Knowing It Isn't the Same as Teaching It

11 hours ago

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Building Powerful Subject Knowledge – ECF Section 3: Subject and Curriculum

“Knowing your subject well is essential. Making it understandable to someone who doesn’t know it yet is another skill entirely.”

The difference between knowing and teaching

Have you ever explained something in a lesson that seemed perfectly straightforward, only to be met with a room full of puzzled expressions?

You know the content. You've taught it before. You've explained it carefully. Yet, somehow, the understanding you expected hasn't materialised.

It's a familiar experience for teachers at every stage of their careers.

One of the most important lessons I've learnt throughout my teaching career is that subject expertise and the ability to teach that subject are not quite the same thing.

Knowing something deeply can actually make it harder to recognise why somebody else might struggle with it.

When we've worked with a concept for years, we develop shortcuts in our thinking. We recognise patterns automatically, make connections instinctively and overlook steps that once required considerable effort.

Our pupils haven't necessarily developed those connections yet.

And that's where the real craft of teaching begins.

What does the research tell us?

In 1986, educational researcher Lee Shulman introduced the concept of pedagogical content knowledge (PCK).

Shulman argued that effective teaching requires more than subject knowledge or general teaching techniques. Teachers also need to understand how particular concepts can be represented, explained and made accessible to learners.

This includes recognising common misconceptions, selecting effective examples and understanding why certain ideas are particularly difficult to grasp.

It's the difference between understanding a concept yourself and knowing how to help somebody else understand it.

The April 2021 Early Career Framework reflects this principle within Section 3: Subject and Curriculum.

It encourages teachers to identify essential subject knowledge, focus pupils' thinking on important ideas and work with experienced colleagues to develop effective explanations, analogies and demonstrations.

These are not simply presentation techniques. They are fundamental elements of effective curriculum delivery.

The problem with expert thinking

Consider teaching binary numbers in Computer Science.

As an experienced teacher, I can look at 1011 and recognise its decimal equivalent almost immediately.

But for a pupil encountering binary for the first time, several separate ideas need to be understood.

They must recognise that binary uses two digits, understand positional value, appreciate why each column represents a power of two and learn how to combine those values.

Simply demonstrating the conversion may produce an answer without developing understanding.

Instead, I might begin with physical place-value cards, move towards visual representations and gradually introduce the abstract notation.

The subject knowledge hasn't changed.

The way I've made that knowledge accessible has.

The same principle applies across the curriculum.

In Mathematics, solving an equation might feel automatic to the teacher, but pupils need to understand why an operation maintains equality.

In English, identifying a metaphor is relatively straightforward once pupils understand figurative language. Explaining how that metaphor shapes meaning requires another layer of thinking.

In Business, pupils might memorise a definition of price elasticity of demand without understanding how businesses use it to make pricing decisions.

Our responsibility is to identify the invisible thinking between the starting point and the desired understanding.

Making expert knowledge accessible

So how can we translate our subject expertise into effective teaching?

1. Identify the hidden steps

Before teaching a challenging concept, work through it as though encountering it for the first time.

Ask yourself:

What prior knowledge does this require?
Which steps am I completing automatically?
Where might pupils become confused?

A useful strategy is to write an explanation without skipping any stages, then identify which steps can gradually be removed as pupils become more confident.

2. Anticipate misconceptions

The Education Endowment Foundation's Improving Secondary Science guidance highlights the importance of identifying and addressing pupils' existing ideas.

For example, pupils may believe that heavier objects always fall faster than lighter ones.

Rather than simply correcting the statement, a teacher can use questioning, prediction and demonstration to challenge the misconception.

The same approach works when pupils confuse correlation with causation in Mathematics or assume that business revenue and profit mean the same thing.

3. Choose representations carefully

Analogies, diagrams, demonstrations and worked examples can make abstract concepts more accessible.

However, every representation has limitations.

Comparing computer memory to a desk and storage to a filing cabinet might help pupils understand the distinction between immediate access and longer-term storage.

But eventually, pupils need to understand where that analogy stops being accurate.

Effective teaching involves knowing when to introduce a representation, when to revisit it and when to move beyond it.

What does this mean for our professional development?

For ECTs: Don't feel that you need to create every explanation independently. Observe experienced colleagues, ask how they approach difficult concepts and build a personal collection of effective examples. When pupils struggle, consider whether an additional representation might help.

For mentors: Move beyond discussing whether a lesson was successful. Explore why particular explanations worked. Ask your ECT which assumptions pupils needed to understand and how misconceptions were identified. Making expert thinking visible is a powerful mentoring activity.

For experienced teachers: Familiarity can sometimes disguise complexity. Revisit topics you teach confidently and examine whether your explanations still meet pupils' needs. Invite colleagues to observe a specific explanation and provide feedback on its clarity.

Professional expertise isn't static. It develops through reflection, collaboration and a willingness to refine our practice.

A moment for reflection

Which concept do you understand so instinctively that you might be overlooking the steps your pupils need to learn it?

Choose one upcoming lesson and identify a single explanation you could unpack more carefully.

You might discover that the smallest adjustment makes the greatest difference.

Final thoughts

Knowing our subject gives us the foundations for effective teaching.

Understanding how pupils encounter, interpret and sometimes misunderstand that subject allows us to build something much more powerful.

The challenge isn't simply to know more.

It's to become increasingly skilled at helping others know, understand and apply what we know.

And that is a craft worth continually refining.