Physics KS3 / GCSE: What happens to sound waves when you record a song?

Jon Chase joins singer-songwriter Charlie-Anne Bradfield in the studio as she performs her song 'Butterfly'.

As Charlie-Anne sings, Jon traces the path of the sound waves.

He builds a large model to see how the sound waves travel through air.

Jon's microphone made out of a plastic cup works just like the real one, turning sound into electrical waves.

After the studio engineer records the song, Jon plays it back on a loudspeaker he has made out of a couple of paper plates.

This clip is from the series Wave World.

Teacher Notes

Key Stage 3

When learning about sound, this is a simple but effective illustration of how microphones and loud-speakers work.

Pupils might explore further by building a model microphone or loudspeaker.

Teachers might demonstrate this effect using a large loudspeaker and placing grains of rice/small pieces of paper on the front diaphragm to show the vibrations at different amplitudes and frequencies of sound.

Teachers could link the science here to careers in sound engineering and music technology.

Key Stage 4

When teaching about electromagnetism, teachers could use this to illustrate two practical applications of the effect of a moving solenoid in a magnetic field or the magnetic effects of currents, and how solenoids enhance the effect.

Students might build a model loudspeaker and microphone.

They might explore and describe the strength and direction of the forces exerted by the magnetic field around a solenoid, using Fleming’s left-hand rule.

They might then apply the equation that links the force exerted, the current and the length of the wire to calculate the forces involved, and use this to explain how motors work.

Curriculum Notes

This clips is relevant for teaching Physics at KS3 or KS4 and National 4/5.

This appears in AQA, OCR, EDEXCEL, WJEC GCSE in England and Wales, CCEA GCSE in Northern Ireland and SQA National 5 in Scotland.