Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Chewing gum boosts your brain power.
285
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Yawns are more contagious among people with closer relationships.
163
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Every year your body replaces 98% of your atoms.
119
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190