What happens to the potential energy of particles when a solid melts into a liquid, and why?

When a solid melts into a liquid, the potential energy of the particles increases. This is because the particles move from a fixed arrangement in the solid to a more free arrangement in the liquid, allowing them to overcome some of the attractive forces holding them together.

Comparison lens: State both sides of the comparison so the contrast is explicit rather than implied. This question asks: What happens to the potential energy of particles when a solid melts into a liquid, and why. The correct response is When a solid melts into a liquid, the potential energy of the particles increases. This is because the particles move from a fixed arrangement in the solid to a more free arrangement in the liquid, allowing them to overcome some of the attractive forces holding them together., because internal energy combines particle kinetic and potential energy. In Internal energy, the marking point should connect directly to describe how changing particle arrangement can change the potential energy of particles. If the question includes values, the working must keep the appropriate unit and operation; if it is an explanation, it must name the relevant particle behaviour or energy change. This item belongs to Internal energy and energy transfers, so avoid answers that switch to a different quantity, confuse heat with temperature, or describe gas pressure without collisions when collisions are the reason. Checkpoint 233 is distinct because it uses this exact question context and the comparison lens rather than a generic particle-model sentence.