Lesson Plan

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Lesson Plan
Grade: Date: 03/03/2026
Subject: Physics
Lesson Topic: Describe the use of a single lens as a magnifying glass
Learning Objective/s:
  • Describe how a convex lens forms a virtual, upright, magnified image when the object is within its focal length.
  • Apply the thin‑lens equation to determine object and image distances for a magnifying glass.
  • Calculate linear magnification for given object distances.
  • Explain the conditions for an effective magnifying glass (object inside focal length, image at near point, lens quality).
  • Demonstrate correct positioning of a hand‑held lens to achieve comfortable viewing.
Materials Needed:
  • Convex lenses (focal length 5–10 cm)
  • Meter sticks or rulers
  • Printed worksheet with calculation tasks
  • Projector and screen for diagram
  • Whiteboard and markers
  • Eye‑relief near‑point reference (≈25 cm card)
 Introduction:
Begin with a quick demonstration: hold a simple convex lens over a printed text and ask students what they notice. Recall prior learning of focal length and image formation from earlier lens lessons. Explain that today they will learn how to use a single lens as a magnifying glass and will be able to predict the image position and magnification.
Lesson Structure:
  1. Do‑now (5’) – Students complete a short quiz on sign conventions for thin lenses.
  2. Mini‑lecture (10’) – Review thin‑lens equation, sign conventions, and magnification formula, using a projected diagram.
  3. Guided calculation (10’) – Work through example table values; students fill in missing distances and magnifications.
  4. Hands‑on activity (15’) – In pairs, students use provided convex lenses and rulers to place an object within focal length, adjust until the image is at the near point, and record u, v, m.
  5. Class discussion (5’) – Groups share findings and discuss lens quality and eye strain.
  6. Exit ticket (5’) – Write one condition for an effective magnifying glass and one real‑world example.
Conclusion:
Summarise that a magnifying glass relies on placing the object inside the focal length to produce a virtual, upright image at the near point. Students complete an exit ticket and are assigned a homework task to calculate magnification for a new lens‑object distance. Reinforce that proper positioning reduces eye strain and maximises clarity.