Uses of Sound Waves
Science: KS3, topic 3.3.9
Everyday Uses of Sound Waves
Using sound waves is important when designing microphones and loudspeakers. We can project an image of a sound wave on an oscilloscope screen.
Oscilloscope
- We can use a microphone to convert sound waves to electrical signals that can be seen on an oscilloscope.
- An oscilloscope shows a sound wave on a screen.
- From looking at an oscilloscope, we might be able to record a wave's:
- Amplitude.
- Wavelength.
- Frequency.
Microphones
- Sound waves hit the ‘diaphragm’ of the microphone.
- The diaphragm then moves backwards and forwards.
- This is attached to a coil and magnet, which produces a magnetic field.
- The movement of the diaphragm through the magnetic field generates an electric current.
- To increase the size of the current, you can use an amplifier.
Loudspeakers
- Electric current flows inside loudspeakers.
- This creates an electromagnet.
- The electromagnet attracts the speaker cone and moves it forwards and backwards towards a permanent magnet.
- This movement creates the sound.
- If you change the current, it will change the frequency of the cone and so the sound created will change.
Test yourself on Uses of Sound Waves
What cannot be found by looking at an oscilloscope screen?
Microphones
Loudspeakers
Why is a microphone needed before a sound wave can be shown on an oscilloscope screen?
A loudspeaker converts an electric current into sound waves. What is the opposite conversion that happens inside a microphone?