In zero gravity, a candle's flame is round and blue.
16
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Sound travels about 4 times faster in water than in air.
408
The bark of an older redwood tree is fireproof.
65
Aluminum used to be more valuable than gold!
84
No matter how cold it gets, gasoline will not freeze.
107
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5