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germanium is the first element in the periodic table , beginning at hydrogen , that ’ s named after a country : it is named after germany . there are other elements named after france and poland and america but we will come to those later . one of the things about germanium and what really makes it important in the per...
if you look at it in visible light it looks like a metal . germanium na , na , n-na na . i have used germanium mirrors in some of my experiments . the lasers that i used when i was younger had a germanium mirror that let the light out at the front of it and germanium is used quite widely in electronics . this is quite ...
germanium is in the same group as carbon and silicon , but while both carbon and silicon have the stable oxidation state of +4 , what about germanium ? why is this the case ?
at pixar , we 're all about telling stories , but one story that has n't been told very much is the huge degree to which math is used in the production of our films . the math that you 're learning in middle school and high school is used all the time at pixar . so , let 's start with a very simple example . anybody re...
it 's dory . okay , that was easy . here 's a little harder one .
design a character that would be really easy to describe mathematically . what makes the design easy ?
is it a flying comma , or a quotation mark chopped in half ? either way , you may already be well-versed in how to use the apostrophe , but here 's a quick refresher on its usage . the apostrophe can be used in three ways : to mark possession , to mark contraction , to mark the plural of single letters . most of the ti...
certain pronouns already have possession built in and do n't need an apostrophe . remembering that will help you avoid one of the trickiest snags in english grammar : its vs. it 's . `` it 's '' only take an apostrophe when it 's a contraction for `` it is '' or `` it has . ''
as the english language evolves , so do english grammar `` rules '' and `` style '' choices . why ?
the biggest kidney stone on record weighed more than a kilogram and was 17 centimeters in diameter . the patient did n't actually swallow a stone the size of a coconut . kidney stones form inside the body , but unfortunately , they 're extremely painful to get out . a kidney stone is a hard mass of crystals that can fo...
stones can also be surgically removed through an incision in the patient 's back or groin . what about just avoiding kidney stones in the first place ? for people prone to them , their doctor may recommend drinking plenty of water , which dilutes the calcium oxalate and other compounds that eventually build up into pai...
what is happening to the incidence of kidney stones in the human population ?
despite advances in medicine , cancer remains one of the most frightening diagnoses patients can receive . what makes it so difficult to cure is that it 's not one illness , but a family of over 100 diseases occurring in different types of cells . and one type of cancer has the unfortunate distinction of afflicting chi...
to restore the normal function of the blood , leukemic cells have to be eliminated . but because leukemias are not solid tumors , they ca n't be removed surgically . instead , the cells are killed inside the body using various treatments that include chemotherapy , a combination of drugs that destroys quickly multiplyi...
doctors ca n't use surgery to remove leukemia because :
brady haran : hey there , everyone . today 's video is about richard feynman -- a lot of people 's favorite scientist -- and safe breaking . but i just wanted to point out at the start that most safes , or secure filing cabinets , actually have one dial . and if you 've got a three number combination , for example , yo...
i do n't want to get all the safe enthusiasts out there too fired up and angry in the comments section . but for now , here 's professor bowley with his pretend safe and the story of richard feynman and his world war ii safe cracking . professor roger bowley : i 'm talking about feynman and how he managed to crack safe...
why did richard feynman start cracking safes ?
right now , you 're probably sitting down to watch this video and staying seated for a few minutes to view it is probably okay . but the longer you stay put , the more agitated your body becomes . it sits there counting down the moments until you stand up again and take it for a walk . that may sound ridiculous . our b...
it sits there counting down the moments until you stand up again and take it for a walk . that may sound ridiculous . our bodies love to sit , right ?
sitting may help your brain function better .
you 've probably heard of the human genome , the huge collection of genes inside each and every one of your cells . you probably also know that we 've sequenced the human genome , but what does that actually mean ? how do you sequence someone 's genome ? let 's back up a bit . what is a genome ? well , a genome is all ...
you probably also know that we 've sequenced the human genome , but what does that actually mean ? how do you sequence someone 's genome ? let 's back up a bit .
if there are 3 billion letters in the reference genome , how much did it cost per letter to sequence the first human genome ?
since the dawn of humanity , an estimated 100.8 billion people have lived and died , a number that increases by about .8 % of the world 's population each year . what happens to all of those people 's bodies after they die and will the planet eventually run out of burial space ? when a person 's heart stops beating , t...
these days , with suitable burial land running out in high-population areas , purchasing private gravesites can be costly , and many people ca n't afford simple burials . even cremation , the second most common burial practice in the world , comes with a high cost . as for the question of running out of space , the iss...
what is the second most common burial method ?
the secrets of the x chromosome . these women are identical twins . they have the same nose , the same hair color , the same eye color . but this one is color blind for green light , and this one is n't . how is that possible ? the answer lies in their genes . for humans , the genetic information that determines our ph...
now we can explain our color blind twin . both sisters inherited one mutant copy of the green receptor gene and one normally functioning copy . the embryo split into twins before x inactivation , so each twin ended up with a different inactivation pattern .
what is one cause of colorblindness ?
testing , testing , one , two , three . when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science ,...
a food web containing twenty populations can generate thousands of loops of up to twenty links in length . but instead of forming a disordered cacophany , feedback loops in ecological systems play together , creating regular patterns just like multiple instruments , coming together to create a complex but harmonious pi...
how do all the feedbacks together in an ecosystem create harmony ? one important mechanism is :
imagine if half the people in your neighborhood , your city , or even your whole country were wiped out . it might sound like something out of an apocalyptic horror film , but it actually happened in the 14th century during a disease outbreak known as the black death . spreading from china through asia , the middle eas...
as a result , most europeans in the early 14th century experienced a steady decline in living standards , marked by famine , poverty and poor health , leaving them vulnerable to infection . and indeed , the skeletal remains of black death victims found in london show telltale signs of malnutrition and prior illness . t...
what proportion of the affected population was killed by the black death ?
with social media sites being used by ⅓ of the entire world , they ’ ve clearly had an major influence on society . but what about our bodies ? here are 5 crazy ways that social media and the internet are affecting your brain right now ! can ’ t log off ? surprisingly , 5-10 % of internet users are actually unable to c...
or wait ... did it even buzz ? phantom vibration syndrome is a relatively new psychological phenomenon where you think you felt your phone go off , but it didn ’ t . in one study , 89 % of test subjects said they experienced this at least once every two weeks .
in your own words , explain phantom vibration syndrome . have you ever experienced it ?
if i say , `` venice , '' do you imagine yourself gliding down the grand canal , serenaded by a gondolier ? there 's no doubt that the gondola is a symbol of venice , italy , but how did this curious banana-shaped black boat get its distinctive look ? the origins of the venetian gondola are lost to history , but by the...
specialized artisans supplied their gondola-making colleagues with elaborate covered passenger compartments , upholstery and ornaments of steel and brass . oar makers became integral partners to the gondola makers . the venetian oarlock , or fórcola , began as a simple wooden fork , but evolved into a high-precision to...
why do you think that gondoliers and gondola makers appear less frequently in historical documents than , let ’ s say , politicians or bankers ?
translator : andrea mcdonough reviewer : bedirhan cinar you might have heard that we 're running out of fresh water . this might sound strange to you because , if you live in a place where water flows freely from the tap or shower at any time , it sure does n't seem like a big deal . it 's just there , right ? wrong ! ...
agricultural and industrial patterns of water use need serious attention . how do our societies value water ? distribute it ?
in your own words , explain how our societies value water .
translator : andrea mcdonough reviewer : bedirhan cinar right now , trillions of chemical reactions are humming away in the cells of your body . you never feel them , but without these reactions , you would n't be alive . unfortunately , each of those reactions needs some help . you see , most molecules are stable , th...
once they are convinced , it 's a piece of cake . bonds break , atoms rearrange , and the rest of the reaction happens automatically . after that first push , the body does n't need to put in any more energy to help the reaction along .
in a chemical reaction , atoms do which of the following ?
you might remember a pair of ted-ed lessons written and performed by two educators , brad voytek and tim verstynen . these two scientists used a drooling , hag-faced , animated zombie as a mechanism to model the symptoms and medical diagnosis process for various neurological conditions . for example , they spent time d...
you might remember a pair of ted-ed lessons written and performed by two educators , brad voytek and tim verstynen . these two scientists used a drooling , hag-faced , animated zombie as a mechanism to model the symptoms and medical diagnosis process for various neurological conditions . for example , they spent time d...
the two educators used a drooling , hag-faced , animated zombie as a mechanism to model the symptoms and medical diagnosis process for various neurological conditions .
testing , testing , one , two , three . when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science ,...
when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science , is a phenomenon called mutual causal in...
describe three examples of positive feedback and three of negative feedback , in other systems that have many interacting parts – such as economic , social , political systems .
when you hear the word art , what comes to mind ? a painting , like the mona lisa , or a famous sculpture or a building ? what about a vase or a quilt or a violin ? are those things art , too , or are they craft ? and what 's the difference anyway ? it turns out that the answer is not so simple . a spoon or a saddle ma...
in fact , some works that might be considered craft , a peruvian rug , a ming dynasty vase , a totem pole , are considered the cultures ' preeminent visual forms . when art historians of the 19th century saw that the art of some non-western cultures did not change for thousands of years , they classified the works as p...
what are some of the ways in which renaissance culture changed people ’ s views of the role of art—and artists—in western society ?
if i were to distill the 20 years of elephant research that i 've done into one sentence , what would it be ? what could i tell you ? i would say that elephants are just like us ! and what do i mean by that ? it takes a lot of patience to be out there in the field and trying to figure out patterns of these very slow an...
well , in fact , their families are very similar to ours . and family is extremely important to elephants . they grow up in very tight-knit families and they have extended families .
when an extended family group of elephants meets up at a waterhole when they haven ’ t seen each other in a while ________ .
this is a tomato plant , and this is an aphid slowly killing the tomato plant by sucking the juice out of its leaves . the tomato is putting up a fight using both physical and chemical defenses to repel the attacking insects . but that 's not all . the tomato is also releasing compounds that signal nearby tomato plants...
they can cause tiny wounds in the inside of animals ' mouths , which create entry points for toxins . the mimosa plant has a strategy designed to prevent herbivores from taking a bite at all . specialized mechanoreceptor cells detect touch and shoot an electrical signal through the leaflet to its base causing cells the...
one of the defense strategies that mimosa plants use against herbivores is :
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...
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 first claw machines were explicitly marketed as highly profitable for owners . when were they invented and why were they so popular at the time ?
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 bl...
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 ...
what is the biggest shopping day of the year in the united states ?
if you ever find yourself gazing at falling snow , why not catch a few snowflakes on your glove and examine their shapes ? you might notice that they look symmetrical , and if you look closely , you 'll see they have six sides . you could say a snowflake is simply frozen water , but compare one with an ice cube from th...
completely dry snow is very difficult to ski on because there 's too much friction between the jagged snowflakes and the ski surface . so what 's happening is that as skis move , they rub the surface of the snow and warm it up , creating a thin layer of water , which helps them slide along . so technically , it 's not ...
why can a skier slide over snow ?
in 1985 , three researchers on a dolphin-studying expedition got a little bored . to lighten things up , one pretended to be poseidon by placing a seaweed garland on his head and then throwing it into the ocean . moments later , a dolphin surfaced with the seaweed crowning her head . sure , this could have been a coinc...
this sort of cultural transmission even extends to tool use . one group of bottlenose dolphins off the australian coast nicknamed the dolphin sponge club , has learned how to cover their rostrums with sponges when rooting in sharp corals , passing the knowledge from mother to daughter . dolphins have even demonstrated ...
the dolphin sponge club :
in 1996 , 56 volunteers took part in a study to test a new painkiller called trivaricaine . on each subject , one index finger was covered in the new painkiller while the other remained untouched . then , both were squeezed in painful clamps . the subjects reported that the treated finger hurt less than the untreated o...
in these cases , placebos are often used as a control to fine-tune the trial so that the effects of the new versus the old or alternative drug can be precisely compared . but of course , we know the placebos exert their own influence , too . thanks to the placebo effect , patients have experienced relief from a range o...
list some of the benefits that patients have been known to experience while under the influence of placebos .
many of the inanimate objects around you probably seem perfectly still . but look deep into the atomic structure of any of them , and you 'll see a world in constant flux . stretching , contracting , springing , jittering , drifting atoms everywhere . and though that movement may seem chaotic , it 's not random . atoms...
translation allows the molecule to move in the direction of any of them . that 's three degrees of freedom . it can also rotate around any of these three axes .
a large protein consisting of 94 atoms has ____ vibrational ‘ degrees of freedom . ’
some people ca n't see the forest for the trees , but before stephen sillett , no one could see or even imagine the forest in the trees . stephen was an explorer of new worlds from the start . he spent his boyhood in harrisburg , pennsylvania reading tolkien and playing dungeons and dragons with his brother scott . but...
he noticed that the higher he went , the thicker the branches were , not the case with most trees . he found moist mats of soil many inches thick , made from fallen needles , bark , other plant debris and dust from the sky piled on the tops of the large branches . he even found reiterations : new redwood tree trunks gr...
soil mats form on the large branches over long periods of time . explain the importance of these soil mats in the redwood canopy ecosystem .
how many times can you fold a piece of paper ? assume that one had a piece of paper that was very fine , like the kind they typically use to print the bible . in reality , it seems like a piece of silk . to qualify these ideas , let 's say you have a paper that 's one-thousandth of a centimeter in thickness . that is 1...
how many times can you fold a piece of paper ? assume that one had a piece of paper that was very fine , like the kind they typically use to print the bible .
if we fold the paper ten times , how thick would it be ?
mastering any physical skill , be it performing a pirouette , playing an instrument , or throwing a baseball , takes practice . practice is the repetition of an action with the goal of improvement , and it helps us perform with more ease , speed , and confidence . so what does practice do in our brains to make us bette...
mastering any physical skill , be it performing a pirouette , playing an instrument , or throwing a baseball , takes practice . practice is the repetition of an action with the goal of improvement , and it helps us perform with more ease , speed , and confidence .
how is slow practice beneficial in the development of complex , coordinated skills in dance , sports , the martial arts , and playing a musical instrument ?
some superheros can move faster than the wind . the men in apollo 10 reached a record-breaking speed of around 25,000 miles per hour when the shuttle re-entered the earth 's atmosphere in 1969 . would n't we save a lot of time to be able to move that fast ? but what 's the catch ? air is not empty . elements like oxyge...
that sounds very romantic , but , in reality , that girl will probably suffer more damage from the hero than the bullet if he moved her at super speed . newton 's first law of motion deals with inertia , which is the resistance to a change in its state of motion . so , an object will continue moving or staying at the s...
newton ’ s first law of motion deals with inertia , which is
so i 'm here today to encourage you to think about new york city , and not just as one of humanity 's greatest achievements , but as home to native wildlife that are subject to a grand evolutionary experiment . so take this forested hillside in northern manhattan , for example . this is one of the last areas left in th...
this guy , we catch in almost every forested area in new york city . this is the white-footed mouse -- not the mouse you find running around your apartment . this is a native species , been here long before humans .
munshi-south and his colleagues are analyzing dna from the white-footed mouse in order to
translator : andrea mcdonough reviewer : jessica ruby how big was that fish you caught ? this big ? this big ? this big ? without photographic evidence , there 's nothing that proves you caught a whopper , and that 's been true since the dawn of fishing . in fact , hundreds of years ago , long before photography could ...
in fact , hundreds of years ago , long before photography could capture the moment , japanese fishermen invented their own way to record trophy catches . they called it gyotaku . gyotaku is the ancient art of printing fish that originated in japan as a way to record trophy catches prior to the modern day camera .
what was the original purpose for gyotaku ?
translator : andrea mcdonough reviewer : bedirhan cinar being human , we each view ourselves as a unique and independent individual , but we 're never alone ! millions of microscopic beings inhabit our bodies , and no two bodies are the same . each is a different habitat for microbial communities : from the arid desert...
every person has a unique and diverse community of gut microbes that can process food in different ways . one person 's gut microbes may be capable of releasing only a fraction of the calories that another person 's gut microbes can extract . so , what determines the membership of our gut microbial community ?
one person 's gut microbes may be capable of releasing only a fraction of the calories that another person 's gut microbes can extract .
4,000 years ago , the ancient sumerians made a surprising discovery . if they scraped the bark off a particular kind of tree and ate it , their pain disappeared . little did they know that why they 'd found was destined to influence the future course of medicine . what the sumerians had discovered was a precursor to th...
in fact , the 1982 nobel prize winners also demonstrated that aspirin slows production of thromboxanes , chemicals that cause clumping of platelets , which in turn form blood clots . a landmark clinical trial showed that aspirin reduced heart attack risk by 44 % in participants who took the drug . today , we prescribe ...
aspirin is one of the various strategies used to prevent heart attacks . what are some of the other approaches people could take to reduce their risk ?
in 1984 , an enterprising australian doctor named barry marshall decided to take a risk . too many of his patients were complaining of severe abdominal pain due to stomach ulcers , which are sores in the lining of the upper intestinal tract . at the time , few effective treatments for ulcers existed , and many sufferer...
but they make up less than 1 % of all cases . dr. marshall and dr. warren pinpointed a spiral-shaped bacteria called helicobacter pylori , or h. pylori , as the real offender . h. pylori is one of humanity 's oldest and most frequent companions , having joined us at least 50,000 years ago , and now found in 50 % of peo...
which of the following factors most influences when helicobacter pylori prompts the development of ulcers ?
in 1978 , louise brown became the world 's first baby to be born by in vitro fertilization , or ivf . her birth revolutionized the field of reproductive medicine . given that approximately one in eight heterosexual couples has difficulty conceiving , and that homosexual couples and single parents often need clinical he...
in 1978 , louise brown became the world 's first baby to be born by in vitro fertilization , or ivf . her birth revolutionized the field of reproductive medicine .
although many patients want twins , a common phenomenon with in vitro fertilization , why has there been a push to try to reduce the number of twins born from ivf ?
figs are one of my favorite foods . they 're sweet and floral , and there 's something about the texture that i find so delightful—the outside is soft , but the seeds in the middle give you this totally satisfying crunch . but it turns out that many species of figs contain the bodies of dead wasps . i 'm anna and this ...
but if the flowers are trapped inside the fig how do they get pollinated ? well , that 's where fig wasps come in . in most species , pregnant female fig wasps carrying pollen are attracted to young figs . they enter through a tiny opening at the fig ’ s bottom that ’ s highly selective—it usually only lets in the exac...
before the newly-hatched female fig wasps leave the fig , they pick up some pollen , then bore their way out through tiny holes . so when they enter a new fig what two tasks are they accomplishing ?
translator : andrea mcdonough reviewer : bedirhan cinar this is zeno of elea , an ancient greek philosopher famous for inventing a number of paradoxes , arguments that seem logical , but whose conclusion is absurd or contradictory . for more than 2,000 years , zeno 's mind-bending riddles have inspired mathematicians a...
now you can see why we choose this particular way of cutting up the square . we 've obtained the same infinite series as we had for the time of zeno 's journey . as we construct more and more blue pieces , to use the math jargon , as we take the limit as n tends to infinity , the entire square becomes covered with blue...
an infinite series :
meet our chemist , harriet . she has a chemical reaction that needs to occur more quickly . a chemist has some processes at her disposal that can help her speed up her reaction , and she knows of five ways . and to remember them , she thinks back to her days as a high school student , and the day she got a date for the...
in order to facilitate this improved dance-date-getting process , i propose five changes to all schools that parallel harriet 's five ways to increase chemical reaction rates . first , i propose that we shrink the size of the hallways . this will make it more difficult to safely navigate the hallways and will cause mor...
in this analogy , shrinking the hallways is analogous to :
there are many stories that can be told about world war ii , from the tragic to the inspring . but perhaps one of the most heartrending experiences was that of the akune family , divided by the war against each other and against their own identities . ichiro akune and his wife yukiye immigrated to america from japan in...
the brothers not only had very limited contact with their family in japan , but found themselves confined to a camp in a remote part of colorado . but their story took another twist when recruiters from the us army 's military intelligence service arrived at the camp looking for japanese-speaking volunteers . despite t...
what was the primary reason harry and ken akune joined the u.s. army 's military intelligence service ?
in 1997 , a french woman named jeanne calment passed away after 122 years and 164 days on this earth , making her the oldest known person in history . her age was so astounding that a millionaire pledged $ 1 million to anyone who could break her record . but in reality , living to this age or beyond is a feat that very...
those changes in turn drive their decline , and subsequently , the failure of the whole organism . the exact mechanisms of aging are poorly understood . but recently , scientists have identified nine physiological traits , ranging from genetic changes to alterations in a cell 's regenerative ability that play a central...
why is it difficult to define aging ?
every year , about 1,000 new words are added to the oxford english dictionary . where do they come from , and how do they make it into our everyday lives ? with over 170,000 words currently in use in the english language , it might seem we already have plenty . yet , as our world changes , new ideas and inventions spri...
and today , the process works both ways , with english lending words like software to languages all over the world . another popular way to fill a vocabulary gap is by combining existing words that each convey part of the new concept . this can be done by combining two whole words into a compound word , like airport or...
a way to fill-in a conceptual gap in a language is to :
today i ’ m going to tell you about one of my favorite creatures to ever grace this planet . it ’ s a frog that ’ s pretty bizarre but also weirdly sweet and adorable . sadly , it went extinct just before i was born , so i thought i ’ d never get the chance to see it . but a few years ago , scientists tried to bring it...
not only would it have major impacts on ecosystems worldwide , and be a loss of beautiful biodiversity , but there is so much we still have to learn from these creatures that might be beneficial to human health and well-being . take the gastric-brooding frog . if we ’ d had more time to study it , maybe we could have l...
what made the gastric brooding frog go extinct ?
you might just want to sneak up so you don ’ t sprinkle any dirt at the bottom of this place where we turned it over . yeah ok. look at that soil , it is all cake looking . yeah it is . where are we ? look up yonder . to the left oh wow ! ok , let me get the soil before you start whacking ok ? oh yeah . salt blast cove...
so if we look into the quarry in the normal daylight in the absence of the snow it would look a bit like a lunar landscape . no the black stuff that is that stuff is crystal , that is the crystal in rocks , now i say that for one specific reason because during the apollo programme the astronauts , they came back from t...
why does this video begin with images of astronauts from the apollo program walking on the moon ?
rising temperatures and seas , massive droughts , changing landscapes . successfully adapting to climate change is growing increasingly important . for humans , this means using our technological advancement to find solutions , like smarter cities and better water management . but for some plants and animals , adapting...
critical climate refuges are being identified and set aside , and projects are underway to help mobile species move to more suitable climates . existing parks and protected areas are also doing climate change check-ups to help their wildlife cope . fortunately , it 's still within our power to preserve much of the wond...
humans will have to adapt to climate change too . predict the future for those people living in areas that will be most affected ( coastal areas , those in warmer climates , arctic areas ) .
flatulence , or passing gas , is a normal daily phenomenon . most individuals , yes , that includes you , will make anywhere from 500-1500 milliliters of gas and can pass gas ten to twenty times a day . but where does this bodily gas come from ? a small proportion may come from ingesting air during sleep , or at other ...
a small proportion may come from ingesting air during sleep , or at other times , but the majority of gas is produced by bacteria in our intestines as they digest parts of food which we can not . our intestine is home to trillions of bacteria living in a symbiotic relationship with us . we provide them with a safe plac...
trillions of bacteria live in a symbiotic relationship with humans . why is this beneficial ?
everyone knows that stories are made up of words , from short poems to epic novels . but did you know that a single word itself can tell an entire story ? you see , just as we can look at a story 's plot , setting , and characters , we can also study the history of an individual word , where it developed , and the cult...
but the older the word , the longer the story and the more it stands to reveal to us not only about itself , but about ourselves and our history . the oldest words in present-day english are those that come from old english , the ancestor of our modern language whose first seeds were planted about 1500 years ago . comp...
english is not as old as some languages ; it dates back only about
in 1984 , an enterprising australian doctor named barry marshall decided to take a risk . too many of his patients were complaining of severe abdominal pain due to stomach ulcers , which are sores in the lining of the upper intestinal tract . at the time , few effective treatments for ulcers existed , and many sufferer...
but they make up less than 1 % of all cases . dr. marshall and dr. warren pinpointed a spiral-shaped bacteria called helicobacter pylori , or h. pylori , as the real offender . h. pylori is one of humanity 's oldest and most frequent companions , having joined us at least 50,000 years ago , and now found in 50 % of peo...
approximately how much of the world ’ s population has helicobacter pylori ?
look at your hand . how do you know it 's really yours ? it seems obvious , unless you 've experienced the rubber hand illusion . in this experiment , a dummy hand is placed in front of you and your real hand is hidden behind a screen . both are simultaneously stroked with a paint brush . no matter how much you remind ...
and we have other senses , besides the typical five , such as the sense of balance and a sense of the relative location of our body parts . the rubber hand illusion , and similar virtual reality experiments , show that our senses can easily mislead us in our judgment of self . they also suggest that our bodies and exte...
what can we learn from rubber hand illusion or other virtual reality experiments ?
in 1997 , in a game between france and brazil , a young brazilian player named roberto carlos set up for a 35 meter free kick . with no direct line to the goal , carlos decided to attempt the seemingly impossible . his kick sent the ball flying wide of the players , but just before going out of bounds , it hooked to th...
too fast and it hooks too late . the same physics make it possible to score another apparently impossible goal , an unassisted corner kick . the magnus effect was first documented by sir isaac newton after he noticed it while playing a game of tennis back in 1670 .
which physics principal underlies the banana kick ?
a , c , e , d , b , k. no , this is n't some random , out of order alphabet . these are vitamins , and just like letters build words , they 're the building blocks that keep the body running . vitamins are organic compounds we need to ingest in small amounts to keep functioning . they 're the body 's builders , defende...
the system 's ability to circulate water-soluble vitamins in the bloodstream so easily means that most of them can be passed out equally easily via the kidneys . because of that , most water-soluble vitamins need to be replenished on a daily basis through the food we eat . but fat-soluble vitamins have staying power be...
how many fruits and vegetables do you need to get enough daily vitamins ?
what 's the worst bug on the planet ? you might vote for the horsefly or perhaps the wasp , but for many people , the worst offender is by far the mosquito . the buzzing , the biting , the itching , the mosquito is one of the most commonly detested pests in the world . in alaska , swarms of mosquitos can get so thick t...
in fact , humans hate mosquitos so much that we spend billions of dollars worldwide to keep them away from us -- from citronella candles to bug sprays to heavy-duty agricultural pesticides . but it 's not just that mosquitos are annoying , they 're also deadly . mosquitos can transmit everything from malaria to yellow ...
what do you do to prevent mosquitos from biting ?
( music ) quick ! what 's common between beef burgers , baseball training and auto mufflers ? tough question . let 's ask it another way . what 's the common factor between mcdonald 's , d-bat and meineke ? you may know the answer if , along with a big mac , you 've absorbed a fragment of the romantic story of ray kroc...
her health and beauty treatments have been copied , and her business model is dominant . in fact , half of retail sales in america are through martha harper 's franchising idea . so the next time you enjoy a mcdonald 's hamburger or a good night 's rest at a days inn , think of martha .
the expansion of martha harper ’ s franchising idea today drives half of all retail sales in america [ 5:07 ] . this means one woman has had a really remarkable effect on america ’ s economy . so why is she relatively unknown ?
we live in a society obsessed with music . we use music to worship , tell stories , to celebrate , to work , exercise , declare our love and sometimes our hatred , and , arguably most importantly , to dance . and , of course , we play music ourselves because , well , it 's a pleasant thing to do . thousands of years ag...
according to plato , only very specific types of music were beneficial to a person 's ethos . one should only listen to music that promotes intelligence , self-discipline , and courage , and all other kinds of music must be avoided . furthermore , plato fervently denounced any music that deviated from established music...
pick one of the muses and think about the art form or science she influenced . what are some ways her discipline is expressed in music or art today ?
as far as we know , medieval england was never invaded by ice zombies , or terrorized by dragons , but it was shaken by a power struggle between two noble families spanning generations and involving a massive cast of characters with complex motives and shifting loyalties . if that sounds familiar , it 's because the hi...
raising an army in france , he crossed the channel in 1485 and quickly defeated richard 's forces . and by marrying elizabeth of york , elder sister of the disappeared princes , the newly crowned henry vii joined the two roses , finally ending nearly a century of war . we often think of historical wars as decisive conf...
what were the ways in which henry tudor managed to finally end the war ?
hmmm , that 's not what we want , is it ? today 's digital cameras do a lot for us , but there 's no replacement for the human eye . it 's important to learn how cameras work with light to create an image , that way we 'll know what 's going on when it 's time to capture a moment . there are three variables that determ...
if we increase sensitivity , we 'll be able to use faster speeds and smaller apertures , but we 'll get noisier images . good thing we have something to tell us if we 're getting the correct amount of light to get a good exposure , the light meter . sound good to you ?
imagine you are shooting an indoor basketball match . players move fast , but you don´t have a large amount of light . which exposure will you use to capture faster action ?
- when you get to space , because you 're in a zero g environment , some really funky things happen to your body . ( upbeat music ) i grew an inch . right now , i 'm 5'11 '' but in space i was six-feet tall . on the ground , gravity compresses your spine , it pulls you down , the force factor going down . in space , wi...
- when you get to space , because you 're in a zero g environment , some really funky things happen to your body . ( upbeat music ) i grew an inch .
4. from the description in the video , determine what the word `` atrophy '' means .
you probably know the feeling . your phone utters its final plaintive `` bleep '' and cuts out in the middle of your call . in that moment , you may feel more like throwing your battery across the room than singing its praises , but batteries are a triumph of science . they allow smartphones and other technologies to e...
he tested his idea with a stack of alternating layers of zinc and copper , separated by paper or cloth soaked in a salt water solution . what happened in volta 's cell is something chemists now call oxidation and reduction . the zinc oxidizes , which means it loses electrons , which are , in turn , gained by the ions i...
oxidation and reduction are processes through which _____
the onset of cancer usually begins as a solitary tumor in a specific area of the body . if the tumor is not removed , cancer has the ability to spread to nearby organs , as well as places far away from the origin , such as the brain . so how does cancer move to new areas , and why are some organs more likely to get inf...
the war against cancer is a constant struggle , and scientists are hard at work developing new methods against metastasis . of recent interest is immunotherapy , a modality which involves harnessing the power of the immune system to destroy the migrating cells . this can be done in different ways , such as training imm...
which of the following is not a type of immunotherapy ?
so comrades , welcome to the lecture . what i am going to do now , we ’ re going to begin with an experiment to illustrate this point that the oxygen molecule , o2 , has unpaired electrons . now we ’ re outside just to show you the reactivity of this lovely stuff here , liquid oxygen . so you can see wonderful liquid o...
so near the earth ’ s surface , where you and i are at the moment , ozone is really quite dangerous because if you breathe it in it can start reacting with any sort of molecule that has bonds between carbon . but in the upper atmosphere , ozone is extremely important because it absorbs ultra-violet light that comes fro...
in the upper atmosphere , we can find a high concentration of ozone . why is this ozone layer so important to us ?
you may know that it takes light a zippy eight minutes to reach us from the surface of the sun , so how long do you think it takes light to travel from the sun 's core to its surface ? a few seconds or a minute at most ? well , oddly enough , the answer is many thousands of years . here 's why . photons are produced by...
the answer is given by this formula : distance equals step size times the square root of the number of steps . so if you were taking a random walk from your front door with a one meter stride each second , it would take you a million steps and eleven days just to travel one kilometer . so then how long does it take for...
list the zones of the sun from the exterior to the interior . give one characteristic of each layer .
caffeine a legal stimulant that most of us are pretty familiar with , many of us use every day , and some of us are addicted to . if you are a caffeine user , you probably know your limits . for me one small cup of coffee in the morning can help keep me alert and focused , whereas two small cups of coffee in the mornin...
oh no . caffeine also stimulates the production of adrenaline or epinephrine . adrenaline is a pretty well known hormone involved in the fight-or-flight response . it causes all sort of physiological reactions !
which of the following is not an effect of adrenaline ?
translator : andrea mcdonough reviewer : jessica ruby in the 11th and 12th centuries , most english commoners were illiterate . since they had no way to learn the bible , the clergy came up with an inventive solution : they 'd create plays out of certain bible stories so even people who could n't read could learn them ...
can you imagine what might happen to the story if the butcher 's guild put on the crucifixion of christ ? yes , without the clergy , the plays soon started changing from their true bible stories . by the end of the 14th century , a new form of drama , called the morality play , had evolved .
why were the plays reenactments of bible stories ?
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 ...
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 .
create a list of all the countries that may be involved in creating the t-shirt you might be wearing today .
in the early hours of august 13 , 1961 , east german construction workers flanked by soldiers and police began tearing up streets and erecting barriers throughout the city of berlin and its surroundings . this night marked the beginning of one of history 's most infamous dividing lines , the berlin wall . construction ...
but the announcement brought thousands of east berliners to the border crossing points in the wall , forcing the surprised guards to open the gates immediately . rejoicing crowds poured into west berlin as people from both sides danced atop the wall . and others began to demolish it with whatever tools they could find ...
the wall was built to :
physicists , air traffic controllers , and video game creators all have at least one thing in common : vectors . what exactly are they , and why do they matter ? to answer , we first need to understand scalars . a scalar is a quantity with magnitude . it tells us how much of something there is . the distance between yo...
what does that mean ? let 's say you and a friend are moving your tent . you stand on opposite sides so you 're facing in opposite directions .
you have walked to a friend ’ s house and suddenly get a phone call . “ where are you ? ” your sister asks . she wants to come and see you at your friend ’ s house . how do you use vectors to diagram the pathway to your friend ’ s house so your sister can arrive without getting lost ?
penguins have long captured the imagination and the hearts of people the world over . but while popular culture depicts them as clumsy , adorable birds with endlessly abundant populations , the truth is that penguins are exceedingly graceful , often ornery , and their populations are in rapid free fall . their real lif...
and sadly , most of this decline is attributable to human activities . historically , penguins have had to deal with multiple disturbances . the mass collection of penguin eggs and the harvesting of the seabird guano they nested in caused the dramatic decline of several penguin species .
penguins are faced with multiple human-based disturbances , and even though they only inhabit the southern hemisphere , things that are done in the northern hemisphere impact penguins as well . what are some of the global practices that harm penguins ? what changes can you make in your daily life to reduce your impact ...
meet our chemist , harriet . she has a chemical reaction that needs to occur more quickly . a chemist has some processes at her disposal that can help her speed up her reaction , and she knows of five ways . and to remember them , she thinks back to her days as a high school student , and the day she got a date for the...
meet our chemist , harriet . she has a chemical reaction that needs to occur more quickly . a chemist has some processes at her disposal that can help her speed up her reaction , and she knows of five ways .
explain how a chemical catalyst helps change the rate of a chemical reaction and give two examples of actual chemical catalysis .
today , more than half of all people in the world live in an urban area . by mid-century , this will increase to 70 % . but as recently as 100 years ago , only two out of ten people lived in a city , and before that , it was even less . how have we reached such a high degree of urbanization , and what does it mean for ...
but about 10,000 years ago , our ancestors began to learn the secrets of selective breeding and early agricultural techniques . for the first time , people could raise food rather than search for it , and this led to the development of semi-permanent villages for the first time in history . `` why only semi-permanent ?...
what led to the development of the first semi-permanent settlements ?
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 co...
a ravenous snake that is capable of devouring an alligator . rabbit populations that eat themselves into starvation . these are n't horror movie concepts .
one of the main problems caused by both the burmese python and european rabbit is :
this is a map of yellowstone national park for the most part the park is in wyoming but it extends a bit into montana and idaho this little 50 square miles section in idaho is what concerns us it 's called the zone of death because of a loophole that exists in the constitution of the united states if someone were to ex...
this is a map of yellowstone national park for the most part the park is in wyoming but it extends a bit into montana and idaho this little 50 square miles section in idaho is what concerns us it 's called the zone of death because of a loophole that exists in the constitution of the united states if someone were to ex...
yellowstone national park is mostly in which state ?
we check the time every day , all day long . but did you ever wonder - where did telling time come from ? why does it matter what time it is ? who determined the clock and why in the world are there so many different time zones ? the first form of telling time was the sundial and the earliest sundials known from the ar...
who determined the clock and why in the world are there so many different time zones ? the first form of telling time was the sundial and the earliest sundials known from the archaeological record are obelisks from nearly 5,000 years ago . sundials indicate the time by casting a shadow onto a surface .
the first form of telling time was the :
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 tu...
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 det...
modern ct data are often collected when the x-ray source moves along _____ around the patient .
in this short video , we 're going to show you how we constructed and animated a pop-up book to explain earth 's tectonic plates . the supercontinent pangaea broke apart 200,000,000 years ago , but the pieces have n't stopped shifting . although with animation we can show this movement easily with drawings , we thought...
although with animation we can show this movement easily with drawings , we thought it 'd be more interesting to depict gigantic sliding slabs of rock using a tangible object that also moves and shifts . and the pop-up book idea was born . ( music ) to make your own pop-up book , you 'll need some basic paper tools , s...
why is it so important to create a prototype of your pop-up book ?
hi , my name is john green , this is crash course world history , and today we ’ re going to talk about the french revolution . admittedly , this wasn ’ t the french flag until 1794 , but we just felt like he looked good in stripes . as does this guy . huh ? so , while the american revolution is considered a pretty goo...
they had a system with kings and nobles we now call the ancien régime . thank you , three years of high school french . and for most french people , it sucked , because the people with the money - the nobles and the clergy - never paid taxes . so by 1789 , france was deeply in debt thanks to their funding the american ...
what conditions existed in france in 1789 that caused the french people to revolt ?
good morning hank , it 's tuesday . so earlier this morning , i was kayaking on the white river . i came to an island that only exists when the water is low , so i had to choose which stream to follow down . i thought as i always do in these situations of robert frost 's poem , the road not taken . you know , the one t...
but of course , there are a bunch of problems . for one thing , if everyone followed the road less travelled , it quickly becomes the road more travelled . furthermore , there are many times when the road more travelled is more travelled for a reason , because for instance , the road less travelled leads to a kayak unf...
what did the speaker ( john green ) discover when he took the road less traveled while in his kayak ?
dear nickelodeon , i 've gotten over how spongebob 's pants are not actually square . i can ignore most of the time that gary 's shell is not a logarithmic spiral . but what i can not forgive is that spongebob 's pineapple house is a mathematical impossibility . there 's three easy ways to find spirals on a pineapple ....
in this case , 21 . the three sets of spirals in any pineapple are pretty much always adjacent fibonacci numbers . the rare mutant cases might show lucas numbers or something , but it will always be three adjacent numbers in a series .
what 5 numbers does the fibonacci sequence begin with ?
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 mo...
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 ...
what was a major difference between dystopian fiction of the 19th century and the 20th ?
energy is not easy to define . things have energy , but you ca n't hold a bushel of energy in your hands . you can see what it does , but you ca n't see it directly . there are different types of energy , but the differences between them are manifested only in how they make stuff behave . we do know that the total amou...
there are different types of energy , but the differences between them are manifested only in how they make stuff behave . we do know that the total amount of all the different types of energy in the universe is always the same . and , for chemists , two important types of energy are chemical potential energy and kinet...
the total amount of all energy in the universe is ________ .
translator : denise rq reviewer : callum downs i just want to start with a little bit of a word of warning and that is my job here tonight it 's to be a little bit of a doctor bring me down . so bear with me for a few minutes , and know that after this , things will get lighter and brighter . let 's start . i know that...
i do n't want to just pick on our friends in the gaming arts , i 'll turn to the graphic arts where we often see these monolithic , homogeneous stories about the great country of africa . but africa is not a country , it 's a continent . it 's 54 countries and thousands and thousands of languages .
dodson observes that the continent of africa encompasses
how do you know you 're real ? it 's an obvious question until you try to answer it , but let 's take it seriously . how do you really know you exist ? in his `` meditations on first philosophy , '' rené descartes tried to answer that very question , demolishing all his preconceived notions and opinions to begin again ...
how do you really know you exist ? in his `` meditations on first philosophy , '' rené descartes tried to answer that very question , demolishing all his preconceived notions and opinions to begin again from the foundations . all his knowledge had come from his sensory perceptions of the world . same as you , right ?
descartes rules out emotions and intuition as foundations for discovering truth . does this provide a fair understanding of human knowledge ?
your rich , eccentric uncle just passed away , and you and your 99 nasty relatives have been invited to the reading of his will . he wanted to leave all of his money to you , but he knew that if he did , your relatives would pester you forever . so he is banking on the fact that he taught you everything you need to kno...
3 x 3 = 9 , but the 3 can only be counted once . therefore , every locker that is a perfect square will remain open . you know that these ten lockers are the solution , so you open them immediately and read the words inside : `` the code is the first five lockers touched only twice . ''
what is the second locker to remain open ?
currently i think there are eight intelligences that i ’ m very confident about and a few more that i ’ ve bene thinking about . i ’ ll share that with our audience . the first two intelligences are the ones which iq tests and other kind of standardized tests valorize and as long as we know there are only two out of ei...
interpersonal intelligence is how you understand other people , how you motivate them , how you lead them , how you work with them , how you cooperate with them . anybody at any workplace with other people needs interpersonal intelligence . leaders hopefully have a lot of interpersonal intelligence . but any intelligen...
what is interpersonal intelligence ? how can it be used in a pernicious way ?
indium is a very soft metal . i haven ’ t got a sample here . it melts at 150 degrees or so . this is an example of indium it is a really , really quite nice chemical element this one . we can use it for lots and lots of selective types of catalysis , but generally when it is forming a complex with other organic ligand...
indium is a very soft metal . i haven ’ t got a sample here .
indium-113 and indium-115 are the 2 natural isotopes of this metal . what other radioactive isotope is used in medicine as a radiotracer to follow the movement of labeled proteins and white blood cells in the body ?
we live in a society obsessed with music . we use music to worship , tell stories , to celebrate , to work , exercise , declare our love and sometimes our hatred , and , arguably most importantly , to dance . and , of course , we play music ourselves because , well , it 's a pleasant thing to do . thousands of years ag...
music was used as a form of medicine to treat illnesses and physical complaints , as a vital accompaniment to sporting contests , and as a means to keep workers in time as they toiled away on monotonous or menial tasks . one of the most important applications of music in ancient greek society is found in the belief tha...
what are some ways that you use or are exposed to music in daily life that someone from ancient greece would recognize ? are there ways that we use music today that an ancient greek citizen would find strange ?
translator : andrea mcdonough reviewer : bedirhan cinar hello , my name is christian rudder , and i was one of the founders of okcupid . it 's now one of the biggest dating sites in the united states . like most everyone at the site , i was a math major , as you may expect , we 're known for the analytic approach we ta...
if both people in a relationship are saying yes to this , they 're going to have massive problems . we realized this early on , and so we decided we needed a bit more data from each question . we had to ask people to specify not only their own answer , but the answer they wanted from someone else .
what was the last data point that okcupid needed from each question ?
the earth intercepts a lot of solar power : 173 thousand terawatts . that 's ten thousand times more power than the planet 's population uses . so is it possible that one day the world could be completely reliant on solar energy ? to answer that question , we first need to examine how solar panels convert solar energy ...
to answer that question , we first need to examine how solar panels convert solar energy to electrical energy . solar panels are made up of smaller units called solar cells . the most common solar cells are made from silicon , a semiconductor that is the second most abundant element on earth .
what is the carrier of the electric current from solar cells ?
caffeine a legal stimulant that most of us are pretty familiar with , many of us use every day , and some of us are addicted to . if you are a caffeine user , you probably know your limits . for me one small cup of coffee in the morning can help keep me alert and focused , whereas two small cups of coffee in the mornin...
well the now what really depends on how your specific body metabolizes caffeine . the average half-life of caffeine in the human body is about six hours . so this means that if you have two hundred milligrams of caffeine in your average cup of coffee at 9am in the morning , then 6 hours later half of that will be left ...
what is the half-life of caffeine in the average human body ?
with every year , machines surpass humans in more and more activities we once thought only we were capable of . today 's computers can beat us in complex board games , transcribe speech in dozens of languages , and instantly identify almost any object . but the robots of tomorrow may go futher by learning to figure out...
there 's body language and vocal tone , changes in heart rate , complexion , and skin temperature , or even word frequency and sentence structure in our writing . you might think that training neural networks to recognize these would be a long and complicated task until you realize just how much data is out there , and...
a major problem for self-driving cars would be :
what do fans of atmospheric post-punk music have in common with ancient barbarians ? not much . so why are both known as goths ? is it a weird coincidence or a deeper connection stretching across the centuries ? the story begins in ancient rome . as the roman empire expanded , it faced raids and invasions from the semi...
here , the word gothic was repurposed again to describe a literary genre that emerged as a darker strain of romanticism . the term was first applied by horace walpole to his own 1764 novel , `` the castle of otranto '' as a reference to the plot and general atmosphere . many of the novel 's elements became genre staple...
the term “ gothic ” was first used as a derogatory term during the :
a , c , e , d , b , k. no , this is n't some random , out of order alphabet . these are vitamins , and just like letters build words , they 're the building blocks that keep the body running . vitamins are organic compounds we need to ingest in small amounts to keep functioning . they 're the body 's builders , defende...
finally , from vitamin k , we score the ability to clot blood , since it helps make the proteins that do this job . without this vitamin variety , humans face deficiencies that cause a range of problems , like fatigue , nerve damage , heart disorders , or diseases like rickets and scurvy . on the other hand , too much ...
humans need the correct amount of vitamins to function . too much or too little of any one vitamin can cause problems . list five vitamins and problems associated with too much of each one .
are you afraid of black cats ? would you open an umbrella indoors ? and how do you feel about the number thirteen ? whether or not you believe in them , you 're probably familiar with a few of these superstitions . so how did it happen that people all over the world knock on wood , or avoid stepping on sidewalk cracks ...
and somehow , this tradition survived long after belief in these spirits had faded away . many superstitions common today in countries from russia to ireland are thought to be remnants of the pagan religions that christianity replaced . but not all superstitions are religious .
many common superstitions come from history of :
you and nine other individuals have been captured by super intelligent alien overlords . the aliens think humans look quite tasty , but their civilization forbids eating highly logical and cooperative beings . unfortunately , they 're not sure whether you qualify , so they decide to give you all a test . through its un...
the tallest captive sees three black hats in front of him , so he says `` black , '' telling everyone else he sees an odd number of black hats . he gets his own hat color wrong , but that 's okay since you 're collectively allowed to have one wrong answer . prisoner two also sees an odd number of black hats , so she kn...
how many wrong guesses is the group allowed to have ?
as 1905 dawned , the soon-to-be 26-year-old albert einstein faced life as a failed academic . most physicists of the time would have scoffed at the idea that this minor civil servant could have much to contribute to science . yet within the following year , einstein would publish not one , not two , not three , but fou...
as 1905 dawned , the soon-to-be 26-year-old albert einstein faced life as a failed academic . most physicists of the time would have scoffed at the idea that this minor civil servant could have much to contribute to science .
einstein 's first `` miracle year '' paper , in march 1905 , put forth a surprising idea . he proposed that :
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 tel...
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...
what factors might account for differences in population pyramids between cities within the same country ?
so , you 're thinking of moving to mars . have you picked out a spot for your new home ? no ? well , i 'm here to help . first things first , here are some of the things you 'll need to bring to the red planet : a high tolerance for cold , loneliness , and radiation ; a lifetime supply of breathable air and food ; a mu...
they play a large part in making the planet red by distributing rusted iron particles across the surface and into the air . thanks to the low gravity and lack of moisture , these dust storms can last for months and cover the planet . so , you might want to build your home as high as possible .
dust storms last longer on mars than on earth . what is the most important reason for this ?
the victory of the underdog over the favored team . the last minute penalty shot that wins the tournament . the high-energy training montages . many people love to glorify victory on the playing field , cheer for favorite teams , and play sports . but here 's a question : should we be so obsessed with sports ? is playi...
the victory of the underdog over the favored team . the last minute penalty shot that wins the tournament .
around what age does bone density begin to decrease ?
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 , ...
too long . think about the first language you learn as a child . more importantly , think about how you learned it .
how did you learn the first language you spoke ? were you allowed to make mistakes ? how do you think those mistakes helped you learn the language ? how do you think that relates to learning to play a musical instrument ?
this room may appear to be holding 600 people , but there 's actually so many more , because in each one of us there is a multitude of personalities . i have two primary personalities that have been in conflict and conversation within me since i was a little girl . i call them `` the mystic '' and `` the warrior . '' i...
from there , we dove in . and we used these questions : share some of your life experiences with me . what issues deeply concern you ?
what are the three questions that lesser used to help structure her conversation ?