Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human brain uses approximately as much energy as a 10 watt light bulb.
120
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
The human brain has the capacity to store everything that you experience.
4k
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Poor eyesight (myopia) is associated with higher IQ.
232
Every year your body replaces 98% of your atoms.
119