Aluminum used to be more valuable than gold!
84
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Sound travels fifteen times faster through steel than through air.
134
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
Oak trees produce 2,200 acorns in a season, but each acorn only has a 1 in 10,000 chance of becoming an oak tree.
304
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
The bark of an older redwood tree is fireproof.
65