When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Sound travels about 4 times faster in water than in air.
408
Because heat expands the metal, the Eiffel Tower always leans away from the sun.
79
One third of the electricity produced on earth is used to power electric light bulbs!
75
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
The only letter not appearing on the Periodic Table is the letter "J".
180
Nylon is made from coal and petroleum.
42