both judge and jury , conducting the trial and deliberating after hearing all the arguments . if it 's the president or vice president being impeached , the chief justice of the supreme court presides . a conviction requires a supermajority of two-thirds and results in automatic removal from power .
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how many votes are required for conviction of a president or vice president ?
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so here i ’ ve got a really nice sample of silicon , alright ? ok. i ’ m going to take it out of the bottle… of the… i ’ m going to have to wash my hands after this . so silicon is a very common element , it ’ s particularly found in sand which is the oxide of silica ; that ’ s the compound of oxygen and silicon . it is also found in a variety of minerals which contain silicon , oxygen and another metal which are known as silicates . and silicates occur in an enormous number of different minerals . it ’ s sort of the part of science that unless you are a specialist you find quite boring but if you really go into it like everything else it becomes really quite interesting . so this is a piece of polycrystalline silicon . it ’ s a really quite fantastic element and it ’ s very often used , or in fact it ’ s used very regularly to make electronic components . all of the computers that we use and actually the camera that you are recording me on now are based upon silicon technology . silicon is also extremely important and the basis of most of the electronic devices we use : my watch , your video camera , and also in computers . and if we look over here , i have got here this is an example of a silicon wafer ; you can see at the back this is silicon . so the silicon is grown as a single crystal from which we can make very highly-refined architectures on silicon chips , but you see here we have a polycrystalline sample so it is very pretty the way that it interacts with the light and you can see the different grain sizes . so let me take it out . did martyn show you the single crystal , the wafer ? yeah , he ’ s got a single chip , yeah , yeah . cause if you can get the light coming off it , you can get all sorts of different coloured affects . here you can see , this is pure silicon on the back and on the front , people have grown chips these are the pentium 4 chips for the computer , i think , i am not absolutely sure but i think these are the chips and these are the connectors on either side . so there are a whole lot of these chips and they grow a large number of them at once . these are chopped up and tested and the ones that worked are put into computers and the ones that are no good are just chucked and so this is a fantastically delicate piece of engineering making these . this is so-called 20cm wafer . they now make silicon chips on a 30cm wafer which is about this size and you can get a large number more on them . if you get a single crystal of this silicon structure , it can diffract the light and change the light so that it diffracts and bends off at different angles so that you get like a rainbow effect off it . it ’ s really quite beautiful . a compound of silicon , silicon nitride is extremely tough and very light so it ’ s very difficult to break and silicon nitride for example is used in the impellers in turbo chargers in cars . so when you put your foot down on the accelerator it will spin up very fast because it is very light but it is very strong so it won ’ t very suddenly fall to bits as it is revving up inside your engine . right i must put that there because i want to put that back in a bag .
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it ’ s really quite beautiful . a compound of silicon , silicon nitride is extremely tough and very light so it ’ s very difficult to break and silicon nitride for example is used in the impellers in turbo chargers in cars . so when you put your foot down on the accelerator it will spin up very fast because it is very light but it is very strong so it won ’ t very suddenly fall to bits as it is revving up inside your engine .
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if you go to the beach on a hot summer ’ s day , where can you find large amounts of silicon compounds ?
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you work at the college library . you 're in the middle of a quiet afternoon when suddenly a shipment of 1,280 different books arrives . the books have been dropped of in one long straight line , but they 're all out of order , and the automatic sorting system is broken . to make matters worse , classes start tomorrow , which means that first thing in the morning , students will show up in droves looking for these books . how can you get them all sorted in time ? one way would be to start at one end of the line with the first pair of books . if the first two books are in order , then leave them as they are . otherwise , swap them . then , look at the second and third books , repeat the process , and continue until you reach the end of the line . at some point , you 'll come across the book that should be last , and keep swapping it with every subsequent book , moving it down the line until it reaches the end where it belongs . then , start from the beginning and repeat the process to get the second to last book in its proper place , and keep going until all books are sorted . this approach is called bubble sort . it 's simple but slow . you 'd make 1,279 comparisons in the first round , then 1,278 , and so on , adding up to 818,560 comparisons . if each took just one second , the process would take over nine days . a second strategy would be to start by sorting just the first two books . then , take the third book and compare it with the book in the second spot . if it belongs before the second book , swap them , then compare it with the book in the first spot , and swap again if needed . now you 've sorted the first three books . keep adding one book at a time to the sorted sub-line , comparing and swapping the new book with the one before it until it 's correctly placed among the books sorted so far . this is called insertion sort . unlike bubble sort , it usually does n't require comparing every pair of books . on average , we 'd expect to only need to compare each book to half of the books that came before it . in that case , the total number of comparisons would be 409,280 , taking almost five days . you 're still doing way too many comparisons . here 's a better idea . first , pick a random book . call it the partition and compare it to every other book . then , divide the line by placing all the books that come before the partition on its left and all the ones that come after it on its right . you 've just saved loads of time by not having to compare any of the books on the left to any of the ones on the right ever again . now , looking only at the books on the left , you can again pick a random partition book and separate those books that come before it from those that come after it . you can keep creating sub-partitions like this until you have a bunch of small sub-lines , each of which you 'd sort quickly using another strategy , like insertion sort . each round of partitioning requires about 1,280 comparisons . if your partitions are pretty balanced , dividing the books into 128 sub-lines of ten would take about seven rounds , or 8,960 seconds . sorting these sub-lines would add about 22 seconds each . all in all , this method known as quicksort could sort the books in under three and a half hours . but there 's a catch . your partitions could end up lopsided , saving no time at all . luckily , this rarely happens . that 's why quicksort is one of the most efficient strategies used by programmers today . they use it for things like sorting items in an online store by price , or creating a list of all the gas stations close to a given location sorted by distance . in your case , you 're done quick sorting with time to spare . just another high-stakes day in the library .
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keep adding one book at a time to the sorted sub-line , comparing and swapping the new book with the one before it until it 's correctly placed among the books sorted so far . this is called insertion sort . unlike bubble sort , it usually does n't require comparing every pair of books .
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in the video , quicksort was faster than insertion sort and bubble sort because :
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( music ) on a typical day at school , endless hours are spent learning the answers to questions . but right now , we 'll do the opposite . we 're going to focus on questions where you ca n't learn the answers , because they 're unknown . i used to puzzle about a lot of things as a boy . for example , what would it feel like to be a dog ? do fish feel pain ? how about insects ? was the big bang just an accident ? and is there a god ? and if so , how are we so sure that it 's a he and not a she ? why do so may innocent people and animals suffer terrible things ? is there really a plan for my life ? is the future yet to be written , or is it already written and we just ca n't see it ? but then , do i have free will ? who am i , anyway ? am i just a biological machine ? but then , why am i conscious ? what is consciousness ? will robots become conscious one day ? i mean , i kind of assumed that some day i would be told the answers to all these questions . i mean , someone must know , right ? huh . guess what ? no one knows . most of those questions puzzle me more now than ever . but diving into them is exciting because it takes you to the edge of knowledge , and you never know what you 'll find there . so , two questions to kick off this series , questions that no one on earth knows the answer to ... text : how many universes are there ? why ca n't we see evidence of alien life ?
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will robots become conscious one day ? i mean , i kind of assumed that some day i would be told the answers to all these questions . i mean , someone must know , right ?
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when anderson was younger , he assumed
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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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was the web invented to share big data ?
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translator : andrea mcdonough reviewer : bedirhan cinar it 's that time again . you need another internship to bolster your college applications . last year you worked at a local art museum , helping organize their collection and giving tours to visitors . this year , it 's going to be much more difficult . you want to work on an organic farm across the country in california . that 's your real passion . unfortunately , your friends ' list of contacts does n't include organic farmers . the same for your parents ' group of friends . they want to help you , but they simply do n't know of any internships in agriculture . the school counselor , she just laughed . to make your farming dreams come true , you 're going to have to press beyond your strong ties , people like your family and closest friends , and try tapping into your weaker ties . weak ties are a broader network , your friends of friends of friends . they 're important because they have access to resources that your strong ties do n't have . this works in both directions , by the way - you have access to resources that they do n't have . let 's say most people speak to three close friends on a regular basis . each time you reach beyond the next degree of contacts , you have access to three more people , like a tree that branches out three times per node , so you can look beyond your closest circles . during the last family get-together , did n't you hear that your aunt 's friend studied lighting with a nature photographer on the west coast ? in fact , you recall this because you saw a recent image by said photographer on the front cover of < i > the new york times < /i > . so , you email him and learn that the photographer 's wife 's cousin publishes a sustainability magazine , which employs a staff writer who pitches on a local baseball team with an umpire who , wait for it , is an organic farmer . bingo ! get ready to trade in those cuff links for some apple seeds , all because you reached out to your weak ties . that 's your key , remember ? every conversation is an opportunity . moreover , do n't wait for opportunity , make it happen . take kathryn minshew for example . she went from not knowing anyone at yahoo to three warm introductions to major executives in 30 days . here are her suggestions for three steps to networking . 1 - always say yes to invitations , even if it 's not clear what you 'll get out of the meeting . many of kathryn 's most productive relationships resulted from a meeting or call without a clear agenda . 2 - when you want something , broadcast it to everyone you meet . that does n't mean you beg everyone for help as soon as you meet them , but talk about what you 're trying to do . be excited , ask for feedback , and try to get them excited too . 3 - show up and often . be at the forefront of other 's minds when opportunities arise . you do n't want to be that person who only shows up when he needs something . be the one that people think of and want to reach out to when a new opportunity presents itself . so while networking may not be the most intuitive , or even for some of you introverts , the most comfortable skill , it 's a helpful tool to have as you think about getting a job , going to school , or most importantly , learning from others . good luck !
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to make your farming dreams come true , you 're going to have to press beyond your strong ties , people like your family and closest friends , and try tapping into your weaker ties . weak ties are a broader network , your friends of friends of friends . they 're important because they have access to resources that your strong ties do n't have . this works in both directions , by the way - you have access to resources that they do n't have .
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weak ties are important because :
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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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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 .
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list three reasons why knowing how to graph movement can help you on a practical level .
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translator : tom carter reviewer : bedirhan cinar dialogue gives a story color , makes it exciting and moves it forward . romeo : o , wilt thou leave me so unsatisfied ? juliet : what satisfaction canst thou have tonight ? romeo : the exchange of thy love 's faithful vows for mine . without dialogue : ( cricket sounds ) so what goes into writing effective dialogue ? well , there are social skills : making friends , solving conflicts , being pleasant and polite . we wo n't be using any of those today . instead , we 'll be working on -- let 's call them `` anti-social skills . '' if you 're a writer , you may already have a few of these . the first is eavesdropping . if you 're riding a bus and hear an interesting conversation , you could write it all down . of course , when you write fiction , you 're not describing real people , you 're making up characters . but sometimes the words you overhear can give you ideas . `` i did not , '' says one person . `` i saw you , '' the other replies . who might be saying those words ? maybe it 's two kids in a class , and the boy thinks the girl pushed him . maybe it 's a couple , but one of them is a vampire , and the woman vampire saw the man flirting with a zombie . or maybe not . maybe the characters are a teenager and his mother , and they 're supposed to be vegetarians , but the mother saw him eating a burger . so let 's say you 've decided on some characters . this is anti-social skill number two : start pretending they 're real . what are they like ? where are they from ? what music do they listen to ? spend some time with them . if you 're on a bus , think about what they might be doing if they were there too . would they talk on the phone , listen to music , draw pictures , sleep ? what we say depends on who we are . an older person might speak differently than a younger person . someone from the south might speak differently than someone from the north . once you know your characters , you can figure out how they talk . at this stage , it 's helpful to use anti-social skill number three : muttering to yourself . when you speak your character 's words , you can hear whether they sound natural , and fix them if necessary . remember , most people are usually pretty informal when they speak . they use simple language and contractions . so , `` do not attempt to lie to me '' sounds more natural as `` do n't try to lie to me . '' also keep it short . people tend to speak in short bursts , not lengthy speeches . and let the dialogue do the work . ask yourself : do i really need that adverb ? for instance , `` 'your money or your life , ' she said threateningly . '' here , `` threateningly '' is redundant , so you can get rid of it . but if the words and the actions do n't match , an adverb can be helpful . `` 'your money or your life , ' she said lovingly . '' so , to recap : first , eavesdrop . next , pretend imaginary people are real . finally , mutter to yourself , and write it all down . you already have everything you need . this is fictional dialogue , or `` how to hear voices in your head . ''
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romeo : the exchange of thy love 's faithful vows for mine . without dialogue : ( cricket sounds ) so what goes into writing effective dialogue ? well , there are social skills : making friends , solving conflicts , being pleasant and polite .
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why is it useful to mutter to yourself while writing dialogue ?
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myths and misconceptions about evolution . let 's talk about evolution . you 've probably heard that some people consider it controversial , even though most scientists do n't . but even if you are n't one of those people and you think you have a pretty good understanding of evolution , chances are you still believe some things about it that are n't entirely right , things like , `` evolution is organisms adapting to their environment . '' this was an earlier , now discredited , theory of evolution . almost 60 years before darwin published his book , jean-baptiste lamarck proposed that creatures evolve by developing certain traits over their lifetimes and then passing those on to their offspring . for example , he thought that because giraffes spent their lives stretching to reach leaves on higher branches , their children would be born with longer necks . but we know now that 's not how genetic inheritance works . in fact , individual organisms do n't evolve at all . instead , random genetic mutations cause some giraffes to be born with longer necks , and that gives them a better chance to survive than the ones who were n't so lucky , which brings us to `` survival of the fittest '' . this makes it sound like evolution always favors the biggest , strongest , or fastest creatures , which is not really the case . for one thing , evolutionary fitness is just a matter of how well-suited they are to their current environment . if all the tall trees suddenly died out and only short grass was left , all those long-necked giraffes would be at a disadvantage . secondly , survival is not how evolution occurs , reproduction is . and the world if full of creatures like the male anglerfish , which is so small and ill-suited for survival at birth that it has to quickly find a mate before it dies . but at least we can say that if an organism dies without reproducing , it 's evolutionarily useless , right ? wrong ! remember , natural selection happens not at the organism level , but at the genetic level , and the same gene that exists in one organism will also exist in its relatives . so , a gene that makes an animal altruistically sacrifice itself to help the survival and future reproduction of its siblings or cousins , can become more widespread than one that is solely concerned with self-preservation . anything that lets more copies of the gene pass on to the next generation will serve its purpose , except evolutionary purpose . one of the most difficult things to keep in mind about evolution is that when we say things like , `` genes want to make more copies of themselves , '' or even , `` natural selection , '' we 're actually using metaphors . a gene does n't want anything , and there 's no outside mechanism that selects which genes are best to preserve . all that happens is that random genetic mutations cause the organisms carrying them to behave or develop in different ways . some of those ways result in more copies of the mutated gene being passed on , and so forth . nor is there any predetermined plan progressing towards an ideal form . it 's not ideal for the human eye to have a blind spot where the optic nerve exits the retina , but that 's how it developed , starting from a simple photoreceptor cell . in retrospect , it would have been much more advantageous for humans to crave nutrients and vitamins rather than just calories . but over the millenia , during which our ancestors evolved , calories were scarce , and there was nothing to anticipate that this would later change so quickly . so , evolution proceeds blindly , step by step by step , creating all of the diversity we see in the natural world .
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this makes it sound like evolution always favors the biggest , strongest , or fastest creatures , which is not really the case . for one thing , evolutionary fitness is just a matter of how well-suited they are to their current environment . if all the tall trees suddenly died out and only short grass was left , all those long-necked giraffes would be at a disadvantage .
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elephants who are past reproductive age often lose their teeth in old age , then slowly starve to death as a result . explain why there is no evolutionary pressure for this terrible and seemingly maladaptive situation to change .
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humans have done a pretty good job of exploring the earth thus far , climbing mountains and crossing continents and planting our flags all over the place in the name of science . but one part of the world that has remained pretty mysterious to us also happens to cover more than 70 % of its surface : the ocean . yes , we ’ ve sailed across it plenty of times . and drilled for oil in it . and managed to create reality shows about fishing in it . but , from glowing oceans to massive deep-sea creatures , and underwater ecosystems with thousands of undiscovered , basically-alien species -- we still have a lot to learn about it . probably more than any place on earth , the ocean is full of fascinating stuff that we just don ’ t know . not yet . [ music playing ] number one : what ’ s the ocean floor like ? fact is , we still don ’ t know exactly what the ocean floor looks like in most places . the national oceanic and atmospheric administration says that 95 % of the ocean 's bottom remains unseen by humans . as a result , we have a way better picture of the surfaces of other planets than we do of most of the seafloor . in 2014 , a team of scientists created a map of the seafloor using data from satellites equipped with special sensors called radar altimeters . these instruments could precisely measure the distance from the satellite to the surface of the ocean below . essentially , any large mountains or canyons on the ocean floor have a slight gravitational effect on the ocean surface , creating bumps and dips , respectively . these variations are of course too subtle to be detected by human eyes , but they can be measured by these ultra-precise satellite altimeters -- and , after adjusting for the effect of waves and tides , tell scientists what ’ s on the seafloor . this map spans the entire ocean floor , which is awesome , and we ’ re all glad that it exists , but it only has a resolution of about 5 kilometers , which is pretty low . by comparison , most of the surface of mars , venus , and the moon have been mapped to resolutions of 100 meters or less . so , if we want to know what ’ s going on down there and really explore the ocean , detecting life , specific mineral formations , or wrecks , we ’ re gon na need a better map . number two : what ’ s under the seafloor ? ok , probably thinking that you know what ’ s down there : rock . yes . but not just rock . in 2015 , scientists reported that they had drilled down about 2 and a half kilometers below the seafloor off the coast of japan , and discovered living microbes . there were only about 10 to 10,000 microorganisms in a cubic centimeter of sediment that they studied , compared to like billions that you ’ d find in the same amount of dirt from your garden . but still : there 's life down there , even in the intense heat and pressure many kilometers below where the ocean stops . and the genomes of these under-sea microbes showed that they were actually more similar to the kind you ’ d find in forest soil , rather than the ones in seafloor sediments . so it ’ s possible that these microbes are descendants of terrestrial ones from 20 million years ago , that just adapted when their habitat began to get buried way beneath the ocean . so , who knows what other kinds of life could exist in deep marine sediments , or what they could tell us about what life on earth used to be like ? number three : brine pools . we ’ ve all seen lakes and rivers on land , but what about lakes that are … underwater ? sounds a little bit unreal , like maybe it ’ s from a sponge bob episode but these features actually exist -- pockets of seawater that have a different composition than the surrounding ocean : because they ’ re super salty . they ’ re known as brine pools , and they seem to have formed when layers of salt from evaporated oceans millions of years ago got buried under layers of sediment . seawater can reach these deposits and mix with the salt , forming a dense brine that flows out of the seafloor , sometimes filled with oils or methane gas . some brine pools , like those found deep in the gulf of mexico , are four times as salty as the ocean water around it . and the brine is so dense that submersibles can even “ float ” on top of it , like a boat on a lake . all of this salt makes brine pools lethal to larger animals . but colonies of halophilic -- or salt-loving -- microorganisms can flourish there , usually in much higher concentrations than the nearby normal seawater . some pools are even lined with mussels that have symbiotic bacteria in their gills , which use the methane in the brine to make energy for the mussels . but there ’ s a ton that we don ’ t know about these weird underwater salt lakes -- like how brine pools can be so different from each other -- and why some have mussels and others don ’ t -- and even how many there are ! number four : milky seas . also known as mareel , this is a phenomenon in which thousands of square kilometers of the ocean ’ s surface glow a brilliant whitish-blue . it lasts for such a short time , and there have been so few recorded sightings , that these glowing seas were thought to be a myth made up by crazy sailors… … until 2005 -- when a group of researchers was studying satellite pictures of a swath of the indian ocean from 1995 . these pictures showed an area of about 15,000 kilometers-square , around the size of connecticut , glowing for 3 nights . it was the first scientific evidence of the phenomenon , but the glowing waters are still not very well understood . some have suggested that the glow is caused by a mass of tiny dinoflagellates called noctiluca scintillans known as “ sea sparkles ” for the way they glow when disturbed . these protists are what cause the picturesque glittering waves along coastlines in some parts of the world . but the 2005 study found that it was “ unlikely , if not impossible ” that the short-lived glowing of dinoflagellates was what scientists had been seeing from space . the prevailing theory these days is that milky seas are caused by massive colonies of bioluminescent bacteria that are growing on top of an algal bloom . but we ’ re still not sure how or why these ephemeral masses of bacteria gather , glow , and disappear . number five : the 52 hertz whale . you ’ d think we would know a lot about whales . i mean , they ’ re big , and we have their skeletons , and we can observe their migratory patterns . but one thing we still have a lot more to learn about is their songs -- from why some whales make them , to how an animal without vocal cords … or lips … manages to make song-like sounds . and then there ’ s this question -- what whale is producing the 52 hertz song , and why ? this whale song was first noted by a technician on december 7th , 1992 in the northeast pacific ocean . it sounded like a blue whale , but blue whale cries usually are somewhere between 15 and 20 hertz in pitch . so , blue whales in the pacific typically sound like this : [ blue whale cry playing ] but this whale song , played at the same speed , sounded like this : [ 52 hertz song playing ] this high-pitch noise seemed to be unique to one animal -- a whale that became known as 52 blue . this raises a lot of questions , and we have to know more about whales to be able to answer some of them , like , why does this one whale sound different ? and can others even hear it ? and if they can hear it , do they understand ? some people latched onto to the idea that 52 blue is a lonely whale crying out to others that might not hear it or wouldn ’ t call back . but several scientists have rejected this lonely narrative , and think that other whales may be able to understand its call , even if they can ’ t make that call themselves . also , 52 blue seems to migrate independently from any other whales . but its migratory patterns do look kind of like those of blue whales -- scientists have been tracking it up and down the north pacific from alaska to mexico for years now . so some researchers think it might have some malformation that has changed how it sings , or maybe it ’ s even a hybrid between a blue whale and another species . whether or not it ’ s a lonely whale , 52 blue is an oddity that people seem to love . number six : upsweep . now , ocean sounds are practically their own field of study , noaa has been monitoring acoustics in the ocean for decades now . instead of microphones , which are used to collect sound in air , noaa uses hydrophones to record underwater sounds . mostly , these hydrophones are used to listen to the ambient sound of the ocean , to see how humans might interfere with it , and to listen for things like earthquakes and whale calls . and sometimes , they record things that are hard to explain , at least for a while . in 1997 , for example , there was what was known as the bloop , an extremely loud , low-frequency sound heard by hydrophones some 5,000 kilometers apart . oceanographers recently determined that it was the result of an icequake -- the cracking and collapse of glaciers into the ocean , in this case on the coast of antarctica . but there ’ s another mystery sound from the ocean , known as upsweep . recorded in august 1991 , it sounds like a repeating “ boop ” that picks up at the end -- sweeping up -- kind of like the “ red alert ” sound effect you hear on spaceships in sci-fi movies . but instead of trying to describe it , i could just play it for you . [ boop playing ] since 1991 , this sound has been heard regularly in the pacific ocean , and it seems to be seasonal , usually becoming more common in spring and fall . researchers have tracked the sound to a part of the pacific that has lots of volcanic and seismic activity , which seem to be important clues . but according to noaa , “ the origin of the sound is unresolved. ” number seven : why are deep-sea creatures so huge ? from the kraken to sea dragons , all of our favorite mythical sea monsters are gigantic . and the fact is , in real life , many deep-sea creatures are unusually huge . this phenomenon is called deep-sea gigantism . but what drives it is … you guessed it ! … unknown ! in the deep sea , and especially near the polar oceans , some animals seem to get really huge -- like colossal squids , giant isopods , and japanese spider crabs . scientists aren ’ t sure why , but they do have some guesses . there ’ s bergmann ’ s rule , for example , which suggests that temperature may influence gigantism . this might be because larger animals have less surface area relative to volume , so they radiate less heat based on their mass and stay warmer in colder climates . and then there ’ s klieber ’ s law , which states that more massive animals generally have lower metabolic rates -- and therefore need less high-quality food -- - to survive . still other theories suggest that gigantism may help organisms resist increased pressure of the deep sea . but we don ’ t really have conclusive biological reasons why these giant creatures exist . so , the ocean is just full o ’ mysteries , maybe because it ’ s so huge and dark and deep . but just so you know that we ’ re not hyping you -- we ’ re not saying that these 7 topics are things that science can ’ t explain . instead , you should just think of them as reminders of how much we still have to learn about the ocean . as our technology improves , and our access to the ocean takes us to new depths , we ’ ll be able to see and hear and sample more stuff than we ever have before . so in time , these puzzles will be solved , and new creatures will be discovered , and our understanding of our planet , and the life on it , will be that much … deeper . thank you for watching this scishow list show , and thanks especially to all of our patrons on patreon who make this show possible . if you want to help us keep making shows like this , you can go to patreon.com/scishow . and don ’ t forget to go to youtube.com/scishow and subscribe !
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scientists aren ’ t sure why , but they do have some guesses . there ’ s bergmann ’ s rule , for example , which suggests that temperature may influence gigantism . this might be because larger animals have less surface area relative to volume , so they radiate less heat based on their mass and stay warmer in colder climates .
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briefly describe bergmann ’ s rule and klieber ’ s law .
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if you know an older left-handed person , chances are they had to learn to write or eat with their right hand . and in many parts of the world , it 's still common practice to force children to use their `` proper '' hand . even the word for right also means correct or good , not just in english , but many other languages , too . but if being left-handed is so wrong , then why does it happen in the first place ? today , about 1/10 of the world 's population are left-handed . archeological evidence shows that it 's been that way for as long as 500,000 years , with about 10 % of human remains showing the associated differences in arm length and bone density , and some ancient tools and artifacts showing evidence of left-hand use . and despite what many may think , handedness is not a choice . it can be predicted even before birth based on the fetus ' position in the womb . so , if handedness is inborn , does that mean it 's genetic ? well , yes and no . identical twins , who have the same genes , can have different dominant hands . in fact , this happens as often as it does with any other sibling pair . but the chances of being right or left-handed are determined by the handedness of your parents in surprisingly consistent ratios . if your father was left-handed but your mother was right-handed , you have a 17 % chance of being born left-handed , while two righties will have a left-handed child only 10 % of the time . handedness seems to be determined by a roll of the dice , but the odds are set by your genes . all of this implies there 's a reason that evolution has produced this small proportion of lefties , and maintained it over the course of millennia . and while there have been several theories attempting to explain why handedness exists in the first place , or why most people are right-handed , a recent mathematical model suggests that the actual ratio reflects a balance between competitive and cooperative pressures on human evolution . the benefits of being left-handed are clearest in activities involving an opponent , like combat or competitive sports . for example , about 50 % of top hitters in baseball have been left-handed . why ? think of it as a surprise advantage . because lefties are a minority to begin with , both right-handed and left-handed competitors will spend most of their time encountering and practicing against righties . so when the two face each other , the left-hander will be better prepared against this right-handed opponent , while the righty will be thrown off . this fighting hypothesis , where an imbalance in the population results in an advantage for left-handed fighters or athletes , is an example of negative frequency-dependent selection . but according to the principles of evolution , groups that have a relative advantage tend to grow until that advantage disappears . if people were only fighting and competing throughout human evolution , natural selection would lead to more lefties being the ones that made it until there were so many of them , that it was no longer a rare asset . so in a purely competitive world , 50 % of the population would be left-handed . but human evolution has been shaped by cooperation , as well as competition . and cooperative pressure pushes handedness distribution in the opposite direction . in golf , where performance does n't depend on the opponent , only 4 % of top players are left-handed , an example of the wider phenomenon of tool sharing . just as young potential golfers can more easily find a set of right-handed clubs , many of the important instruments that have shaped society were designed for the right-handed majority . because lefties are worse at using these tools , and suffer from higher accident rates , they would be less successful in a purely cooperative world , eventually disappearing from the population . so by correctly predicting the distribution of left-handed people in the general population , as well as matching data from various sports , the model indicates that the persistence of lefties as a small but stable minority reflects an equilibrium that comes from competitive and cooperative effects playing out simultaneously over time . and the most intriguing thing is what the numbers can tell us about various populations . from the skewed distribution of pawedness in cooperative animals , to the slightly larger percentage of lefties in competitive hunter-gatherer societies , we may even find that the answers to some puzzles of early human evolution are already in our hands .
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but the chances of being right or left-handed are determined by the handedness of your parents in surprisingly consistent ratios . if your father was left-handed but your mother was right-handed , you have a 17 % chance of being born left-handed , while two righties will have a left-handed child only 10 % of the time . handedness seems to be determined by a roll of the dice , but the odds are set by your genes .
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give examples from a sport 's perspective of how being left-handed can serve as an advantage in competition .
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which is the hardest word to translate in this sentence ? `` know '' is easy to translate . `` pep rally '' does n't have a direct analog in a lot of languages and cultures , but can be approximated . but the hardest word there is actually one of the smallest : `` you . '' as simple as it seems , it 's often impossible to accurately translate `` you '' without knowing a lot more about the situation where it 's being said . to start with , how familiar are you with the person you 're talking to ? many cultures have different levels of formality . a close friend , someone much older or much younger , a stranger , a boss . these all may be slightly different `` you 's . '' in many languages , the pronoun reflects these differences through what 's known as the t–v distinction . in french , for example , you would say `` tu '' when talking to your friend at school , but `` vous '' when addressing your teacher . even english once had something similar . remember the old-timey `` thou ? '' ironically , it was actually the informal pronoun for people you 're close with , while `` you '' was the formal and polite version . that distinction was lost when the english decided to just be polite all the time . but the difficulty in translating `` you '' does n't end there . in languages like hausa or korana , the `` you '' form depends on the listener 's gender . in many more , it depends on whether they are one or many , such as with german `` du '' or `` ihr . '' even in english , some dialects use words like `` y'all '' or `` youse '' the same way . some plural forms , like the french `` vous '' and russian `` вы '' are also used for a single person to show that the addressee is that much more important , much like the royal `` we . '' and a few languages even have a specific form for addressing exactly two people , like slovenian `` vidva . '' if that was n't complicated enough , formality , number , and gender can all come into play at the same time . in spanish , `` tú '' is unisex informal singular , `` usted '' is unisex formal singular , `` vosotros '' is masculine informal plural , `` vosotras '' is feminine informal plural , and `` ustedes '' is the unisex formal plural . phew ! after all that , it may come as a relief that some languages often leave out the second person pronoun . in languages like romanian and portuguese , the pronoun can be dropped from sentences because it 's clearly implied by the way the verbs are conjugated . and in languages like korean , thai , and chinese , pronouns can be dropped without any grammatical hints . speakers often would rather have the listener guess the pronoun from context than use the wrong one and risk being seen as rude . so if you 're ever working as a translator and come across this sentence without any context : `` you and you , no , not you , you , your job is to translate 'you ' for yourselves '' ... well , good luck . and to the volunteer community who will be translating this video into multiple languages : sorry about that !
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phew ! after all that , it may come as a relief that some languages often leave out the second person pronoun . in languages like romanian and portuguese , the pronoun can be dropped from sentences because it 's clearly implied by the way the verbs are conjugated .
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in some languages , the person you are talking to may find it shocking or rude if you use the wrong “ you ” to refer to them . why do you think people may get upset if you use a pronoun that is too formal or too informal ?
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there 's a quote usually attributed to the writer mark twain that goes , `` a lie can travel halfway around the world while the truth is putting on its shoes . '' funny thing about that . there 's reason to doubt that mark twain ever said this at all , thus , ironically , proving the point . and today , the quote , whoever said it , is truer than ever before . in previous decades , most media with global reach consisted of several major newspapers and networks which had the resources to gather information directly . outlets like reuters and the associated press that aggregate or rereport stories were relatively rare compared to today . the speed with which information spreads now has created the ideal conditions for a phenomenon known as circular reporting . this is when publication a publishes misinformation , publication b reprints it , and publication a then cites b as the source for the information . it 's also considered a form of circular reporting when multiple publications report on the same initial piece of false information , which then appears to another author as having been verified by multiple sources . for instance , the 1998 publication of a single pseudoscientific paper arguing that routine vaccination of children causes autism inspired an entire antivaccination movement , despite the fact that the original paper has repeatedly been discredited by the scientific community . deliberately unvaccinated children are now contracting contagious diseases that had been virtually eradicated in the united states , with some infections proving fatal . in a slightly less dire example , satirical articles that are formatted to resemble real ones can also be picked up by outlets not in on the joke . for example , a joke article in the reputable british medical journal entitled `` energy expenditure in adolescents playing new generation computer games , '' has been referenced in serious science publications over 400 times . user-generated content , such as wikis , are also a common contributer to circular reporting . as more writers come to rely on such pages for quick information , an unverified fact in a wiki page can make its way into a published article that may later be added as a citation for the very same wiki information , making it much harder to debunk . recent advances in communication technology have had immeasurable benefits in breaking down the barriers between information and people . but our desire for quick answers may overpower the desire to be certain of their validity . and when this bias can be multiplied by billions of people around the world , nearly instantaneously , more caution is in order . avoiding sensationalist media , searching for criticisms of suspicious information , and tracing the original source of a report can help slow down a lie , giving the truth more time to put on its shoes .
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outlets like reuters and the associated press that aggregate or rereport stories were relatively rare compared to today . the speed with which information spreads now has created the ideal conditions for a phenomenon known as circular reporting . this is when publication a publishes misinformation , publication b reprints it , and publication a then cites b as the source for the information .
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what are some ways you can avoid falling for false information , and avoid contributing to the cycle of circular reporting ?
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translator : andrea mcdonough reviewer : bedirhan cinar the universe , rather beautiful , is n't it ? it 's quite literally got everything , from the very big to the very small . sure , there are some less than savory elements in there , but on the whole , scholars agree that its existence is probably a good thing . such a good thing that an entire field of scientific endeavor is devoted to its study . this is known as cosmology . cosmologists look at what 's out there in space and piece together the tale of how our universe evolved : what it 's doing now , what it 's going to be doing , and how it all began in the first place . it was edwin hubble who first noticed that our universe is expanding , by noting that galaxies seem to be flying further and further apart . this implied that everything should have started with the monumental explosion of an infinitely hot , infinitely small point . this idea was jokingly referred to at the time as the `` big bang , '' but as the evidence piled up , the notion and the name actually stuck . we know that after the big bang , the universe cooled down to form the stars and galaxies that we see today . cosmologists have plenty of ideas about how this happened . but we can also probe the origins of the universe by recreating the hot , dense conditions that existed at the beginning of time in the laboratory . this is done by particle physicists . over the past century , particle physicists have been studying matter and forces at higher and higher energies . firstly with cosmic rays , and then with particle accelerators , machines that smash together subatomic particles at great energies . the greater the energy of the accelerator , the further back in time they can effectively peek . today , things are largely made up of atoms , but hundreds of seconds after the big bang , it was too hot for electrons to join atomic nuclei to make atoms . instead , the universe consisted of a swirling sea of subatomic matter . a few seconds after the big bang , it was hotter still , hot enough to overpower the forces that usually hold protons and neutrons together in atomic nuclei . further back , microseconds after the big bang , and the protons and neutrons were only just beginning to form from quarks , one of the fundamental building blocks of the standard model of particle physics . further back still , and the energy was too great even for the quarks to stick together . physicists hope that by going to even greater energies , they can see back to a time when all the forces were one and the same , which would make understanding the origins of the universe a lot easier . to do that , they 'll not only need to build bigger colliders , but also work hard to combine our knowledge of the very , very big with the very , very small and share these fascinating insights with each other and with , well , you . and that 's how it should be ! because , after all , when it comes to our universe , we 're all in this one together .
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instead , the universe consisted of a swirling sea of subatomic matter . a few seconds after the big bang , it was hotter still , hot enough to overpower the forces that usually hold protons and neutrons together in atomic nuclei . further back , microseconds after the big bang , and the protons and neutrons were only just beginning to form from quarks , one of the fundamental building blocks of the standard model of particle physics . further back still , and the energy was too great even for the quarks to stick together .
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how do we know that all of the fundamental forces of nature will simplify into one force at a very high energy ?
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bean bags are awesome . but i see a few people out there who are standing , we 've got some over here , and standing takes more work than lounging . using the live strong organization 's online database of weight loss resources , you can calculate that by the time i 'm done with this speech , those of you who are standing will have burned 7.5 more calories than those of you who are bean-bagging it . ( laughter ) okay , here 's a question , speaking of weight loss , specifically weight , this speech is live . i 'm actually here in front of you guys , we 're all here together . but this speech is being recorded and it will become a video that people can access all over the world on computers , mobile devices , televisions . i weight about 190 pounds . how much will the video weigh ? asking questions like that is what i do every week on my channel vsauce . for the last two years , i have been asking really fun questions , mind-boggling questions , and approaching them as sincerely as i can , celebrating scientific concepts and scientists . and i research and write and produce and host and edit and upload and run the social media all by myself , but it 's not lonely , because vsauce has more than 2 million subscribers , and every month , my videos are seen by more than 20 million people . yeah . ( applause ) it 's very exciting . i 've found that asking a strange question is a great way to get people in , not just people , but fans . and fans are different than just viewers or an audience , because fans want to come back . they subscribe to you on youtube and they want to watch everything you 've made and everything you plan to make in the future because we are curious people and sparking curiosity is great bait . it 's a great way to catch a human . and once you 've caught them , you have this captive audience that you can , with the goal in mind of answering the question , accidentally teach a lot of things to . so , let 's take a look at some of my videos . here are eight of them . but down here in the lower-right corner , `` what color is a mirror ? '' when people see that , it 's very difficult not to click , because you think , `` come on , are you serious ? how could you possibly answer that question ? '' well , so far , 7.6 million people have watched this five-minute video about what color a mirror is . and in that episode , i answer the question and i get a chance to explain what would normally be kind of dry topics : optics , diffuse versus specular reflection , how light works , how light works on the retina , and even the etymology of color terms like white and black . okay , spoiler alert : mirrors are not clear , they are not silvery , like they 're often illustrated . mirrors , technically speaking , are just a tiny , tiny , little bit ... green . you can demonstrate this by putting two mirrors next to each other , facing so they reflect back and forth forever . look down that infinite reflection , and it will get dimmer , because some light is lost or absorbed every time , but it will also become greener , because green light , that is light of a wavelength that we perceive as green , is best reflected by most mirrors . okay , so , how much does a video weigh ? well , when you stream a video onto your computer , that information is temporarily stored using electrons . and the number of electrons on your device wo n't actually increase or decrease . but it takes energy to store them in one place , and , thanks to our friend albert einstein , we know that energy and mass are related . okay , so here 's the thing : let 's say you 're watching a youtube video at a really nice resolution , 720p . assuming a typical bit rate , we can figure that a minute of youtube video is going to need to involve about 10 million electrons on your device . plugging all those electrons and the energy it takes to hold them in the correct place for you to see the video , into that formula , we can figure out that one minute of youtube video increases the mass of your computer by about 10 to the negative 19th grams . written out , it looks like this . ( whistle ) that 's like nothing . you could call that nothing , and you would n't really get in trouble , because the best scales we 've ever invented that we could try to use to actually to detect that change are only accurate to 10 to the negative 9th grams . so , we ca n't measure it , but we can , like we just did , calculate it . and that 's really cool because when i was a kid , my school had two shelves of science books . that was really cool , but i read all of them within , like , two grades , and it was hard to get more books because books are heavy , you need space for them and moving books around is tougher than what we can do today . with numbers that small , i can fit thousands of books on my own little personal electronic reader . i can stream hours and hours and days and days of youtube video without my computer ever getting measurably heavier . and as information becomes that light , it becomes a lot more democratic , meaning that more teachers and presenters and creators and viewers than ever before can be involved . right now , on youtube , there is an explosion of content like this happening . the three vsauce channels are down there in the corner . but everyone else , all together , collectively , their views dwarf what i can do alone or with the people that i work with , and that is really , really exciting . it turns out that tapping into people 's curiosity and responsibly answering their questions is a brilliant way to build fans and an audience and get in viewers . it 's even a great way for brands and companies to build trust . so , calculating the weight of a video is kind of a funny question , but i can not wait to see what we ask and answer next . as always , thanks for watching . ( applause )
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and as information becomes that light , it becomes a lot more democratic , meaning that more teachers and presenters and creators and viewers than ever before can be involved . right now , on youtube , there is an explosion of content like this happening . the three vsauce channels are down there in the corner .
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according to stevens , what is good youtube bait ?
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translator : andrea mcdonough reviewer : bedirhan cinar what does `` going viral '' on the internet really mean , and why does it happen so quickly ? why is a financial institution too big to fail ? how does a virus in africa end up in the united states in a matter of hours ? why are facebook and google such powerful companies at creating global connections ? well , in a word : networks . but what are networks ? everyone knows about their social network , but there are all different kinds of networks you probably have n't thought about . networks are collections of links which combine by specific rules and behaviors if they are alive . we say that networks are alive because they are in constant change . over time , the connections within a network migrate and concentrate in new places , forming evolving structures . how the evolution and concentration of constantly changing connections occurs is the subject of a whole discipline called network theory . we can think of networks as neighborhoods . neighborhoods are defined by maps . a google map demonstrates the relationship between locations in exactly the same fashion a network connects hubs and nodes , using streets as links to connect neighborhoods . the reason a network can expand and evolve so quickly is based upon a mathematical concept called power functions . a power function is a mathematical amplification mechanism , which over specific and very small ranges , accelerates changes logarithmically . that is , a very small change in one parameter produces a huge change in another over a very specific range of values . an example of how network structure emerges is the algorithm used by google . as the number of links around a search term , say `` friends '' , increases , connections begin to form among millions of different searches using the term `` friend '' . what google has cleverly accomplished is a real-time mathematical model for how to predict the emergence of growing connections among billions of search terms . the algorithm google derived collects the number of references to any search object . as references to a search object increase , the number of links also increases , creating a node . as the node increases in size , it eventually becomes a hub , which links to many nodes . networks will continue to emerge as new ways of connecting and creating neighborhoods are defined . perhaps you can begin to see why networks are so powerful . as google continues to collect the billions of daily searches , new clusters of links will rapidly emerge , forming additional and growing networks . despite the logarithmic expansion of your network , the laws of six degrees of separation still apply . therefore , if you explore a close friend or acquaintances in you facebook network , everyone on average will be separated by six individuals or less and a map of your social network will create neighborhoods linked by common connections among friends .
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but what are networks ? everyone knows about their social network , but there are all different kinds of networks you probably have n't thought about . networks are collections of links which combine by specific rules and behaviors if they are alive .
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what advantages does a person have who is involved in social networking that a person not involved in social networking lacks ?
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in 1895 , a physicist named wilhelm roentgen was doing experiments with a cathode tube , a glass container in which a beam of electrons lights up a fluorescent window . he had wrapped cardboard around the tube to keep the fluorescent light from escaping , when something peculiar happened . another screen outside the tube was glowing . in other words , invisible rays had passed through the cardboard . wilhelm had no idea what those rays were , so he called them x-rays , and his discovery eventually won him a nobel prize . here 's what we now know was happening . when high energy electrons in the cathode tube hit a metal component , they either got slowed down and released extra energy , or kicked off electrons from the atoms they hit , which triggered a reshuffling that again released energy . in both cases , the energy was emitted in the form of x-rays , which is a type of electromagnetic radiation with higher energy than visible light , and lower energy than gamma rays . x-rays are powerful enough to fly through many kinds of matter as if they are semi-transparent , and they 're particularly useful for medical applications because they can make images of organs , like bones , without harming them , although they do have a small chance of causing mutations in reproductive organs , and tissues like the thyroid , which is why lead aprons are often used to block them . when x-rays interact with matter , they collide with electrons . sometimes , the x-ray transfers all of its energy to the matter and gets absorbed . other times , it only transfers some of its energy , and the rest is scattered . the frequency of these outcomes depends on how many electrons the x-rays are likely to hit . collisions are more likely if a material is dense , or if it 's made of elements with higher atomic numbers , which means more electrons . bones are dense and full of calcium , which has a relatively high atomic number , so they absorb x-rays pretty well . soft tissue , on the other hand , is n't as dense , and contains mostly lower atomic number elements , like carbon , hydrogen , and oxygen . so more of the x-rays penetrate tissues like lungs and muscles , darkening the film . these 2-d pictures are only useful up to a point , though . when x-rays travel through the body , they can interact with many atoms along the path . what is recorded on the film reflects the sum of all those interactions . it 's like trying to print 100 pages of a novel on a single sheet of paper . to see what 's really going on , you would have to take x-ray views from many angles around the body and use them to construct an internal image . and that 's something doctors do all the time in a procedure called a ct , computed tomography scan , another nobel prize winning invention . think of ct like this . with just one x-ray , you might be able to see the density change due to a solid tumor in a patient , but you would n't know how deep it is beneath the surface . however , if you take x-rays from multiple angles , you should be able to find the tumor 's position and shape . a ct scanner works by sending a fan or cone of x-rays through a patient to an array of detectors . the x-ray beam is rotated around the patient , and often also moved down the patient 's body , with the x-ray source tracing a spiral trajectory . spiral ct scans produce data that can be processed into cross sections detailed enough to spot anatomical features , tumors , blood clots , and infections . ct scans can even detect heart disease and cavities in mummies buried thousands of years ago . so what began as roentgen 's happy accident has become a medical marvel . hospitals and clinics now conduct over 100 millions scans each year worldwide to treat diseases and save lives .
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the x-ray beam is rotated around the patient , and often also moved down the patient 's body , with the x-ray source tracing a spiral trajectory . spiral ct scans produce data that can be processed into cross sections detailed enough to spot anatomical features , tumors , blood clots , and infections . ct scans can even detect heart disease and cavities in mummies buried thousands of years ago . so what began as roentgen 's happy accident has become a medical marvel .
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what are some ways in which ct data can be collected faster so that moving structures such as a beating heart can be better imaged ?
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we usually think of rhythm as an element of music , but it 's actually found everywhere in the world around us , from the ocean tides to our own heartbeats , rhythm is essentially an event repeating regularly over time . even the ticking of a clock itself is a sort of rhythm . but for musical rhythm , a steady string of repeating single beats is not enough . for that , we need at least one opposing beat with a different sound , which can be the unstressed off beat or the accented back beat . there are several ways to make these beats distinct , whether by using high and low drums , or long and short beats . which ends up being heard as the main beat is not a precise rule , but like the famous rubin 's vase , can be reversed depending on cultural perception . in standard notation , rhythm is indicated on a musical bar line , but there are other ways . remember that ticking clock ? just as its round face can trace the linear passage of time , the flow of rhythm can be traced in a circle . the continuity of a wheel can be a more intuitive way to visualize rhythm than a linear score that requires moving back and forth along the page . we can mark the beats at different positions around the circle using blue dots for main beats , orange ones for off beats , and white dots for secondary beats . here is a basic two beat rhythm with a main beat and an opposing off beat . or a three beat rhythm with a main beat , an off beat , and a secondary beat . and the spaces between each beat can be divided into further sub-beats using multiples of either two or three . layering multiple patterns using concentric wheels lets us create more complex rhythms . for example , we can combine a basic two beat rhythm with off beats to get a four beat system . this is the recognizable backbone of many genres popular around the world , from rock , country , and jazz , to reggae and cumbia . or we can combine a two beat rhythm with a three beat one . eliminating the extra main beat and rotating the inner wheel leaves us with a rhythm whose underlying feel is three-four . this is the basis of the music of whirling dervishes , as well as a broad range of latin american rhythms , such as joropo , and even bach 's famous chaconne . now if we remember rubin 's vase and hear the off beats as the main beats , this will give us a six-eight feel , as found in genres such as chacarera , and quechua , persian music and more . in an eight beat system , we have three layered circles , each rhythm played by a different instrument . we can then add an outermost layer consisting of an additive rhythmic component , reinforcing the main beat and increasing accuracy . now let 's remove everything except for this combined rhythm and the basic two beat on top . this rhythmic configuration is found as the cuban cinquillo , in the puerto rican bomba , and in northern romanian music . and rotating the outer circle 90 degrees counterclockwise gives us a pattern often found in middle eastern music , as well as brazilian choro , and argentinian tango . in all of these examples , the underlying rhythm reinforces the basic one-two , but in different ways depending on arrangement and cultural context . so it turns out that the wheel method is more than just a nifty way of visualizing complex rhythms . by freeing us from the tyranny of the bar line , we can visualize rhythm in terms of time , and a simple turn of the wheel can take us on a musical journey around the world .
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in all of these examples , the underlying rhythm reinforces the basic one-two , but in different ways depending on arrangement and cultural context . so it turns out that the wheel method is more than just a nifty way of visualizing complex rhythms . by freeing us from the tyranny of the bar line , we can visualize rhythm in terms of time , and a simple turn of the wheel can take us on a musical journey around the world .
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the rhythms of which of following groups share a common rhythm wheel ?
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have you ever walked into a grocery store and wondered where all those variety of apples came from ? you might find snapdragon , pixie crunch , cosmic crisp , jazz , or ambrosia next to the more familiar red delicious and granny smith . these delightfully descriptive names belong to just a handful of the over 7,500 apple varieties in the world . this huge diversity exists largely because of humanity 's efforts to bear new fruit . fruit breeding is a way to fulfill the expectations of farmers and consumers who seek specific qualities in an apple . on the one hand , farmers may want them to be disease-resistant and to store well . on the other , consumers are swayed by appearance , taste , and novelty . so , breeders have to consider everything from how well apples grow in certain climates to their color , taste , and size . and sometimes finding the perfect fit means breeding something new . to create apples with desirable characteristics , breeders first need to find parent apples that carry those characteristics . once the parents have been selected , they have to wait until the trees bloom in the spring . the breeder takes the pollen from one bloom , called the father , and transfers it by hand to the other parent bloom , called the mother , through a process called cross-pollination . once the mother bloom turns into an apple , the seeds are collected and then planted . it takes about five years for these seeds to grow into trees that produce apples , but because of the way traits are inherited , all of the seedlings produced will have different sets of genes and characteristics . this means that to achieve a desired quality , it takes a lot of offspring , not to mention patience on the breeder 's part . when a seedling does bear fruit with the desired qualities , it 's selected for further evaluation . of the original crossed seedlings , about one in every 5,000 makes it to this prestigious stage . they 're then sent to new farms where breeders can assess how various climates and soil types affect the plant 's growth . the fruit of the seedling and its many clones must then be collected and sampled to ensure consistency . breeders study about 45 traits in an apple , like the texture and firmness of the flesh , when it ripens , how sugary its juice is , and how long it stays fresh . over several years , they weed out all the bad apples , selecting only those whose fruits are the best . these exclusive plants officially form the cultivar , or new apple variety . to ensure an exact copy of this cultivar , all apple trees must be grafted from the original seedling . branches , called scion wood , are cut from the original tree and grown to generate more scion wood . segments of these trees are then grafted onto root stalk - that 's the lower section of another tree that 's been chosen from a different cultivar for its superior roots and growing ability . finally , this fusion creates a new apple tree with the desired qualities . each new plant takes up to four years before it starts producing the fruit we eat . apple breeding may be a difficult art , but it 's accessible to all : universities , companies , and even individuals can create new cultivars . but to fully own an apple , the breeder faces a final challenge - naming the fruit . after a cultivar is patented , a breeder chooses a name for its trademark . that final step grants them long-lasting rights over the apple and its clones . that name must be completely original , and the catchier , the better , of course . with over 7,500 varieties and counting , that 's why we have apples called pink lady , sweet tango , kiku , and evercrisp . the more we work with nature 's bounty to breed new cultivars , the more creative and delectable these names will become .
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over several years , they weed out all the bad apples , selecting only those whose fruits are the best . these exclusive plants officially form the cultivar , or new apple variety . to ensure an exact copy of this cultivar , all apple trees must be grafted from the original seedling .
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what is the purpose of creating new apple varieties ?
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if you 're ever walking down the street and come across an oddly stretched out image , like this , you 'll have an opportunity to see something remarkable , but only if you stand in exactly the right spot . that happens because these works employ a technique called anamorphosis . anamorphosis is a special case of perspective art , where artists represent realistic three-dimensional views on two-dimensional surfaces . though it 's common today , this kind of perspective drawing has only been around since the italian renaissance . ancient art often showed all figures on the same plane , varying in size by symbolic importance . classical greek and roman artists realized they could make objects seem further by drawing them smaller , but many early attempts at perspective were inconsistent or incorrect . in 15th century florence , artists realized the illusion of perspective could be achieved with higher degrees of sophistication by applying mathematical principles . in 1485 , leonardo da vinci manipulated the mathematics to create the first known anamorphic drawing . a number of other artists later picked up the technique , including hans holbein in `` the ambassadors . '' this painting features a distorted shape that forms into a skull as the viewer approaches from the side . in order to understand how artists achieve that effect , we first have to understand how perspective drawings work in general . imagine looking out a window . light bounces off objects and into your eye , intersecting the window along the way . now , imagine you could paint the image you see directly onto the window while standing still and keeping only one eye open . the result would be nearly indistinguishable from the actual view with your brain adding depth to the 2-d picture , but only from that one spot . standing even just a bit off to the side would make the drawing lose its 3-d effect . artists understand that a perspective drawing is just a projection onto a 2-d plane . this allows them to use math to come up with basic rules of perspective that allow them to draw without a window . one is that parallel lines , like these , can only be drawn as parallel if they 're parallel to the plane of the canvas . otherwise , they need to be drawn converging to a common point known as the vanishing point . so that 's a standard perspective drawing . with an anamorphic drawing , like `` the ambassadors , '' directly facing the canvas makes the image look stretched and distorted , but put your eye in exactly the right spot way off to the side , and the skull materializes . going back to the window analogy , it 's as if the artist painted onto a window positioned at an angle instead of straight on , though that 's not how renaissance artists actually created anamorphic drawings . typically , they draw a normal image onto one surface , then use a light , a grid , or even strings to project it onto a canvas at an angle . now let 's say you want to make an anamorphic sidewalk drawing . in this case , you want to create the illusion that a 3-d image has been added seamlessly into an existing scene . you can first put a window in front of the sidewalk and draw what you want to add onto the window . it should be in the same perspective as the rest of the scene , which might require the use of those basic rules of perspective . once the drawing 's complete , you can use a projector placed where your eye was to project your drawing down onto the sidewalk , then chalk over it . the sidewalk drawing and the drawing on the window will be nearly indistinguishable from that point of view , so viewers ' brains will again be tricked into believing that the drawing on the ground is three-dimensional . and you do n't have to project onto a flat surface to create this illusion . you can project onto multiple surfaces , or assemble a jumble of objects , that from the right point of view , appears to be something else entirely . all over the planet , you can find solid surfaces giving way to strange , wonderful , or terrifying visions . from your sidewalk to your computer screen , these are just some of the ways that math and perspective can open up whole new worlds .
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in order to understand how artists achieve that effect , we first have to understand how perspective drawings work in general . imagine looking out a window . light bounces off objects and into your eye , intersecting the window along the way .
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parallel lines leading away from the window will have projected images on the window that :
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imagine that one day , you 're summoned before a government panel . even though you have n't committed any crime , or been formally charged with one , you are repeatedly questioned about your political views , accused of disloyalty , and asked to incriminate your friends and associates . if you do n't cooperate , you risk jail or losing your job . this is exactly what happened in the united states in the 1950s as part of a campaign to expose suspected communists . named after its most notorious practitioner , the phenomenon known as mccarthyism destroyed thousands of lives and careers . for over a decade , american political leaders trampled democratic freedoms in the name of protecting them . during the 1930s and 1940s , there had been an active but small communist party in the united states . its record was mixed . while it played crucial roles in wider progressive struggles for labor and civil rights , it also supported the soviet union . from the start , the american communist party faced attacks from conservatives and business leaders , as well as from liberals who criticized its ties to the oppressive soviet regime . during world war ii , when the usa and ussr were allied against hitler , some american communists actually spied for the russians . when the cold war escalated and this espionage became known , domestic communism came to be seen as a threat to national security . but the attempt to eliminate that threat soon turned into the longest lasting and most widespread episode of political repression in american history . spurred on by a network of bureaucrats , politicians , journalists , and businessmen , the campaign wildly exaggerated the danger of communist subversion . the people behind it harassed anyone suspected of holding left-of-center political views or associating with those who did . if you hung modern art on your walls , had a multiracial social circle , or signed petitions against nuclear weapons , you might just have been a communist . starting in the late 1940s , fbi director j. edgar hoover used the resources of his agency to hunt down such supposed communists and eliminate them from any position of influence within american society . and the narrow criteria that hoover and his allies used to screen federal employees spread to the rest of the country . soon , hollywood studios , universities , car manufacturers , and thousands of other public and private employers were imposing the same political tests on the men and women who worked for them . meanwhile , congress conducted its own witchhunt subpoenaing hundreds of people to testify before investigative bodies like the house un-american activities committee . if they refused to cooperate , they could be jailed for contempt , or more commonly , fired and blacklisted . ambitious politicians , like richard nixon and joseph mccarthy , used such hearings as a partisan weapon accusing democrats of being soft on communism and deliberately losing china to the communist bloc . mccarthy , a republican senator from wisconsin became notorious by flaunting ever-changing lists of alleged communists within the state department . egged on by other politicians , he continued to make outrageous accusations while distorting or fabricating evidence . many citizens reviled mccarthy while others praised him . and when the korean war broke out , mccarthy seemed vindicated . once he became chair of the senate 's permanent subcommittee on investigations in 1953 , mccarthy recklessness increased . it was his investigation of the army that finally turned public opinion against him and diminished his power . mccarthy 's colleagues in the senate censured him and he died less than three years later , probably from alcoholism . mccarthyism ended as well . it had ruined hundreds , if not thousands , of lives and drastically narrowed the american political spectrum . its damage to democratic institutions would be long lasting . in all likelihood , there were both democrats and republicans who knew that the anti-communist purges were deeply unjust but feared that directly opposing them would hurt their careers . even the supreme court failed to stop the witchhunt , condoning serious violations of constitutional rights in the name of national security . was domestic communism an actual threat to the american government ? perhaps , though a small one . but the reaction to it was so extreme that it caused far more damage than the threat itself . and if new demagogues appeared in uncertain times to attack unpopular minorities in the name of patriotism , could it all happen again ?
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if they refused to cooperate , they could be jailed for contempt , or more commonly , fired and blacklisted . ambitious politicians , like richard nixon and joseph mccarthy , used such hearings as a partisan weapon accusing democrats of being soft on communism and deliberately losing china to the communist bloc . mccarthy , a republican senator from wisconsin became notorious by flaunting ever-changing lists of alleged communists within the state department .
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how can something like mccarthyism be used as a partisan weapon against another political party ? give an example .
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there 's a quote usually attributed to the writer mark twain that goes , `` a lie can travel halfway around the world while the truth is putting on its shoes . '' funny thing about that . there 's reason to doubt that mark twain ever said this at all , thus , ironically , proving the point . and today , the quote , whoever said it , is truer than ever before . in previous decades , most media with global reach consisted of several major newspapers and networks which had the resources to gather information directly . outlets like reuters and the associated press that aggregate or rereport stories were relatively rare compared to today . the speed with which information spreads now has created the ideal conditions for a phenomenon known as circular reporting . this is when publication a publishes misinformation , publication b reprints it , and publication a then cites b as the source for the information . it 's also considered a form of circular reporting when multiple publications report on the same initial piece of false information , which then appears to another author as having been verified by multiple sources . for instance , the 1998 publication of a single pseudoscientific paper arguing that routine vaccination of children causes autism inspired an entire antivaccination movement , despite the fact that the original paper has repeatedly been discredited by the scientific community . deliberately unvaccinated children are now contracting contagious diseases that had been virtually eradicated in the united states , with some infections proving fatal . in a slightly less dire example , satirical articles that are formatted to resemble real ones can also be picked up by outlets not in on the joke . for example , a joke article in the reputable british medical journal entitled `` energy expenditure in adolescents playing new generation computer games , '' has been referenced in serious science publications over 400 times . user-generated content , such as wikis , are also a common contributer to circular reporting . as more writers come to rely on such pages for quick information , an unverified fact in a wiki page can make its way into a published article that may later be added as a citation for the very same wiki information , making it much harder to debunk . recent advances in communication technology have had immeasurable benefits in breaking down the barriers between information and people . but our desire for quick answers may overpower the desire to be certain of their validity . and when this bias can be multiplied by billions of people around the world , nearly instantaneously , more caution is in order . avoiding sensationalist media , searching for criticisms of suspicious information , and tracing the original source of a report can help slow down a lie , giving the truth more time to put on its shoes .
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for example , a joke article in the reputable british medical journal entitled `` energy expenditure in adolescents playing new generation computer games , '' has been referenced in serious science publications over 400 times . user-generated content , such as wikis , are also a common contributer to circular reporting . as more writers come to rely on such pages for quick information , an unverified fact in a wiki page can make its way into a published article that may later be added as a citation for the very same wiki information , making it much harder to debunk .
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what makes circular reporting 'circular ' ?
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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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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 .
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why do scientists need to be able to study cells in a laboratory environment ?
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on october 4 , 1957 , the world watched in awe and fear as the soviet union launched sputnik , the world 's first man-made satellite , into space . this little metal ball , smaller than two feet in diameter , launched a space race between the u.s. and u.s.s.r. that would last for eighteen years and change the world as we know it . sputnik was actually not the first piece of human technology to enter space . that superlative goes to the v-2 rocket used by germany in missile attacks against allied cities as a last-ditch effort in the final years of world war ii . it was n't very effective , but , at the end of the war , both the u.s. and u.s.s.r. had captured the technology and the scientists that had developed it and began using them for their own projects . and by august 1957 , the soviet 's successfully tested the first intercontinental ballistic missile , the r-7 , the same rocket that would be used to launch sputnik two months later . so , the scary thing about sputnik was not the orbiting ball itself , but the fact that the same technology could be used to launch a nuclear warhead at any city . not wanting to fall too far behind , president eisenhower ordered the navy to speed up its own project and launch a satellite as soon as possible . so , on december 6 , 1957 , excited people across the nation tuned in to watch the live broadcast as the vanguard tv3 satellite took off and crashed to the ground two seconds later . the vanguard failure was a huge embarassment for the united states . newspapers printed headlines like , `` flopnik '' and `` kaputnik . '' and a soviet delegate at the u.n. mockingly suggested that the u.s. should receive foreign aid for developing nations . fortunately , the army had been working on their own parallel project , the explorer , which was successfully launched in january 1958 , but the u.s. had barely managed to catch up before they were surpassed again as yuri gargarin became the first man in space in april 1961 . almost a year passed and several more soviet astronauts completed their missions before project mercury succeeded in making john glenn the first american in orbit in february 1962 . by this time , president kennedy had realized that simply catching up to each soviet advance a few months later was n't going to cut it . the u.s. had to do something first , and in may 1961 , a month after gargarin 's flight , he announced the goal of putting a man on the moon by the end of the 1960s . they succeeded in this through the apollo program with neil armstrong taking his famous step on july 20 , 1969 . with both countries ' next turning their attention to orbital space stations , there 's no telling how much longer the space race could have gone on . but because of improving relations negotiated by soviet premier leonid breshnev and u.s. president nixon , the u.s.s.r. and u.s. moved toward cooperation rather than competition . the successful joint mission , known as apollo-soyuz , in which an american apollo spacecraft docked with a soviet soyuz craft and the two crews met , shook hands , and exchanged gifts , marked the end of the space race in 1975 . so , in the end , what was the point of this whole space race ? was it just a massive waste of time ? two major superpowers trying to outdo each other by pursuing symbolic projects that were both dangerous and expensive , using resources that could have been better spent elsewhere ? well , sure , sort of , but the biggest benefits of the space program had nothing to do with one country beating another . during the space race , funding for research and education , in general , increased dramatically , leading to many advances that may not have otherwise been made . many nasa technologies developed for space are now widely used in civilian life , from memory foam in mattresses to freeze-dried food , to leds in cancer treatment . and , of course , the satellites that we rely on for our gps and mobile phone signals would not have been there without the space program . all of which goes to show that the rewards of scientific research and advancement are often far more vast than even the people pursuing them can imagine .
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the successful joint mission , known as apollo-soyuz , in which an american apollo spacecraft docked with a soviet soyuz craft and the two crews met , shook hands , and exchanged gifts , marked the end of the space race in 1975 . so , in the end , what was the point of this whole space race ? was it just a massive waste of time ?
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what marked the end of the space race ?
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mysteries of vernacular : robot , a machine capable of carrying out a programmable series of actions . the origin of the word robot dates back more than a thousand years to the era of serfdom in central europe when servitude was the currency for rent . in those days , the old church slavonic word rabota described the forced labor of the people . a slight adjustment of spelling , and rabota became the czech robota , which , in addition to defining the toil of the serfs , was also used figuratively to describe any kind of hard work or drudgery . in 1920 , czech writer karel capek published a science fiction play called `` r.u.r . `` , short for `` rossum 's universal robots . '' the story featured automated machines with distinctly human features that , until they revolt , catered to the whims of the people of earth . capek originally considered calling these hard-working machines labori from the latin word for labor , but he worried it sounded a bit too scholarly . he opted , instead , to emphasize their enslaved state by naming them roboti , or robot in english . `` r.u.r . '' was wildly successful , and when it was translated into english in 1923 , the word robot was enthusiastically embraced . though most of today 's robots look quite different than capek imagined , they 've become just as popular as he predicted . unlike in `` r.u.r . `` , though , our robots have n't risen up against us , and here 's hoping it stays that way !
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the story featured automated machines with distinctly human features that , until they revolt , catered to the whims of the people of earth . capek originally considered calling these hard-working machines labori from the latin word for labor , but he worried it sounded a bit too scholarly . he opted , instead , to emphasize their enslaved state by naming them roboti , or robot in english . `` r.u.r . ''
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do you think karel čapek made the right choice when he named the machines in his play roboti instead of labori ?
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what gives the trumpet its clarion ring and the tuba its gut-shaking `` omm pah pah ? '' and what makes the trombone so jazzy ? the answer lies not in the brass these instruments are made of , but in the journey air takes from the musician 's lungs to the instrument 's bell . like any sound , music consists of vibrations traveling through air . instruments are classified based on how those vibrations are produced . percussion instruments are struck . string instruments are plucked or bowed . woodwinds have air blown against a reed or sharp edge . for brass instruments , however , the vibration come directly from the musician 's mouth . one of the first things a brass player must learn is to breathe in deeply , until every possible particle of air is crammed into the lungs . once all that air is inside , it must come out through the mouth , but there , an internal battle takes place as the musician simultaneously tries to hold their lips firmly closed while blowing enough air to force them open . the escaping air meets resistance from the lip muscles , forms an opening called the aperture and creates the vibration that brass players call `` the buzz . '' when a mouthpiece is held up to those vibrating lips , it slightly refines the buzz , amplifying the vibration at certain frequencies . but things get really interesting depending on what instrument is attached to that mouthpiece . a brass instrument 's body is essentially a tube that resonates with the air column blowing through it . the way that sound waves travel through this column forms a limited pattern of pitches known as the harmonic series , with notes spaced far apart at the lower end , but coming closer together as the pitch increases . the musician can alter the pitch of the note through slight contractions of the lips and alterations to air volume and speed . slower , warm sighing air produces lower pitches , and faster , cool , flowing air produces higher pitches in the series . but any single harmonic series has gaps where pitches are missing and the versatility of brass instruments lies in their ability to switch between multiple series . on instruments like the trumpet , valves can be lowered to increase the length of tubing the air travels through , while on a trombone , this is done by extending its slide . lengthening the tube stretches the vibrating air column , reducing the frequency of vibrations and resulting in a lower pitch . this is why the tuba , the largest brass instrument , is also the one capable of playing the lowest notes . so changing the instrument length shifts its harmonic series , while slight variations of the air flow and the player 's lips produce the different notes within it . and those notes finally emerge through the flared bell opening at the end . what started as a deep breath and a vibrating buzz on the lips has now been transformed into a bold and brassy tune . the musician 's skillful manipulation of every part of the process from lungs , to lips , to the mouthpiece , to the instrument itself creates an amazing palette of pitches that can be heard in musical genres across the globe . by harnessing the power of natural resonance in a flexible and controllable way , brass instruments are great examples of the fusion of human creativity with the physics of our world .
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the escaping air meets resistance from the lip muscles , forms an opening called the aperture and creates the vibration that brass players call `` the buzz . '' when a mouthpiece is held up to those vibrating lips , it slightly refines the buzz , amplifying the vibration at certain frequencies . but things get really interesting depending on what instrument is attached to that mouthpiece .
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the buzz results from _____ .
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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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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 .
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what is `` bad faith ? ''
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have you ever seen static electricity cause a spark of light ? what is that spark ? what about lightning , the northern lights , or the tail of a comet ? all of those things , and many others , in fact 99.9 % of the universe , are made of plasma . plasma is a state of matter drastically different from the more familiar forms . take ice , for example . ice , a solid , melts to become water , a liquid , which , when heated , vaporizes into steam , a gas . continued heating of the steam at a high enough temperature causes the water molecules in it to separate into freely roaming hydrogen and oxygen atoms . with a little more heat , the ionization process occurs and the negatively charged electrons escape the atoms , leaving behind positively charged ions . this mixture of freely roaming negative and positive charges is plasma , and at a high enough temperature , any gas can be made into one . these freely moving charged particles behave very differently from the particles in other types of matter . when a doorknob , a solid , has static electricity on it , it does n't look or behave any differently . and with the exception of a compass or other magnetic object , we rarely see matter respond to a magnetic field . but put a plasma in an electric field or magnetic field , and you 'll get a very different reaction . because plasmas are charged , electric fields accelerate them , and magnetic fields steer them in circular orbits . and when the particles within plasma collide , or accelerated by electricity or magnetism , light is generated , which is what we see when we look at plasmas like the aurora borealis . plasmas are n't just beautiful , celestial phenomena , though . imagine a tiny cube made of normal gas with a very high voltage across it . the resulting electric field pushes some of the electrons off the atoms and accelerates them to high speeds causing the ionization of other atoms . imbedded impurities in the tiny cube of gas cause it to gain and release a precise amount of energy in the form of ultraviolet radiation . attached to each tiny cube , a fluorescent material glows with a specific color when ultraviolet light at just the right intensity reaches it . now , make a rectangle out of a million of these tiny cubes , each separately controlled by sophisticated electronics . you may be looking at one now . this is called a plasma tv . plasmas also have implications for health care . plasma chemists create highly specific plasmas that can destroy or alter targeted chemicals , thereby killing pathogenic organisms on food or hospital surfaces . plasmas are all around us , in forms that are both spectacular and practical . and in the future , plasma could be used to permanently rid landfills of their waste , efficiently remove toxins from our air and water , and provide us with a potentially unlimited supply of renewable clean energy .
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you may be looking at one now . this is called a plasma tv . plasmas also have implications for health care .
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electrons in conductors , like copper wire , are free to roam throughout the metal in the presence of the ions that have released them . would you consider a metal to be a plasma ?
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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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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 .
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ani was a theban scribe who lived in the :
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translator : andrea mcdonough reviewer : bedirhan cinar let me guess , you 've got facebook albums full of photos . you have photos on your computer desktop , on your mobile phone , on your bedroom wall . you see photos in magazines and newspapers , on the side of buses , and of course , in your family albums . we take photos for granted in a major way . but , creating a picture that looked exactly like the person or thing that you were photographing was n't always obvious . in fact , in the past , it was a big mystery . how could you , in essence , take your reflection in the mirror and freeze it in there ? in the 9th century , the arab scientist alhazen had come up with the idea of using the camera obscura , which was literally a dark room , or box , with a single , small hole in one side that let light through . this would project the image outside into the wall inside . during the renaissance , artists like leonardo davinci used this method to introduce 3-d scenes onto a flat plane so that they could copy things , like perspective , more easily . in 1724 , johann heinrich schultz discovered that exposing certain silver compounds to light altered their appearance and left marks wherever the light touched . essentially , schultz found a way to record the images that alhazen was able to project , but only for a little while . schultz 's images disappeared soon after he had made them . it was n't until 1839 that people figured out how to project images onto light-sensitive surfaces that would retain the image after exposure , and thus , photography was born . at that point , it was mostly two inventors who fought for the best way to make photos . one was british scientist henry fox talbot , whose calotype process used paper and allowed many copies to be made from a single negative . the other inventor , louis daguerre , was an artist and chemist in france . he developed something called a daguerreotype , which used a silvered plate and which produced a sharper image . but the daguerreotype could only make positive images so copies had to be made by taking another photo . in the end , the daguerreotype won out as the first commercially successful photographic process mostly because the government made it freely available to the public . so now that photography was available , getting a picture of yourself would be a snap , right ? well , not exactly ! this process still required a whole dark room at the location of the photograph , which was a big hassle . picture the early photographers lugging enormous trailers with all their equipment wherever they wanted to take a picture . not only that , but the early processes had extremely long exposure times . to get a good photo , you would have to stand perfectly still for up to two minutes ! this led to development of inventions like the head holder , a wire frame that would hide behind you while supporting your head . it 's also why you do n't see people smiling in early photographs . it 's not that life was that bad , it was just hard to keep a steady grin for more than a few seconds , so people opted for a straight-faced look . and then george eastman came along . eastman believed that everyone should have access to photography , and he spent many late nights mixing chemicals in his mother 's kitchen to try to achieve a dry plate photographic process . this would allow exposed negatives to be stored and developed later at a more convenient place instead of carting those dark rooms , necessary for wet plates , around . after starting a business , which initially made dry plates , eastman eventually discovered plastic roll film that would fit in hand-held , inexpensive cameras . these cameras sold by the millions under the tag line , `` you push the button , we do the rest . '' while eastman was largely responsible for making photography a universal pastime , even he could not have dreamed of the ways photography had since shaped the world . it 's now estimated that over 380 billion photographs are taken each year . that 's more photographs each day than were taken in the first hundred years after photography was invented . say cheese !
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well , not exactly ! this process still required a whole dark room at the location of the photograph , which was a big hassle . picture the early photographers lugging enormous trailers with all their equipment wherever they wanted to take a picture .
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describe your favorite photograph , and explain why it 's so memorable to you .
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you know how sometimes you go to bake a cake but your bananas have all gone rotten , your utensils have rusted , you trip and pour all of your baking soda into the vinegar jug , and then your oven explodes ? my friend , you and your chemical reactions have fallen victim to enthalpy and entropy and , boy , are they forces to be reckoned with . now , your reactants are all products . so , what are these `` e '' words , and what 's their big idea ? let 's start with enthalpy , an increase or decrease of energy during a chemical reaction . every molecule has a certain amount of chemical potential energy stored within the bonds between its atoms . chemicals with more energy are less stable , and thus , more likely to react . let 's visualize the energy flow in a reaction , the combustion of hydrogen and oxygen , by playing a round of crazy golf . our goal is to get a ball , the reactant , up a small rise and down the other much steeper slope . where the hill goes up , we need to add energy to the ball , and where it goes down , the ball releases energy into its surroundings . the hole represents the product , or result of the reaction . when the reaction period ends , the ball is inside the hole , and we have our product : water . this , like when our oven exploded , is an exothermic reaction , meaning that the chemical 's final energy is less than its starting energy , and the difference has been added to the surrounding environment as light and heat . we can also play out the opposite type of reaction , an endothermic reaction , where the final energy is greater than the starting energy . that 's what we were trying to achieve by baking our cake . the added heat from the oven would change the chemical structure of the proteins in the eggs and various compounds in the butter . so that 's enthalpy . as you might suspect , exothermic reactions are more likely to happen than endothermic ones because they require less energy to occur . but there 's another independent factor that can make reactions happen : entropy . entropy measures a chemical 's randomness . here 's an enormous pyramid of golf balls . its ordered structure means it has low entropy . however , when it collapses , we have chaos everywhere , balls bouncing high and wide . so much so that some even go over the hill . this shift to instability , or higher entropy , can allow reactions to happen . as with the golf balls , in actual chemicals this transition from structure to disorder gets some reactants past the hump and lets them start a reaction . you can see both enthalpy and entropy at play when you go to light a campfire to cook dinner . your match adds enough energy to activate the exothermic reaction of combustion , converting the high-energy combustible material in the wood to lower energy carbon dioxide and water . entropy also increases and helps the reaction along because the neat , organized log of wood is now converted into randomly moving water vapor and carbon dioxide . the energy shed by this exothermic reaction powers the endothermic reaction of cooking your dinner . bon appétit !
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entropy also increases and helps the reaction along because the neat , organized log of wood is now converted into randomly moving water vapor and carbon dioxide . the energy shed by this exothermic reaction powers the endothermic reaction of cooking your dinner . bon appétit !
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which of the following is an example of an exothermic reaction ?
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translator : andrea mcdonough reviewer : bedirhan cinar i am going to start with a challenge . i want you to imagine each of these two scenes in as much detail as you can . scene number one : `` they gave us a hearty welcome . '' well , who are the people who are giving a hearty welcome ? what are they wearing ? what are they drinking ? ok , scene two : `` they gave us a cordial reception . '' how are these people standing ? what expressions are on their faces ? what are they wearing and drinking ? fix these pictures in your mind 's eye and then jot down a sentence or two to describe them . we 'll come back to them later . now on to our story . in the year 400 c.e . the celts in britain were ruled by romans . this had one benefit for the celts : the romans protected them from the barbarian saxon tribes of northern europe . but then the roman empire began to crumble , and the romans withdrew from britain . with the romans gone , the germanic tribes , the angles , saxons , jutes , and frisians quickly sailed across the water , did away with the celts , and formed kingdoms in the british isles . for several centuries , these tribes lived in britain , and their germanic language , anglo saxon , became the common language , what we call old english . although modern english speakers may think old english sounds like a different language , if you look and listen closely , you 'll find many words that are recognizable . for example , here is what the lord 's prayer looks like in old english . at first glance , it may look unfamiliar , but update the spelling a bit , and you 'll see many common english words . so the centuries passed with britains happily speaking old english , but in the 700 's , a series of viking invasions began , which continued until a treaty split the island in half . on one side were the saxons . on the other side were the danes who spoke a language called old norse . as saxons fell in love with their cute danish neighbors and marriages blurred the boundaries , old norse mixed with old english , and many old norse words like freckle , leg , root , skin , and want are still a part of our language . 300 years later , in 1066 , the norman conquest brought war again to the british isles . the normans were vikings who settled in france . they had abandoned the viking language and culture in favor of a french lifestyle , but they still fought like vikings . they placed a norman king on the english throne and for three centuries , french was the language of the british royalty . society in britain came to have two levels : french-speaking aristocracy and old english-speaking peasants . the french also brought many roman catholic clergymen with them who added latin words to the mix . old english adapted and grew as thousands of words flowed in , many having to do with government , law , and aristocracy . words like council , marriage , sovereign , govern , damage , and parliament . as the language expanded , english speakers quickly realized what to do if they wanted to sound sophisticated : they would use words that had come from french or latin . anglo saxon words seemed so plain like the anglo saxon peasants who spoke them . let 's go back to the two sentences you thought about earlier . when you pictured the hearty welcome , did you see an earthy scene with relatives hugging and talking loudly ? were they drinking beer ? were they wearing lumberjack shirts and jeans ? and what about the cordial reception ? i bet you pictured a far more classy and refined crowd . blazers and skirts , wine and caviar . why is this ? how is it that phrases that are considered just about synonymous by the dictionary can evoke such different pictures and feelings ? `` hearty '' and `` welcome '' are both saxon words . `` cordial '' and `` reception '' come from french . the connotation of nobility and authority has persisted around words of french origin . and the connotation of peasantry , real people , salt of the earth , has persisted around saxon words . even if you never heard this history before , the memory of it persists in the feelings evoked by the words you speak . on some level , it 's a story you already knew because whether we realize it consciously or only subconsciously , our history lives in the words we speak and hear .
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with the romans gone , the germanic tribes , the angles , saxons , jutes , and frisians quickly sailed across the water , did away with the celts , and formed kingdoms in the british isles . for several centuries , these tribes lived in britain , and their germanic language , anglo saxon , became the common language , what we call old english . although modern english speakers may think old english sounds like a different language , if you look and listen closely , you 'll find many words that are recognizable . for example , here is what the lord 's prayer looks like in old english .
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old english derives from which family of languages :
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good morning , john ! today is the day after thanksgiving here in america . traditionally , the day when we buy all the things ! actually , more traditionally at my house , it 's the day when we do n't leave the house ; because black friday.. terrifies me . for people who are n't american , the very ominous-sounding black friday is an accident of history . so , back in 1621 , it was hard livin ' here in america ; and the first english settlers had a really bountiful crop . apparently . this is somewhat mythological ... and , it was on a thursday ; and they were thankful ! that inspired a holiday ; which is a nice kind of idea for a holiday , where you just talk about the things that you 're thankful for . and eat a bunch of food ! you also eat a bunch of food . until the 1860 's , different states celebrated this holiday on different days . until abraham lincoln said : `` this.. is the day ! we 're gon na have a national day . `` ; and , the south was like : `` we 're not even part of you anymore . what are you talking about ? ! '' but then , when we got back together again , that was good ; and it became the national holiday . the fourth thursday in november . now , because it 's a national holiday on the thursday , you also sort of get that friday as a de facto day off . 'cause you do n't want to go back to work for one day and then have the weekend ; that 's just dumb ! in the '60 's [ 1960 's ] , because so many people were going on vacation on this day , or , to a lesser extent , going shopping ; this became such a terrible traffic mess that police and taxi drivers started calling it `` black friday '' . as stores , and also just general consumerist cultures , started pushing the idea of christmas shopping further and further away from christmas ; the big block in the road , where you ca n't push it back any further , is thanksgiving . 'cause that 's its own holiday . you ca n't start christmas before thanksgiving . and so , black friday became the official tipping point into the consumerist bonanza that is the holiday shopping season ! despite the fact that it has kind of this ominous-sounding name , it has been billed as the biggest and most important and best holiday shopping day of the year ; which is actually not true . we are.. a nation of procrastinators ; and thus , the biggest shopping day of the year is christmas eve . it seems a little bit upsetting that the day after we all get done telling the world why we should be satisfied with our lives , we are.. barraged with an advertising blitz showing us all of the things that we lack ! at the same time , it is very important to the american economy . i mean , you ca n't really get angry at people for wanting to give each other things ... and yes , dftba.com has its own black friday and cyber monday deals ; and you can go to dftba.com and check those out now . it 's also our 4th anniversary of being a company , which is very exciting ! and , to celebrate that fourth anniversary , all shipping within the united states this weekend , starting tomorrow , i think , is just $ 4.00 ! no matter what you buy ! ! but , i do think it 's important that we do n't just scrub the idea of satisfaction and thankfulness out of our brains as soon as we 're done for thanksgiving . and so , on this black friday , i want to continue being thankful . i 'm thankful to my wonderful and supportive parents ; to my beautiful , and intelligent , and hilarious wife . i 'm thankful to my new wii u . if you want to go to youtube.com/hankgames , you can see us playing the new super mario brothers there soon . i 'm thankful to all of my great friends here in missoula and across the world . i 'm thankful to finally have a robust and stable forum that can handle the weight of nerdfighteria . there 's a link in the description . i 'm thankful to youtube and google for funding scishow and crash course , and for supporting vlogbrothers , and all of our endeavors through the years . i 'm thankful to reddit , and qi , and mental floss magazine , for making sure that i keep learning interesting things . i 'm thankful to jonas salk for giving away the patent to his polio vaccine to the world , so that it could be less expensive to manufacture ; and tim berners-lee for doing basically the same thing with the internet . i 'm thankful to the nerdcrafteria minecraft server and tumblr , and the ning ; and all the other places on the internet where nerdfighters do nerdfighter things . and , i 'm thankful to all the wonderful , thoughtful , intelligent people who watch and support the things that i do on the internet ; even when it 's sappy , silly videos like this one . and i 'm thankful , of course , for my brother who 's always driving me to do new and interesting and difficult things ; and who 's raising a wonderful family , and who says wise and intelligent things on tumblr . and john , i 'll see you on tuesday . *music plays*
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you ca n't start christmas before thanksgiving . and so , black friday became the official tipping point into the consumerist bonanza that is the holiday shopping season ! despite the fact that it has kind of this ominous-sounding name , it has been billed as the biggest and most important and best holiday shopping day of the year ; which is actually not true .
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black friday follows what holiday in the united states ?
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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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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 .
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what are some reasons that scientists have proposed as the reason for this wrinkling of skin ?
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as a wildfire rages through the grasslands , three lions and three wildebeest flee for their lives . to escape the inferno , they must cross over to the left bank of a crocodile-infested river . fortunately , there happens to be a raft nearby . it can carry up to two animals at a time , and needs as least one lion or wildebeest on board to row it across the river . there 's just one problem . if the lions ever outnumber the wildebeest on either side of the river , even for a moment , their instincts will kick in , and the results wo n't be pretty . that includes the animals in the boat when it 's on a given side of the river . what 's the fastest way for all six animals to get across without the lions stopping for dinner ? pause here if you want to figure it out for yourself . answer in : 3 answer in : 2 answer in : 1 if you feel stuck on a problem like this , try listing all the decisions you can make at each point , and the consequences each choice leads to . for instance , there are five options for who goes across first : one wildebeest , one lion , two wildebeest , two lions , or one of each . if one animal goes alone , it 'll just have to come straight back . and if two wildebeest cross first , the remaining one will immediately get eaten . so those options are all out . sending two lions , or one of each animal , can actually both lead to solutions in the same number of moves . for the sake of time , we 'll focus on the second one . one of each animal crosses . now , if the wildebeest stays and the lion returns , there will be three lions on the right bank . bad news for the two remaining wildebeest . so we need to have the lion stay on the left bank and the wildebeest go back to the right . now we have the same five options , but with one lion already on the left bank . if two wildebeest go , the one that stays will get eaten , and if one of each animal goes , the wildebeest on the raft will be outnumbered as soon as it reaches the other side . so that 's a dead end , which means that at the third crossing , only the two lions can go . one gets dropped off , leaving two lions on the left bank . the third lion takes the raft back to the right bank where the wildebeest are waiting . what now ? well , since we 've got two lions waiting on the left bank , the only option is for two wildebeest to cross . next , there 's no sense in two wildebeest going back , since that just reverses the last step . and if two lions go back , they 'll outnumber the wildebeest on the right bank . so one lion and one wildebeest take the raft back leaving us with one of each animal on the left bank and two of each on the right . again , there 's no point in sending the lion-wildebeest pair back , so the next trip should be either a pair of lions or a pair of wildebeest . if the lions go , they 'd eat the wildebeest on the left , so they stay , and the two wildebeest cross instead . now we 're quite close because the wildebeest are all where they need to be with safety in numbers . all that 's left is for that one lion to raft back and bring his fellow lions over one by one . that makes eleven trips total , the smallest number needed to get everyone across safely . the solution that involves sending both lions on the first step works similarly , and also takes eleven crossings . the six animals escape unharmed from the fire just in time and begin their new lives across the river . of course , now that the danger 's passed , it remains to be seen how long their unlikely alliance will last .
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so those options are all out . sending two lions , or one of each animal , can actually both lead to solutions in the same number of moves . for the sake of time , we 'll focus on the second one .
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which animal ( s ) can go across first ( for the first crossing ) to make the most efficient number of moves ?
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muscles . we have over 600 of them . they make up between 1/3 and 1/2 of our body weight , and along with connective tissue , they bind us together , hold us up , and help us move . and whether or not body building is your hobby , muscles need your constant attention because the way you treat them on a daily basis determines whether they will wither or grow . say you 're standing in front of a door , ready to pull it open . your brain and muscles are perfectly poised to help you achieve this goal . first , your brain sends a signal to motor neurons inside your arm . when they receive this message , they fire , causing muscles to contract and relax , which pull on the bones in your arm and generate the needed movement . the bigger the challenge becomes , the bigger the brain 's signal grows , and the more motor units it rallies to help you achieve your task . but what if the door is made of solid iron ? at this point , your arm muscles alone wo n't be able to generate enough tension to pull it open , so your brain appeals to other muscles for help . you plant your feet , tighten your belly , and tense your back , generating enough force to yank it open . your nervous system has just leveraged the resources you already have , other muscles , to meet the demand . while all this is happening , your muscle fibers undergo another kind of cellular change . as you expose them to stress , they experience microscopic damage , which , in this context , is a good thing . in response , the injured cells release inflammatory molecules called cytokines that activate the immune system to repair the injury . this is when the muscle-building magic happens . the greater the damage to the muscle tissue , the more your body will need to repair itself . the resulting cycle of damage and repair eventually makes muscles bigger and stronger as they adapt to progressively greater demands . since our bodies have already adapted to most everyday activities , those generally do n't produce enough stress to stimulate new muscle growth . so , to build new muscle , a process called hypertrophy , our cells need to be exposed to higher workloads than they are used to . in fact , if you do n't continuously expose your muscles to some resistance , they will shrink , a process known as muscular atrophy . in contrast , exposing the muscle to a high-degree of tension , especially while the muscle is lengthening , also called an eccentric contraction , generates effective conditions for new growth . however , muscles rely on more than just activity to grow . without proper nutrition , hormones , and rest , your body would never be able to repair damaged muscle fibers . protein in our diet preserves muscle mass by providing the building blocks for new tissue in the form of amino acids . adequate protein intake , along with naturally occurring hormones , like insulin-like growth factor and testosterone , help shift the body into a state where tissue is repaired and grown . this vital repair process mainly occurs when we 're resting , especially at night while sleeping . gender and age affect this repair mechanism , which is why young men with more testosterone have a leg up in the muscle building game . genetic factors also play a role in one 's ability to grow muscle . some people have more robust immune reactions to muscle damage , and are better able to repair and replace damaged muscle fibers , increasing their muscle-building potential . the body responds to the demands you place on it . if you tear your muscles up , eat right , rest and repeat , you 'll create the conditions to make your muscles as big and strong as possible . it is with muscles as it is with life : meaningful growth requires challenge and stress .
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in fact , if you do n't continuously expose your muscles to some resistance , they will shrink , a process known as muscular atrophy . in contrast , exposing the muscle to a high-degree of tension , especially while the muscle is lengthening , also called an eccentric contraction , generates effective conditions for new growth . however , muscles rely on more than just activity to grow . without proper nutrition , hormones , and rest , your body would never be able to repair damaged muscle fibers . protein in our diet preserves muscle mass by providing the building blocks for new tissue in the form of amino acids . adequate protein intake , along with naturally occurring hormones , like insulin-like growth factor and testosterone , help shift the body into a state where tissue is repaired and grown .
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the fda recommends adults get at least 50g or protein a day to replace tissue that is broken down during the day . how might someone who engages in regular physical activity need to change his or her diet to support increased activity and muscle growth ? what happens to muscle tissue if you workout without eating ?
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what do euclid , twelve-year-old einstein , and american president james garfield have in common ? they all came up with elegant proofs for the famous pythagorean theorem , the rule that says for a right triangle , the square of one side plus the square of the other side is equal to the square of the hypotenuse . in other words , a²+b²=c² . this statement is one of the most fundamental rules of geometry , and the basis for practical applications , like constructing stable buildings and triangulating gps coordinates . the theorem is named for pythagoras , a greek philosopher and mathematician in the 6th century b.c. , but it was known more than a thousand years earlier . a babylonian tablet from around 1800 b.c . lists 15 sets of numbers that satisfy the theorem . some historians speculate that ancient egyptian surveyors used one such set of numbers , 3 , 4 , 5 , to make square corners . the theory is that surveyors could stretch a knotted rope with twelve equal segments to form a triangle with sides of length 3 , 4 and 5 . according to the converse of the pythagorean theorem , that has to make a right triangle , and , therefore , a square corner . and the earliest known indian mathematical texts written between 800 and 600 b.c . state that a rope stretched across the diagonal of a square produces a square twice as large as the original one . that relationship can be derived from the pythagorean theorem . but how do we know that the theorem is true for every right triangle on a flat surface , not just the ones these mathematicians and surveyors knew about ? because we can prove it . proofs use existing mathematical rules and logic to demonstrate that a theorem must hold true all the time . one classic proof often attributed to pythagoras himself uses a strategy called proof by rearrangement . take four identical right triangles with side lengths a and b and hypotenuse length c. arrange them so that their hypotenuses form a tilted square . the area of that square is c² . now rearrange the triangles into two rectangles , leaving smaller squares on either side . the areas of those squares are a² and b² . here 's the key . the total area of the figure did n't change , and the areas of the triangles did n't change . so the empty space in one , c² must be equal to the empty space in the other , a² + b² . another proof comes from a fellow greek mathematician euclid and was also stumbled upon almost 2,000 years later by twelve-year-old einstein . this proof divides one right triangle into two others and uses the principle that if the corresponding angles of two triangles are the same , the ratio of their sides is the same , too . so for these three similar triangles , you can write these expressions for their sides . next , rearrange the terms . and finally , add the two equations together and simplify to get ab²+ac²=bc² , or a²+b²=c² . here 's one that uses tessellation , a repeating geometric pattern for a more visual proof . can you see how it works ? pause the video if you 'd like some time to think about it . here 's the answer . the dark gray square is a² and the light gray one is b² . the one outlined in blue is c² . each blue outlined square contains the pieces of exactly one dark and one light gray square , proving the pythagorean theorem again . and if you 'd really like to convince yourself , you could build a turntable with three square boxes of equal depth connected to each other around a right triangle . if you fill the largest square with water and spin the turntable , the water from the large square will perfectly fill the two smaller ones . the pythagorean theorem has more than 350 proofs , and counting , ranging from brilliant to obscure . can you add your own to the mix ?
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so the empty space in one , c² must be equal to the empty space in the other , a² + b² . another proof comes from a fellow greek mathematician euclid and was also stumbled upon almost 2,000 years later by twelve-year-old einstein . this proof divides one right triangle into two others and uses the principle that if the corresponding angles of two triangles are the same , the ratio of their sides is the same , too .
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euclid ’ s elegant proof of the pythagorean theorem ( also stumbled upon by einstein ) relies on which of the following principles ?
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some are longer than a blue whale . others are barely larger than a grain of sand . one species unleashes one of the most deadly venoms on earth . another holds a secret that 's behind some of the greatest breakthroughs in biology . they 've inhabited the ocean for at least half a billion years , and they 're still flourishing as the sea changes around them . jellyfish are soft-bodied sea creatures that are n't really fish . they 're part of a diverse team of gelatinous zooplankton , zooplankton being animals that drift in the ocean . there are more than 1,000 species of jellyfish , and many others that are often mistaken for them . a noted feature of jellyfish is a translucent bell made of a soft delicate material called mesoglea . sandwiched between two layers of skin , the mesoglea is more than 95 % water held together by protein fibers . the jellyfish can contract and relax their bells to propel themselves . they do n't have a brain or a spinal cord , but a neural net around the bell 's inner margin forms a rudimentary nervous system that can sense the ocean 's currents and the touch of other animals . jellyfish do n't have typical digestive systems , either . these gelatinous carnivores consume plankton and other small sea creatures through a hole in the underside of their bells . the nutrients are absorbed by an inner layer of cells with waste excreted back through their mouths . but the jellyfish 's relatively simple anatomy does n't prevent it from having some remarkable abilities . one kind of box jellyfish has 24 eyes . scientists think it can see color and form images within its simple nervous system . four of its eyes are curved upward on stalks . this allows the jellyfish to peer through the surface of the water , looking for the canopy of the mangrove trees where it feeds . in fact , this may be one of the only creatures with a 360-degree view of its environment . the jellyfish 's sting , which helps it capture prey and defend itself , is its most infamous calling card . in the jelly 's epidermis , cells called nematocysts lie coiled like poisonous harpoons . when they 're triggered by contact , they shoot with an explosive force . it exerts over 550 times the pressure of mike tyson 's strongest punch to inject venom into the victim . some jellyfish stings barely tingle , but others cause severe skin damage . the venom of one box jellyfish can kill a human in under five minutes , making it one of the most potent poisons of any animal in the world . other jellyfish superpowers are less lethal . one species of jellyfish glows green when it 's agitated , mostly thanks to a biofluorescent compound called green fluorescent protein , or gfp . scientists isolated the gene for gfp and figured out how to insert it into the dna of other cells . there , it acts like a biochemical beacon , marking genetic modifications , or revealing the path of critical molecules . scientists have used the glow of gfp to watch cancer cells proliferate , track the development of alzheimer 's , and illuminate countless other biological processes . developing the tools and techniques from gfp has netted three scientists a nobel prize in 2008 , and another three in 2014 . but it 's jellyfish who may be the most successful organisms on earth . ancient fossils prove that jellyfish have inhabited the seas for at least 500 million years , and maybe go back over 700 million . that 's longer than any other multiorgan animal . and as other marine animals are struggling to survive in warmer and more acidic oceans , the jellyfish are thriving , and perhaps getting even more numerous . it does n't hurt that some can lay as many as 45,000 eggs in a single night . and there 's some jellyfish whose survival strategy almost sounds like science fiction . when the immortal jellyfish is sick , aging , or under stress , its struggling cells can change their identity . the tiny bell and tentacles deteriorate and turn into an immature polyp that spawns brand new clones of the parent . as far as we know , these are the only animals who found a loophole when facing mortality . that 's pretty sophisticated for species that are 95 % water and predate the dinosaurs .
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it exerts over 550 times the pressure of mike tyson 's strongest punch to inject venom into the victim . some jellyfish stings barely tingle , but others cause severe skin damage . the venom of one box jellyfish can kill a human in under five minutes , making it one of the most potent poisons of any animal in the world .
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as the climate changes , jellyfish are thriving in some places and disappearing in others . why is an understanding of jellyfish important ?
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massive vines that blanket the southern united states , climbing as high as 100 feet as they uproot trees and swallow buildings . a ravenous snake that is capable of devouring an alligator . rabbit populations that eat themselves into starvation . these are n't horror movie concepts . they 're real stories , but how could such situations exist in nature ? all three are examples of invasive species , organisms harmful not because of what they are , but where they happen to be . the kudzu vine , for example , had grown quality in its native east asia , eaten by various insects and dying off during the cold winters . but its fortunes changed when it was imported into the southeastern united states for porch decoration and cattle feed . its planting was even subsidized by the government to fight soil erosion . with sunny fields , a mild climate , and no natural predators in its new home , the vine grew uncontrollably until it became known as the plant that ate the south . meanwhile in florida 's everglades , burmese pythons , thought to have been released by pet owners , are the cause of decreasing populations of organisms . they 're successfully outcompeting top predators , such as the alligator and panther , causing a significant reduction in their food sources . they 're not a problem in their native asia because diseases , parasites , and predators help to control their population size . and in australia , european rabbits eat so many plants that they wipe out the food supply for themselves and other herbivores . they 're a pretty recent addition , intentionally introduced to the continent because one man enjoyed hunting them . like the burmese pythons , various factors in their native habitat keep their numbers in control . but in australia , the lack of predators and a climate perfect for year-long reproduction allows their populations to skyrocket . so why does this keep happening ? most of the world 's ecosystems are the result of millennia of coevolution by organisms , adapting to their environment and each other until a stable balance is reached . healthy ecosystems maintain this balance via limiting factors , environmental conditions that restrict the size or range of a species . these include things like natural geography and climate , food availability , and the presence or absence of predators . for example , plant growth depends on levels of sunlight and soil nutrients . the amount of edible plants affects the population of herbivores , which in turn impacts the carnivores that feed on them . and a healthy predator population keeps the herbivores from becoming too numerous and devouring all the plants . but even minor changes in one factor can upset this balance , and the sudden introduction of non-native organisms can be a pretty major change . a species that is evolved in a separate habitat will be susceptible to different limiting factors , different predators , different energy sources , and different climates . if the new habitat 's limiting factors fail to restrict the species growth , it will continue to multiply , out-competing native organisms for resources and disrupting the entire ecosystem . species are sometimes introduced into new habitats through natural factors , like storms , ocean currents , or climate shifts . the majority of invasive species , though , are introduced by humans . often this happens unintentionally , as when the zebra mussel was accidentally brought to lake erie by cargo ships . but as people migrate around the world , we have also deliberately brought our plants and animals along , rarely considering the consequences . but now that we 're learning more about the effects of invasive species on ecosystems , many governments closely monitor the transport of plants and animals , and ban the imports of certain organisms . but could the species with the most drastic environmental impact be a group of primates who emerged from africa to cover most of the world ? are we an invasive species ?
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most of the world 's ecosystems are the result of millennia of coevolution by organisms , adapting to their environment and each other until a stable balance is reached . healthy ecosystems maintain this balance via limiting factors , environmental conditions that restrict the size or range of a species . these include things like natural geography and climate , food availability , and the presence or absence of predators .
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some examples of limiting factors are :
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[ music playing ] my goal is to not actually do any measurements other than using pie . so the entire thing is going to pie based . we get the circumference in the exact number of pies -- give or take -- we get the diameter in number of pies . divide one by the other , we get pi . [ music playing ] pi was historically rarely calculated this way , because it 's notoriously inaccurate to try and get -- i know , we 're idiots -- it 's notoriously inaccurate to try and calculate pi by measuring a circle . [ music playing ] to get any kind of accuracy on our final answer we have to be as precise as we can be . [ music playing ] this is a mild problem , because i want to go from the very edge of the circle . but as you can see , i 've positioned all the pies exactly on the line as if they 're little mini tangents . so i 'm going to have to move these two out and then i can start doing the diameter exactly on the circumference there , like that . [ music playing ] so that 's 84 and 1/3 . 264 and 2/3 pies around , we have the diameter , is 84 and 1/3 pie . to get pi , we just divide the circumference by the diameter . ok , and if we actually work out what that is , it equals -- that 's pretty good . pi from pies , we got 3.13834 , which is approximately 3.14 . so using pies , we 've got pi to be 3.14 . i am a very happy man right now . with the diameter , and if i know that ratio , i can just measure the diameter . that 's the easy bit to measure . the center point will be my pen , and the outside will be the chalk . so the pies , in theory , are a fairly consistent size . so they 're all -- yeah they 're about the same . ok. [ music playing ]
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so the entire thing is going to pie based . we get the circumference in the exact number of pies -- give or take -- we get the diameter in number of pies . divide one by the other , we get pi .
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in the video a circle is drawn with chalk - if the pies ( each with a 10.5cm diameter ) had been placed on the centre circle of a full-sized soccer pitch , how many pies would have been needed to cover the circle and its diameter ?
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the dna in just one of your cells gets damaged tens of thousands of times per day . multiply that by your body 's hundred trillion or so cells , and you 've got a quintillion dna errors everyday . and because dna provides the blueprint for the proteins your cells need to function , damage causes serious problems , such as cancer . the errors come in different forms . sometimes nucleotides , dna 's building blocks , get damaged , other times nucleotides get matched up incorrectly , causing mutations , and nicks in one or both strands can interfere with dna replication , or even cause sections of dna to get mixed up . fortunately , your cells have ways of fixing most of these problems most of the time . these repair pathways all rely on specialized enzymes . different ones respond to different types of damage . one common error is base mismatches . each nucleotide contains a base , and during dna replication , the enzyme dna polymerase is supposed to bring in the right partner to pair with every base on each template strand . adenine with thymine , and guanine with cytosine . but about once every hundred thousand additions , it makes a mistake . the enzyme catches most of these right away , and cuts off a few nucleotides and replaces them with the correct ones . and just in case it missed a few , a second set of proteins comes behind it to check . if they find a mismatch , they cut out the incorrect nucleotide and replace it . this is called mismatch repair . together , these two systems reduce the number of base mismatch errors to about one in one billion . but dna can get damaged after replication , too . lots of different molecules can cause chemical changes to nucleotides . some of these come from environmental exposure , like certain compounds in tobacco smoke . but others are molecules that are found in cells naturally , like hydrogen peroxide . certain chemical changes are so common that they have specific enzymes assigned to reverse the damage . but the cell also has more general repair pathways . if just one base is damaged , it can usually be fixed by a process called base excision repair . one enzyme snips out the damaged base , and other enzymes come in to trim around the site and replace the nucleotides . uv light can cause damage that 's a little harder to fix . sometimes , it causes two adjacent nucleotides to stick together , distorting the dna 's double helix shape . damage like this requires a more complex process called nucleotide excision repair . a team of proteins removes a long strand of 24 or so nucleotides , and replaces them with fresh ones . very high frequency radiation , like gamma rays and x-rays , cause a different kind of damage . they can actually sever one or both strands of the dna backbone . double strand breaks are the most dangerous . even one can cause cell death . the two most common pathways for repairing double strand breaks are called homologous recombination and non-homologous end joining . homologous recombination uses an undamaged section of similar dna as a template . enzymes interlace the damaged and undamgaed strands , get them to exchange sequences of nucleotides , and finally fill in the missing gaps to end up with two complete double-stranded segments . non-homologous end joining , on the other hand , does n't rely on a template . instead , a series of proteins trims off a few nucleotides and then fuses the broken ends back together . this process is n't as accurate . it can cause genes to get mixed up , or moved around . but it 's useful when sister dna is n't available . of course , changes to dna are n't always bad . beneficial mutations can allow a species to evolve . but most of the time , we want dna to stay the same . defects in dna repair are associated with premature aging and many kinds of cancer . so if you 're looking for a fountain of youth , it 's already operating in your cells , billions and billions of times a day .
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even one can cause cell death . the two most common pathways for repairing double strand breaks are called homologous recombination and non-homologous end joining . homologous recombination uses an undamaged section of similar dna as a template . enzymes interlace the damaged and undamgaed strands , get them to exchange sequences of nucleotides , and finally fill in the missing gaps to end up with two complete double-stranded segments .
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for homologous recombination to occur :
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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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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 .
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what value of produce was wasted in america in 2010 ?
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there have been many different things written and said about marriage . from the sweetly inspirational to the hilariously cynical . but what many of them have in common is that they sound like they express a universal and timeless truth , when in fact nearly everything about marriage , from its main purpose to the kinds of relationships it covers to the rights and responsibilities involved , has varied greatly between different eras , cultures and social classes . so , let 's take a quick look at the evolution of marriage . pair bonding and raising children is as old as humanity itself . with the rise of sedentary agricultural societies about 10,000 years ago , marriage was also a way of securing rights to land and property by designating children born under certain circumstances as rightful heirs . as these societies became larger and more complex , marriage became not just a matter between individuals and families , but also an official institution governed by religious and civil authorities . and it was already well established by 2100 b.c . when the earliest surviving written laws in the mesopotamian code of ur-nammu provided many specifics governing marriage , from punishments for adultery to the legal status of children born to slaves . many ancient civilizations allowed some form of multiple simultaneous marriage . and even today , less than a quarter of the world 's hundreds of different cultures prohibit it . but just because something was allowed does n't mean it was always possible . demographic realities , as well as the link between marriage and wealth , meant that even though rulers and elites in ancient mesopotamia , egypt and israel had multiple concubines or wives , most commoners could only afford one or two tending towards monogamy in practice . in other places , the tables were turned , and a woman could have multiple husbands as in the himalayan mountains where all brothers in a family marrying the same woman kept the small amount of fertile land from being constantly divided into new households . marriages could vary not only in the number of people they involved but the types of people as well . although the names and laws for such arrangements may have differed , publicly recognized same-sex unions have popped up in various civilizations throughout history . mesopotamian prayers included blessings for such couples , while native american two-spirit individuals had relationships with both sexes . the first instances of such arrangements actually being called `` marriage '' come from rome , where the emperors nero and elagabalus both married men in public ceremonies with the practice being explictly banned in 342 a.d . but similar traditions survived well into the christian era , such as adelphopoiesis , or `` brother-making '' in orthodox churches , and even an actual marriage between two men recorded in 1061 at a small chapel in spain . nor was marriage even necessarily between two living people . ghost marriages , where either the bride or groom were deceased , were conducted in china to continue family lineages or appease restless spirits . and some tribes in sudan maintain similar practices . despite all these differences , a lot of marriages throughout history did have one thing in common . with crucial matters like property and reproduction at stake , they were way too important to depend on young love . especially among the upperclasses , matches were often made by families or rulers . but even for commoners , who had some degree of choice , the main concern was practicality . the modern idea of marriage as being mainly about love and companionship only emerged in the last couple of centuries . with industrialization , urbanization and the growth of the middle class more people became independent from large extended families and were able to support a new household on their own . encouraged by new ideas from the enlightenment , people began to focus on individual happiness and pursuits , rather than familial duty or wealth and status , at least some of the time . and this focus on individual happiness soon led to other transformations , such as easing restrictions on divorce and more people marrying at a later age . so , as we continue to debate the role and definition of marriage in the modern world , it might help to keep in mind that marriage has always been shaped by society , and as a society 's structure , values and goals change over time , its ideas of marriage will continue to change along with them .
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but similar traditions survived well into the christian era , such as adelphopoiesis , or `` brother-making '' in orthodox churches , and even an actual marriage between two men recorded in 1061 at a small chapel in spain . nor was marriage even necessarily between two living people . ghost marriages , where either the bride or groom were deceased , were conducted in china to continue family lineages or appease restless spirits .
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when did marriage originate ?
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just now , somewhere in the universe , a star exploded . there goes another one . in fact , a supernova occurs every second or so in the observable universe , and there is one on average every 25 to 50 years in a galaxy the size and age of the milky way . yet we 've never actually been able to watch one happen from its first violent moments . of course , how would we ? there are hundreds of billions of stars close enough that we could watch the supernova explosion break through the surface of the star . but we 'd have to have our best telescopes focused on the right one at precisely the right time to get meaningful data . suffice it to say , the odds of that happening are astronomically low . but what if we could anticipate a supernova before its light reached us ? that may seem impossible . after all , nothing travels faster than the speed of light , right ? as far as we know , yes . but in a race , fast does n't matter if you take a detour while someone else beelines it for the finish line . for exactly that reason , photons do n't win the supernova race to earth . neutrinos do . here 's why . there are two types of supernova . type 1 is when a star accumulates so much matter from a neighboring star , that a runaway nuclear reaction ignites and causes it to explode . in type 2 , the star runs out of nuclear fuel , so the gravitational forces pulling in overwhelm the quantum mechanical forces pushing out , and the stellar core collapses under its own weight in a hundredth of a second . while the outer reaches of the star are unaffected by the collapsed core , the inner edges accelerate through the void , smash into the core , and rebound to launch the explosion . in both of these scenarios , the star expels an unparalleled amount of energy , as well as a great deal of matter . in fact , all atoms heavier than nickel , including elements like gold and silver , only form in supernova reactions . in type 2 supernovae , about 1 % of the energy consists of photons , which we know of as light , while 99 % radiates out as neutrinos , the elementary particles that are known for rarely interacting with anything . starting from the center of the star , the exploding matter takes tens of minutes , or even hours , or in rare cases , several days , to reach and break through the surface of the star . however , the neutrinos , thanks to their non-interactivity , take a much more direct route . by the time there is any visible change in the star 's suface , the neutrinos typically have a several hour head start over the photons . that 's why astronomers and physicists have been able to set up a project called snews , the supernova early warning system . when detectors around the world pick up bursts of neutrinos , they send messages to a central computer in new york . if multiple detectors receive similar signals within ten seconds , snews will trigger an alert warning that a supernova is imminent . aided by some distance and direction information from the neutrino detectors , the amateur astronomers and scientists alike will scan the skies and share information to quickly identify the new galactic supernova and turn the world 's major telescopes in that direction . the last supernova that sent detectable neutrinos to earth was in 1987 on the edge of the tarantula nebula in the large magellanic cloud , a nearby galaxy . its neutrinos reached earth about three hours ahead of the visible light . we 're due for another one any day now , and when that happens , snews should give you the opportunity to be among the first to witness something that no human has ever seen before .
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but in a race , fast does n't matter if you take a detour while someone else beelines it for the finish line . for exactly that reason , photons do n't win the supernova race to earth . neutrinos do .
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why are supernova neutrinos able to travel to earth without getting caught in the plasma envelope like photons do ?
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translator : marcia de brito reviewer : ariana bleau lugo ( guitar music throughout ) music is a language . both music and verbal languages serve the same purpose . they are both forms of expression . they can be used as a way to communicate with others . they can be read and written . they can make you laugh or cry , think or question , and can speak to one or many . and both can definitely make you move . in some instances , music works better than the spoken word , because it does n't have to be understood to be effective . although many musicians agree that music is a language , it is rarely treated as such . many of us treat it as something that can only be learned by following a strict regimen , under the tutelage of a skilled teacher . this approach has been followed for hundreds of years with proven success , but it takes a long time . too long . think about the first language you learn as a child . more importantly , think about how you learned it . you were a baby when you first started speaking , and even though you spoke the language incorrectly you were allowed to make mistakes . and the more mistakes you made , the more your parents smiled . learning to speak was not something you were sent somewhere to do only a few times a week . and the majority of the people you spoke to were not beginners . they were already proficient speakers . imagine your parents forcing you to only speak to other babies until you were good enough to speak to them . you would probably be an adult before you could carry on a proper conversation . to use a musical term , as a baby , you were allowed to jam with professionals . if we approach music in the same natural way we approached our first language , we will learn to speak it in the same short time it took to speak our first language . proof of this could be seen in almost any family where a child grows up with other musicians in the family . here are a few keys to follow in learning or teaching music . in the beginning , embrace mistakes , instead of correcting them . like a child playing air guitar , there are no wrong notes . allow young musicians to play and perform with accomplished musicians on a daily basis . encourage young musicians to play more than they practice . the more they play the more they will practice on their own . music comes from the musician , not the instrument . and most importantly , remember that a language works best when we have something interesting to say . many music teachers never find out what their students have to say . we only tell them what they are supposed to say . a child speaks a language for years before they even learn the alphabet . too many rules at the onset , will actually slow them down . in my eyes , the approach to music should be the same . after all , music is a language too .
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like a child playing air guitar , there are no wrong notes . allow young musicians to play and perform with accomplished musicians on a daily basis . encourage young musicians to play more than they practice .
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should beginning musicians play with accomplished musicians ? why ? how often should it happen ? who are some of your musical idols ? do you think they improve when they play with other musicians ?
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