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How To Demonstrate a Stirling Engine

How To Demonstrate a Stirling Engine

Stirling engines are often discussed in the thermodynamics topic for GCSE Physics and can illustrate the concepts of heat engines, energy transfer, and efficiency. Students may learn about how Stirling engines work, their advantages and disadvantages, and how they can be applied in various practical applications.

What is a Stirling engine?
A Stirling engine is a heat engine that operates by cyclic compression and expansion of air or other gas (the working fluid) at different temperature levels, which converts thermal energy to mechanical work. Unlike traditional internal combustion engines, Stirling engines use an external heat source, such as fuel or solar energy, to operate. They are known for their high efficiency and low noise and can be used in a variety of applications, such as power generation, heating, and cooling.

You will need:

  • A kettle with lid
  • A 400ml beaker
  • 300ml of water
  • A small Stirling engine (either purchased or homemade)
  • Dropper bottle with blue food colouring (optional)
  • Ice cubes (optional)


  1. Fill the kettle with water, wait for the water to boil.
  2. Once boiled, transfer 300ml of water into the beaker, add a few drops of blue colouring to demonstrate diffusion (optional).
  3. Place the Stirling engine on top of the beaker, it might be necessary to move the fly wheel to get the engine going.
  4. The heat will cause the air in the kettle to expand and rise up through the Stirling engine’s hot side. This will cause the engine’s piston to move, generating mechanical energy.
  5. As the air cools down, it will sink back down into the beaker through the engine’s cold side. This will cause the engine’s piston to move in the opposite direction, generating more mechanical energy.
  6. To demonstrate the Stirling engine’s operation more clearly, you can add a few ice cubes to the kettle to speed up the cooling process. This will cause the piston to move faster.

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