Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Chemistry
Lesson Topic: Polymers: addition and condensation polymerisation
Learning Objective/s:
  • Describe the mechanisms of addition (chain‑growth) and condensation (step‑growth) polymerisation.
  • Compare the characteristics, by‑products and industrial conditions of the two polymerisation types.
  • Identify common polymers produced by each method and explain how polymer structure influences properties.
  • Analyse factors such as degree of polymerisation, branching and cross‑linking on material properties.
  • Apply knowledge to predict which polymerisation route is suitable for a given set of monomers.
Materials Needed:
  • Projector or interactive whiteboard
  • Slides/PowerPoint on polymerisation mechanisms
  • Handout with comparison table and example reactions
  • Molecular model kits or 3‑D polymer visualisation software
  • Whiteboard markers and chart paper
  • Exit‑ticket slips
 Introduction:
Begin with a short video showing everyday plastic items and ask students what they have in common.
Review the definition of a polymer and recall that monomers join to form macromolecules.
Explain that today they will explore how different polymerisation pathways affect the structure and properties of plastics, and that success will be demonstrated by correctly comparing addition and condensation processes.
Lesson Structure:
  1. Do‑now (5') – Students list everyday products made from polymers and note any visible differences.
  2. Mini‑lecture (15') – Present addition polymerisation (initiation, propagation, termination) using polyethylene as example.
  3. Guided practice (10') – In pairs, complete a flow‑chart of the radical mechanism on the board.
  4. Mini‑lecture (15') – Introduce condensation polymerisation, illustrate PET formation and discuss by‑product removal.
  5. Comparison activity (10') – Groups fill a Venn diagram comparing the two methods using the provided table.
  6. Concept check (5') – Quick quiz via clickers or show of hands on key differences.
  7. Application task (10') – Given a set of monomers, decide which polymerisation route is appropriate and justify the choice.
  8. Exit ticket (5') – Write one key difference and one real‑world example of each polymerisation type.
Conclusion:
Summarise that addition polymerisation yields rapid chain growth without by‑products, whereas condensation requires removal of small molecules and proceeds more slowly.
Invite a few students to share their exit‑ticket responses to reinforce the comparison.
Assign homework to research a polymer of interest and describe its synthesis route.
Collect exit tickets as the final check for understanding.