Unplugged Coding Lesson – Debugging and Problem-Solving

debug code lesson



Students will learn the concept of debugging by identifying mistakes in sequences of actions and figuring out how to correct them. This lesson emphasizes critical thinking and problem-solving skills.

Materials Needed

  • A series of picture cards or storyboards depicting a simple story or process, with deliberate mistakes or “bugs” inserted into the sequence.
  • “Bug” stickers or markers to identify errors.
  • “Solution” cards for students to write or draw their fixes to the bugs.
  • A “Debugging” poster that explains what debugging is in simple terms.

Lesson Duration

45 minutes

Lesson Overview

This lesson introduces students to the idea of debugging—a critical component of coding and programming. Through interactive storytelling or a simple physical activity, students will learn to identify errors, think critically about solutions, and understand that making mistakes is a part of learning and problem-solving.

Introduction to Debugging (5 minutes)

Start by explaining debugging in child-friendly terms:

  • Debugging is like being a detective. When something doesn’t work as expected, a programmer has to find out why and fix it. In coding, these mistakes are called “bugs.”

Storyboard Activity: Find the Bugs (15 minutes)

  • Activity Setup:
  • Arrange picture cards or storyboards in a sequence that tells a simple story or outlines a process but includes several deliberate mistakes.
  • Activity Instructions:
  • Students work in small groups to identify the “bugs” in the story or process.
  • They place “bug” stickers or markers on the cards they believe contain errors.
  • Discuss as a class why these are considered “bugs” and how they affect the story or process.

Debugging Challenge: Correct the Bugs (15 minutes)

  • Activity Setup:
  • Provide “Solution” cards to the groups.
  • Activity Instructions:
  • Students brainstorm solutions to correct the identified bugs.
  • They write or draw their fixes on the “Solution” cards and explain their reasoning.
  • Compare solutions among groups to showcase different approaches to problem-solving.

Reflection and Discussion (5 minutes)

  • Reflect on the importance of debugging in programming and other areas of life.
  • Discuss how identifying and fixing bugs helps improve critical thinking and problem-solving skills.


This lesson demystifies the concept of debugging for third graders, teaching them that finding and fixing errors is a natural part of the learning process. By embracing mistakes and viewing them as opportunities for growth, students develop valuable skills in critical thinking and problem-solving that are essential in coding and beyond.


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