Iron weighs more after it rusts.
68
Marie Curie, the Nobel prize winning scientist who discovered radium, died of radiation poisoning.
57
Approximately 70 percent of the earth is covered by water. Only 1 percent of this water is drinkable.
65
The average home creates more pollution than does the average car.
33
Hot water can freeze faster than cold water.
181
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
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