Hot water can freeze faster than cold water.
181
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
Stannous fluoride, which is the cavity fighter found in toothpaste is made from recycled tin.
65
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
A ball of glass will bounce higher than a ball made of rubber.
73
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199