Gas Pressure

Key Stage 3

Gas pressure is the pressure on an object caused by a gas.

Pressure in gases is caused by particles colliding with the object or walls of the container.

Each time a particle in the gas hits an object or the walls it provides a force.

The more particles that hit the object or walls, the bigger the overall force it will experience.

The faster the particles hit the object or walls, the bigger the force that each particle collides with.


The particle model of a gas showing the particles as red balls and their speed and direction shown by the arrows. The longer the arrows the faster they are moving.

The gas pressure can be increased in two ways:


Increasing the temperature of the gas which makes the particles move faster. This causes the particles to hit the walls of the container more often and with a greater force.	Increasing the number of particles in the container.

Gas pressure is the pressure on an object caused by a gas.

Pressure in gases is caused by particles colliding with the object or walls of the container.

The pressure from a gas always acts at right angles to the surface.

Each time a particle in the gas hits an object or the walls it changes momentum which causes a force to be applied to the surface.

The more particles that hit the surface, the bigger the overall force it will experience.

The faster the particles hit the object or walls, the bigger the force that each particle collides with.

The frequency and speed with which the particles collide with the surface determines the pressure on that surface.


The particle model of a gas showing the particles as red balls and their speed and direction shown by the arrows. The longer the arrows the faster they are moving.

The gas pressure can be increased in three ways:


Increasing the temperature of the gas which makes the particles move faster. This causes the particles to hit the walls of the container more often and with a greater force.	Increasing the number of particles in the container.	Decreasing the volume of the container. The additional pressure caused by the force causes the gas to be compressed. The force does work on the gas increasing its temperature.