Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
The average person's skin weighs twice as much as their brain.
131
The human body contains over a billion miles of DNA.
147
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
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
Your body is creating and killing about 2.4 million red blood cells per second.
17