Technologies · Foundation

Active learning ideas

Debugging Our Programs: Finding and Fixing

Active debugging builds foundational computational thinking by letting young learners see cause and effect in real time. When students physically manipulate and test blocks, they connect abstract errors to concrete fixes, which strengthens problem-solving skills aligned with the Australian Curriculum. This hands-on approach helps them understand that debugging is a natural part of programming, not a sign of failure.

• ACARA Content Descriptions
• AC9TDEFP04

• 20–40 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Mystery Object
• 25 min · Pairs

Pair Debug Swap: Fix Partner's Code

Students create a simple program with one intentional bug, then swap with a partner. Partners predict the outcome, run it, note the error using a checklist, and fix it step by step. Pairs test the corrected version together and explain their process.

Analyze common types of errors in block-based coding.

Facilitation Tip

During Pair Debug Swap, model how to ask clarifying questions before making changes to encourage thoughtful fixes rather than random edits.

What to look for

Present students with a short, intentionally buggy block-based program (e.g., a character that doesn't move correctly). Ask them to point to the block they think is causing the problem and explain why.

• Understand
• Analyze
• Evaluate
• Self-Management
• Social Awareness

Activity 02

• Stations Rotation
• 40 min · Small Groups

Stations Rotation: Error Type Hunts

Set up three stations, each with a program showing one error type (sequence, logic, connection). Small groups visit each, run the code, describe the bug, and fix it on paper first. Rotate every 10 minutes and share fixes as a class.

Construct a plan to debug a given program with an error.

Facilitation Tip

In Station Rotation, rotate groups so students experience different error types and build a broader toolkit for debugging.

What to look for

Ask students: 'Imagine your program is supposed to make a cat meow twice, but it only meows once. What are three steps you would take to figure out why?' Record their ideas on the board.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 03

• Mystery Object
• 30 min · Whole Class

Testing Relay: Systematic Checks

Whole class lines up with a shared buggy program projected. Each student tests one input, notes if it matches expected output, and passes to the next. Discuss patterns in results before fixing as a group.

Justify the importance of systematic testing in finding bugs.

Facilitation Tip

During Testing Relay, emphasize silent observation first so students notice patterns before discussing solutions as a class.

What to look for

Give students a simple program with a clear error. Ask them to write down one bug they found and one change they made to fix it. They can also draw a picture of the program working correctly.

• Understand
• Analyze
• Evaluate
• Self-Management
• Social Awareness

Activity 04

• Mystery Object
• 20 min · Individual

Debug Plan Builder: Individual Practice

Give students a buggy program printout. They draw their debug plan: predict, test ideas, fix steps. Then code it digitally and verify. Share one plan with the class.

Analyze common types of errors in block-based coding.

What to look for

Present students with a short, intentionally buggy block-based program (e.g., a character that doesn't move correctly). Ask them to point to the block they think is causing the problem and explain why.

• Understand
• Analyze
• Evaluate
• Self-Management
• Social Awareness

A few notes on teaching this unit

Teach debugging as a routine skill by framing it as a detective game where students gather clues before acting. Avoid correcting errors for students; instead, ask guiding questions like, 'What did you expect this block to do?' Research shows that self-explanation strengthens debugging skills more than direct instruction. Keep sessions short and focused to match young learners’ attention spans.

By the end of these activities, students will confidently locate and correct common errors in block-based programs using clear steps. They will explain their fixes with simple reasoning and test their solutions systematically. Successful learning shows in students’ ability to articulate the problem and the fix, not just correct the code.

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Watch Out for These Misconceptions

• During Pair Debug Swap, students may believe bugs only happen to beginners. Watch for this when pairs discuss their programs.

  Direct pairs to predict what will happen before running the code together. Use sentence stems like, 'I think this will happen because...' to normalize debugging as a shared step for all programmers.

• During Station Rotation, students may try adding blocks randomly to fix errors. Watch for this as they move between stations.

  Provide a one-page checklist at each station with steps like, 'Test one change at a time' and 'Describe what changed.' Have students check off each step as they work.

• During Testing Relay, students may think one test run is enough. Watch for quick fixes without varied inputs.

  After each round, ask students to test their program with three different starting positions or inputs. Record the results on a class chart to highlight the need for multiple tests.

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Methods used in this brief

• Mystery Object
• Stations Rotation