Technologies · Year 5

Active learning ideas

Debugging Simple Algorithms

Hands-on debugging helps students see algorithms as living, testable systems rather than static instructions. When learners physically test and correct step-by-step plans, they grasp that errors are normal parts of problem-solving, not just typing mistakes.

• ACARA Content Descriptions
• AC9TDI6P07

• 25–45 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Collaborative Problem-Solving
• 30 min · Pairs

Bug Hunt Challenge: Printed Algorithms

Provide printed algorithms with deliberate bugs, such as a recipe or dance sequence. Students circle errors, explain impacts, and rewrite fixes. Pairs test fixes by acting them out. Share one fix with the class.

Explain common types of errors found in algorithms.

Facilitation Tip

During Bug Hunt Challenge, have students physically act out the algorithm to reveal logic errors that static inspection might miss.

What to look for

Provide students with a short, buggy algorithm for a simple task (e.g., making a sandwich). Ask them to write down: 1. One bug they found. 2. How they would fix it. 3. One step they took to find the bug.

• Apply
• Analyze
• Evaluate
• Create
• Relationship Skills
• Decision-Making
• Self-Management

Activity 02

• Stations Rotation
• 45 min · Small Groups

Stations Rotation: Debug Types

Set up stations for syntax bugs (fix code notation), logic bugs (trace paths), and sequence bugs (reorder steps). Groups rotate, documenting fixes with before-and-after examples. Debrief common patterns.

Design a strategy for systematically finding and fixing bugs.

Facilitation Tip

In Station Rotation, assign each station a distinct bug type so students build a mental map of error categories.

What to look for

Present a flowchart or pseudocode for a common task with a deliberate error. Ask students to hold up fingers indicating the step number where they think the bug is located and be ready to explain why.

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

Activity 03

• Collaborative Problem-Solving
• 40 min · Pairs

Pair Programming Debug: Block-Based

Using visual tools like Scratch Jr or unplugged blocks, pairs run a buggy program, input test data, and note failures. They swap roles to fix and retest. Record strategy in journals.

Assess the importance of testing and debugging in program development.

Facilitation Tip

For Pair Programming Debug, require students to verbalize their reasoning before coding fixes to build metacognition.

What to look for

Pose the question: 'Imagine you've spent a long time creating an algorithm, and it's not working. What is the first thing you should do, and why is it important to be patient during this process?'

• Apply
• Analyze
• Evaluate
• Create
• Relationship Skills
• Decision-Making
• Self-Management

Activity 04

• Collaborative Problem-Solving
• 25 min · Whole Class

Whole Class Algorithm Trace

Project a long algorithm; class votes on next steps at branches, revealing bugs collectively. Students note where tests would help. Revise as a group.

Explain common types of errors found in algorithms.

Facilitation Tip

Conduct Whole Class Algorithm Trace with colored markers so students can visually track variable changes across steps.

What to look for

Provide students with a short, buggy algorithm for a simple task (e.g., making a sandwich). Ask them to write down: 1. One bug they found. 2. How they would fix it. 3. One step they took to find the bug.

• Apply
• Analyze
• Evaluate
• Create
• Relationship Skills
• Decision-Making
• Self-Management

A few notes on teaching this unit

Start with unplugged tasks to normalize debugging as a thinking process before moving to digital tools. Model your own debugging aloud, including false starts and dead ends, to show that iteration is expected. Avoid rushing to fix errors yourself; give students time to observe, hypothesize, and test. Research shows that explicit error-analysis routines build stronger debugging habits than isolated practice.

Students will confidently identify bugs, explain how they affect outcomes, and revise algorithms to work correctly. Success looks like clear explanations paired with corrected code or flowcharts that produce the expected result.

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Watch Out for These Misconceptions

• During Bug Hunt Challenge, watch for students who only look for typos and ignore missing or out-of-order steps.

  Have students physically walk through the algorithm with props, asking peers to notice when the expected outcome doesn’t match the actual result, forcing attention to logic and sequence.

• During Station Rotation, watch for students who assume one test case proves an algorithm is correct.

  Introduce edge cases at each station, such as an empty list or reversed order, and require students to test with multiple inputs before moving on.

• During Whole Class Algorithm Trace, watch for students who believe their first fix will always solve the problem.

  After each correction, rerun the algorithm with a different input to show that new bugs may emerge, normalizing iteration and patience.

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Methods used in this brief

• Collaborative Problem-Solving
• Stations Rotation