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
A single speck of dust is half way in size between a subatomic particle and the Earth.
15
One cubic foot of gold weighs more than 1,200 pounds!
78
Iron weighs more after it rusts.
16
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
At room temperature, the average air molecule travels at the speed of a rifle bullet.
55
Stannous fluoride, which is the cavity fighter found in toothpaste is made from recycled tin.
65