Yawns are more contagious among people with closer relationships.
163
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
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Poor eyesight (myopia) is associated with higher IQ.
232
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
It takes about 20 seconds for a red blood cell to circle the whole body.
102