DCF Cymru Digital competence for Wales

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GCSE Computer Science

Both units are sat on screen. Unit 1 tests theory (algorithms, data representation, networks, cybersecurity, logic, the systems development life cycle) and Unit 2 asks learners to design, write, test and refine Python 3 programs with a Tkinter interface in IDLE against a pre-released scenario. The single biggest thing KS3 should build is confident algorithm design and debugging: pupils who can decompose a problem, write it as a flowchart or pseudocode, then code, test and fix it arrive ready for Unit 2.

Awarding body
WJEC
Level
Level 1 and Level 2
First taught
September 2025
Amount of digital work
High
Specification
Open the specification
How this qualification is assessed
  • Unit 1: Understanding Computer Science: Digital examination 1 hour 30 minutes, 50%, 80 marks
  • Unit 2: Computer Programming: On-screen examination based on a pre-released brief, 2 hours, 50%, 80 marks, set and marked by WJEC

Skills that use Creating digital content

  1. Designing and building a graphical user interface

    Assessed: In the exam

    Learners design and document input and output facilities for an effective user interface, then create and modify Tkinter windows, frames, widgets and buttons, including authentication routines.

    DCF: Evaluating and improving digital content, Creating digital content

    Getting pupils ready

    Year 7
    Pupils sketch the screen for a Scratch game, labelling every button and message, and explain why each is placed where it is.
    Year 8
    Pupils design a login screen wireframe in PowerPoint, gather classmates' feedback using comments, and improve the layout.
    Year 9
    Pupils build a simple Python Tkinter window with a label, an entry box and a button that checks a password and shows a message.
    Show the specification wording and the DCF statements

    Where it is in the specification: Unit 2, Section 2.3.1 Implementation, page 25

    “create new and modify existing intuitive Graphical User Interfaces (GUI) using the Python 3 built in Tkinter libraries, including:”
    Progression step 3

    • I can explain reasons for layout and content of my own work and the work of others.

    • I can ensure my output is appropriate for specific purposes.

    Progression step 4

    • I can justify the reasons for choices and explain the advantages and disadvantages of the different digital outputs I create.

    • I can suggest and make improvements that are relevant for audience and purpose, based on feedback and self-evaluation of my digital work.

    Progression step 5

    • I can justify reasoning to critical audiences in terms of layout and content of my digital work.

    • I can use a variety of software, tools and techniques to create a professional, individual or collaborative project outcome incorporating a range of multimedia components.

  2. Representing data in binary and calculating file sizes and compression

    Assessed: In the exam

    Learners convert between denary, binary and hexadecimal, explain how text, images and sound are stored, calculate storage requirements from resolution, colour depth and sample rate, and compare lossy and lossless compression.

    DCF: Storing and sharing, Creating digital content

    Getting pupils ready

    Year 7
    Pupils colour an 8 by 8 pixel grid from a binary code sheet, then count how many bits the image needs.
    Year 8
    Pupils record the same sound in Audacity at two sample rates, compare the quality and file sizes, and explain the difference.
    Year 9
    Pupils save one photo as BMP, PNG and JPEG, compare the file sizes and quality, and calculate the compression ratio in Excel.
    Show the specification wording and the DCF statements

    Where it is in the specification: Unit 1, Section 1.2.1 Data types, including representation, storage and compression, pages 13 to 14

    “how to calculate the storage requirements for graphics using different dimensions, bit depths and colour depths.”
    Progression step 3

    • I can manage files and folders locally or online, e.g. move files to a folder.

    • I can use a range of software to select, produce and edit a range of multimedia components for a purpose, such as:

      • text and images, e.g. format text (bold, underline, italics, highlight); insert and edit text boxes; columns; use refine tools (spellchecker, find and replace); word wrap; crop; alter size and shape; alter images; add effects; trim and split sound and video clips; transitions; onion skin
      • presentation, e.g. page orientation; animations; transitions; remove and alter images; use background; use action buttons to create hyperlink; embed objects.
    Progression step 4

    • I can use appropriate advanced file management techniques, e.g. version history, restore previous version, tagging, compression.

    Progression step 5

    • I can make informed choices about file types and understand compatibility issues, e.g. the difficulties of editing PDFs, differences between sound files.

Good to know

Links with other qualifications

GCSE Digital Technology shares the binary data representation, compression calculation, cyber threats (phishing, social engineering, man-in-the-middle attacks), data validation and legal and ethical content, and its practical work also involves coding (JavaScript arrays, string methods and form validation), so Years 7 to 9 work on these skills serves both GCSEs; the binary, logic and storage calculations also draw on Mathematics number skills.

Source: WJEC GCSE Computer Science specification, teaching from 2025, for award from 2027, Version 3, September 2025.