Text, sound and images

About this lab: Text, sound and images

Interactive simulation for Cambridge IGCSE Computer Science 0478 topics 1.2 and 1.3 and AS & A Level 9618 topics 1.1 to 1.3: see text as ASCII and Unicode codes, sample a sound wave at different rates and resolutions, change the resolution and colour depth of an image, convert storage units with 1024, calculate sound and image file sizes, compress with run length encoding and lossy methods, and compare bitmap and vector graphics.

IGCSE Computer Science 0478, topics 1.2 and 1.3, and A-Level 9618, topics 1.1 to 1.3. Character sets, sampled sound, bitmap images, storage units and file sizes, lossless and lossy compression, and bitmap versus vector graphics.

Text, sound and images is a free, browser-based simulation for Cambridge IGCSE Computer Science 0478 (topic 1 Data representation, sections 1.2 Text, sound and images, 1.3 Data storage and compression). The same lab serves both Cambridge IGCSE Computer Science 0478 and AS & A Level Computer Science 9618; tabs marked A-Level go beyond the IGCSE syllabus. The course is assessed in Paper 1 (Computer Systems), Paper 2 (Algorithms, Programming and Logic). Syllabus for examination in 2026-2028. There are 6 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.

Syllabus coverage

• 1.2 Text, sound and images. Lessons: Representing text: ASCII and Unicode, Representing sound: sample rate and resolution, Representing images: resolution and colour depth.
• 1.3 Data storage and compression. Lessons: Measuring data storage and calculating file sizes, Lossy and lossless compression.
• 9618 1.1 Data Representation. Lessons: Binary and decimal prefixes, Binary, denary, hexadecimal and BCD, Two's complement and binary arithmetic.
• 9618 1.2 Multimedia: Graphics, Sound. Lessons: Bitmap and vector graphics, Sampled sound.
• 9618 1.3 Compression. Lessons: Lossy and lossless compression, run-length encoding.

Full syllabus map: IGCSE Computer Science 0478 topic 1 and A Level Computer Science 9618 topic 1.

How to use this simulation

1. 1. Text and character sets.
2. 2. Sound.
3. 3. Images.
4. 4. Storage units.
5. 5. Compression.
6. 6. Bitmap or vector.
7. The buttons at the end of the tab strip give the scene the whole window (Full screen, Hide controls) and, on a dark stage, a projector-friendly palette (Light scene). Many scenes also have drag handles: drag them to change the set-up directly.

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