Melting

When a solid is exposed to heat, the particles start to move apart. All of the particles in the solid soon break free, and the solid melts into a liquid.

We will use ice as an example. Ice is a solid because it has a definite shape and volume, it cannot be compressed (without breaking) and it cannot flow.
When we expose ice to heat, it slowly starts to melt, and soon enough, becomes a liquid.
So, we turn a solid into a liquid by melting the solid.

Ice melting