An important part of teaching is explaining a new concept or skill. As science teachers, we have to use explanations to help our pupils visualise microscopic and sub-microscopic particles and organisms. pupils Too often the importance of this is downplayed through misguided advice like “The pupils should be talking more than the teacher” or “If you’re talking, they’re not learning”. Yes, pupils discussing and learning from each other can be a good thing, but this doesn’t mean that the teacher talking and explaining things is a bad thing.

There’s two aspects to explaining a concept or skill. Firstly, there’s thinking about the structure and content of the explanation, and secondly there’s the mechanics of giving the explanation. In this first part, we’ll look at crafting the content of an explanation.

Despite the importance of teachers skills and abilities in explaining new concepts or skills, there is very little writing about it. Bruce Robertson and Shaun Allison have written about giving explanations in The Teaching Delusion 3 and Making Every Science Lesson Count, respectively. However, the most comprehensive piece of writing I have seen on the subject of giving explanations is by Adam Boxer, who has dedicated a good sized chunk of his Teaching Secondary Science: A Complete Guide to how to craft explanations.

So how do we craft an explanation?

The first thing to remember is that we learn in the context of what we already know. If we want to explain what an alkene is, then we should reactivate knowledge of what an alkane is, covalent bonding etc. If we want to explain what a nuclear decay equation is, then we should reactivate knowledge of nuclide notation and conservation of mass. We should try to take our pupils on a journey from what they currently know or can do, to the new concept or skill.​ If the required prior knowledge isn’t present then there is nothing for the new content to ‘stick’ to. for example, if we are explaining an abstract concept, then it’s good to give concrete examples of the concept that pupils can understand.

We need to take into account the limitations of working memory and introduce new content in short manageable chunks​. If we overload our pupils’ limited working memory with too much new content at once, then learning will suffer. If we embellish our explanations with too many anecdotes, then we could be increasing extraneous cognitive load. We may even find that our pupils remember the anecdotes but not the concept/skill that we wanted to be learned.

Finally, we need to make complex ideas clear and simple – we can do this using diagrams, props, animations, simulations, demonstrations etc, for example as chemistry teachers we could use Molymods to support an explanation of addition reactions. This helps our pupils to ‘visualise’ the abstract concept.

We can hook our pupils’ interest in our explanation by starting with a question that we will then proceed to answer, for example “How does the bonding and structure of an ionic compound explain its properties?”

Finally, we may have crafted and delivered a great explanation with lots of great questioning thrown in to keep pupils engaged and thinking. However, we can’t give ourselves a pat on the back and bask in the glow of our excellent explanation. We need to have a check for understanding to see if the explanation of the new knowledge or skill has indeed been followed and understood by our pupils. For example, this could be done with a series of questions to be answered on mini whiteboards, or getting pupils to turn and talk to a partner to share their learning, and then questioning to get feedback on the discussions.

In the next part of this blog, we’ll look at the mechanics of delivering a good explanation, i.e. voice, positioning, posture, use (or misuse) of PowerPoint etc.