Describe what happens to the temperature of a substance during a change of state, such as melting or boiling, and explain why this occurs.

During a change of state, the temperature of a substance remains constant even though energy is being transferred. This occurs because the energy is used to change the potential energy of the particles rather than increasing their kinetic energy.

Unit lens: Check the units before giving the final statement so the physics quantity is not swapped. This question asks: Describe what happens to the temperature of a substance during a change of state, such as melting or boiling, and explain why this occurs. The correct response is During a change of state, the temperature of a substance remains constant even though energy is being transferred. This occurs because the energy is used to change the potential energy of the particles rather than increasing their kinetic energy., because changes of state are explained by particle energy and arrangement. In Changes of state and specific latent heat, the marking point should connect directly to interpret heating and cooling graphs that show temperature changes and flat sections during changes of state. 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 433 is distinct because it uses this exact question context and the unit lens rather than a generic particle-model sentence.