Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Poor eyesight (myopia) is associated with higher IQ.
232
The average sperm cell swims at 8 inches per hour.
76
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
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Your heart will pump about 212 million liters in its lifetime.
26
Yawns are more contagious among people with closer relationships.
163
One human hair can support 3 ounces.
191