Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Your heart will pump about 212 million liters in its lifetime.
26
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111