Lesson Plan

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Lesson Plan
Grade: Date: 25/02/2026
Subject: Physics
Lesson Topic: Know that stars are powered by nuclear reactions that release energy and that in stable stars the nuclear reactions involve the fusion of hydrogen into helium
Learning Objective/s:
  • Describe how nuclear fusion powers stars and the Sun.
  • Explain the three steps of the proton‑proton chain and the resulting energy release.
  • Analyse why the Sun remains stable through hydrostatic equilibrium and self‑regulating fusion.
  • Compare hydrogen‑fusion rates in stars of different masses.
Materials Needed:
  • Projector or interactive whiteboard
  • Slide deck with Sun cross‑section diagram
  • Handout summarising the p‑p chain and energy calculations
  • Calculator or PhET “Stars” simulation
  • Worksheet with concept questions
  • Whiteboard and markers
 Introduction:
Begin with a striking image of the Sun’s surface and ask students what they think powers its light and heat. Recall prior learning about energy forms and the mass‑energy equivalence concept. Explain that today they will uncover how nuclear fusion in the core generates the Sun’s energy and how this process keeps a star stable.
Lesson Structure:
  1. Do‑now (5') – Quick quiz on energy sources; students write what they think powers the Sun.
  2. Mini‑lecture (10') – Present core temperature/pressure, introduce the proton‑proton chain with diagram.
  3. Guided practice (12') – Walk through each reaction step; calculate mass defect and energy using the handout.
  4. Interactive simulation (8') – Students explore the PhET “Stars” model to see how temperature affects fusion rate.
  5. Group discussion (10') – Explain hydrostatic equilibrium and self‑regulation; compare with massive stars.
  6. Check for understanding (5') – Exit ticket: one sentence describing why the Sun is stable.
Conclusion:
Summarise that stars shine because hydrogen nuclei fuse into helium, releasing energy via mass‑energy conversion, and that the Sun’s stability arises from hydrostatic equilibrium and self‑regulating fusion rates. Students complete an exit ticket and are assigned a short worksheet to calculate the energy released from a given mass for homework.