In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Iron weighs more after it rusts.
16
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
If you are locked in a completely sealed room, you will die of carbon dioxide poisoning first before you will die of oxygen deprivation.
117
Hot water can freeze faster than cold water.
181
Only 12,000 years ago there was a species closely related to modern humans called Homo floresiensis that had been living on an Indonesian Island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
15