Gas Pressure and Temperature

This lesson covers the relationship between gas pressure and temperature as required by the AQA GCSE Physics specification (4.3.3). Understanding how gas particles create pressure and how temperature affects gas pressure is essential for explaining everyday phenomena such as why tyres expand in hot weather and why pressure cookers work.

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What Is Gas Pressure?

Gas pressure is caused by the collisions of gas particles with the walls of their container. Gas particles are in constant random motion — they move rapidly in all directions. When these particles collide with the walls of the container, they exert a force on the walls. The total effect of billions of these tiny collisions per second creates a measurable pressure.

Pressure is defined as the force per unit area:

pressure = force / area

p = F / A

Where:

• p = pressure, measured in pascals (Pa) or newtons per square metre (N/m2)
• F = force, measured in newtons (N)
• A = area, measured in square metres (m2)

1 Pa = 1 N/m2