Computing · Year 9

Active learning ideas

Introduction to Functions

Active learning works because functions are best understood through doing. Students need to see definitions become reusable blocks of code to grasp their power. Writing, calling, and debugging functions in pairs or groups makes abstract concepts concrete and memorable.

• National Curriculum Attainment Targets
• KS3: Computing - Programming and Development
• KS3: Computing - Computational Thinking

• 20–45 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Flipped Classroom
• 30 min · Pairs

Pair Programming: Rectangle Area Function

Pairs write a function def rectangle_area(length, width): that returns length * width. They call it with user inputs and print results. Switch roles after 10 minutes to test and refine each other's code.

Explain how functions contribute to making code more readable and manageable.

Facilitation Tip

During Pair Programming, have students alternate roles every 5 minutes so both contribute to writing and debugging the rectangle area function.

What to look for

Provide students with a simple Python code snippet that uses a function. Ask them to: 1. Identify the function definition. 2. Write down the function call. 3. State the output of the code, explaining what the return value is.

• Understand
• Apply
• Analyze
• Self-Management
• Self-Awareness

Activity 02

• Flipped Classroom
• 45 min · Small Groups

Small Groups: Function Chain Challenge

Groups create three functions: one for perimeter, one for area, one combining both for a shape report. Chain calls so the report function uses the others. Share and run on class projector.

Construct a function that calculates the area of a rectangle given its length and width.

Facilitation Tip

In the Function Chain Challenge, provide starter code with missing links to force students to trace parameter flow between functions.

What to look for

Present students with a scenario: 'You need to write code that converts temperatures from Celsius to Fahrenheit multiple times.' Ask them to write a function definition that takes Celsius as a parameter and returns Fahrenheit. Then, ask them to write the code to call this function with 25 degrees Celsius.

• Understand
• Apply
• Analyze
• Self-Management
• Self-Awareness

Activity 03

• Flipped Classroom
• 20 min · Whole Class

Whole Class: Code Review Relay

Project a buggy function code. Students take turns suggesting fixes for parameter errors or missing returns. Vote on best fixes and test live as a class.

Analyze the benefits of using functions to avoid code repetition.

Facilitation Tip

For Code Review Relay, assign roles like ‘reader’, ‘tester’, and ‘documenter’ so every student engages with the code’s purpose and structure.

What to look for

Pose the question: 'Imagine you are building a website. How could using functions help you and your team organize the code for displaying user profiles and handling login requests? Give one specific example of a function you might create.'

• Understand
• Apply
• Analyze
• Self-Management
• Self-Awareness

Activity 04

• Flipped Classroom
• 25 min · Individual

Individual: Extension Functions

Students build a personalised function, like grade calculator with score parameter, then return letter grade. Submit for peer review next lesson.

Explain how functions contribute to making code more readable and manageable.

What to look for

Provide students with a simple Python code snippet that uses a function. Ask them to: 1. Identify the function definition. 2. Write down the function call. 3. State the output of the code, explaining what the return value is.

• Understand
• Apply
• Analyze
• Self-Management
• Self-Awareness

A few notes on teaching this unit

Teach functions by starting with a clear problem, like calculating rectangle areas, then solving it step by step. Avoid rushing to advanced topics; mastery of simple functions builds confidence. Research shows that students grasp scope and returns better when they debug their own code, so design activities that surface errors naturally.

Successful learning looks like students confidently defining functions with parameters, calling them correctly, and explaining why returns matter. They should articulate how functions reduce repetition and improve code structure in their own words.

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Watch Out for These Misconceptions

• During Pair Programming, watch for students who assume the function runs as soon as it is defined.

  Have partners add a print statement after the function definition to confirm it only executes when called, using area(5, 3) to demonstrate the sequence.

• During Function Chain Challenge, listen for students who think parameters alter values outside the function.

  Ask groups to swap variables before and after calling functions, then compare values to show parameters create local copies.

• During Code Review Relay, observe students treating return values as print statements.

  Require students to assign the return to a variable and print that variable separately, so they see returns and prints serve different purposes.

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Methods used in this brief

• Flipped Classroom