| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: understand that a piezo-electric crystal changes shape when a p.d. is applied across it and that the crystal generates an e.m.f. when its shape changes |
Learning Objective/s:
- Describe the direct and converse piezo‑electric effects.
- Explain how a crystal produces ultrasound when driven at its resonant frequency and how it generates a voltage when it receives ultrasound.
- Calculate the resonant frequency and maximum strain for a given crystal thickness and applied voltage.
- Compare quartz and PZT crystals for different medical and industrial applications.
- Apply the concepts to solve typical A‑Level exam questions.
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Materials Needed:
- Projector and screen
- Slide deck with diagrams of the piezo‑electric effect
- Handout/worksheet containing formulas and practice problems
- Demo kit: piezo‑electric crystal or transducer with voltage source (video if physical demo unavailable)
- Scientific calculators
- Whiteboard and markers
- Safety goggles (if lab demo is performed)
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Introduction:
Begin with a short video of a medical ultrasound scan to capture interest. Ask students what physical phenomenon allows the probe to “see” inside the body, linking it to prior knowledge of waves and electric fields. State that by the end of the lesson they will be able to describe both sides of the piezo‑electric effect and predict how crystal properties affect ultrasound generation.
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Lesson Structure:
- Starter quiz (5') – quick MCQ on wave frequency and voltage concepts; collect responses via clickers.
- Mini‑lecture (10') – introduce direct and converse effects with annotated slides and a simple animation.
- Demonstration (8') – apply a sinusoidal voltage to a piezo crystal (or show video) and discuss observed deformation and sound emission.
- Guided practice (12') – work through the example calculation of resonant frequency and ΔL; students complete a similar problem in pairs.
- Application discussion (10') – compare quartz vs PZT, explore medical vs industrial uses; students list advantages on sticky notes.
- Revision questions (5') – students answer one of the four suggested exam‑style questions and share reasoning.
- Exit ticket (5') – write a one‑sentence summary of how the converse and direct effects are linked.
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Conclusion:
Recap the two complementary piezo‑electric effects and their role in generating and receiving ultrasound. Collect exit tickets to gauge understanding, and assign the worksheet’s extra problems as homework for further practice.
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