Describe how the potential energy of water molecules changes as water changes from a solids to a liquid.

When water changes from a solid to a liquid, the potential energy of the water molecules increases. This is because the molecules in a solid are held together by strong attractive forces, which give the molecules a lower potential energy. 

As the temperature of the solid increases, the energy of the molecules increases as well. When the temperature reaches the melting point, the molecules have enough energy to overcome the attractive forces that hold them in place in the solid, and they begin to move more freely. As a result, the potential energy of the water molecules increases as they change from a solid to a liquid.

During the process of melting, the temperature of the water remains constant until all the solid has changed to a liquid. This is because the energy absorbed by the water as it melts is used to overcome the attractive forces between the molecules, rather than to increase the kinetic energy of the molecules (which is what causes an increase in temperature). 

Once all the solid has melted, the temperature of the water will begin to increase again as the water absorbs more heat and the kinetic energy of the molecules increases.