Great Lessons 6: Explaining

"Stick it to the man...." Let me Explain.
“Stick it to the man….” Let me Explain.

At the core of a great teacher’s skill-set is the ability to explain the concepts, theories and techniques that make up their subject.  On the reputational scale, there is no doubt that teachers who explain things well, making the complex simple, score highly as Great Teachers.  I’ve observed countless lessons where the teacher exposition accelerated the learning process for everyone through the clarity of the explanation. It can be a joy to listen and learn as an expert teacher tells the story that lifts the fog and makes it possible to see clearly.

Einstein: “If you can’t explain it simply you don’t understand it well enough”

Classic cartoon...  not too far from reality?!
“Then a miracle occurs”      Classic cartoon… not too far from reality?!

For me there are two implications of this

1)    Getting students to explain ideas to the teacher and to each other is a great way to determine the depth of understanding. In fact it is a bread-and-butter element of all great lessons that they are rich with explanatory dialogue. I come back to this later on.

2)    As teachers, for high quality explanations to be habitual, we need to know our subjects, taking time to develop our own capacity to explain the key concepts simply.  I think departmental CPD time would be well spent with colleagues rehearsing the ways they explain the more difficult material.  Too often we assume we can do this but, over the years, I’ve found this is a key area for improvement and experimentation, for me personally and for others.

Crucially, Explaining doesn’t have to suggest didactic one-way traffic. Explaining well is an important aspect of highly interactive learning of all kinds.  Without doubt enquiry and discovery are vital elements of learning; however, very often the most appropriate thing to do is to push ahead and cut through the confusion by delivering a sharp explanation that brings clarity and takes everyone forward to greater challenges that lie beyond.

The penny-drop moment happens for different learners in different ways at different times and sometimes the barriers to understanding can appear unassailable:

No point standing there explaining...hoping that it's hitting home.
No point standing there explaining…hoping that it’s hitting home.

In talking about explaining, we are obviously talking about doing this in conjunction with probing questioning, differentiation and challenge.  We’re also talking about gaining attention and engagement in the process; not merely droning on oblivious to our students’ capacity to receive.  However, even with the conditions right, we still need to have at our disposal a number of lines of attack that we can use habitually and instinctively as we seek to bring the barriers down.

A quick guide to Explaining
(Most of this may seem really obvious…but I think it is worth spelling out; we can always explain better!)

1) Make connections from abstract ideas to everyday life

Professor Brian Cox is a master in this area – he is not just a pretty face.  Here is a perfect example:

The disintegrating sand castle as a model of entropy works brilliantly… order into disorder over time, but in a context that feels real.   There are countless examples in every subject, but you need to have them at your fingertips.

2) Show it in action; the walk-through

No point talking in theoretical abstract terms, when you can just provide an example and talk it through.  Here is someone explaining iambic pentameter.  I didn’t properly know what this was until I watched this clip – and now I do!

3) Use models…

You can’t teach science properly without models but this also applies to other subjects.  In developing deep scientific understanding, it is important to develop models of atoms and molecules and to relate them to macro everyday materials – this takes time.  For example in understanding the chemistry of burning magnesium, a model is necessary to explain observations and link them to the equation:

The diagram, the molecular model and the equation
The diagram, the molecular model and the equation

A great science teacher will automatically explain observations by building models. Linking the observation that ‘shiny stuff turns into white stuff’ to an abstract model that explains the chemistry, showing that new substances are formed.

Magnesium metal 'turns into' a white powder: Magnesium Oxide
Magnesium metal ‘turns into’ a white powder: Magnesium Oxide

Actually, enabling students to construct ever more sophisticated mental models is the key to all good science teaching.  Last week I had big sheet stretched out across my lab as we tried make space-time to explain gravitational fields…. it worked well.  Models, models, models.  These aren’t merely tricks up your sleeve; they are ideas that form your core knowledge and are embedded in your default mode teaching habits.

4) Use pictures

The idea of being a “Visual learner” may now be regarded officially as pseudo-scientific bobbins, but personally, I love a diagram. I often find that, if I’m getting a verbal description… I need to sketch it out before it makes sense. I’m not alone. One of the least well understood phenomena (I find) is the origin of the changing phases of the moon (Do not say it’s the Earth’s shadow….please!!).  Take a look here:

The power of a diagram to explain in ways that words never can.
The power of a diagram to explain in ways that words never can.

I’d suggest that the most important diagram in the universe is the number line.  The key to good numeracy is a strong mental model of numbers in sequence and scale.

Number lines...
Number lines…

The same is true with fractions and decimals

Diagrams are vital to a proper conceptual grasp of fractions.
Diagrams are vital to a proper conceptual grasp of fractions.

I’ve often found that people with weak numeracy skills have a poor foundation at this basic level.  Before we get into complex operations, just having a really good feel for number is vital.  Having an intuition that 0.6 is less than 2/3 or that 3/4 is bigger than 0.7 – and so on- come from a good visual map of numbers in scale and sequence.

5) Analogies

Another vital weapon in the arsenal is using an analogy to make sense of an abstract idea. Possibly one of the most difficult concepts to convey in science, from my experience, is the relationship between voltage and current.  When I was at school.. and I still remember this vividly… our teacher Mr Taylor (red Capri with white Starsky and Hutch stripe on his car… to digress just slightly) told us to think of throwing oranges through a tennis net.  Really! The harder you throw (more volts) the more oranges would get through each minute (current) and the size of the holes would link the two (resistance).  It worked for me… and I still use it.

Here is another:

An analogy for V = IR. Does it work?
An analogy for V = IR. Does it work?

There are also analogies using the flow of water with a pump for a cell; traffic flow or the movement of people down corridors… all kinds.  The key is to evaluate how good each analogy is – they all have limits – and to make that part of the learning.

6) Set a depth gauge

A key skill in putting together a good explanation is knowing how to pitch it.  I love questions that can be answered at different levels. For example:

  • Why does your heart beat faster during exercise?
  • Was Henry VIII a good King and how do we know?
  • What makes this a good poem?
  • Is it ever acceptable for one person to kill another?

Students could be asked these questions in Y5, Year 9, Year 13…   The difference is in the depth. Knowing how to pitch the answers is important.  I’ve found that asking for answers in a sentence or for a 4 mark or 6 mark answer helps students to gauge the depth of their explanations… but, it is often very helpful to know what you’d expect in advance.  What would be a good answer to these questions at the level expected?   Again, as part of developing our teacher-knowledge, rehearsing these things can be extremely powerful; clarifying your own understanding in order to provide the appropriate explanation – in the Goldilocks zone of difficulty: not too easy; not too hard – just right!

Reciprocal Teaching

This is a high-scoring strategy in John Hattie’s effect size scale.  (see here for Hattie videos) Why? Because it involves getting students to construct and produce explanations of concepts so that others can understand them.  This requires a secure grasp of the concepts and provides teachers with strong feedback as to the depth of understanding… which can then be further deepened by probing questions. In a recent lesson I observed at KEGS, students’ explanations were subjected to superb questioning by the teacher: “So, were we convinced by that?” “I’m confused – is A or B a better explanation – help me out? ” And so on…. the explanations and questioning interwoven.

One of the strongest bits of feedback I get from my co-construction groups is that they feel they learn the most when they are doing the teaching themselves.  Here is a picture of Tom helping Karan to understand nuclear fission in a recent Y11 Physics lesson.

Explaining is at the core of co-construction
Explaining is at the core of co-construction

He has become expert in this area, having been given responsibility to lead on teaching the unit with his group – and the quality of his explanations are excellent.  He can go around the class providing support to others in a highly effective manner.  All the students do this, when it is their turn.

Online reference points:  all the flipping videos.

In putting this post together, I’ve been looking for good examples of explanations.  The fact is that there are now thousands of videos on the internet where teachers are explaining concepts.  Some are made specifically to facilitate ‘flipped learning’ as I discuss in this post.  I find it fascinating watching these teachers do their thing.  Do they do it well? Would you do it any better?  If so how?  These videos become reference points for our self-reflection… take a look:

Of Mice and Men Revision lesson:

Solving Simultaneous Equations by elimination

Le Futur Simple  (In French…)

In conclusion, Explaining is something I feel we take for granted too often.  It is very obviously  a core teacher skill but to deliver routine Great Lessons,  we may need to do it better.. and there are lots of possibilities to explore!


  1. This is one of the most important elements of teaching, and very well… explained. It is the key to successful languages teaching, where issues are too often not explained at all (eg, why do words have a gender when they have no masculine or feminine characteristics) or else mis-explained (eg a verb is a “doing word”, when the most common verbs, to be and to have, do not do anything).

    A key element in explanation, though, is to identify where what is said is counter-intuitive, anticipate it and chart a way through it. I’ve done this for French in presentations on my site below.


  2. Very good as always. The magnesium oxygen example, though making a clear point, seems to bond the magnesium covalently to the oxygen. When using models and diagrams, we have to make sure that they are correct!


    • Hi Benjamin. Good spot! I should have made it clear where this would sit along the sequence of concepts. Here the key learning is simply that atoms are rearranged in a chemical reaction; also can ‘bond’ as a concept not be introduced before worrying about the details of ionic and covalent version? It’s one of those things with explaining – you need to simplify or add complexity at the right moment.


  3. Thank you so much. As always so interesting and even for us primary teachers such great food for thought and reflection. Thank you Tom.


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