CIE IGCSE Physics

Revision Notes

2.3.1 Conduction

What is Conduction?

  • Conduction is the main method of thermal energy transfer in solids
  • Metals are extremely good at conducting heat
  • Non-metals are poor at conducting heat whilst liquids and gases are extremely poor
  • Poor conductors are called insulators
  • Materials containing small pockets of trapped air are especially good at insulating, as air is a gas and hence a poor conductor

 

Extended Only

How does Conduction Occur?

  • When a substance is heated, the atoms start to move around (vibrate) more
  • As they do so they bump into each other, transferring energy from atom to atom

Conduction, IGCSE & GCSE Physics revision notes

Conduction: the atoms in a solid vibrate and bump into each other

 

  • Metals are especially good at conducting heat as the delocalised electrons can collide with the atoms, helping to transfer the vibrations through the material

 

Demonstrating Conduction

  • A simple experiment to demonstrate the relative conducting properties of different materials can be carried out using apparatus similar to that shown in the diagram below

Conduction experiment, IGCSE & GCSE Physics revision notes

The above apparatus consists of 4 different metal strips of equal width and length arrange around an insulated circle

 

  • Ball bearings can be stuck to each of the strips and equal distance from the centre, using a small amount of wax
  • The strips should then be turned upside down and the centre heated gently using a candle, so that each of the strips is heated at the point where they meet
  • When the heat is conducted along to the ball bearing, the wax will melt and the ball bearing will drop
  • By timing how long this takes for each of the strips, their relative thermal conductivities can be determined

 

Exam Tip

If a question on heat mentions metal, the answer will probably be to do with conduction.

 

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Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.
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