For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Your thumb is about the same size as your nose.
124
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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The human brain uses approximately as much energy as a 10 watt light bulb.
120
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