Enamel is hardest substance in the human body.
61
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
The average person's skin weighs twice as much as their brain.
131
Your thumb is about the same size as your nose.
124
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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Your heart will pump about 212 million liters in its lifetime.
26