In zero gravity, a candle's flame is round and blue.
16
Approximately 70 percent of the earth is covered by water. Only 1 percent of this water is drinkable.
65
Indoor pollution is 10 times more toxic than outdoor pollution.
62
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
A cubic yard of air weighs about 2 pounds at sea level.
31
Scientists are now able to grow 'beating' heart tissue in a lab!
162
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199