The smell of freshly cut grass is actually a plant distress call.
31
Iron weighs more after it rusts.
16
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
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
The average temperature at 40,000 feet above sea level is -60 F.
56
Nylon is made from coal and petroleum.
42
There are more atoms in one teaspoon of water than there are teaspoons of water in the Atlantic Ocean.
13