How computers represent data: text, images & sound
Technologies · Year 8
Name: ______________________Date: ____________
Computers only understand binary — sequences of 1s and 0s — so every type of data must be converted into this form. Text is represented using a character encoding standard like ASCII or Unicode, where each letter, number or symbol is assigned a specific binary code. Images are broken into a grid of tiny pixels, each storing binary colour information (often as red, green and blue values combined). Sound is represented by sampling — measuring and recording the sound wave's amplitude thousands of times per second, storing each measurement as binary. More detail (higher resolution images, higher sample-rate audio) means more accurate representation, but also a much larger file size.
Example
A simple black-and-white image made of 10x10 pixels only needs 1 bit per pixel (0 for white, 1 for black) — 100 bits total. A full-colour photo needs far more data per pixel to store precise red, green and blue values, which is why colour photos are much larger files than simple black-and-white ones, even at the same pixel dimensions.
Key terms
Pixel:
The smallest unit of a digital image, storing colour information.
Sampling:
Measuring a sound wave's amplitude at regular intervals to convert it into binary data.
Questions
1. Computers represent all data using:
Binary (1s and 0s)
Only decimal numbers
Only letters
Coloured light with no numbers
2. A pixel is:
The smallest unit of a digital image
A unit of sound only
A type of text character
Something unrelated to images
3. Text is converted to binary using:
A character encoding standard like ASCII or Unicode
Random guessing
Colour values only
Sound samples
4. Sampling is used to represent:
Sound
Only text
Only colour
Nothing digital
5. Higher resolution images generally mean:
Larger file sizes
Always smaller file sizes
No change in file size
Files that cannot be stored
6. A pixel's colour is often stored using:
Combined red, green and blue values
Only a single number with no components
Sound samples
Text characters
7. A black-and-white image needs how much data per pixel compared to a full-colour image?
Less
Always more
Exactly the same
An unrelated amount
8. Why do full-colour photos typically take up more storage space than simple black-and-white images of the same pixel dimensions?
Each pixel needs to store more detailed colour information (red, green and blue values) rather than a single black/white bit
Colour photos and black-and-white images always require an identical amount of data
File size has no connection to how much colour information is stored
Black-and-white images always require more data than colour ones
9. Why might a higher sample rate for recorded audio result in a more accurate but larger sound file?
More frequent measurements of the sound wave capture more detail, but require storing more data points
Sample rate has no connection to either accuracy or file size
A higher sample rate always makes an audio file smaller
Accuracy and file size are always completely unrelated to each other in audio
10. Why does a character encoding standard like Unicode need to assign a unique binary code to every letter, number and symbol?
Computers can only process binary, so every distinct character needs its own specific binary representation to be stored or displayed
Computers can directly understand and display text without any binary conversion
Character encoding standards serve no practical purpose
Text does not actually need to be converted into any digital form
11. Why might compressing an image (reducing its file size) sometimes result in a slight loss of visual quality?
Compression can reduce or approximate some of the original detailed pixel data to save storage space
Compression always perfectly preserves every detail of the original image with zero data loss
Reducing file size has no connection to image quality
Image compression only ever affects text files, not images
12. Why might a streaming music service offer different audio quality options (like "low" and "high" quality)?
Higher quality audio uses a higher sample rate and more data, which affects file size and required internet bandwidth
Audio quality has no connection to file size or data usage
All audio quality settings use an identical amount of data
Sample rate has no bearing on perceived sound quality
13. Why is understanding binary representation useful for understanding why some files (like videos) are much larger than others (like plain text documents)?
Video combines detailed image and sound data sampled many times per second, requiring vastly more binary data than simple text
All types of digital files always require an identical amount of binary data
Video files and text files are always exactly the same size
File type has no connection to how much data is required to represent it
14. Why might increasing an image's pixel count (resolution) improve its visual clarity, especially when enlarged?
More pixels mean more individual points of colour information, capturing finer detail across the image
Pixel count has no effect on how clear or detailed an image appears
Fewer pixels always produce a clearer, more detailed image
Enlarging an image never reveals any difference in pixel count
15. Why might two different audio files of the same song, recorded at different sample rates, sound noticeably different in quality when played back?
A lower sample rate captures less detail of the original sound wave, potentially losing subtle audio information a higher sample rate would preserve
Sample rate never has any audible effect on how a recording actually sounds
All sample rates always produce audio of completely identical quality
Audio quality is determined entirely by the file format, not the sample rate
16. Why might understanding how data is represented in binary help explain why converting a large, uncompressed video file for online sharing often takes noticeable processing time?
The sheer volume of binary data involved in high-quality video and audio requires significant computation to process, compress or convert
Video conversion never requires any meaningful processing time regardless of file size
Binary representation has no connection to how long file processing takes
All files, regardless of type or size, take an identical time to process
17. Why might a designer need to balance image or audio quality against file size when creating content for a website?
Higher quality media increases file size, which can slow down page loading, especially for users with limited internet bandwidth
File size has no effect on website loading speed or user experience
Quality and file size are always completely unrelated to each other
Every website visitor always has unlimited, extremely fast internet access
18. Why might understanding binary data representation help explain the limits of what a very old computer with limited storage could display or play?
Limited storage capacity directly restricts how much binary data (and therefore how much image, text or audio detail) can be stored and processed
Storage capacity has no connection to a computer's ability to display data
Old computers could always store and process an unlimited amount of binary data
Binary representation has no connection to storage or processing limitations
19. A photo taken on a phone in "RAW" format is much larger than the same photo saved as a compressed JPEG. Why does this file size difference occur even though both represent the same image?
RAW stores far more detailed, unprocessed pixel data, while JPEG compression reduces file size by discarding some of that detail
RAW and JPEG formats always store exactly the same amount of binary data
File format choice has no effect on how much binary data is required
JPEG compression always increases file size compared to RAW
20. Why might early computer systems with very limited memory have used simple, low-resolution graphics and short, low-quality sound clips rather than the rich media common today?
Limited storage and processing power meant less binary data could be handled, restricting how much image and audio detail could be represented
Storage and processing limitations have no connection to the quality of graphics or sound a system can handle
Early computers always had unlimited capacity to store any amount of binary data
The amount of available memory has no bearing on achievable media quality
21. Understanding how computers represent text, images and sound mainly helps you to:
Explain how digital data is stored as binary, and why detail and file size are closely connected
Assume all digital files are always exactly the same size regardless of content
Ignore the connection between data detail and storage requirements
Treat binary representation as unrelated to real digital media
Answer key (parent copy)
1. Binary (1s and 0s)
2. The smallest unit of a digital image
3. A character encoding standard like ASCII or Unicode
4. Sound
5. Larger file sizes
6. Combined red, green and blue values
7. Less
8. Each pixel needs to store more detailed colour information (red, green and blue values) rather than a single black/white bit
9. More frequent measurements of the sound wave capture more detail, but require storing more data points
10. Computers can only process binary, so every distinct character needs its own specific binary representation to be stored or displayed
11. Compression can reduce or approximate some of the original detailed pixel data to save storage space
12. Higher quality audio uses a higher sample rate and more data, which affects file size and required internet bandwidth
13. Video combines detailed image and sound data sampled many times per second, requiring vastly more binary data than simple text
14. More pixels mean more individual points of colour information, capturing finer detail across the image
15. A lower sample rate captures less detail of the original sound wave, potentially losing subtle audio information a higher sample rate would preserve
16. The sheer volume of binary data involved in high-quality video and audio requires significant computation to process, compress or convert
17. Higher quality media increases file size, which can slow down page loading, especially for users with limited internet bandwidth
18. Limited storage capacity directly restricts how much binary data (and therefore how much image, text or audio detail) can be stored and processed
19. RAW stores far more detailed, unprocessed pixel data, while JPEG compression reduces file size by discarding some of that detail
20. Limited storage and processing power meant less binary data could be handled, restricting how much image and audio detail could be represented
21. Explain how digital data is stored as binary, and why detail and file size are closely connected