Lesson Plan

• Describe the three steps of the proton–proton chain that powers the Sun.
• Explain how the loss of mass in fusion is converted to energy using E = mc².
• Compare nuclear fusion with fission in terms of energy release and binding energy.
• Analyse why solar fusion provides a renewable energy source for Earth.
• Calculate the total energy released per helium‑4 nucleus (≈ 26.7 MeV) and express it in joules.

• Projector or interactive whiteboard
• Slide deck with diagrams of the proton–proton chain
• Printed handout summarising steps, equations, and energy values
• Scientific calculators
• Whiteboard and markers
• Optional: PhET “Nuclear Fission/Fusion” simulation

Begin with a striking image of the Sun and ask, “What makes this giant star shine so brightly?” Connect to prior knowledge of nuclear reactions from the previous lesson on fission. State that by the end of class students will be able to trace the Sun’s energy source and quantify the energy released.

1. Do‑now (5 minutes): Quick quiz on nuclear reactions and binding energy.
2. Mini‑lecture (10 minutes): Explain why the Sun’s core conditions enable fusion; show temperature/pressure values.
3. Guided walkthrough (12 minutes): Present each step of the proton–proton chain, write the equations on the board, and discuss the associated energy release.
4. Group calculation activity (15 minutes): Using the handout, students compute the total energy (26.7 MeV) and convert it to joules, then relate it to the Sun’s total power output.
5. Fusion vs. fission comparison (8 minutes): Students complete a Venn diagram on a worksheet.
6. Formative check (5 minutes): Exit ticket – one sentence answering “Why is solar fusion a sustainable energy source?”

Summarise how the proton–proton chain converts mass into the Sun’s immense energy output and why this makes solar power renewable. Collect exit tickets and remind students to complete the homework worksheet that asks them to model the energy flow from the Sun to a solar panel.