As the old saying goes, half of what we learn in school isn't true at all, and it's up to us to learn which half.
Well, prepare to shatter a few illusions today. We've listed 20 facts that everyone accepts as common knowledge. The only problem? None of them are true.
1. There's a "Five Second Rule" for dropped food
Maybe you don't really believe this rule, which claims that food dropped on the floor is safe to eat if it's picked up within 5 seconds. For most of us that's just a good excuse to eat any Skittles that we drop.
In fact, 5 seconds is more than enough time for lots of dangerous bacteria, including salmonella, to get on your food. The food's moisture content and the floor's condition have more to say about whether you'll get sick than the length of time it stays there.
2. The Great Wall of China can be seen from space
People often claim that this giant wall or other man-made landmarks can be "seen from space," but it's just not true. Even huge buildings are too small to be spotted on the ground by the naked eye.
What astronauts see when they look at the Great Wall.
As Canadian astronaut Chris Hadfield said, the Great Wall "is too narrow, and it follows the natural contours and colors [of the landscape]," so it's even harder to see than most buildings.
3. Goldfish have a 3-second memory
Poor goldfish, these pets never get the credit or respect that other domestic animals do. In fact goldfish can remember cues, sounds and symbols for months. Dedicated owners have even trained them to do tricks.
4. Alcohol warms you up
Sure, we could use an excuse to dip into the brandy on a nippy winter day, but this old wives' tale isn't true. Alcohol does make you skin feel warm, because it dilates blood vessels, bringing blood near the surface of your skin.
Meanwhile, your body's core temperature actually drops. So reach for the hot cocoa this winter instead.
5. If you touch a baby bird, it's mother will smell you and abandon it
First and foremost, most birds do not have a very strong sense of smell. Even if a mama bird could tell that you touched her chick, she wouldn't care.
Usually if you see a young bird out of the nest, its mother is actually watching nearby. If you return it to the nest and it dies anyway, it was simply sick or injured, not ignored.
Let's get biblical for the next phony fact.
6. Eve eats an apple in the Garden of Eden
Eve is described as eating the "Forbidden Fruit," which most religious scholars say was referring to a fig or a pomegranate. The connection between Eve and apples comes from a Latin pun. Apple and evil are both "malum" in that language.
7. Bananas grow on trees
Take a closer look. What we call a "banana tree" is actually a giant flowering plant. In fact, bananas can be considered herbs as well as fruit. The more you know!
8. Before Columbus arrived in America, people believed the world was flat
There are a few myths mixed up as facts here: first, Columbus never set foot in what we think of as America. He explored the Caribbean and the South American coast.
And while Columbus made a lot of miscalculations about his trip, even the ancient Greeks knew the world was not flat. Columbus just thought he was sailing to India.
9. If you drop a penny from the top of a building, it could kill someone standing at the bottom
Logic like this makes sense in a Bugs Bunny cartoon, but not real life. Friction from the air would slow the penny down as it dropped, so the coin could only fall at 30-60 miles per hour, tops. That's enough to hurt someone, but they would be fine.
10. Camels store water in their hump
Camels can drink up to 90 liters at once, and go days without drinking, but something different is actually happening here. Camels store that extra water in their bloodstream. So what's in the hump?
Fat, it turns out. There's not much water or food in the dessert, so camels store extra in their body. Storing fat in a hump keeps their body cooler than spreading it out in different areas would.
11. You lose most of your body heat through your head
Mothers love to recite this one when their kids leave the house without a warm hat, but it's not true. Infants do lose heat mainly through their head, but as we get older all exposed skin loses heat pretty evenly.
12. A trio of food facts
When you assume, you make a you-know-what out of you and me, and that applies to food too. German Chocolate cake is really an American invention, named for baker Samuel German.
Here are 2 other food origins most people overlook: spaghetti is considered an all-Italian dish, but it was actually introduced to the country by Arabs. Also, croissants are not the classic French pastry we all believed them to be (they're actually Austrian).
13. Salt water boils faster than regular water
Cooking myths are the most stubborn of all, so let's break this one down: adding salt to your pan will not make it boil any faster. In fact, depending on how much salt you add you might raise the boiling point of your water.
14. Albert Einstein failed math
We probably tell ourselves this story so we feel better about our grades in high school, but it's not true. Einstein was a math master by age 15, and was already studying advanced calculus.
He did fail the entrance exam for Switzerland's prestigious Federal Polytechnic Schools, but only because his non-science grades were poor. Einstein failed French, not math.
15. Removing plaque loosens your teeth
If you're scared of visiting the dentist you've probably convinced yourself this is true. In fact, if plaque on your teeth is ignored it solidifies into tartar that will actually loosen your teeth.
You teeth might feel "loose" after a cleaning, because when the built-up plaque is gone you notice the space where it used to be.
So is it true that we only use 10% of our brains?
16. We only use 10% of our brains
Only a very small part of our brain is being used at any given moment, but every part does something useful. See for yourself:
17. It's dangerous to suddenly wake up a sleepwalker
This is useful information, because as many as 4% of all American adults sleepwalk. There's nothing wrong with waking them up, and it won't "send them into shock" despite the rumors.
The only downside to waking a sleepwalker is they might be a bit confused when they wake up. And it could be pretty awkward if they sleep naked!
18. Napoleon Bonaparte was very short
The one thing most people can tell you about this French emperor is that he was famously short, but he really wasn't. While Napoleon was 5'2" when he died, that's actually 5'7" using modern measurements, and the average man of his time was only 5'5".
So where does the rumor come from? Napoleon's bodyguards were very tall, some famous paintings show him smaller than he should be, and he was nicknamed "the Little Corporal," all of which confused the public into thinking he was petite.
19. Nails and hair continue to grow after you die
Even very smart people can be fooled by this one. In fact your hair and nails stop growing when you die, but your skin retracts and your muscles tense, making it appear like they continue to grow.
20. NASA wasted money developing a space pen while the Russians used pencils
Everyone has heard this famous story at some point: during the Space Race of the 1960s, American scientists spent time and money developing a special "Space Pens" while Russian astronauts simply used pencils.
Actually, both sets of astronauts used pencils. The first Space Pen was a private company's invention.
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