熱水會有煙,點解冰又會有煙呢??

the two kind of smoke (or better known as visible vapor) are different in nature

Hot water
because the heat give the water energy to turn from liquid to gas, so visible vapor appear, THIS VAPOR COME FORM THE HOT WATER ITESLF.

Ice
because the melting of the ice take away (absorb) the heat energy from the surrounding air, it make the surrounding air temperature lower, as cold air can contain less water than warm (if you recall why humidity is call RELATIVE humidity in your high school) so the water vapor in the cold air condense and form visible [smoke] (tiny water droplet). THIS VAPOR COME FROM THE SURROUNDING AIR.

let me know if you want to know more detail

因為d冰好涷
四周既空氣比佢泠涷咗
變咗做一d好輕既霜
睇落就好似出煙咁囉~