One 75-watt bulb gives more light than three 25-watt bulbs.
57
If the chemical sodium is dropped into water it will immediately and violently explode.
67
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Indoor pollution is 10 times more toxic than outdoor pollution.
62
In zero gravity, a candle's flame is round and blue.
16
The hair of an adult man or woman can stretch 25 percent of its length without breaking.
116
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108