Introduction to Block Coding

Active learning works well for debugging because it turns abstract errors into visible problems students can solve together. Students remember debugging strategies better when they experience the frustration of a bug and then find the fix themselves, rather than just hearing about it.

• Year 3
• Computing
• 3 activities
• 20 min–30 min

Learning Objectives

1. Explain how dragging and dropping code blocks translates into sequential instructions for a sprite.
2. Compare the functionality of different types of code blocks (e.g., motion, looks, events) within a block-based programming environment.
3. Predict the precise sequence of movements and actions a sprite will perform based on a given set of code blocks.
4. Create a simple program using block coding to make a sprite move across the screen and change its appearance.
5. Identify and correct errors in a sequence of code blocks that prevent a sprite from performing its intended actions.

Simulation Game

⏱ 30 min·Pairs

Simulation Game: Bug Hunt

The teacher provides a 'broken' program where a sprite doesn't do what it's supposed to. In pairs, students must use a 'detective checklist' to test each block one by one until they find the 'culprit'.

Prepare & details

Explain how dragging and dropping blocks creates instructions for a computer.

Facilitation Tip: During Bug Hunt, circulate with a checklist of common bugs to help students notice patterns in their errors.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Role Play

⏱ 25 min·Pairs

Role Play: The Debugging Doctor

Students take turns being the 'Doctor' and the 'Patient' (the programmer). The Patient explains what is 'hurting' in their code, and the Doctor asks logical questions to help diagnose the bug without just fixing it for them.

Prepare & details

Compare the different types of blocks available in a programming environment.

Facilitation Tip: In The Debugging Doctor, model how to ask questions like, ‘What did you expect this block to do? What did it do instead?’

Setup: Open space or rearranged desks for scenario staging

Materials: Character cards with backstory and goals, Scenario briefing sheet

• Apply
• Analyze
• Evaluate
• Social Awareness
• Self-Awareness

Think-Pair-Share

⏱ 20 min·Whole Class

Think-Pair-Share: Resilience Strategies

After a challenging coding session, students share one thing that went wrong and how they felt. They then brainstorm a list of 'Keep Calm' strategies for when code doesn't work, which is displayed in the classroom.

Prepare & details

Predict what a simple sequence of blocks will make a sprite do.

Facilitation Tip: During Resilience Strategies, give specific praise when students say things like, ‘I tried one block at a time and it worked.’

Setup: Standard classroom seating; students turn to a neighbor

Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Teaching This Topic

Start by normalizing mistakes: share your own ‘buggy’ code and solve it in front of them. Teach debugging as a structured process, not trial and error. Avoid rushing to fix errors for students; instead, guide them with questions like, ‘Which block seems to be causing the problem?’ Research shows that students who practice debugging regularly develop stronger computational thinking skills over time.

What to Expect

Successful learning looks like students testing code in small steps, explaining their fixes clearly, and persisting after setbacks. They should confidently use vocabulary like ‘detach,’ ‘isolate,’ and ‘test’ when discussing their programs.

Watch Out for These Misconceptions

Common Misconception

During Bug Hunt, watch for students who erase the entire program when they encounter a bug.

What to Teach Instead

Prompt them to detach one block at a time and test, reminding them that professionals do this too.

Common Misconception

During The Debugging Doctor, watch for students who guess fixes without testing their ideas.

What to Teach Instead

Have them physically test each change and describe what happened before moving to the next.

Assessment Ideas

Exit Ticket

After Bug Hunt, provide a simple program with one bug. Ask students to circle the buggy block, explain what it does incorrectly, and write the corrected block.

Quick Check

During The Debugging Doctor, display a program with a missing block and ask students to hold up fingers for which block is missing (motion, looks, or events).

Discussion Prompt

After Resilience Strategies, present a program where the sprite turns the wrong way. Ask students to discuss in pairs what they notice and how they would fix the rotation block.

Extensions & Scaffolding

• Challenge: Provide a program with two bugs and ask students to find and fix both.
• Scaffolding: Give students a partially completed troubleshooting checklist with prompts like ‘Check the order of blocks.’
• Deeper exploration: Introduce conditional statements as a way to prevent certain bugs in the future.

Key Vocabulary

Sprite	A small graphic character or object on the screen that can be moved around and programmed.
Code Block	A visual, puzzle-like piece of code that snaps together with other blocks to create instructions for a program.
Sequence	The order in which instructions are executed. Changing the order of blocks changes the sequence of actions.
Event	A trigger that starts a script, such as clicking the green flag or pressing a key.
Bug	An error or mistake in a computer program that causes it to behave unexpectedly or stop working.