How can you determine the volume of an irregular solid?

The correct answer is By using water displacement.

Comparison lens: State both sides of the comparison so the contrast is explicit rather than implied. This question asks: How can you determine the volume of an irregular solid. The correct response is By using water displacement, because the particle model explains the observable property using particles. In Density of materials, the marking point should connect directly to required practical activity 5: use appropriate apparatus to determine densities of liquids. 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 Changes of state and the particle model, 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 65 is distinct because it uses this exact question context and the comparison lens rather than a generic particle-model sentence.