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
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
A cubic yard of air weighs about 2 pounds at sea level.
31
Cellophane is not made of plastic. It is made from a plant fiber, cellulose, which has been shredded and aged.
44
Iron weighs more after it rusts.
68
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
Scientists in Germany have developed a candy that doesn't cause cavities.
11
