Lesson Plan

Resources → Subject Notes → Physics → Notes
Lesson Plan
Grade: Date: 25/02/2026
Subject: Physics
Lesson Topic: Describe, qualitatively, the effect of the position of the centre of gravity on the stability of simple objects
Learning Objective/s:
  • Describe how the vertical and horizontal position of the centre of gravity influences an object's stability.
  • Explain the relationship between restoring torque, CG position, and tipping.
  • Compare stability of objects with low versus high CG using real‑world examples.
  • Predict the stability of a given simple object based on its CG location and base width.
  • Propose design modifications to improve the stability of everyday objects.
Materials Needed:
  • Projector or interactive whiteboard
  • PowerPoint slides with CG diagrams
  • Simple objects (wooden block, baseball bat, toy pyramid, small table)
  • Ruler or measuring tape
  • Worksheet with scenario questions
  • Sticky notes or markers for group brainstorming
 Introduction:
Begin with a quick demonstration: balance a ruler on your fingertip and ask students why it stays up. Recall that the centre of gravity is the point where an object's weight acts and that stability depends on its position relative to the base. Explain that by the end of the lesson they will be able to describe and predict stability qualitatively.
Lesson Structure:
  1. Do‑now (5') – Students answer a short worksheet question about everyday objects that tip over easily.
  2. Mini‑lecture (10') – Define centre of gravity, stability, and introduce restoring torque with a diagram.
  3. Guided demonstration (10') – Show low‑CG vs high‑CG objects, tilt them, and discuss observations.
  4. Group activity (15') – Teams locate the CG of assigned objects, predict stability, and record reasoning.
  5. Concept check (5') – Quick quiz using clickers or a show of hands.
  6. Design challenge (10') – Teams suggest one modification to improve an object's stability and justify it.
  7. Summary recap (5') – Teacher revisits key points and checks understanding.
Conclusion:
Summarise that a low centre of gravity and a wide base increase stability, while a high centre of gravity makes tipping easier. Ask each pair to write one exit‑ticket sentence predicting the stability of a new object. Assign homework to find a household item, sketch its CG position, and suggest a way to make it more stable.