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Lesson Sequence |
Previous Lesson | Next Lesson |
| P1 part 1 | P1 Lesson 1 Kinetic theory and changes of state. | P1 Lesson 3&4 Conduction and Convection |
| Year 9 | Yr 9 Energy Lesson 2 Boiling point | Y9 Energy Lesson 4&5 Assignment 1 |
Learning outcomes and Specification reference[]
| P1.2.1 Energy transfers and efficiency | P1 Lesson 2 Energy transfers, Sankey diagrams and Efficiency. | ||
| a | Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed. | Describe the energy transfers and the main energy wastages that occur in a range of situations or appliances. | |
| b | When energy is transferred only part of it may be usefully transferred, the rest is ‘wasted’. | Interpret and draw a Sankey diagram. | |
| c | Wasted energy is eventually transferred to the surroundings, which become warmer. The wasted energy it becomes increasingly spread out and so becomes less useful. | Understand the concept of efficiency and why efficiency can never be greater than 100%. | |
| d | To calculate the efficiency of a device using: | Use the equation to calculate efficiency as a decimal or percentage. | |
Full Specification Text[]
a) Energy can be transferred usefully, stored, or dissipated, but cannot be created or destroyed. b) When energy is transferred, only part of it may be usefully transferred; the rest is ‘wasted’. c) Wasted energy is eventually transferred to the surroundings, which become warmer. The wasted energy becomes increasingly spread out and so becomes less useful.
Candidates may be required to calculate efficiency as a decimal or as a percentage. d) To calculate the efficiency of a device using:
efficiency =useful energy out / total energy in ( x 100%)
efficiency = useful power out / total power in (x 100%)
Starter Activities[]
- Write up 8 forms of energy and have students illustrate each with a simple diagram
- Giant pendulum (1kg mass on rope suspended from secure place) to show how energy is transferred from GPE into KE and back into GPE but with some wasted energy.
- Video of roller coaster - discuss where the roller coaster travels the slowest and why
- Show a filament light bulb and energy efficient light bulb and compare heat given off by both.
- Plasma light bulbs. Youtube video
Activities to introduce new ideas[]
- Students divide a sheet up into 8. Illustrate the 8 forms of energy with a diagram and write a sentence to explain each. Powerpoint slide with 8 forms of energy.File:Forms of energy.ppt
- Energy transformation diagrams to label
- Energy Efficiency worksheet
- Powerpoint Question Draw your own Sankey diagramFile:Draw a sketch of a Sankey diagram.ppt
- Excellent sankey diagram worksheet
- Online test with m/c questions calculating efficiency from Sankey diagrams http://www.myphysics.org.uk/ks4p3hotpot04.htm
Activities to practice applying new knowledge[]
- AQA Progress Check Questions http://application.doublestruck.eu/resources/AG_PHYS/resources/Physics/Unit1/P1_1_3_pc_q.pdf
- AQA Progress Check Answers http://application.doublestruck.eu/resources/AG_PHYS/resources/Physics/Unit1/P1_1_3_pc_ms.pdf
Practical activities[]
Demonstrations[]
- Giant pendulum (1kg mass on rope suspended from secure place) to show how energy is transferred from GPE into KE and back into GPE but with some wasted energy.
Class practicals[]
- No class practicals have been added to this lesson plan
Links[]
- Catalyst article on efficiency of solar cells
- This bloke likes sankey diagrams so much he writes a blog about them. He must be an engineer.