Scratch Bug Hunt: 20 Debugging Challenges with Buggy + Fixed Files | KS2 & KS3 Computing | Ages 7-13

Debugging is in the National Curriculum, but it’s hard to teach without good bugs to find. This pack gives you 20. Each bug card is a bug report: what the project should do, and what it does instead. Pupils open the buggy Scratch file, run it, hunt down the mistake and fix it. The code is printed on each card too, so they can hunt on paper as well.

What’s included

• 20 bug report cards, from easy (ages 7+) to tricky (ages 10+), with a clue printed upside down
• A “How to be a Bug Hunter” card and a Bug Hunter Log for pupils to tick off each bug they squash
• 20 buggy Scratch files, and 20 fixed versions
• A teacher guide with every answer: the buggy and fixed code side by side, and why the bug happens

The bugs cover
Wrong numbers, missing blocks, blocks in the wrong place, message names that don’t match, missing loops and the wrong block, across games, music, art and quizzes.

Why teachers like it

• Directly covers the KS2 objective: detect and correct errors in algorithms and programs.
• Brilliant for fast finishers, homework, coding clubs or a whole debugging lesson.
• Every bug was checked in the Scratch engine: each one breaks the project, and each fix works.
• No Scratch knowledge needed. The answers explain every bug.

Scratch is a project of the Scratch Foundation, in collaboration with the Lifelong Kindergarten Group at the MIT Media Lab. It is available for free at scratch.mit.edu. This resource is not made or endorsed by the Scratch Foundation.