Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
One human hair can support 3 ounces.
191
Your heart will pump about 212 million liters in its lifetime.
26
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The average sperm cell swims at 8 inches per hour.
76
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
The human brain uses approximately as much energy as a 10 watt light bulb.
120