When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
In zero gravity, a candle's flame is round and blue.
16
Iron weighs more after it rusts.
16
The only letter not appearing on the Periodic Table is the letter "J".
180
The storage capacity of human brain exceeds 4 Terrabytes.
140
Hot water can freeze faster than cold water.
181