Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Enamel is hardest substance in the human body.
61
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
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
Yawns are more contagious among people with closer relationships.
163