Iron weighs more after it rusts.
16
One cubic foot of gold weighs more than 1,200 pounds!
78
The bark of an older redwood tree is fireproof.
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
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
No matter how cold it gets, gasoline will not freeze.
107
Hot water can freeze faster than cold water.
181