The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Stannous fluoride, which is the cavity fighter found in toothpaste is made from recycled tin.
65
Columbia University has developed an artificial tree that passively soaks up carbon dioxide from the air using "leaves" that are 1,000 times more efficient than true leaves that use photosynthesis.
15
Because heat expands the metal, the Eiffel Tower always leans away from the sun.
79
A ball of glass will bounce higher than a ball made of rubber.
73
One barrel of petroleum holds 42 gallons.
20
Pure water (H2O) does not conduct electricity on its own.
46
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199