5 Things You Were Taught Wrong in Elementary School | Compilation

[Music] alright let's establish this up front we are not here to rag on science teachers their jobs are very difficult and they are making the world so much better by doing that and when science gets blown out of proportion or oversimplified it's almost never their fault so science teachers we love you thank you for your hard work now that said thanks to misleading Articles oversimplified books or plain old misunderstandings sometimes you walk out of elementary school with a few misconceptions about the world ones that stick around for the rest of your life and we've debunked many of these over the years so now it's time to lay them out let's start way up in space the first time you learned about astronauts on the International Space Station you might have heard that they're weightless because there's no gravity up there and from their perspective they definitely feel weightless but it's not because there's no gravity here's a very old video from Hank with more we spend our lives stuck to this planet the best of us can jump on astounding 2 meters off the ground the record for a land animal is the tiger with a vertical leap of barely double that that's some serious force dragging us down into this thing and we don't usually think about it because we're always under its spell our entire lives unless of course we get to space because everyone knows that space has no gravity except of course everyone is wrong ok probably not everyone in fact you may have seen a number of YouTube videos that have set you straight on this topic but if not let's get down to it space is packed wall-to-wall with gravity without gravity everything would just shoot off in straight lines there would be no galaxies or solar systems or planets in the universe would be a supremely boring place so let's talk real quick about how gravity works this equation was figured out by Sir Isaac Newton and he used it to do all sorts of awesome stuff there are three variables in this equation the mass of two objects say the earth and the moon and the distance between them there's also a constant the gravitational constant which Newton just worked out by observation so according to this equation the gravitational force between two objects is dependent upon the mass of both of the objects and the distance between them the masses are divided by the distance so as the distance increases the force decreases at 370 kilometers above the earth the height of the Space Station there is still plenty of gravity indeed without that gravity it would just fly off into deep space so it's good that there's gravity the space station is in orbit stuck there by the Earth's gravity the astronauts are not weightless they are falling a lot sounds weird because they're safe I mean relatively they're not as safe as I am but they aren't about to crash into the earth that's because they are falling at the speed of gravity while moving horizontally enough to continually miss the earth instead of plummeting toward the earth they're plummeting around it that's what we call an orbit and just like when in a plane you don't feel like you're moving 400 miles per hour the astronauts have already done all of their acceleration and are at a constant speed so to them it feels like they're weightless and motionless their only frame of reference is inside of the spacecraft the same sensation can be experienced without being in space by getting in a plane having the plane drop toward the earth at the same acceleration gravity it looks to all the world like you're floating in the plane because the fuselage is your frame of reference but really you're crashing toward the earth a terrible speed plane and everything inside all the objects and people everything is falling toward the earth at the same rate so the contents of the plane appear to float because gravity is acting on all the objects equally so let's go back to Isaac's equation no matter what we do to that distance number no matter how big how far apart things are it always exists that force never goes to zero that means that every object in the universe is constantly attracting every other object in the universe so hypothetical situation for you there are two things in the universe nothing else just one planet and you it doesn't matter how far away you are if you're sitting there motionless you're not floating you are falling and eventually you will fall into that planet it may take longer than the life of the universe but you will eventually fall into the planet man since 2013 scishow has grown a lot now in your first science classes you may have started learning about physics while you probably didn't get too far into the weeds there's a good chance you at least saw this diagram of an atom it's a really popular symbol and it would be easy to think that's what atoms look like it turns out that atoms are a lot more complicated than that but I'll let Olivia explain have you ever looked carefully at the intro for this show I mean really carefully if you have you might have noticed that there's a diagram of an atom with little electrons orbiting the nucleus but here's the thing atoms don't actually look like that over the years scientists have come up with different atomic models based on what we know about how they work the atomic model that's in the scishow intro was one of them and it has a lot of history behind it but the most accurate atomic models are a little more complicated because atoms are complicated by the start of the 20th century scientists knew that atoms were made up of negatively charged electrons plus some sort of positive charge the tricky part was figuring out how these charges fit together the running theory was that the electrons were embedded in a positive sphere which was called the plum pudding model because it looked like a traditional Christmas pudding but that all changed around 1911 when a scientist named Ernest Rutherford along with his team at Manchester University published the results of the famous gold foil experiment Rutherford and his colleagues fired alpha particles which are positively charged at thin gold foil according to the plum pudding model the alpha particles should have just passed straight through the foil because atoms would be mostly empty space with some charges scattered around and atoms are mostly empty space so most of the alpha particles did pass straight through the foil but to Rutherford surprise some alpha particles were deflected by a lot he concluded that an atoms positive charge was concentrated in a tiny central nucleus and these nuclei were deflecting alpha particles that bounced off of them he also predicted that the electrons were orbiting around the nucleus kind of like how planets orbit the Sun that's why this model is sometimes called the planetary model Rutherford was right about protons being in the middle with electrons around them and you'll still see his model used today to explain the very basics of the atom it's the one in the scishow intro but there was one major problem with the planetary model it predicted that orbiting electrons would lose energy in the form of radiation which would make them spiral inward and eventually crash into the nucleus this implied that all atoms would eventually collapse but we know that stable atoms do exist so there had to be something missing just two years later in 1913 Danish scientist Niels Bohr proposed an adjustment to the Rutherford model that solved this problem Bohr's model predicted that electrons orbit at very specific energy levels which he called orbits the electrons could only orbit at precisely those levels and so they couldn't spiral inwards an electron could switch levels if it absorbed or released some energy but only specific discrete levels were allowed and electrons couldn't go below the lowest level that explained why stable atoms didn't just collapse Bohr's model quickly became the most popular model of an atom and it's often used today to show the basic way that an atom is arranged but it still wasn't totally right one breakthrough was in 1932 when English physicist James Chadwick discovered that neutrons exist neutrons weren't electrically charged and they helped explain why the nucleus was so heavy another breakthrough involved quantum mechanics and the idea that electrons don't necessarily orbit the nucleus at all in fact electrons aren't even really in a specific place at any given time instead they're kind of in lots of different places at once within a bigger area then when you actually measure an electron suddenly it's in one specific spot within that area it's a weird concept that's very different from the way that we normally experience the world but that's quantum mechanics for you the area where you might find it if you tried to measure it is called the electron cloud in diagrams normally the cloud is drawn darker where there's a high probability of the electron being there when you measure it with the most basic atoms like hydrogen and helium this cloud looks kind of like a big sphere and it turns out that electrons have the highest probability of being in one of Bohr's orbits which is why you can use Bohr's model to simplify things but when you get into bigger and bigger atoms with more and more electrons these clouds begin to interfere with each other and start to have weirder shapes so the electron cloud model is the most up-to-date model of an atom and it's used by scientists around the world but that doesn't make the other models useless like Bohr's model can be helpful if you need to focus on energy levels and radiation but if you studying chemical bonds you might need the electron cloud model to know where the electrons are and if you want a model that shows off the fundamentals and still looks pretty cool you might want to go for the planetary model now back in elementary school there's also a chance you first learned about the human body in death stuff like how your body makes urine to get rid of waste and along the way you might have picked up this idea that urine is sterile maybe from some kid on the playground who'd been watching survival documentaries with their older siblings and it's understandable I mean it's what people were taught for a long time but the next time you or one of your friends gets stung by a jellyfish you should probably hold your bladder here's Hank to explain why for some reason the TV seems to be full of guidance about what you can do with your pee like maybe you're watching one of those wilderness survival shows and the guy falls down into the ravine and gets a big gash on his leg and he's like oh no worries others pee on it a little urinal spruce that right up maybe you're watching lost and Hurley steps on a sea urchin or jelly vision or whatever and he's like bit suddenly pay on my front I Got News for you despite televisions teachings and in fact what many doctors and nurses were taught there's increasing evidence that your urine is not sterile the idea that urine and by extension your bladder is free of bacteria stems from the fact that under normal circumstances it won't produce results in a laboratory culture that means is that if a sample of your urine is added to a growth medium and incubated in the right conditions it won't produce big flourishing colonies of bacteria if you're healthy doctors have been using these urine cultures for generations because they're really good at detecting large amounts of certain kinds of bacteria like e-coli and Klebsiella that can cause infections in your bladder or urethra however if your culture comes back negative that does not mean that there's nothing there for one thing the threshold that labs used to diagnose bacterial infection in your urine is kind of high to get your results lab technicians count colonies of bacteria and each colony is basically a little speck growing on the growth medium and if there are fewer than 100,000 colonies growing in a single milliliter of your urine that's about one-fifth of a teaspoon they will give that a negative result they just assume that those germs were picked up on the way out of your body or simply aren't statistically significant and they want to avoid reporting a false positive but even then the bacteria that show up in these cultures are only the ones that we can test for fact is only a small percentage of bacteria can actually be cultured in labs there are entire general of bacteria thriving out there in nature eating and being eaten recycling elements and basically making the world work that we don't know how to grow in petri dishes it's also worth considering that you're literally teeming with bacteria right now I'm talking on the order of trillions of microorganisms inside and out forming what scientists call your human microbiome basically the habitats your body provides for lots and lots of tiny livestock and recent research has shown that your bladder is part of it several studies in the past few years have found lots of uncle trouble bacteria swimming around in the urine of otherwise healthy people and they found them not by using the old petri dish technique but by scanning the pee for tiny sequences of DNA specifically telltale genetic markers that we use to identify and classify bacteria one study urine was sampled from two groups of women one who had some symptoms of urinary infections and another healthy control group all of the women had already tested negative for bacteria by conventional means but 91% of them turned out to have bacteria living in their pee including some kinds that cause infections and a separate experiment similar techniques were used to compare the urine of healthy women with that of women who had overactive bladder syndrome a condition that makes patients feel like they have to be frequently even when their bladders aren't full results showed that both groups had two ample bacteria growing in their urine but the populations and the women with overactive bladder --zz were different than those in the control group suggesting that the syndrome might be microbially caused in the end the researchers say your urine may well have some bacteria in it that are causing problems they're just hard to detect but it's even more likely that it contains bacteria that pose no danger and who knows some of them might even be beneficial the next time you pass your pee test at the doctor's office keep in mind that that doesn't mean your pee is sterile so don't do anything crazy with it and if you happen to skin Unni while you're out in the woods wash it with soap and water not with pee okay next up animals because if there's anything kids love learning about its animals especially their pets if you had a dog when you were a kid or even if you didn't somebody probably told you that dogs can't see color maybe in a show-and-tell presentation or in some program about animal biology and you can probably guess where I'm going with this there is a little truth to that idea but it's still not quite right here's Michael with more maybe you've heard that dogs can only see in black and white it's one of those fun factoids that people like to toss around sometimes but this like so many things we talked about on quick questions is a misconception and the misconception stems from the fact that dogs are from a human perspective colorblind but that doesn't mean they can't see color we perceive color through a series of receptors in the retinas of our eyes called cones and humans have three kinds each of which is activated by a specific wavelength of light corresponding to a certain set of colors most humans have cones that can detect blue green and red wavelengths of light but dogs kind of like humans who are colorblind only have two kinds of cones that work for dogs the two colors they can register are blue and yellow so dogs can't see the color red but they can see and distinguish between various shades of yellow blue gray and something that probably comes through as a dirty greenish Brown so while we see this your dog sees something more like this it's not exactly Technicolor but it's a lot more information than just black and white and setting the record straight about dogs partial color vision is teaching us a lot about how pups experience the world recent experiments have found that dogs who are trained to find dark yellow objects could still find them even if they were replaced with very light yellow ones and they didn't mistake dark blue objects for the dark yellow ones either suggesting that dogs can clearly distinguish between many different shades and colors and don't just see in greyscale so the next time you ask your dog to fetch your blue slippers and he comes back with a pair of bananas he's not colorblind he's just messing with you yeah all this time we've been selling dogs short now there's a lot of things we could put into this episode but for now let's end on a big one your senses in grade school you likely learned that you have five senses and you may have even done games and activities to really help you remember what they are well it's time to break out the markers and popsicle sticks again because you've got at least three more senses to add to your list here's one last video in which Hank explains at some point you've probably learned about the five senses sight sound smell taste and touch these five don't explain all of our sensations how can we tell how hot or cold we are keep ourselves balanced now scientists are beginning to add more senses to that classic list here are three of those it's probably no surprise that sensing temperature is pretty important which we call thermo ception it helps us keep our body temperature constant and lets us know when our environment is too hot or too cold so we can avoid tissue damage like from burns or frostbite so how do we do it scientists have found a couple of potential mechanisms connected with the transient receptor protein channel or trip family there are lots of these channels and they react to lots of different stimuli we're still trying to figure out what they all do but one thing's for sure a lot of them help us respond to changes in temperature scientists aren't exactly sure how these channels work but with the physical stimuli of the environment getting warmer or colder depending on the channel they're more likely to open one of these channels trip v1 plays a role in the sensation of painful heat the receptor is activated when temperatures get uncomfortably warm around 40 degrees Celsius trip m8 on the other hand response to cold stimuli below 20 degrees Celsius so pretty much anything below room temperature these channels and others can be found throughout our bodies but when they're on nociceptors or pain sensing nerves activation of the channel triggers a rush of calcium into the cell and sends a signal to the brain about painful temperature all that information goes to the primary somatosensory cortex a thick fold of tissue on the top of the brain where most of the mechanical sensations like touch pain and vibration are processed then you can consciously process the temperature and yank your hand away from that campfire or decide whether you want to put on a jacket now have you ever thought about how you just know where your body is in space well that's proprioception the word comes from the Latin for one's own grasp it's how you can type without looking at a keyboard and walk without looking at your feet and there are a bunch of specialized receptors in our skin joints and muscles that help us do it for example muscle spindles respond to changes in muscle length and the speed of muscle movement while Golgi tendon organs send signals about muscle tension and exertion and then cutaneous mechanoreceptors respond to Treach and pressure in the skin and joints all of these receptors work together to provide the brain especially the cerebellum with information about your movement and the positions of your Lin the cerebellum is responsible for coordinating things like balance posture and voluntary movement weirdly though scientists recently discovered a case of a woman born without a cerebellum who has some balance and movement issues but seems to be doing relatively fine so there is still a lot to understand about how our brains process proprioceptive information separately we have equilibria ception our sense of balance and we need balance whenever we move like walking and running ears are important for our sense of hearing but they're also a key part of equilibria ception especially the inner ear it contains the vestibular system which includes three fluid-filled semicircular canals lined with tiny hair cells your head moves these hair cells are sloshed around by the fluid and sends signals to the brain specifically to the vestibular nuclei in the brainstem each canal is responsible for a different kind of movement one for up and down one for left and right and one for side-to-side Oh Duluth organ is located just below the semicircular canals are similar but in addition to liquid they have tiny crystals made of calcium carbonate as the head moves these crystals rub against the hair cells attached to the membrane which send information to the brain stem brain then sends information out to your eyes joints and muscles so they can respond accordingly and help you navigate the world now problems with this system can lead to issues with balance vertigo for example can be caused by loose stones in the otolith organs they can also fall into the semicircular canals disrupt the normal fluid movement and put unexpected pressure on the hair cells that pressure conflicts with what your eyes are seeing which can make you feel dizzy when you move your head together these three senses are really important in helping us navigate our environments successfully and safely so even though they don't make the list of our traditional senses I think we do ourselves a disservice by forgetting about them so in a lot of ways the world is way cooler than we learned when we're kids and that's okay it doesn't mean your teacher did a bad job or that you should have definitely learned what Adams really look like when you were seven or eight especially when you're first learning about science it can be easier to take things one step at a time and then as we get older we can learn that things are more complex than they see thank you for watching this episode of scishow and thank you to all of our patrons who have made this show possible over the years if you want to learn about more misconceptions that you might be carrying around you can check out our episodes about animal misconceptions right after this [Music] you [Music]

Channel: SciShow

Views: 744,206

Rating: 4.8761773 out of 5

Keywords: SciShow, science, Hank, Green, education, learn, teacher, taught, elementary, gravity, space, class, atom, urine, sterile, dog, see, color, colorblind, black & white, sense

Id: WPL3pUFtpJk

Length: 20min 36sec (1236 seconds)

Published: Wed Apr 01 2020