100 points
why did ancient people bite into gold
This common fake gold metal is harder than real gold and does not show teeth marks, helping people distinguish between the two.
Why does water on the ground evaporate faster?
spilled water on the ground dries faster than water in a bowl.
Why is water absorbed by paper?
Because the fibres inside the paper suck in water
Why does salt melt snow/ice?
Because salt water freezes at -20, and when mixed with the water, which freezes at 0 degrees, it doesn't harden and instead melts.
This special kind of metal can "remember" its original shape and return to it when you heat it, even after you bend or stretch it. What is it?
记忆合金