The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Iron weighs more after it rusts.
16
The gas that gives rotten eggs their distinctive foul smell may slow ageing and block damaging chemical reactions inside cells, according to scientists in China.
5
The force of a suction cup is calculated using F=AP.
15
Columbia University has developed an artificial tree that passively soaks up carbon dioxide from the air using "leaves" that are 1,000 times more efficient than true leaves that use photosynthesis.
15
Forensic scientists can determine a person's sex, age, and race by examining a single strand of hair.
101
One barrel of petroleum holds 42 gallons.
20
Brass doorknobs automatically disinfect themselves in about 8 hours.
18