Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: Explain that charging of solids by friction involves only a transfer of negative charge (electrons)
Learning Objective/s:
  • Describe the two types of electric charge and the principle of charge quantisation.
  • Explain why only electrons are transferred during frictional charging.
  • Predict which material becomes positively or negatively charged based on electron affinity.
  • Apply the law of charge conservation to friction experiments.
  • Interpret experimental evidence (electroscope, charge measurements) that supports the electron‑transfer model.
Materials Needed:
  • Glass rod and silk cloth
  • Rubber rod and wool cloth
  • Small pieces of dry paper
  • Electroscope (or simple electroscope apparatus)
  • Metal probe or foil
  • Clamp and stand
  • Projector or interactive whiteboard for diagrams
  • Worksheet with material‑pair table and questions
 Introduction:
Begin with a quick demonstration: rub a glass rod with silk and watch a paper strip jump to it. Ask students what they think has changed on the rod and recall that charge comes in two types. Explain that today they will investigate why only electrons move during friction and how this leads to opposite charges. Success will be measured by their ability to predict charge outcomes and explain the electron‑transfer model.
Lesson Structure:
  1. Do‑Now (5'): Short quiz on positive/negative charge and charge conservation.
  2. Mini‑lecture (10'): Explain the electron‑transfer model and why only electrons move.
  3. Demonstration (8'): Teacher rubs glass rod with silk, shows paper attraction and electroscope response.
  4. Guided inquiry (12'): Pairs repeat the experiment with different material pairs (rubber‑wool, silk‑glass) and record which object becomes positive or negative.
  5. Data analysis (8'): Groups discuss donor/acceptor concepts and relate results to electron affinity.
  6. Concept check (5'): Quick exit questions via clickers or show of hands.
  7. Summary (2'): Teacher revisits key points and links to upcoming topics on conduction and induction.
Conclusion:
Recap that frictional charging transfers only electrons, making the donor positive and the acceptor negative while total charge stays constant. Ask a few students to articulate the evidence that supports this model. Collect an exit ticket where each learner writes one real‑world example of frictional charging. For homework, assign a worksheet to predict charges for additional material pairings.