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
Your thumb is about the same size as your nose.
124
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Every year your body replaces 98% of your atoms.
119
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
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197