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Year 9

Representing sound with binary data

I can describe how sound is represented in digital devices.

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New
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Year 9

Representing sound with binary data

I can describe how sound is represented in digital devices.

Download all resources
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Share activities with pupils
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Lesson details

Key learning points

  1. Sounds are represented as sequences of bits.
  2. Sample rate is the number of sound samples taken per second.
  3. Sample resolution (bit depth) is the number of bits used to represent each sample.
  4. Changes to sample rate and sample resolution (bit depth) affect the file size and quality of a sound file.

Keywords

  • Sample - a single measurement of an analogue signal, typically sound

  • Sample rate - the number of samples captured per second

  • Sample resolution (bit depth) - the number of bits used to store each sample, which determines how accurately the sample is represented

  • Channel - a single stream of audio used to reproduce sound

Common misconception

A single audio file contains only one channel of sound.

Many formats (e.g., stereo or surround sound) contain multiple channels within one file. The information contained in the audio track can be reproduced on separate channels.


To help you plan your year 9 computing lesson on: Representing sound with binary data, download all teaching resources for free and adapt to suit your pupils' needs...

Engage pupils interest in this topic by finding connections in the resources to applications like music production, podcasting or video game design.
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This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Starter quiz

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6 Questions

Q1.
When you change the resolution of an image in image editing software, what are you actually changing?
the number of colours in the image
the size of the image file on your computer
the physical dimensions of the image, increasing the height and width
Correct answer: the number of pixels that make up the image
Q2.
When you change the physical dimensions of an image in an image editor by increasing its height and width, what happens to the image?
the resolution increases, so it becomes more detailed
the image stays the same size, but the file size increases
Correct answer: the pixels increase in size
the number of pixels increases
Q3.
What is the purpose of zooming in on an image in an image editor?
to make the image file size larger
Correct answer: to see the image in more detail
to change the colours in the image
to make the image blurry
Q4.
What does it mean to 'export' an image in an image editor?
to open the image in a different program
Correct answer: to save the image in a specific file format
to print the image
to delete the image from the computer
Q5.
What is a common use of artificial intelligence (AI) in image editing?
to print the image
Correct answer: to enhance or restore old photographs
to create physical paintings from digital images
to make images load faster on websites
Q6.
Which of the following is a potential concern about AI to create art?
AI art can be too creative and original.
AI art is always low quality and not visually appealing.
Correct answer: AI art can be difficult to distinguish from human-created art.
AI art cannot be used for commercial purposes.

Exit quiz

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6 Questions

Q1.
What is the purpose of a microphone in digital audio?
Correct answer: to convert sound waves into electrical signals
to display sound waves visually
to store sound waves as digital files
to play back digital sound
Q2.
What does 'sample rate' refer to in digital audio?
the number of speakers used to play a sound
the volume of the sound being recorded
Correct answer: the number of sound samples taken per second
the length of the sound file
Q3.
What does changing the sample resolution (bit depth) change in a digital audio file?
the length of the sound recording
the number of channels in the audio
Correct answer: the accuracy of the sound wave's representation
the type of file format used to store the sound
Q4.
What is a channel in digital audio?
Correct answer: a single stream of audio used to reproduce sound
the frequency of a sound wave
the volume level of a sound
the type of microphone used to record the sound
Q5.
If you increase the sample rate of a digital audio recording, what is the effect on the sound quality and file size?
The sound quality will decrease, and the file size will decrease.
Correct answer: The sound quality will increase, and the file size will increase.
The sound quality will increase, and the file size will decrease.
The sound quality will decrease, and the file size will increase.
Q6.
Why might a musician choose to record their music in stereo instead of mono?
to make the recording louder
Correct answer: to create a richer and more immersive listening experience
to reduce the file size of the recording
to make the recording easier to edit