Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
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.
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)
 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.
Lesson Structure:
  1. Do‑now (5'): students write their bulb‑efficiency estimate on a sticky note; teacher collects responses.
  2. Mini‑lecture (10'): present definition, formula, and reasons for losses using slides and the schematic diagram.
  3. Guided analysis (10'): examine the table of typical efficiencies; pairs rank resources by efficiency and discuss reasons.
  4. Real‑world examples (8'): discuss light‑bulb, bicycle, and kettle examples; students calculate approximate efficiency percentages.
  5. Factors investigation (7'): groups list design, operating conditions, maintenance, etc., and predict how changes affect efficiency.
  6. Quick quiz (5'): exit ticket with 2‑3 short questions on definition and one example.
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.