Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Chewing gum boosts your brain power.
285
The human brain doesn't stop developing until about 25 years old.
102
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
Every year your body replaces 98% of your atoms.
119