When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Forensic scientists can determine a person's sex, age, and race by examining a single strand of hair.
101
Nylon is made from coal and petroleum.
42
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
The gas that gives rotten eggs their distinctive foul smell may slow ageing and block damaging chemical reactions inside cells, according to scientists in China.
5