For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The average sperm cell swims at 8 inches per hour.
76
Yawns are more contagious among people with closer relationships.
163
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
Chewing gum boosts your brain power.
285