When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Balsa wood is classified as a hard wood!
41
Indoor pollution is 10 times more toxic than outdoor pollution.
62
German chemists made a replica of a trophy the size of one molecule.
68
Cellophane is not made of plastic. It is made from a plant fiber, cellulose, which has been shredded and aged.
44
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Sound travels about 4 times faster in water than in air.
408
Nearly 50% of the world's scientists are assigned to military projects.
71