What happens when a substance changes state from solid liquid?

Answer 1

The molecules/atoms move far apart. As the separation between paricles increase, the state is changed. The temperature does not rise because the heat is used to overcome inter-molecular forces.

Answer 2

Nothing, a state change as the one you described above is merely the loosening and quickening of the atoms in a material. Nothing takes the place of the area it occupied as a solid.

Answer 3

This physical phenomenon (a change of phase) is called melting; during melting the chemical nature of molecules is not changed.

Answer 4

This change in the state of matter (solid to liquid) is called melting; it is a physical change, the chemical nature of the molecules is not changed.