Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Your thumb is about the same size as your nose.
124
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
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
One human hair can support 3 ounces.
191
Your body is creating and killing about 2.4 million red blood cells per second.
17
The largest cell in the human body is the female egg and the smallest is the male sperm.
682