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AQA · GCSE · Combined Science · Higher

Wall insulation and heat transfer

Q05.1 3 marks

Figure 7 shows cavity wall insulation being installed in the wall of a house.

A worker installing cavity wall insulation into a house wall. The wall has labelled brick, block and insulation layers.

Figure 7

Enlarged question image

A worker installing cavity wall insulation into a house wall. The wall has labelled brick, block and insulation layers.
Figure 7

Explain how the wall reduces unwanted energy transfers.

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Marking points

  1. 1 State that the wall has multiple layers, or is thick.
  2. 2 State that the insulation, brick or block has low thermal conductivity.
  3. 3 Explain that this reduces energy transfer by conduction, or lowers the rate of energy transfer.

Full-mark answer

The wall has several layers and the insulation has low thermal conductivity. This reduces the rate at which energy is transferred through the wall by conduction.

Why this answer loses marks

The wall stops all heat escaping.

The mark scheme credits reduced rate of energy transfer by conduction, not complete prevention.

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