Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
4.5 pounds of sunlight strike the Earth each day.
27
Approximately 70 percent of the earth is covered by water. Only 1 percent of this water is drinkable.
65
0.3% of solar energy from the Sahara is enough to power the whole of Europe.
310
Diamonds can be shattered with a hammer.
-104
Cold water weighs more than hot water.
93
In zero gravity, a candle's flame is round and blue.
16