Brass doorknobs automatically disinfect themselves in about 8 hours.
18
A single cup of gasoline, when ignited, has the same explosive power as five sticks of dynamite.
57
During photosynthesis, plants emit light humans can’t see, but NASA can see that light from space - and they've even made maps of it!
21
One 75-watt bulb gives more light than three 25-watt bulbs.
57
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Pumice is the only rock that floats on water.
14
One barrel of petroleum holds 42 gallons.
20
In zero gravity, a candle's flame is round and blue.
16