Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Enamel is hardest substance in the human body.
61
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Yawns are more contagious among people with closer relationships.
163
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
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Chewing gum boosts your brain power.
285