Airports that are at higher altitudes require a longer airstrip due to lower air density.
39
Research indicates that plants grow healthier when they are stroked.
173
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
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
Iron weighs more after it rusts.
16
There are more than 270 people cryogenically frozen in the hope that one day the technology will exist that can revive them and extend their lives.
13