Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Enamel is hardest substance in the human body.
61
Your heart will pump about 212 million liters in its lifetime.
26
Yawns are more contagious among people with closer relationships.
163
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
The average sperm cell swims at 8 inches per hour.
76
The human brain uses approximately as much energy as a 10 watt light bulb.
120