Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: Describe the composition of the nucleus in terms of protons and neutrons
Learning Objective/s:
  • Describe the composition of an atomic nucleus in terms of protons and neutrons.
  • Explain the meaning of atomic number (Z), neutron number (N) and mass number (A) and write nuclear notation.
  • Distinguish isotopes by their neutron count and mass number.
  • Interpret simple nuclear diagrams showing nucleons and electron shells.
  • Relate nuclear composition to concepts of stability and binding energy.
Materials Needed:
  • Projector or interactive whiteboard
  • Slides with nuclear diagrams
  • Printed worksheet for isotope identification
  • Model set of nucleon balls (proton & neutron spheres)
  • Periodic table handouts
  • Exit‑ticket cards
 Introduction:
Begin with a quick poll: “What part of the atom contributes most to its mass?” Students recall that electrons are light, leading to focus on the nucleus. Explain that today they will learn how protons and neutrons make up the nucleus and how this is written in nuclear notation. Success will be measured by correctly labeling examples and identifying isotopes.
Lesson Structure:
  1. Do‑now (5’) – Students answer the poll question on a sticky note and share; teacher notes misconceptions.
  2. Mini‑lecture (10’) – Present slides on protons, neutrons, Z, N, A and nuclear notation; highlight symbols.
  3. Guided practice (10’) – Work through carbon‑12 and uranium‑235 examples; students complete worksheet.
  4. Interactive activity (10’) – Using nucleon model balls, groups build nuclei for given A and Z values and label isotopes.
  5. Concept check (5’) – Quick quiz (Kahoot or show of hands) to differentiate isotopes and discuss stability.
  6. Summary & exit ticket (5’) – Students write one sentence summarising nuclear composition and answer a short exit question.
Conclusion:
Review that the nucleus consists of protons and neutrons, with Z indicating protons and A the total nucleons. Ask a few students to state the isotope notation for a given element as a final check. Collect exit tickets and assign homework to research a real‑world application of isotopes.