Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
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 average sperm cell swims at 8 inches per hour.
76
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
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515