A gas pushes on its container because its molecules keep hitting the walls and bouncing off, and each bounce gives the wall a small kick. Pressure is the total force of those kicks per unit area. Push the piston in and the molecules hit the walls more often, so halving the volume doubles the pressure. Heat the gas and each molecule hits harder and more often, so doubling the absolute temperature also doubles the pressure. The measured value is noisy because the hits are random, and it tracks the ideal gas law.