What’s the point in practical work?

I’d planned to write this post and had a bit of an idea drafted out, but I finished it earlier than I planned because I was inspired by this tweet:

Until very recently, the idea of teaching science with limited practical work horrified me. How can it be science if they aren’t doing practical work? Well, then it struck me. They aren’t doing science, they are learning science. Let me explain the difference as I see it.

Doing science is what you do when you have trained for a number of years, developed a broad understanding and a deep knowledge of your subject and craft and are applying it in novel ways to answer questions about the world around us and the wider universe.
Learning science is how you get there! A bit like in the classroom, where we start with precise and clear explanation and ensure the pupils have gained the knowledge we are trying to teach them before we expect them to apply it in new situations, so we have to learn how to be scientists before we can work like them. Never forget that no actual scientist goes into the lab knowing exactly what the result of the experiment they are doing that day is going to be. While thousands of practicals are done every day, very few actual experiments happen in school science labs.

The majority of students in school are not going to go on to work in academia or industry in a laboratory. If they do, there is ample time for them to develop the practical ability needed to carry out research. What will prevent them getting there is not understanding the science behind what they are doing. I’m actually embarrassed at how many times the students have been doing some practical task in my lessons without any deeper understanding of what’s happening in front of them than following instructions. I think the biggest cause of me getting this wrong was that I was doing the job backwards and trying to use the practical work to teach them the content. Here’s how I think practical work should be used in school.

1 – Cover the scientific ideas before you set the practical work. This way you avoid the students trying to manipulate apparatus, potentially handle chemicals, follow written instructions and also apply the results of their work at the same time. Cognitive science tells us that this will inevitably overload the students working memory and make it very unlikely that they take anything away from the experience.

2 – Go slowly. The temptation is always to rush into it and get them going as fast as you can so that they can get everything done and packed up in a nice neat little package. This makes sense if your only aim is completing the practical. Now, I teach how to do the practical. This means model each step. Bit by bit, step by step. Send the children to do each stage one by one. This keeps them more focused because they know exactly what to do and, if you manage it correctly, how long they have to do it. It means you can support the class more easily because every student in the room should be at the same stage. You’re not having to work out where they are in the practical, what’s gone wrong and how to fix it for the whole activity at once. It even improves the flow of students around the room, as they are all collecting the same things and using them at the same time. Neater and safer.

3 – Link the outcome to the theory. By this, I mean that obtaining the data or getting the right product at the end is all well and good, but if you leave it there you’re missing a trick. Don’t assume that they can make the relatively complex leap from abstract ideas in their head to what’s on the bench in front of them. Clear explanation with a concrete example in front of them is a good way to help pupils shunt that information from short term into long term memory, especially if you reinforce with questions about what they did and what they saw over the next few lessons, and then again the next term etc.

4 – Think carefully about whether the pupils need to do it at all. Is it tricky to get exactly the right result? Is it notorious for going wrong? Is it, if you’re really honest, just a bit basic and only there to highlight a point? In these situations you should demonstrate. Live, on a video, or under a visualiser you can show them exactly what they need to see. There’s nothing wrong with a live, concrete example. Whether they have mixed the solutions or measured a spring or dissected a leaf or if you did it doesn’t really matter. Think about the opportunity cost though. You can demonstrate it faster than they can. Could the time difference have been spent on retrieval or practise questions? Class practical has many benefits, but don’t underestimate the costs.

I really enjoy practical work in science. There is clearly some invaluable enrichment in practical work and the big demonstrations, particularly in chemistry, stay with young people for the rest of their lives. This is really important however, there is a romantic idea that science is a fundamentally practical subject and that we should be allowing them to explore and discover scientific ideas for themselves through the medium of practical work. Sadly the more I’ve reflected on this, the more I’ve come to realise that we too often fall into the trap of ‘laboratory play time’. The work gets done and data is collected, but as for learning? I’m not so sure. Following my four tips above, students retain the method better, they understand each step of the method better and they are less phased by practical questions in tests or exams. They may not be discovering the science all by themselves, but they are learning a series of laboratory methods and techniques as an end in themselves.

Published by mrgreenw00d

Lead Practitioner in Science, chemistry specialist and Metacognition/Cog Sci nerd.

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