• A change in temperature or pressure affects the volume of gases

• As the air inside a hot air balloon is heated up, it expands and the balloon gets bigger

• This is because the volume of a gas increases as temperature increases

• If you have a gas stored inside a container that is squeezed, the pressure increases as you decrease the volume

• This is what happens in a bicycle pump

• As you compress the bicycle pump, the high pressure allows you to inflate a tyre

• You can feel the force of the high pressure if you put your finger on the end of the pump

How does temperature affect the volume of a gas?

• Increasing the temperature increases the kinetic energy of each particle

  • Remember: The thermal energy from increasing the temperature is converted to kinetic energy in the particles

• As the temperature increases, the particles in the gas move faster and spread out more

• If the gas particles are inside a container, they will collide with the container walls more frequently

  • If the container walls are flexible and stretchy then the container will get bigger and bigger, just like the hot air balloon!