| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Describe the uses of ultrasound in nondestructive testing of materials, medical scanning of soft tissue and sonar including calculation of depth or distance from time and wave speed |
Learning Objective/s:
- Describe how ultrasound is applied in nondestructive testing, medical imaging, and sonar.
- Explain the relationship between travel time, speed of sound, and depth calculation.
- Compare typical frequencies and media for each ultrasound application.
- Apply the distance formula to solve depth‑calculation problems in NDT and sonar contexts.
- Evaluate safety considerations associated with medical ultrasound.
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Materials Needed:
- Projector and screen
- Whiteboard and markers
- Printed handouts with diagrams of NDT, medical ultrasound, and sonar
- Calculator for each pair
- Worksheet with practice depth‑calculation problems
- Short video demonstration of an ultrasonic NDT probe
- Speed‑of‑sound reference tables for steel, soft tissue, and water
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Introduction:
Imagine detecting a crack inside a metal beam without cutting it open. You already know that sound travels as a wave and that speed = distance ÷ time. Today you will see how high‑frequency sound lets us “see” inside solids, bodies, and the ocean. By the end of the lesson you will be able to explain each application and calculate depths from echo times.
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Lesson Structure:
- Do‑now (5'): Quick written quiz on wave speed and medium properties.
- Mini‑lecture (10'): Introduce ultrasound, the distance formula d = vt⁄2, and key terminology.
- Video demonstration (8'): Show NDT ultrasound probe in action; discuss typical frequencies and resolution.
- Guided practice (12'): Pairs calculate flaw depths in metal and organ depths in soft tissue using given speeds.
- Sonar activity (10'): Simulate a sonar depth problem; students compute seabed depth.
- Comparison discussion (5'): Whole‑class compare frequencies, media, and uses of the three applications.
- Check for understanding (5'): Exit ticket – write one ultrasound application and the speed of sound used.
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Conclusion:
We revisited how the same basic principle—measuring echo travel time—underpins NDT, medical scanning, and sonar, each with its own frequency range and medium speed. Complete the worksheet for homework, which includes additional depth‑calculation problems and a short reflection on safety in medical ultrasound.
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