When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Airports that are at higher altitudes require a longer airstrip due to lower air density.
39
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
The average home creates more pollution than does the average car.
33
In 1999, Harvard physicist Lene Hau was able to slow down light to 17 meters per second and in 2001, was able to stop light completely.
39
The hair of an adult man or woman can stretch 25 percent of its length without breaking.
116