Iron weighs more after it rusts.
68
There are more atoms in one teaspoon of water than there are teaspoons of water in the Atlantic Ocean.
13
4.5 pounds of sunlight strike the Earth each day.
27
A cubic yard of air weighs about 2 pounds at sea level.
31
Airports that are at higher altitudes require a longer airstrip due to lower air density.
39
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