Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Every year your body replaces 98% of your atoms.
119
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
The average sperm cell swims at 8 inches per hour.
76
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Chewing gum boosts your brain power.
285
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127