Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
When you take a step, you are using up to 200 muscles.
886
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
Every year your body replaces 98% of your atoms.
119
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
One human hair can support 3 ounces.
191
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
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99