Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
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
Your thumb is about the same size as your nose.
124
Most of us have microscopic, worm like mites named Demodex that live in our eyelashes and have claws and a mouth.
-137
Yawns are more contagious among people with closer relationships.
163