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Year 8 Computer Science: Algorithms and flowcharts lesson pack

A complete, ready-to-teach KS3 lesson on algorithms and flowcharts. Below is a real sample of what ChalkHour makes: the full pack adds three levels of worksheet, model answers, a teaching explainer and print-ready PDF and Word files.

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Real sample

Introduction to Algorithms and Flowcharts

This lesson introduces Year 8 students to the fundamental concepts of computational thinking through algorithms and flowcharts. Students will learn how to break down problems (decomposition) and represent solutions visually using industry-standard flowchart symbols. The lesson covers sequencing and basic selection (decision making).

Learning objectives

  • Define an algorithm as a set of precise instructions to solve a problem.
  • Identify and use standard flowchart symbols (Terminal, Process, Decision, Input/Output).
  • Explain the importance of sequencing, selection, and iteration in algorithms.
  • Design and trace flowcharts to solve simple logic problems.

Lesson plan (60 minutes)

  1. Introduction · 5 min

    Do Now: List the steps required to make a piece of toast. Identify where decisions are made (e.g., is it brown enough?).

  2. Direct Instruction · 10 min

    Teacher Explainer: Introduction to algorithmic thinking and flowchart symbols using the teaching script.

  3. Guided Practice · 10 min

    Worked Example: Together, draw a flowchart for an alarm clock that snoozes.

  4. Independent Practice · 25 min

    Differentiated Worksheet Activity: Students work through Support, Core, or Stretch tasks based on prior attainment.

  5. Review and Assessment · 10 min

    Plenary: Multiple choice quiz and self-marking of worksheets.

Key vocabulary

Algorithm
A sequence of logical instructions for completing a task.
Flowchart
A visual representation of an algorithm using standard shapes.
Decomposition
Breaking down a complex problem into smaller, easier-to-solve parts.
Selection
A step in an algorithm where a choice is made (usually an IF statement).
Iteration
The process of repeating a set of instructions (a loop).

Core worksheet (first questions)

  1. Explain what 'decomposition' is and why it is useful when designing algorithms.
  2. Which flowchart symbol is used for Input/Output? Give two examples of what might be written inside one.
  3. Describe the difference between a 'Process' box and a 'Decision' box.
  4. Draw a simple flowchart for a system that asks for a student's test score. If the score is 50 or more, output 'Pass'. Otherwise, output 'Fail'.

Quiz (sample)

  1. 1. What is the definition of an algorithm?

    • A. A type of computer hardware
    • B. A set of step-by-step instructions to solve a problem
    • C. A programming language like Python
    • D. A decorative diagram for a presentation

  2. 2. What does an oval shape represent in a flowchart?

    • A. Process
    • B. Decision
    • C. Terminal (Start/End)
    • D. Input/Output

  3. 3. Which symbol is used to show data being entered into a system?

    • A. Rectangle
    • B. Diamond
    • C. Circle
    • D. Parallelogram

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