Pearson Edexcel · GCSE · Physics
Course version: 1PH0 · Version from Sept 2016
Explain ways of reducing unwanted energy transfer including through…
Full specification wording
Topic 3 – Conservation of energy: 3.9 Explain ways of reducing unwanted energy transfer including through lubrication, thermal insulation
Unwanted energy transfer moves energy into stores you do not want, usually the thermal store of the surroundings.
Checked against the Pearson Edexcel 1PH0 specification (opens in a new tab) on .
- Point 7 of 10
Study notes
From the checked teaching notes for this specification point.
The idea
Unwanted energy transfer moves energy into stores you do not want, usually the thermal store of the surroundings. Lubrication reduces friction between moving surfaces: oil or grease forms a layer so the surfaces slide over each other with less resistance, so less energy is transferred by heating to the surroundings. Thermal insulation reduces transfer by conduction, convection and radiation: loft insulation traps air, double glazing traps a gas layer, and shiny foil reflects radiation. In each case the method reduces the rate of unwanted transfer, keeping more energy in the useful store. A multiple-choice question may ask which method reduces a named unwanted transfer, so match the method to the mechanism it blocks.
What earns the marks
- Identifies lubrication as a way of reducing friction between moving surfaces.
- Explains that a lubricant forms a layer so surfaces slide with less resistance, reducing energy transferred by heating.
- Identifies thermal insulation as a way of reducing energy transfer to the surroundings.
- Explains that insulation traps air or gas, reducing conduction and convection, and that shiny surfaces reflect radiation.
- Matches a named unwanted transfer to the method that reduces it, such as oil for a moving machine part.
Common mistakes and how to put them right
Chooses lubrication to stop heat escaping through a wall.
Put it right: Select thermal insulation, which reduces conduction, convection and radiation.
States that insulation stops all energy transfer.
Put it right: Explain that it reduces the rate of transfer.
Assumes a lubricant removes friction completely.
Put it right: Describe it as reducing friction between the surfaces.
Exam tips
- Read the question to identify which unwanted transfer is named before choosing a method.
- Link each method to the mechanism it reduces: friction, conduction, convection or radiation.
- Eliminate options that claim energy transfer is stopped completely rather than reduced.
Try the lesson
The start of the Topic 3 – Conservation of energy: 3.9 Explain ways of reducing unwanted energy transfer including through lubrication, thermal insulation lesson, made from checked teaching notes for this specification point.
Have a go first
A bicycle chain becomes warm as the bicycle is pedalled because friction transfers energy to the surroundings. Which change would reduce this unwanted energy transfer?
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Topic 3 – Conservation of energy: 3.9 Explain ways of reducing unwanted energy transfer including through lubrication, thermal insulation
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge