For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The average sperm cell swims at 8 inches per hour.
76
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
Chewing gum boosts your brain power.
285
Your heart will pump about 212 million liters in its lifetime.
26
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
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18