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 average home creates more pollution than does the average car.
33
A cesium atom in an atomic clock beats over nine billion times a second.
43
Scientists aren't sure what color dinosaurs were.
312
The left ear is more responsive to words of love and emotion whispered into it than the right.
40