| Lesson Plan |
| Grade: |
Date: 03/03/2026 |
| Subject: Physics |
| Lesson Topic: Understand, qualitatively, the concept of efficiency of energy transfer |
Learning Objective/s:
- Describe the definition and formula for efficiency of energy transfer.
- Explain why real devices never achieve 100 % efficiency, citing common loss mechanisms.
- Compare typical efficiencies of various energy resources and everyday devices.
- Analyse how improving efficiency impacts economic and environmental outcomes.
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Materials Needed:
- Projector or interactive whiteboard
- Slides/PowerPoint on efficiency concepts
- Handout with efficiency table and example scenarios
- Calculator for quick percentage calculations
- Whiteboard and markers
- Sample devices (e.g., LED bulb, small motor) for demonstration (optional)
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Introduction:
Begin with a quick demonstration: ask students to estimate how much of the electricity used by a typical incandescent bulb becomes visible light. Recall their prior learning of energy conversion and the formula η = (useful output / input) × 100 %. Today they will be able to explain why devices are never 100 % efficient and identify factors that influence efficiency.
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Lesson Structure:
- Do‑now (5'): students write their bulb‑efficiency estimate on a sticky note; teacher collects responses.
- Mini‑lecture (10'): present definition, formula, and reasons for losses using slides and the schematic diagram.
- Guided analysis (10'): examine the table of typical efficiencies; pairs rank resources by efficiency and discuss reasons.
- Real‑world examples (8'): discuss light‑bulb, bicycle, and kettle examples; students calculate approximate efficiency percentages.
- Factors investigation (7'): groups list design, operating conditions, maintenance, etc., and predict how changes affect efficiency.
- Quick quiz (5'): exit ticket with 2‑3 short questions on definition and one example.
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Conclusion:
Summarise that efficiency measures the proportion of input energy turned into useful output and that losses are inevitable. Ask students to write one way they could improve the efficiency of a common household device as an exit ticket. For homework, they will research the efficiency of a renewable energy technology and prepare a short paragraph.
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