Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
One human hair can support 3 ounces.
191
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The average person's skin weighs twice as much as their brain.
131
Every year your body replaces 98% of your atoms.
119
Poor eyesight (myopia) is associated with higher IQ.
232
The human body contains over a billion miles of DNA.
147