Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: Describe, qualitatively, the thermal expansion of solids, liquids and gases at constant pressure
Learning Objective/s:
  • Describe qualitatively how solids, liquids, and gases expand when heated at constant pressure.
  • Explain the role of linear and volume expansion coefficients for each state of matter.
  • Compare the relative magnitude of expansion among solids, liquids, and gases using real‑world examples.
  • Apply the formulas ΔL = αL₀ΔT and ΔV = βV₀ΔT (or Charles’s Law) to predict dimensional changes.
  • Identify engineering designs that accommodate thermal expansion, such as expansion joints.
Materials Needed:
  • Projector or interactive whiteboard
  • Slide deck on thermal expansion
  • Printed worksheet with coefficient tables and practice problems
  • Metal rod, beaker of water, and sealed syringe for simple demos
  • Rulers or measuring tapes
  • Exit‑ticket cards
 Introduction:
Begin with a quick demonstration of a heated metal rod lengthening. Ask students what they observed and connect it to everyday examples such as bridge joints. Review that today’s focus is on how all matter expands at constant pressure, and state that success will be shown by correctly explaining the three states and using the relevant formulas.
Lesson Structure:
  1. Do‑now (5'): Students answer a prompt about everyday expansion (e.g., gaps in sidewalks) and share responses.
  2. Mini‑lecture (10'): Present key concepts and formulas with slides; emphasize linear vs. volume coefficients.
  3. Guided demonstration (12'): Heat the metal rod, water in a bulb, and a syringe; students record observed changes and link them to the equations.
  4. Collaborative worksheet (15'): Groups calculate ΔL or ΔV for given ΔT values using provided coefficients.
  5. Concept check (8'): Quick quiz via clickers or show of hands on which state expands most and why.
  6. Summary discussion (5'): Recap main ideas, address misconceptions, and preview the next topic.
Conclusion:
Summarise that all matter expands when heated, with solids expanding least and gases most, and that material‑specific coefficients quantify these changes. Have students write an exit‑ticket describing a real‑world design that uses an expansion joint. Assign homework: complete additional thermal‑expansion problems and read the next section on heat transfer.