Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Yawns are more contagious among people with closer relationships.
163
Chewing gum boosts your brain power.
285
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Your thumb is about the same size as your nose.
124