Define density and provide the formula used to calculate it.

Density is defined as the mass of an object divided by its volume. The formula for density is density = mass / volume.

Practical lens: Link apparatus, readings, and uncertainty to the exact measurement named in the objective. This question asks: Define density and provide the formula used to calculate it. The correct response is Density is defined as the mass of an object divided by its volume. The formula for density is density = mass / volume., 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 define density as mass per unit volume. 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 2 is distinct because it uses this exact question context and the practical lens rather than a generic particle-model sentence.