It is a familiar scenario for a science teacher: Mr Davies is a Biology teacher, but due to staffing issues he is having to teach GCSE Physics.

When Mr Davies attempts to teach elastic potential energy, he must support pupils to tackle calculation problems that ramp up in difficulty. And so, he shows them how to answer the first question, then the pupils get cracking on some calculation practice. However, pupils quickly get confused and the class only manage around 20 minutes of practise before the bell goes.

Mr Davies would like to spend more time practising with them – with an upcoming assessment looming – but they’re already far behind where they should be due to Mr Davies having to self-isolate for 10 days back in October. The results of the calculation questions, two weeks later, are a disaster.

Mr Davies’ scenario is fictional, but it will feel very familiar to many of us. It’s a perennial challenge for teachers. How can we teach a densely packed, often very challenging curriculum, whilst ensuring pupils learn, understand, and retain it?

The impact of Covid has likely amplified this issue, leading to gaps in pupils’ knowledge and understanding. It appears that it is pupils from disadvantaged backgrounds that have been the most significantly affected. A focus on high-quality teaching can make a real difference to pupil outcomes and could provide the best chance we have of reducing these gaps, and tackling educational inequality.

**Problem solving: part of the solution**

Science is a complex domain, one which can be very challenging for novices to learn and remember.

With its intricate concepts, tricky language, and difficult problems, it routinely maxes out the limited working memory of our novice pupils. ‘Cognitive overload’ ensues.

In Science, problem solving can be uniquely problematic. Pupils are often presented with a wealth of information to process and a procedure to follow. Novice pupils that manage to solve these problems tend to use a process known as ‘means end analysis’^{1}. That is to say, working backwards from the goal until they find something that links to the information given, and then working forwards again.

Although this strategy gets them to the final answer, it imposes a significant ‘cognitive load’ on pupils. This means they are less likely to recall the correct method when faced with a similar problem later. This lack of transfer from one problem to another is something most teachers will be very familiar with (Mr Davies grapples with this daily!).

So, what can we do? Making use of worked examples can help.

First, let’s define worked examples. As a teaching strategy, they provide students with a step-by-step demonstration of how to solve a problem. By making the problem-solving strategy explicit, pupils first learn the process. This then frees up working memory for them to use when putting the process into action. As a result, pupils are more likely to be able to remember the strategy when faced with a similar problem later. There are many studies which show that using worked examples can have a positive impact on learning outcomes.

Worked examples tend to be most obviously applicable to procedural tasks, such as solving calculations or completing diagrams.

Figure 1 below shows the kind of worked example that can support pupils with completing titration calculations in Chemistry. The teacher has completed the procedure (purple pen). This means the pupil can look at the process required, and then use it themselves.

Teachers can also model the problem-solving process by completing the worked example live. This can reduce the demand on pupils by breaking the problem into smaller steps and posing ‘Think aloud’ strategies.

What is the next step? Teachers can further support pupils in moving to independent practice by providing partial or faded examples alongside worked examples.

In Figure 2 below, the teacher has modelled how to complete the worked example. There is then a (nearly identical) partial example next to it for pupils to complete. The teacher has partially completed the solution, providing an additional scaffold for the pupil on their journey to independent practice.

Increasing and improving how we use worked examples in the science classroom could play a useful role in both combatting Covid related ‘lost learning’ and improving learning outcomes for pupils. For Mr Davies, and his GCSE physics class, they are likely to prove essential to making physics – elastic potential energy, and much more – better understood and remembered.

1. Sweller, John. “Cognitive Load During Problem Solving: Effects on Learning.” Cogn. Sci. 12 (1988): 257 – 285.

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### Improving Secondary Science

Guidance Reports