Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
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
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
Your body is creating and killing about 2.4 million red blood cells per second.
17
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Enamel is hardest substance in the human body.
61