Why does decreasing the volume of a gas at constant temperature increase its pressure (Pressure in gases (physics only))

The correct answer is Particles collide more often with greater force.

Practical lens: Link apparatus, readings, and uncertainty to the exact measurement named in the objective. This question asks: Why does decreasing the volume of a gas at constant temperature increase its pressure (Pressure in gases (physics only)). The correct response is Particles collide more often with greater force, because density links mass and volume, so the answer must preserve which quantity is being calculated. In Pressure in gases (physics only), the marking point should connect directly to (Physics only) Explain how changing the volume of a fixed mass of gas changes the frequency of particle collisions with container walls. 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 Particle model and pressure, 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 518 is distinct because it uses this exact question context and the practical lens rather than a generic particle-model sentence.