Graphs lesson for Pearson Edexcel International A Level Computer Science, with editable PowerPoint slides, a student worksheet and full answers. A graph links nodes with edges, which may be directed or weighted; students represent graphs and use them to model networks and routes.

Written for Unit 3 Advanced Principles of Computer Science, topic 14 Structuring data (specification 14.1.3). Everything is editable, so you can adapt it to your class.

What’s included

• PowerPoint lesson (16 slides) with teacher notes on every slide
• Student worksheet (Word), ready to print or edit
• Answer sheet (Word) with mark-scheme style answers for every question

U3.25 Graphs

By the end of the lesson students can:

• Describe graphs: vertices, edges, and undirected, directed and weighted types
• Represent a graph as an adjacency matrix and as an adjacency list
• Hand-trace insert, delete, search, and breadth-first and depth-first traversals

Worksheet sections: A. Key words; B. Represent a directed graph; C. Change and traverse; D. Exam-style questions; E. Challenge

Every lesson includes

• Learning goals and a starter question
• Clear explanations, diagrams and worked examples (Python 3 throughout, as the specification requires)
• A quick check and a “your turn” task linked to the worksheet
• Exam-style questions with marks, and an exit ticket

Format

• PowerPoint (.pptx) and Word (.docx), fully editable
• Works in PowerPoint and Google Slides
• Calm, muted sixth-form design, consistent across the whole course

These are independent resources written for the Pearson Edexcel International Advanced Level Computer Science specification (Issue 1, first teaching 2026; IAS XCP01, IAL YCP01). They are not produced or endorsed by Pearson.

More lessons in this series

• Previous lesson: Hash tables – Edexcel IAL Computer Science lesson
• Next lesson: Trees and binary search trees – Edexcel IAL Computer Science
• Save with the bundle: Structuring data – Edexcel IAL Computer Science (5 lessons)

Last updated: November 2026.