Recently, I was observed by a member of my SLT (the wonderful @BrettWYale), and he gave me some feedback that sparked a brilliantly clarifying conversation. In this post, I want to share my reflections on this discussion.

During the lesson, I was teaching my Year 9s why simple covalent substances have low melting and boiling points. This part of the lesson proceeded as such:

We read a paragraph from our self-written textbooks, and made some annotations. I asked pupils simple questions to check their prior knowledge. I then used a pre-prepared diagram (dual-coding) to give an explanation, interspersed with questions to check the understating of the diagram as I explained it.

Most pupils could successfully answer my questions. However, Brett pointed out that there were a few pupils who were not putting their hands up – and so did not gain a clear understanding of the concept. This boiled down to two suggestions:

Instead of having a pre-prepared visual, in this case, I could have drawn the diagram live, so that pupils’ working memories were not overloaded and the information was chunked to build up an explanation. (Hydrogen atoms first, covalent bonds added next, then more molecules and then the intermolecular forces). Instead of interspersing my explanation with questions, hold back my questions until the end so that my explanation was not interrupted.

The first suggestion makes a lot of sense (and I’ve blogged about it before!) It was a judgement call on my part where I thought pupils would follow easily. Never assume! Live dual-coding has benefits over using pre-made diagrams, and is supported by the ideas of cognitive load theory.

The second suggestion sparked a fascinating conversation. The crux of it led to this realisation:

Pupils have a fixed, limited amount of time to learn content. Time is split between: teacher explanations, pupil practice and feedback. Explanation includes presenting new content, using questions to build up a concept, and modelling. Pupil practice involves individual practice of taught knowledge such as answering questions, solving problems etc. Feedback includes any form of response to pupil work which allows them to confirm or challenge their understanding. Given the time constraint, there exists a trade-off between these three factors. These three things tug at each other for time: for example, any extra time I spend explaining, is time taken away from pupils to practice.

This begs the question: how efficient is my explanation? I had never thought of extra explanation as a cost to pupil practice time before. I had always assumed that extra explanations are useful to pupils. And they might well be. But are they more useful than them spending that time practicing more in class?

Of course, there is no correct answer to how much time should you spend on each of explanation – it depends entirely on your pupils and the topic (and what occurs outside of lessons]. But I realised that I should always be critical of my explanations. Are they as efficient as they could be at helping pupils to understand the content?

When explaining, pupils may be able to answer your questions and seem like they are confident because you have scaffolded the explanation and questioning. But with individual practice, they are less reliant on your cues.

This changes the planning game for me, and I think the following three questions are useful:

1. Where could I be more efficient in my explanations?

E.g. should I include questioning during or after my explanation? Sometimes, it is more useful to ask during an explanation to ensure pupils are following. But sometimes this can interrupt the flow of a build-up of a concept in pupils’ minds. A solution could be to ask questions to yourself to model your thought-process.

Refelcting on your explanations can include questions such as: ‘Do I need to spend more time explaining, or will the individual practice and feedback be more useful for pupils?’ ‘Should I use diagrams to support my explanation, or will text suffice?’

The use of concrete examples and non-examples are an excellent way of explaining more abstract ideas. An abstract concept can be hard to imagine; a concrete example will help pupils to make sense of a concept. Multiple examples with variation (including non-examples) are even better since they highlight the deep structures of a concept rather than surface features of one example (e.g. see this post on concrete examples).

2. At what point is the practice pupils are doing sufficient?

Practice must be chunked up into the components of the final skill. Planning a lesson isn’t sufficient – a unit must be planned with thought given to all prior knowledge that must be mastered before moving on and making links E.g. pupils should be clear what a covalent bond, a molecule, melting point, intermolecular force etc. is before being able to explain why simple covalent substances have low melting and boiling points. Have the individual components been practiced by pupils before moving on?

This is also where ideas of interleaving and spaced practice should be considered. Pupils who spend a given amount of time on spaced practice outperform pupils who spend the same amount of time on massed practice (e.g. see Kang, 2016).

In the example above, I gave pupils a structure for their explanations, and they practiced using this to explain the melting and boiling point of different substances. The structure was: state the type of bond that is to broken, state whether the bond is weak or strong, and state whether this means little or a lot of energy will be required to break the bond. This scaffold succeeded in helping them to explain the concept well.

3. When and how should I give feedback to optimise time?

Check pupils have mastered key sub-skills and knowledge. Include spaced retrieval practice to check mastery of prior knowledge. We use 6-12 question drills at the start of every lesson which tests knowledge within and beyond the current topic. Pre-empt and explain misconceptions before pupils practice. Circulate during tasks to catch misconceptions, and give whole class feedback on these. Share examples under the visualiser and dissect together.

Brett suggested using ‘nearly correct’ answers as a form of checking pupil understanding. Pupils love spotting mistakes and it is very revealing when they think something is correct. For example, a few weeks later, I showed pupils a sentence: ‘Diamonds have four covalent bonds whereas graphite has three’. Nearly all pupils said this sentence was factually correct and would give it a mark in an exam. This made me realise that I had not given them sufficient opportunity to practice, since their language was not precise enough to warrant being awarded marks for a question on the bonding in diamond and graphite. (There was an audible gasp when I suggested that they should say ‘Every carbon atom in diamond makes four covalent bonds, whereas every carbon atoms makes three covalent bonds in graphite’. Making this explicit was necessary, but allowing them to make the mistake initially probably makes the idea stick!)

This reveals another aspect of science teaching to consider: pupils need time practising building their understanding of facts, but practice and feedback of the facts must include the language and correct articulation. When explicitly teaching a concept, a focus on language is crucial. This will be a topic of a future blog post.

A final realisation: the (new) science GCSE is tough. With limited lesson time, the onus is on pupils to work hard at home. If they rely on practice in class, and lesson time only, it is unlikely to be sufficient. They must review content and practice. If you let the lack of hard work from some pupils stop you from moving on, you will be doing a disservice their harder-working counterparts.