An oscilloscope is a displacement-time graph of a wave
Connected to a microphone, an oscilloscope shows a displacement-time graph of a sound wave
The distance between two wave crests on an oscilloscope’s graph is equal to the period of the wave
The time period is measured most accurately by measuring the time for, say, 10 waves and dividing time by 10
The bigger the amplitude of a sound wave, the louder the sound

Common misconception

The distance between two crests of an oscilloscope graph is equal to one wavelength.

Emphasise the need to read scales of graphs first and that the horizontal scale of an oscilloscope graph is time.

Keywords

Oscilloscope - an oscilloscope is a piece of equipment that can display a representation of a sound wave.
Displacement-time graph - a displacement-time graph shows how the displacement of one part of a wave changes as the wave moves forward.
Period - the period of a wave is the time for one complete oscillation.
Frequency - the frequency of a wave is the number of complete oscillations in one second.
Loudness - the loudness of a sound wave is a measure of how loud it is.

Ocilloscopes often appear complex and confusing. It is important to identify the main controls and to develop understanding of each one, one at a time.

Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.

What does a loudspeaker do when it makes a louder sound?

vibrates in and out more slowly

vibrates in and out more quickly

Correct answer: vibrates in and out a bigger distance

vibrates in and out a smaller distance

Q2.

What causes a soundwave to have a bigger amplitude?

Correct answer: a bigger vibration

a smaller vibration

a faster vibration

a slower vibration

Q3.

What sort of sound has a bigger amplitude?

Correct answer: a louder sound

a quieter sound

a sound with a higher note

a sound with a lower note

Q4.

What does a loudspeaker do when it makes a higher pitched sound?

vibrates in and out more slowly

Correct answer: vibrates in and out more quickly

vibrates in and out a bigger distance

vibrates in and out a smaller distance

Q5.

What causes a sound to have a lower frequency?

a bigger vibration

a smaller vibration

a faster vibration

Correct answer: a slower vibration

Q6.

What sort of sound has a higher frequency?

a louder sound

a quieter sound

Correct answer: a sound with a higher note

a sound with a lower note

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6 Questions

Q1.

What sort of graph is shown on an oscilloscope?

a displacement-distance graph

Correct answer: a displacement-time graph

a distance-time graph

Q2.

What type of sound causes the height of a graph on an oscilloscope to increase?

quieter sound

Correct answer: louder sound

higher pitched (squeakier) sound

lower pitched (deeper note) sound

Q3.

What type of sound causes the length of wave on a graph on an oscilloscope to increase?

quieter sound

louder sound

higher pitched (squeakier) sound

Correct answer: lower pitched (deeper note) sound

Q4.

What is the distance between two wave crests on an oscilloscope graph equal to?

amplitude

frequency

Correct answer: period

wavelength

Q5.

An oscilloscope shows two complete waves on a screen and it takes 0.1 s for the line to move across the screen. What is the period of the wave?

0.5 s

0.2 s

0.1 s

Correct answer: 0.05 s

0.02 s

Q6.

The period of a wave is 0.05 s. How many complete waves are seen on the screen of an oscilloscope if it takes 0.2 s for the line to move across the screen?

0.2

2.5

Correct answer: 4