Pumice is the only rock that floats on water.
14
Scientists concluded that the chicken came first, not the egg, because the protein which makes the egg shells is only produced by hens.
11
In zero gravity, a candle's flame is round and blue.
16
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
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
Airports that are at higher altitudes require a longer airstrip due to lower air density.
39
Cold water weighs more than hot water.
93
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5