When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
One cubic foot of gold weighs more than 1,200 pounds!
78
One gallon of used motor oil can ruin approximately one million gallons of fresh water!
71
Indoor pollution is 10 times more toxic than outdoor pollution.
62
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Scientists are learning from the 1700-year-old Lycurgus Cup, which changes colour thanks to nano particles.
0
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
Sound travels about 4 times faster in water than in air.
408