When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
The average temperature at 40,000 feet above sea level is -60 F.
56
Hot water can freeze faster than cold water.
181
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
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
German chemists made a replica of a trophy the size of one molecule.
68
Each day, up to 150 species of life become extinct.
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