Lesson Plan

• Describe mass defect and its relationship to nuclear binding energy.
• Apply E = c² Δm to calculate the energy released in a nuclear reaction.
• Convert mass defect from atomic mass units to kilograms and then to MeV.
• Analyse sample fusion and fission reactions using a mass table.
• Identify common calculation pitfalls and verify results with a checklist.

• Projector or interactive whiteboard
• Printed atomic‑mass tables (in u)
• Worksheet with sample nuclear reactions
• Scientific calculators or spreadsheet software
• Scientific‑notation conversion cheat‑sheet
• Diagram of a nucleus illustrating mass defect

Start with the striking fact that a gram of uranium can release the energy equivalent of thousands of tonnes of coal, sparking curiosity. Review students’ prior knowledge of atomic mass units and the equation E = mc². State that by the end of the lesson they will reliably calculate the energy released in any given nuclear reaction.

1. Do‑now (5 '): quick conversion of 1 u to kg; collect answers to gauge readiness.
2. Mini‑lecture (10 '): introduce mass defect, binding energy, and E = c²Δm; display nucleus diagram.
3. Guided practice (15 '): work through the He‑4 formation example together, students fill worksheet steps.
4. Independent practice (15 '): students calculate the energy released in the fission of ²³⁵U using the provided mass table; teacher circulates for support.
5. Concept check (10 '): clicker quiz / exit ticket asking for common pitfalls and correct unit conversions.
6. Summary & reflection (5 '): revisit the checklist, discuss real‑world relevance, and preview homework.

Summarise the step‑by‑step method for finding Δm and converting it to energy, reinforcing the checklist. Collect an exit ticket where each student writes one key conversion they must remember. Assign the three practice questions from the source as homework to solidify the skill.