| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: derive, using W = Fs, the formula ∆EP = mg∆h for gravitational potential energy changes in a uniform gravitational field |
Learning Objective/s:
- Describe the work‑energy principle and its expression W = Fs.
- Derive the gravitational potential‑energy change formula ΔEP = mgΔh using the work‑energy principle.
- Apply the derived formula to calculate potential‑energy changes in simple vertical‑motion problems.
- Explain the assumptions (uniform g, neglect of air resistance, vertical displacement) underlying the derivation.
- Relate the potential‑energy change to kinetic‑energy change in energy‑conservation contexts.
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Materials Needed:
- Whiteboard or interactive display
- Projector with slides of the derivation
- Printed worksheet containing the derivation steps and example problem
- Set of masses and a metre ruler for a quick demonstration
- Scientific calculators for each student
- Reference sheet of symbols and units
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Introduction:
Begin with a thought‑provoking question: “If you lift a book, where does the energy go?” Connect this to students’ prior knowledge of work = force × distance. State the success criteria: students will be able to derive ΔEP = mgΔh and use it in a calculation.
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Lesson Structure:
- Do‑now (5'): Quick written task on work done by a constant horizontal force; teacher reviews answers.
- Mini‑lecture (10'): Review the work‑energy principle, define weight (mg), and discuss sign conventions using the projector.
- Guided derivation (15'): Walk through the six‑step derivation, prompting students to fill in each algebraic step on their worksheet.
- Collaborative practice (10'): Pairs solve the example problem (2 kg block lifted 0.5 m) and list the assumptions made.
- Concept check (5'): Clicker/hand‑raise quiz on statements about the sign of work and energy conservation.
- Summary & reflection (5'): Recap the derivation and ask each student to write one sentence explaining why ΔEP = mgΔh holds.
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Conclusion:
Briefly recap the key steps that linked work to potential‑energy change and highlight the importance of the uniform‑g assumption. Collect an exit ticket where students state the formula and one real‑world example of its use. Assign homework: complete a set of three problems applying ΔEP = mgΔh to different heights and masses.
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