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
When you take a step, you are using up to 200 muscles.
886
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
Poor eyesight (myopia) is associated with higher IQ.
232
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The average sperm cell swims at 8 inches per hour.
76