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
The most expensive material on the planet is antimatter - worth $62.5 trillion per gram.
18
The only letter not appearing on the Periodic Table is the letter "J".
180
Sound at the right vibration can bore holes through a solid object.
134
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5