Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Yawns are more contagious among people with closer relationships.
163
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The human brain uses approximately as much energy as a 10 watt light bulb.
120
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Enamel is hardest substance in the human body.
61