Calculating efficiency (in terms of energy and power)
I can calculate the efficiency of an energy transfer and describe ways in which energy is dissipated.
Calculating efficiency (in terms of energy and power)
I can calculate the efficiency of an energy transfer and describe ways in which energy is dissipated.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Energy is dissipated due to friction which causes particles to vibrate more quickly and heats up the surroundings.
- Energy is dissipated due to drag which causes particles in the surroundings to move more quickly.
- Efficiency = useful output energy transfer / total input energy transfer
- Efficiency = useful power output / total power input
- Efficiency can be increased by lubrication, bearings or wheels.
Keywords
Dissipate - Friction can cause energy to dissipate (spread out and becomes unusable) into the surroundings, causing them to heat up.
Efficiency - Efficiency is the fraction of energy supplied to an object or system that is usefully transferred by it.
Useful output energy transfer - The amount of energy usefully transferred by an object or system is the useful output energy transfer.
Total input energy transfer - The total amount of energy transferred to an object or system is the total input energy transfer.
Common misconception
Pupils may not realise that energy transfers usually result in the heating of the surroundings and therefore some energy ends up in a thermal store.
Pupils should have opportunity to identify and describe places in a system where energy is dissipated and transferred into a thermal store.
To help you plan your year 10 combined science lesson on: Calculating efficiency (in terms of energy and power), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 10 combined science lesson on: Calculating efficiency (in terms of energy and power), download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 4 combined science lessons from the Energy of moving objects unit, dive into the full secondary combined science curriculum, or learn more about lesson planning.
Equipment
A selection of balls that bounce, a metre ruler, masking tape.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
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Starter quiz
6 Questions
1500 W
3.4 kJ
340 J
0.015 kW