Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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 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
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Poor eyesight (myopia) is associated with higher IQ.
232
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111