What happens to the entropy of a sample of matter when it changes state from a solid to a liquid?

When a sample of matter changes state from a solid to a liquid, its entropy increases.

Explanation:

The entropy is a thermodinamic variable that measures the disorder of radomness of a substance or system.

In the solid stated the particles (molecules, atoms or ions) are tightly packed, forming an organized structure. So, the particles barely can move, just vibrating around their fixed positions.

In the liquid state the particles are more free to move (that is why liquids flow and take the shape of the vessel in which they are contained).

Then, you can predict that when a matter changes state from a solid to a liquid, the parciles will gain motion leading to a higher disorder, which means that the entropy increases.