Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The human brain doesn't stop developing until about 25 years old.
102
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
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
Chewing gum boosts your brain power.
285
The human body contains over a billion miles of DNA.
147