Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: Know that friction (drag) acts on an object moving through a liquid
Learning Objective/s:
  • Describe what drag is and how it differs from solid‑surface friction.
  • Explain the factors that affect the magnitude of drag in liquids.
  • Apply the drag equation to predict how changes in speed, area, density, or shape influence drag force.
  • Analyse experimental data to compare drag on different shaped objects.
  • Identify real‑world examples where drag is a key consideration.
Materials Needed:
  • Projector or interactive whiteboard
  • Printed worksheet with drag equation and data table
  • Model objects (sphere, flat plate, streamlined shape) of equal mass
  • Water tank and pulley‑spring balance apparatus
  • Stopwatch or speed‑control device
  • Markers and ruler for measuring dimensions
 Introduction:
Begin with a short video of a swimmer cutting through water, asking students why they feel resistance. Recall that friction opposes motion and introduce drag as the fluid equivalent. Explain that today they will explore how shape, speed and liquid properties affect this force and will be able to predict drag using an equation.
Lesson Structure:
  1. Do‑now (5’) – Quick quiz on friction vs. drag concepts.
  2. Mini‑lecture (10’) – Define drag, viscosity, present the drag equation and illustrate the influencing factors.
  3. Demonstration (8’) – Pull three shaped objects through water with a spring balance and display force readings.
  4. Guided investigation (15’) – Students record data, calculate predicted drag, and compare with measurements.
  5. Misconception check (5’) – Discuss common misconceptions using click‑answers.
  6. Application discussion (7’) – Relate drag to everyday examples (boats, skydivers) and engineering design.
  7. Exit ticket (5’) – Write one factor that most influences drag for a given object and why.
Conclusion:
Summarise that drag is a fluid friction whose magnitude depends on speed, area, density, shape and viscosity, following a quadratic speed relationship. Have students complete an exit ticket stating the most significant factor for a streamlined object. Assign homework to research how drag is minimised in competitive swimming suits.