Define density as mass per unit volume.

Define density as mass per unit volume. Method lens: First identify the measured quantity, then match the equation or particle idea to the command word. In Density of materials, this means density links mass and volume, so the answer must preserve which quantity is being calculated. The answer should use the approved wording from Changes of state and the particle model, include density, mass, volume, and avoid drifting into another section of Particle model of matter. For revision, practise saying the exact objective aloud, then add the one calculation, particle movement, collision, graph, or practical detail that makes the statement true. A strong exam response for checkpoint 1 is specific to define density as mass per unit volume and does not reuse a generic explanation from a neighbouring objective.