Respuesta :
The potential energy of a material is its ability to do work. So I would suspect the potential energy to increase during phase changes that increase entropy (solid →→ liquid and liquid →→ gas), and decrease in the opposite direction.
Answer is: cooling.
Cooling is change from liquids to solids.
Another example is crystalisation, many elements and compounds form crystals.
A physical change occurs when a substance changes phase.
Physical property can be observed and measured without any changes in molecular composition. The same substance is present before and after the change.