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
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
Poor eyesight (myopia) is associated with higher IQ.
232
The average person's skin weighs twice as much as their brain.
131
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149