Approximately 70 percent of the earth is covered by water. Only 1 percent of this water is drinkable.
65
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
Hot water can freeze faster than cold water.
181
The most expensive material on the planet is antimatter - worth $62.5 trillion per gram.
18
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 only letter not appearing on the Periodic Table is the letter "J".
180