a) Melting:Heating can change a solid in into a liquid.This process is called melting.We observe the melting process daily. e.g ice starts to melt when we keep it above its melting point i.e 0°C. Boiling:When we heat a liquid ,its particles move at a very high speed.These fast moving particles make bubbles of vapur and rise to the top.In other words ,heating changes a liquid state into gaseous state in the form of vapour.This process is called boiling.Water boils at 100°C.