Lesson Plan

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Lesson Plan
Grade: Date: 18/01/2026
Subject: Chemistry
Lesson Topic: Explain sacrificial protection in terms of the reactivity series and in terms of electron loss
Learning Objective/s:
  • Describe the corrosion process and the role of electron transfer.
  • Explain how the reactivity series determines the choice of a sacrificial anode.
  • Illustrate the redox half‑reactions that occur in sacrificial protection.
  • Predict which metals can protect iron based on standard electrode potentials.
  • Evaluate real‑world applications of sacrificial (cathodic) protection.
Materials Needed:
  • Projector and screen
  • PowerPoint slides with diagrams and the reactivity series
  • Worksheet containing reaction equations and application questions
  • Samples: iron nail, zinc strip, magnesium ribbon
  • Multimeter (optional for showing electron flow)
  • Whiteboard and markers
  • Handout of the reactivity series table
 Introduction:

Begin with a short video of a rusting bridge to hook interest, then ask students what they think causes the rust. Review the definition of corrosion and remind them of the reactivity series they studied last week. State that by the end of the lesson they will be able to explain how a more reactive metal can protect a less reactive one.
Lesson Structure:
  1. Do‑now (5'): Quick quiz on corrosion definitions and examples (written on board).
  2. Mini‑lecture (10'): Present the overall corrosion reaction and introduce the reactivity series with electrode potentials.
  3. Demonstration (15'): Attach a zinc strip to an iron nail, immerse in salt water, and observe protection; discuss electron flow and write the half‑reactions.
  4. Guided practice (10'): Students complete a worksheet writing oxidation and reduction half‑reactions and selecting appropriate sacrificial anodes for iron.
  5. Application discussion (10'): Small groups list real‑world uses (galvanised steel, marine fittings, pipelines) and justify metal choices.
  6. Check for understanding (5'): Exit ticket – one sentence explaining why zinc protects iron.
Conclusion:

Recap the key points: the reactivity series dictates sacrificial anode selection and electron loss prevents oxidation of the protected metal. Collect exit tickets and address any lingering misconceptions. Assign homework to research another industry where cathodic protection is used and write a short paragraph.