What is melting?

Melting is a phase change process, specifically meaning the change of phase from solid to liquid. In simple terms, when something melts, it changes from a solid state to a liquid state. That is what happens when you leave the ice cream out of the freezer for a long time or when we heat metals to high temperatures. The temperature at which a substance melts is known as its melting point. 

Melting is a physical change since the chemical composition of the substance remains the same. For example, when we melt iron, it still remains iron and the only change it undergoes is a change of state (from solid to liquid). Generally, substances expand on melting. That is, they occupy a larger volume after melting. 

Hope this helps.