One 75-watt bulb gives more light than three 25-watt bulbs.
57
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
0.3% of solar energy from the Sahara is enough to power the whole of Europe.
310
Nuclear power prevented an average of over 1.8 million deaths between 1971-2009 as a result of lower air pollution from reduced coal usage according to NASA.
5
A cubic yard of air weighs about 2 pounds at sea level.
31
Columbia University has developed an artificial tree that passively soaks up carbon dioxide from the air using "leaves" that are 1,000 times more efficient than true leaves that use photosynthesis.
15