0.3% of solar energy from the Sahara is enough to power the whole of Europe.
310
It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
In zero gravity, a candle's flame is round and blue.
16
Iron weighs more after it rusts.
68
If the chemical sodium is dropped into water it will immediately and violently explode.
67
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75