In zero gravity, a candle's flame is round and blue.
16
The bark of an older redwood tree is fireproof.
65
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
A ball of glass will bounce higher than a ball made of rubber.
73
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Iron weighs more after it rusts.
16
The smell of freshly cut grass is actually a plant distress call.
31
Scientists have revived a flowering plant from a fruit stored away in permafrost by Arctic ground squirrel 32,000 years ago.
16