Iron weighs more after it rusts.
68
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
At room temperature, the average air molecule travels at the speed of a rifle bullet.
55
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
One 75-watt bulb gives more light than three 25-watt bulbs.
57
If you are locked in a completely sealed room, you will die of carbon dioxide poisoning first before you will die of oxygen deprivation.
117
Indoor pollution is 10 times more toxic than outdoor pollution.
62