Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
In zero gravity, a candle's flame is round and blue.
16
Approximately 70 percent of the earth is covered by water. Only 1 percent of this water is drinkable.
65
A 'jiffy' is an actual unit of time for 1/100th of a second!
66
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
Nuclear power prevented an average of over 1.8 million deaths between 1971-2009 as a result of lower air pollution from reduced coal usage according to NASA.
5
Each day is longer than the previous on by 0.00000002 seconds which is 13 seconds each century!
116
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199