Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
When you take a step, you are using up to 200 muscles.
886
Poor eyesight (myopia) is associated with higher IQ.
232
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Your body is creating and killing about 2.4 million red blood cells per second.
17
One human hair can support 3 ounces.
191
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190