Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: Describe an experiment to demonstrate that there is no resultant moment on an object in equilibrium
Learning Objective/s:
  • Describe the concept of moment (torque) and how to calculate it.
  • Explain the conditions for static equilibrium in terms of forces and moments.
  • Design and carry out an experiment to verify that the net moment on an object in equilibrium is zero.
  • Analyse experimental data to confirm the relationship m₁d₁ = m₂d₂ within experimental error.
Materials Needed:
  • Rigid wooden board (≈0.5 m) with central low‑friction pivot
  • Calibrated masses (50 g, 100 g, 200 g)
  • Two identical strings with hooks
  • Meter rule or measuring tape
  • Clamp stand
  • Stopwatch
  • Worksheet/Data table for recording results
 Introduction:
Begin with a quick demonstration of a seesaw tipping to capture interest. Recall that forces cause linear motion while moments cause rotation, and that equilibrium requires both net force and net moment to be zero. Today’s success criteria: students will be able to describe the experiment, predict the balance condition, and analyse data to show the resultant moment is zero.
Lesson Structure:
  1. Do‑now (5’) – Students answer a short question on torque definition on a worksheet.
  2. Mini‑lecture (10’) – Review the moment formula, sign convention, and equilibrium conditions.
  3. Demonstration set‑up (5’) – Show the board, pivot, strings, and masses; explain safety.
  4. Guided lab activity (20’) – Students measure distances, attach masses, adjust until the board balances, and record data for three different trials.
  5. Data analysis (10’) – Calculate moments, verify ΣM≈0, and discuss sources of error.
  6. Check for understanding (5’) – Quick quiz/exit ticket: state the relationship m₁d₁ = m₂d₂.
Conclusion:
Summarise that when the clockwise and anticlockwise moments are equal, the net moment is zero and the board stays level. For exit, pupils write one sentence describing how they would test equilibrium with different lever arms. Assign homework to design a similar experiment using everyday objects and predict the balance condition.