Sound Wave
Light Sound and Waves

Sounds and vibrating sources

Teaching Guidance for 5-11 11-14 Supporting Physics Teaching

Vibration

Wrong Track: If you hit a cymbal it vibrates to make the sound. If you drop a spoon on the kitchen table it just makes a noise.

Right Lines: All sounds are produced by vibrations. If you drop a spoon on the table, the sound you hear comes from the vibrations that are set up in the table and spoon.

Teaching and learning about vibrations

Thinking about the learning

The challenge here is for pupils to come to appreciate that all sounds are generated by the vibration of a source.

In some situations the vibrating object is obvious; in others it is less so. Where the vibration is less obvious, pupils tend to revert to ad-hoc explanations for the generation of the sound, often focusing on human action. For example, The hammer makes the bang because you hit the wood hard with it. The learning challenge for pupils is to develop the general idea that all sounds are produced by vibrations.

Thinking about the teaching

In your teaching it is worth identifying where the sound is coming from each time you consider a new sound-making context. Take the time to chase down what it is that is vibrating to act as the source of the sound.

A teaching colleague entertains her classes each year with the invitation:

Teacher: Let's play spot the vibration!

She uses a range of examples in class:

  • In a reed instrument (clarinet, saxophone, oboe): the reed vibrates, setting all of the air in the instrument tube vibrating.
  • In a stringed instrument: the strings are first set into vibration, by either bowing or plucking, then air is set in motion in the box behind the strings.
  • In a flute or recorder: the mouthpiece is shaped so that the air striking one edge of it is set into vibration. This small vibration sets up a larger vibration of the air in the instrument tube.
  • When two stones are clinked together: it is the stones that vibrate, changing shape as they do so, much like the surface of a drum.
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