Ok, ok, I'll give you a good one.
You can disprove one of the many myths about human hair. I'll give you a list, and you can just pick the one you like the best.
Shaving your legs makes your hair grow back thicker and darker (This is false)
Shaving your face makes your hair grow back thicker and darker (This is false)
Men lose their hair when they go bald. (This is false. Baldness is NOT the result of losing hair, the hair follicle actually still produces hair, but the hair is like the hair on your forehead, which is very hard to see.)
People have as many hairs on their forehead per square inch as they do on their head. (this is True)
After you cut you hair it grows faster. (This is false)
If you never cut your hair, it will just keep growing. (This is false, even the hair on your head grows through a growth cycle, and will only get some long before it falls out.)
If you don't cut your hair it will stop growing because of the split ends (This is false, hair grows from the follicle not the end)
BTW, the post I made about boiling water in a paper cup is NOT a myth, I have done it many times, including once a couple of weeks ago for my daughters.
Best regards,
--Tachus