Iron weighs more after it rusts.
68
In zero gravity, a candle's flame is round and blue.
16
Stannous fluoride, which is the cavity fighter found in toothpaste is made from recycled tin.
65
A cubic yard of air weighs about 2 pounds at sea level.
31
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
Your brain is 80% water.
525
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