Lies you learned in science class

It's the ultimate insult. You've spent years studying, memorizing, and taking tests to prove that you understand some of the world's most fundamental workings. You missed television shows, nights out with your friends, and binge-gaming sessions. You know what? A lot of that stuff you were studying was just wrong. Let's get it right.

Diamonds are made from coal

The world is full of incredibly awesome natural phenomena. Unfortunately, the shiniest of these phenomena you learned about as a child does not exist. Diamonds, the story goes, are made from coal that's been subjected to a huge amount of pressure. Superman says so, so it must be true, right?

Let's ask Dr. Kat Arney of The Naked Scientists. According to her, geological studies have shown natural diamonds were actually created about a billion years ago by factors like temperatures in the thousands of degrees and the kind of pressure you'd feel if you had around 100 miles of earth and rock on top of you. Those forces acted on carbon-rich minerals to form diamonds, and diamonds can also be formed by high-impact strikes caused by meteorites either hitting the Earth or hitting each other in space. What definitely wasn't involved? Coal.

We know coal has nothing to do with diamonds because coal only started forming about 300 million or 400 million years ago (give or take), long after the Earth started making diamonds. In order to get coal, you need plants, and plants didn't happen until about 450 million years ago. That makes diamonds even cooler. It makes your teacher less cool.

Evolution is driven by survival of the fittest and natural selection

When you learned about evolution, chances are your teachers talked about how natural selection and survival of the fittest shaped the world today. If you were the type of student who pointed out something was off because humans still have some major design flaws — like not being able to see in the dark while the lions that wanted to eat our ancestors clearly could — well, your teachers probably told you to shut the heck up. That's because they were teaching it wrong.

According to Princeton biological anthropologist Alan Mann (via io9), survival of the fittest isn't based on how tough or smart a creature is. The important thing is how likely they are to reproduce. Mann says you can look at it this way: "Evolution acts to produce function, not perfection." That's why we still can't see in the dark, why we still pass on deadly genetic diseases, and why we haven't grown awesome prehensile tails.

UC Berkeley researchers took on ideas about natural selection, and you're wrong there, too. Natural selection isn't about organisms trying to adapt, it's about random genetic mutations that happened to increase odds of reproduction. They also say that "survival of the fit enough" is a better way to think of the process. There you have it — you're not here because your ancestors were the best, but because they were "eh, good enough."

We taste different things with different parts of the tongue

You were probably quizzed on the map of your taste buds before you were old enough to make any inappropriate tongue jokes. You were taught your taste buds were arranged in groups and you tasted different things — bitter, salty, sweet, and sour — in different areas of the tongue. If you were the kid who put a salty pretzel on the tip of your tongue and wondered why you could still taste saltiness, you were right to be skeptical.

The tongue map dates back to 1901, and according to LiveScience, it was the work of a German scientist named D.P. Hanig. He was measuring how sensitive certain areas of the tongue were to certain tastes, and later that turned into the idea that different parts of the tongue only taste certain things. We even know who screwed things up — a Harvard psychology historian with the epic name of Edwin Boring. He transcribed Hanig's data in 1942 but didn't label his graph correctly.

It's wrong for another reason, too, because we also have the ability to taste something called umami. That's not even on the standard tongue map. It's almost as if the tongue is an extremely complex and sensitive object that can't be easily reduced to pithy half-truths.

We have five senses

Quick, name your senses. Taste, touch, smell, hearing, and sight, right? It's so well-known that M. Night Shyamalan wrote about The Sixth Sense like it was something epic and unheard of, but grown-up science says we keep teaching the five sense thing because your dumb kid brain can't understand what your senses really are.

According to psychologists at the University of Glasgow, it was actually Aristotle who came up with the idea of five senses, and while we're not actually sure what the right answer is, it sure isn't five. The problem comes in defining just what a "sense" is. One answer is that we only have three senses that correspond to the kind of stimuli (chemical, light, and mechanical) our bodies can interpret. Nine is another possibility, and that theory adds mechanoreception (which includes things like balance and muscle stretch), pain, temperature, and interoreceptors (like knowing when you need to pee, when you're thirsty, and knowing when your stomach's had enough and it's time to stop shoving food in your head) onto Aristotle's five. Break those nine out into their components, and you can legitimately argue for 21 or 33 senses. Whatever the answer is, it's definitely not five.

All mammals are warm-blooded

Think back to what you were told defines a mammal, and you'll probably remember something about giving birth to live young, having hair or fur, and being warm-blooded. It's in the generally accepted definition of being a mammal, so this one can't possibly be wrong. Can it?

Of course it is, because it turns out teachers lie all the darn time. According to BBC Earth, there are some mammals that bend the definition of warm-blooded to the point of breaking. In case you forgot, warm-blooded creatures maintain a constant body temperature, like a human's toasty 98.6 degrees. But there's a subdivision of mammals no one told you about, animals whose core temperature varies, and not by a small amount. The Arctic ground squirrel (the cute little guy above) has been found to drop its body temperature to 26 degrees, and yes, that means it should freeze solid … but it doesn't. That's an extreme example, but there are other mammals who are clearly not the traditional definition of warm-blooded, like the pygmy mouse lemur and the naked mole rat.

In fact, the very idea of calling something "warm-blooded" has fallen out of fashion with the actual science world. According to The Washington Post, scientists now prefer terms like endothermic (animals that regulate their own body temperature), ectothermic (animals that can't retain body heat), and heterothermic (animals that do a bit of both). Man, was your science teacher wrong.

Dinosaurs were cold-blooded reptiles

If dinosaurs were one of the only things you really paid attention to in class, you're not alone. Dinosaurs are cool. Unfortunately, your knowledge about dinosaurs is built on a lie, starting with the so-called "fact" that they're cold-blooded reptiles.

You can thank John Grady, a biologist from the University of New Mexico in Albuquerque, for busting this one. His study examined 381 different animal species and their growth rates, including 21 dinosaurs. He compared how fast a creature grows with its metabolic rates and found that dinosaurs weren't as cold-blooded as we thought. They're what Grady's team called mesotherms, and they have the best of both worlds. Cold-blooded creatures move pretty slowly — think of how a crocodile spends most of its day — but a mesotherm dinosaur would have been able to move faster than that. Since they're not as warm-blooded as mammals, they wouldn't have needed as much food to keep them going, another big advantage.

Grady's study isn't without its naysayers, though, and according to Michael D'Emic, a researcher from the Stony Brook University School of Medicine in New York, the data suggested something completely different to him. He reanalyzed it to claim most dinosaurs were actually warm-blooded, and Grady agreed to disagree. Either way, they weren't the cold-blooded monsters we were taught.

There are seven colors in the rainbow

"But … I can see them! Right there! In that picture!" you might be saying. Well, your eyes deceive you. Here's how.

Whenever anyone draws a rainbow, they'll go with seven standard colors: red, orange, yellow, green, blue, indigo, and violet. But QI suggests picking seven colors is just the Western world continuing its obsession with seven: days of the week, musical scales, and all that jazz. It was Isaac Newton who decided on seven colors when he was observing rainbows from his self-imposed quarantine outside plague-ridden Cambridge. He added orange and indigo to the previous five. If you go back farther, you'll find Greek philosophers said there were three (red, yellow-green, and purple). Homer, for some reason, insisted there was only one color in a rainbow: purple. (No one knows what was up with Homer.)

Not so clear now, is it? The answer is even worse: there's no "real" number to find. The rainbow's shading from one color to the next means there's no definite, solid way to separate one from another. ScienceBlogs worked out the math, using wavelengths to estimate that there are around a million different colors you're actually seeing when you look at a rainbow. And purple is one of them.

Black holes are funnel-shaped and crush everything

Black holes are one of the most mysterious, confusing phenomenons in the universe, so it goes without saying there's a lot we don't know about them. We do know some things, though, but when that gets translated into grade-school level … well, no one's perfect.

First, let's take a look at the idea they're funnel-shaped. You probably saw that drawing in your textbooks, but it's totally wrong. Kind of. According to Phil Plait's Bad Astronomy, they're actually spherical. That funnel shape you see drawn all the time is actually an attempt to depict the four-dimensional phenomenon of bending gravity in the two dimensions on your piece of paper. A little weird, but just remember: spherical.

Now, the crushing thing. Were you taught that anything passing a black hole's event horizon is sucked in and crushed under its insane gravity? It's the opposite: things get stretched out. Black holes are huge, and their size means there's a massive difference in gravitational pull even across relatively short spaces — say, for example, your 6-foot self. It's such a drastic change that if you're swimming toward a black hole, your head is going to feel hundreds of millions of times more gravity than your feet, and that's going to stretch you — not crush you — in a process called spaghettification. No wonder your teachers lied.

Mammals were nothing but dinosaur prey

Picture the prehistoric world, back when dinosaurs were roaming the Earth. Even the little ones were impressive, right? They were top dogs for sure, and mammals were sort of nature's rejects.

However, in 2005, researchers in China made a discovery that completely changed everything we thought we knew about the relationship between mammals and dinosaurs. They coexisted during the Mesozoic era — between 248 million and 65 million years ago — and we've always sort of thought all mammals were just trying not to be dinner. But according to National Geographic, the specimens found in China were diners, not dinners. They're Repenomamus robustus and Repenomamus giganticus, and they were found to have been eating dinosaurs. They weren't the little rat-like creatures we usually think of, either — R. giganticus was about 3 feet long and weighed around 30 pounds. They were predators, and dinosaurs were the prey.

These two might not have been the only dinosaur-eating mammals out there. According to LiveScience, close examination of prehistoric mammal teeth suggests they were climbing their way up millions of years before the dinosaurs were wiped away, which should make the next Jurassic Park a very different movie, indeed.

There's no gravity in space

You've heard your teachers talk about zero gravity, but it's not a thing. NASA says so! There are actually tiny amounts of gravity everywhere in space. It's what keeps planets safely tucked away in their orbits. Without it, everything would be a mess. What you find in space is more accurately called microgravity.

Rumors about zero gravity seem to be completely reinforced by the pictures of astronauts floating around in their capsules, but that happens because they're actually in free fall, falling around the Earth's horizon. When things are in free fall, gravity makes everyone fall at the same rate and, therefore, seem to float. It's still gravity doing things, we just aren't used to it.

According to Scientific American, you can technically escape gravity, but you'd have to go way, way, way out into the middle of deep space, and there couldn't be any planets, asteroids, or, well, anything at all around you. That's unlikely to happen, and you'd probably be too terrified with the insignificance of your own existence to think about it if it did. Don't grow up to be astronauts, kids.

You only use 10 percent of your brain

This idea is so prevalent even among adults that entire movies are based on the premise that using more than 10 percent of your brain will turn you into some sort of superpowered demigod. Those movies are stupid movies.

Scientific American has debunked this entire myth and has possibly even found the source of the idea, if not for the incredibly specific number of 10 percent — it's a 1907 text called The Energies of Men. But it's just not true. Now, we know that although our brains make up a relatively small percentage of our meat-sacks, it uses about 20 percent of the energy we burn. Researchers have used imaging technology to get a peek at which parts of the brain govern which functions, and we do use all of it (although not always at the same time) for both conscious and unconscious activities. We even use it when we're sleeping. Mayo Clinic neurologist John Henley erases any doubt: "Evidence would show over a day you use 100 percent of the brain." Sorry, folks. You've already got all the brainpower you're going to get.

There's no such thing as the missing link

You learned a lot about evolution and Darwin's theories, but unfortunately, you were taught all kinds of lies. We could write a book about it, but let's just talk about one piece of the evolutionary puzzle here: the missing link.

Anthropologist Cameron McPherson Smith and author Charles Sullivan explain what's going on in this one. The term "missing link" suggests there's an individual animal that fills in a gap between an organism with one set of traits and the "future" version of that same organism, but that's not how evolution works. At all. Contrary to our theories a few hundred years ago, species aren't arranged in neat sort of chains or trees. Lots of things have changed in 400 years, but while we had no problem giving up outhouses, we've clung to this outdated idea of a missing link. Instead of thinking of evolution as a chain think of it more as colors. Smith and Sullivan say the better way to explain evolution is in shades, so let's do that. Take a crayon. Start coloring, but make it darker and darker as you go on. At some point, that pink is going to become red, and it's sort of the same color, but not. See?

There's no one color that bridges the gap between pink and red, like there's no one missing link that connects modern species to their ancient ancestors. Now, please excuse us. This space-faring dinosaur getting sucked into a black hole isn't going to draw itself.