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
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
One human hair can support 3 ounces.
191
It takes about 20 seconds for a red blood cell to circle the whole body.
102
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
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46