4-WAV-03b

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Outcomes

  • Pupils can recall the hearing range of a human and determine whether a frequency lies within the range and understand that
  • Pupils understand that any sound wave with a frequency greater than 20kHz is known as ultrasound.
  • Pupils can recall different uses of ultrasound and can explain the idea of ultrasound scanning using an echo.
  • Pupils can describe how to measure the speed of sound using a clapping method and an electronic method.

Specification References

Starter

  • Carry out pupil hearing range experiment using speaker and signal generator. Pupils will probably bring up the The Mosquito at this point.

Main Body of Lesson

  • Discuss the nature of ultrasonic sound.
  • Discuss the uses of ultrasound in diagnostic sonography, therapeutic medicine, industrial nondestructive testing and cleaning. Why not bring in some jewellery and clean it in the lesson.
  • Demonstrate nature of sound waves
  • Show pupils the comparative speed of sound in solids, liquids and gases (set a large value for distance (≈50000m)).
  • Demonstrate how to find the speed of sound. For reasons unknown to me you must demonstrate the use of the "clapper" method. Whatever that is.
  • Demonstrate that sound waves cannot travel through a vacuum.
  • Demonstrate the effect of changing the frequency and amplitude of a sound wave on the oscilloscope trace produced.

Plenary

  • Link frequency and amplitude to sound waves using audio clips.

Homework

Additional Information

Resources Required

  • Signal Generator
  • Speaker
  • Vacuum pump connected to Bell Jar
  • Ultrasonic cleaner
  • Oscilloscope

Textbook References

  • Pople 6.03 pp. 128-135

Website References

Skills Addressed

  • Awesomeosity

Safety/Hazards

Notes