Gas Pressure and Temperature

This lesson explains how the particle model accounts for gas pressure, how temperature affects gas pressure at constant volume, and the relationship $P \propto T$P∝T (in kelvin). This topic is part of the Particle Model section of the Edexcel GCSE Combined Science specification (1SC0).

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What Causes Gas Pressure?

Gas particles are in constant random motion. They collide with each other and with the walls of their container. Each collision exerts a force on the container wall. The total effect of billions of collisions per second produces a measurable pressure.

$\text{Pressure} = \frac{\text{Force}}{\text{Area}}$Pressure=AreaForce​

Symbol	Quantity	Unit
$P$P	Pressure	pascals (Pa) or newtons per square metre (N/m²)
$F$F	Force	newtons (N)
$A$A	Area	square metres (m²)

graph TD
    A["Gas particles move randomly"] --> B["Particles collide with container walls"]
    B --> C["Each collision exerts a tiny force"]
    C --> D["Total force over area = Pressure"]