A block of wood has a density of 600 kg/m³ and a volume of 0.5 m³. What is the mass of the block of wood (Density of materials) (Density of materials; definition focus: Calculate mass when density and volume are known) (Density of materials; particle reasoning focus: Calculate mass when density and volume are known)

The correct answer is 300 kg.

Comparison lens: State both sides of the comparison so the contrast is explicit rather than implied. This question asks: A block of wood has a density of 600 kg/m³ and a volume of 0.5 m³. What is the mass of the block of wood (Density of materials) (Density of materials; definition focus: Calculate mass when density and volume are known) (Density of materials; particle reasoning focus: Calculate mass when density and volume are known). The correct response is 300 kg, because density links mass and volume, so the answer must preserve which quantity is being calculated. In Density of materials, the marking point should connect directly to calculate mass when density and volume are known. 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 29 is distinct because it uses this exact question context and the comparison lens rather than a generic particle-model sentence.