Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Your thumb is about the same size as your nose.
124
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
Your body is creating and killing about 2.4 million red blood cells per second.
17
If you are cold you are more likely to be hungry because you use energy to keep warm.
143