20 March 2023
Debugging: Scratching the surface
Finding and fixing errors in a computer program is an essential skill for any programmer, as even the smallest mistake can cause a program to malfunction or fail entirely. Debugging teaches many key skills:
- Perseverance and patience as students need to carefully analyse their code and test their program multiple times to find and fix errors.
- Critical thinking skills to look through their code and identify where the error might be occurring.
- Problem-solving skills to break down complex problems into smaller, manageable parts, and to use logical reasoning and creativity to find solutions.
- Attention to detail as they need to check their code line by line to find errors.
- Collaboration with peers to learn new strategies for finding and fixing errors.
I hear teachers complaining about learners in year 10 not having the computational thinking skills to obtain the higher grades; the sooner we teach pupils debugging techniques and provide ample opportunities for them to develop them in a methodically and effective way, the better they will be ready for GCSE programming and algorithm/problem solving exam questions.
I am sharing here some strategies you can use with your Key Stage 3 pupils in lessons when they are coding using Scratch:
- Read through your code!
- Have a friend review your code!
- Say it out loud. When I click the flag, this Sprite will move 2 steps, change costume and say hello for 2 seconds.
- Thoughtful questions and commentsfor helping students get unstuck in Scratch
- Have student share project with the class- talk it through as a group. Helpful for teachers who are learning as well.
- Use some sort of screen sharing software or project the project for group discussions.
- Pull apart blocks that aren't working and add them back together one at a time, incrementally testing your code.
- Set up a bug wallfor your students.
[Source: Scratched resources for debugging. https://tinyurl.com/2ur7dp2n]
I share below some activities with full resources you can use in the classroom to teach debugging and fixing errors to young learners in your computing lesson:
Pizza Pickle Scratch Debugging Activity: This Computing activity challenges children to debug simple Scratch programs. A simple four-step process for systematic debugging is demonstrated. https://tinyurl.com/mrv84ujv
Debugging Challenges in Scratch: Multiple Scratch programs unfinished with instructions on how to solve the challenges. https://scratch.mit.edu/studios/219583
Finally, I would like to share with you this site in which Sean McManus offers some top tips for finding and fixing the 5 most common errors in Scratch programs. Really useful to share with pupils. https://tinyurl.com/yfswexj3
- Creating variables for one sprite or all sprites when it should be the other way around.
- Using the wrong (lookalike) block.
- Putting the wrong blocks in brackets.
- Putting scripts on the wrong sprite.
- Putting blocks in the wrong order.
Please share any other strategies you use if different.