Indoor pollution is 10 times more toxic than outdoor pollution.
62
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
Forensic scientists can determine a person's sex, age, and race by examining a single strand of hair.
101
It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
Aluminum used to be more valuable than gold!
84
Iron weighs more after it rusts.
16
The only letter not appearing on the Periodic Table is the letter "J".
180
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