The average temperature at 40,000 feet above sea level is -60 F.
56
One third of the electricity produced on earth is used to power electric light bulbs!
75
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
One 75-watt bulb gives more light than three 25-watt bulbs.
57
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
A coal power station puts 100 times more radiation into the air than a nuclear power plant producing the same amount of energy.
7
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Sound at the right vibration can bore holes through a solid object.
134