One 75-watt bulb gives more light than three 25-watt bulbs.
57
One barrel of petroleum holds 42 gallons.
20
A cesium atom in an atomic clock beats over nine billion times a second.
43
A single speck of dust is half way in size between a subatomic particle and the Earth.
15
Indoor pollution is 10 times more toxic than outdoor pollution.
62
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
One cubic foot of gold weighs more than 1,200 pounds!
78
