Describe what happens to the average kinetic energy of particles when a substance is heated.

When a substance is heated, the average kinetic energy of its particles increases. This is because the added thermal energy causes the particles to move faster, resulting in an increase in temperature.

Definition lens: Give the precise definition, then add a context sentence that shows how it is used. This question asks: Describe what happens to the average kinetic energy of particles when a substance is heated. The correct response is When a substance is heated, the average kinetic energy of its particles increases. This is because the added thermal energy causes the particles to move faster, resulting in an increase in temperature., because the particle model explains the observable property using particles. In Changes of state and specific latent heat, the marking point should connect directly to apply MS 4a and MS 4c skills when interpreting graphs of temperature against time. 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 438 is distinct because it uses this exact question context and the definition lens rather than a generic particle-model sentence.