Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your thumb is about the same size as your nose.
124
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
One human hair can support 3 ounces.
191
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193