Number 10.

The Great Wall of China is the only man-made object visible from space.

To see something on Earth from space, it would have to be pretty big, which the Great Wall

of China, all 5,000 miles of it certainly is, but it's only 30 feet across at its widest.

Here's a photo taken from the International Space Station 200 miles above Earth.

Can you spot the Great Wall amid the mountaintops? Here, right? No, that's a river. The wall is actually here. Even if you guessed the right lines by pure luck, this photo was taken with a zoom lens, so from the window of the International Space Station it would look more like this. Which pretty clearly makes the Great Wall count as not visible. As for the man-made part of this misconception, our glorious man-made cities blasting light into the void certainly are visible. Number nine, cracking your knuckles causes arthritis. Socially obnoxious? Yes. Gives you arthritis later in life as karma punishment? No. Number eight, people only use 10% of their brain. If you haven't seen a medical drama in the past, oh, 30 years, you might not be aware that doctors now have machines that can see inside people's brains, and, contrary to popular belief, 90% of the neurons don't sit around all day doing nothing. While scientists don't yet know exactly what each part does, they do know that all the bits matter. So if you think that someone could scoop out 90% of your brain and you'd still be just fine, then perhaps you really only do use 10% of it. Number 7. Eskimos have hundreds of words for snow. This one is technically correct but misleading. Some languages, such as German, like to make compound words by running several smaller ones together, which is why German words are sometimes absurdly long. Inuit languages use compound words as well, so rather than say yellow snow, as you would in English, an Inuit speaker combines the two words into one, but it's not really a new word, just a quirk of grammar. So technically, Eskimos do have hundreds of ways to describe snow, but then so does every language. Number six, you need eight glasses of water a day. While doubtless some people would benefit from drinking more water and drinking less crap, there is no scientific evidence that eight glasses of water a day is the required amount and some evidence that it might be too much. And while we're talking about water, number five, tap water is bad, but bottled water is good. If you live in a paradise free from government regulations like, say, Somalia, then you might have good reason to prefer bottled water over tap.

But modern functioning countries have something called health regulations, which cover both kinds of water.

Also, water is extremely dense, making transporting it from those pristine mountaintops and glaciers enormously expensive, which is why bottled water companies don't bother.

Bottled water is often just local tap water with a fancy label and an enormous markup.

Number 4. Gum takes 7 years to pass through your digestive system.

This is pretty easy to disprove yourself, but it's understandable why most people don't try the experiment.

Number 3. Blood in your veins is blue.

The idea here is that blood and veins is blue and it only turns red when exposed to the oxygen in the air. Thinking this isn't unreasonable, after all your veins look blue, and medical diagrams show arteries as red and veins is blue, but it's the same mistake as thinking that Mountain Dew is green because it's in a green bottle. Pour it out and you discover that Mountain Dew is really piss yellow, which is probably why it's in a green bottle to begin with. The next time you get blood withdrawn from a vein, take a look. What color is it? Red. How much oxygen is inside a good syringe? None. Unless you're a horseshoe crab or plava laguna, your blood isn't blue. Number two, fan death. This misconception is a specialty of South Korea. the belief is that if you spend too much time with a rotating fan in a confined space,

it will use up all your oxygen and you'll asphyxiate to death.

Exactly how the fan, made of a lifeless anaerobic plastic, competes for your oxygen is unclear,

but hilariously, South Korean fan manufacturers, who surely must know better,

include timers on fans to prevent them from running too long. Number one, people swallow eight spiders a year while sleeping.

Supposedly while you're in bed, helplessly unconscious with your gobb wide open,

each year eight spiders find their way into your mouth and you reflexively swallow them.

This is plainly ridiculous. Spiders love warm, moist places, so eight is far too low an estimate.