Iron weighs more after it rusts.
68
Hot water can freeze faster than cold water.
181
A ball of glass will bounce higher than a ball made of rubber.
73
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
Forensic scientists can determine a person's sex, age, and race by examining a single strand of hair.
101
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
The average temperature at 40,000 feet above sea level is -60 F.
56