Lesson Plan

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Lesson Plan
Grade: Date: 18/01/2026
Subject: Physics
Lesson Topic: Apply the principle of the conservation of momentum to solve simple problems in one dimension
Learning Objective/s:
  • Describe momentum as a vector quantity and state its SI unit.
  • Explain the principle of conservation of momentum in one dimension.
  • Apply the step‑by‑step method to solve elastic, inelastic and perfectly inelastic collision problems.
  • Identify and correct common errors such as sign mistakes and misuse of kinetic‑energy equations.
Materials Needed:
  • Projector or interactive whiteboard
  • Printed worksheet with collision problems
  • Set of carts and track for a classroom demonstration
  • Calculator for each student
  • Physics textbook (IGCSE 0625) or reference sheet
  • Whiteboard and markers
 Introduction:
Begin with a quick demonstration: two small carts on a track collide, prompting students to predict the motion after impact. Review the definition of momentum and its vector nature, linking to prior work on forces. Explain that today’s success criteria are to correctly set up and solve one‑dimensional momentum equations for different collision types.
Lesson Structure:
  1. Do‑Now (5') – Students solve a short momentum‑vector question on the board to activate prior knowledge.
  2. Demonstration (10') – Teacher shows the cart collision, asks students to record initial velocities and predict the outcome.
  3. Mini‑lecture (15') – Review momentum formula, conservation law, sign conventions, and introduce the step‑by‑step problem‑solving method.
  4. Guided practice (20') – Work through the worked example together, filling each step on the projector; students complete a worksheet in pairs.
  5. Independent practice (15') – Students tackle three practice questions (elastic, inelastic, and skater problem), using the method; teacher circulates for misconceptions.
  6. Check for understanding (5') – Quick exit ticket: write the conservation equation for a given scenario and state whether kinetic energy is also conserved.
Conclusion:
Summarise that momentum is always conserved in isolated systems, while kinetic energy may not be, depending on the collision type. Ask a few students to share one check they used to verify their answer. Collect exit tickets and assign a homework worksheet with additional one‑dimensional collision problems.