The average temperature at 40,000 feet above sea level is -60 F.
56
In zero gravity, a candle's flame is round and blue.
16
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The only letter not appearing on the Periodic Table is the letter "J".
180
Scientists at the Zhejiang University in China have developed an ultra-light material known as carbon aerogel.
3
Pumice is the only rock that floats on water.
14
The bark of an older redwood tree is fireproof.
65