One human hair can support 3 ounces.
191
The average sperm cell swims at 8 inches per hour.
76
The human brain doesn't stop developing until about 25 years old.
102
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
Your thumb is about the same size as your nose.
124
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197