In zero gravity, a candle's flame is round and blue.
16
The hair of an adult man or woman can stretch 25 percent of its length without breaking.
116
The average temperature at 40,000 feet above sea level is -60 F.
56
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Indoor pollution is 10 times more toxic than outdoor pollution.
62