Modelling is one of the most useful things a physics teacher can do, but it is easy to underestimate what it actually involves.
It is not simply putting a worked answer on the board. Good modelling shows pupils how a physicist approaches a problem. It makes visible the decisions that experienced teachers often make without thinking: which information matters, which equation might work, what a diagram should show, whether an answer is sensible and what to do when the first approach does not work.
There is also another meaning of modelling in physics. We use models to represent things that are difficult or impossible to see directly: particles, fields, rays, waves, energy transfers and forces. Helping pupils understand both kinds of modelling is an important part of GCSE physics. The EEF’s secondary science guidance specifically identifies the effective use of models as an important part of developing scientific understanding.
Here are 17 ways to make modelling work harder in the GCSE physics classroom.
1. Say what you are thinking
Do not just solve the question. Let pupils hear the decisions you are making.
Put a question on the board:
A car of mass 1,200 kg accelerates at 2 m/s². Calculate the resultant force.
Rather than immediately writing F = ma, start with:
“I am being asked for a force. I have been given mass and acceleration. I know an equation that connects those three things.”
It sounds simple, but that sentence contains a lot of expert thinking.
The EEF’s guidance on metacognition recommends teachers explicitly model their thinking so pupils can see how an expert plans, monitors and evaluates an approach.
2. Model how you start a physics question
For many pupils, the hardest part of a calculation is not doing the mathematics. It is knowing how to begin.
Give them a routine:
What am I trying to find?
What information have I been given?
Which physics idea connects them?
Which equation might help?
Do I need to convert any units?
If you consistently model the same process, pupils gradually acquire a method they can use when you are no longer standing beside them.
3. Keep the first example clean
When introducing a new type of problem, there is little benefit in making the first question complicated.
If pupils have just learnt W = mg, start with something such as:
mass = 60 kg
g = 10 N/kg
weight = ?
Do not immediately add grams, rearranging, standard form and several pieces of irrelevant information.
The first model should make the new physics clear. Complexity can be added once the basic process is secure.
Worked examples can help pupils concentrate on the steps and reasoning involved in solving an unfamiliar problem rather than having to discover the whole procedure themselves.
4. Model how to select the useful information
Physics exam questions frequently contain more information than pupils actually need.
Put an exam question under the visualiser and work through it slowly.
Circle the quantity you need to calculate.
Underline the useful data.
Cross out something that is irrelevant.
Then ask:
“Why haven’t I used this number?”
That is a valuable question. Successful problem solving includes knowing what not to use.
5. Make units part of the model
Do not treat units as decoration added at the end of an answer.
Write them from the beginning:
mass = 0.50 kg
velocity = 8.0 m/s
kinetic energy = ? J
If the question gives a mass of 500 g, stop before substituting.
“Can I put 500 into this equation?”
Pupils should become used to checking units before reaching for the calculator.
AQA’s GCSE Physics mathematical requirements explicitly include using appropriate units, changing the subject of equations, estimates, ratios, graphs and a range of numerical skills.
6. Model diagrams by drawing them live
A completed diagram appearing on a PowerPoint slide is not the same as watching one being constructed.
Draw a force diagram step by step.
Where is the object?
Which forces act on it?
Which direction does each force act?
Should the arrows be the same length?
Do the same with circuit diagrams, ray diagrams and magnetic fields.
The finished diagram matters, but so does seeing how it was built.
7. Show pupils how physicists simplify the world
One of the most powerful ideas in physics is deciding what can safely be ignored.
A force diagram of a falling ball does not need the colour of the ball, its stitching or the person who dropped it.
A ray diagram represents a beam of light using a simple line.
A circuit diagram replaces complicated pieces of equipment with symbols.
Ask pupils:
“What have we deliberately left out?”
That question starts to build a much better understanding of what scientific models actually do.
8. Be explicit that models are not reality
This needs saying more often.
Magnetic field lines are not physical strings surrounding a magnet.
Particles are not really coloured circles with letters inside them.
Light rays are not thin glowing lines.
The particle model, ray model and field model help us explain and predict behaviour, but they are representations rather than photographs of reality.
Scientific models are central to school physics and feature throughout the GCSE curriculum, from the particle model of matter to forces, waves and fields.
9. Ask where the model breaks down
Once pupils understand a model, push a little further.
Ask:
“What does this model explain well?”
“What doesn’t it show?”
“When might we need a better model?”
For example, the simple particle diagrams used at GCSE are excellent for explaining density and changes of state but cannot represent everything happening at an atomic level.
Understanding that models have limitations is a much more sophisticated idea than simply learning the model itself.
10. Model movement between representations
Physics pupils constantly have to move between different ways of representing the same situation.
Take a moving car.
You could represent its motion using:
a written description
a distance-time graph
a velocity-time graph
an equation
a diagram
a table of data.
Do not assume pupils automatically see the connection.
Point between them.
“This steep section of the graph represents what the car is doing here.”
“This arrow on my force diagram links to the resultant force in our equation.”
Those links are where much of the understanding develops.
11. Model practical work before handing out the equipment
Sometimes pupils are given apparatus and several instructions at the same time and are expected to work everything out themselves.
For a difficult practical, demonstrate the important parts first.
Show where the ruler needs to be positioned.
Show how to read the scale without parallax.
Show where the ammeter goes.
Show how to change one variable while keeping the others controlled.
Show what a sensible results table looks like.
GCSE practical skills are assessed through the written examinations, so pupils need to understand the thinking behind an investigation as well as completing the practical itself. AQA states that working scientifically and apparatus skills are assessed across its GCSE Physics papers.
12. Model the mistakes you want pupils to avoid
Occasionally put a wrong answer on the board deliberately.
For example:
mass = 500 g
g = 10 N/kg
W = 500 × 10
W = 5000 N
Then ask:
“Would I get the mark?”
The discussion about why it is wrong is often more memorable than another correct example.
You can do the same with:
an ammeter connected in parallel
a voltmeter in series
a ray diagram without a normal
a graph with an inappropriate scale
an energy calculation without units.
Mistakes become something to analyse rather than simply something to fear.
13. Model how to check an answer
Pupils can become very trusting of calculators.
Build estimation and checking into your modelling.
If a calculation suggests that a family car has a mass of 1.6 kg, do not simply mark the working wrong.
Ask:
“Does that sound possible?”
Likewise:
Can efficiency be 170%?
Is a walking speed of 250 m/s realistic?
Would a phone charger normally transfer 80,000 W?
Physics gives pupils plenty of opportunities to check mathematics against the real world.
AQA’s mathematical requirements include making estimates of simple calculations, so this is also part of the mathematical thinking expected at GCSE.
14. Model how to read graphs, not just how to draw them
Pupils spend plenty of time being taught to plot graphs.
Spend just as much time showing them how a physicist looks at one.
Think aloud:
“The line gets steeper here, so what is changing?”
“This section is horizontal. What does that mean physically?”
“Should this relationship pass through the origin?”
“What would the gradient tell me?”
Graphs should be treated as representations of physical behaviour rather than simply pieces of mathematics.
15. Model the construction of a written explanation
A four-mark physics explanation can be intimidating when pupils are staring at an empty answer box.
Build one in front of them.
For example:
Explain why the resistance of a filament lamp increases as the potential difference across it increases.
Talk it through first.
“What changes first?”
“The current increases.”
“What happens to the filament?”
“It becomes hotter.”
“What happens to the ions?”
“They vibrate more.”
“What does that do?”
“It makes it harder for the electrons to pass through, so resistance increases.”
Only then turn the reasoning into a polished written response.
Pupils see that extended answers are constructed from linked pieces of physics rather than magically appearing as perfect paragraphs.
16. Move from worked examples to faded examples
Do not jump directly from a complete teacher example to a completely unsupported exam question.
Fade the support.
Question 1: everything is worked through.
Question 2: the equation is provided but the substitution is missing.
Question 3: pupils select the equation.
Question 4: pupils complete the whole problem independently.
The EEF has highlighted faded worked examples as a way of moving pupils from supported examples towards independent problem solving.
This can work particularly well for rearranging equations, electricity calculations, energy problems and multi-stage GCSE questions.
17. Stop modelling before pupils become spectators
There is a danger with good explanations: pupils enjoy watching them.
Everything feels clear while the teacher is doing the physics.
Then the teacher removes the example and suddenly the pupil cannot start the next question.
That is why modelling needs to lead quickly into participation.
A simple pattern works well:
I do one.
We do one.
You do one.
Then remove a little more support.
The test of successful modelling is not whether pupils can follow the teacher’s solution. It is whether, a little later, they can tackle a new problem without it.
That is ultimately what we want from modelling in GCSE physics. We show pupils the hidden processes behind solving problems, interpreting diagrams, conducting practical work and constructing explanations. Then, bit by bit, we hand those processes over to them.
The board becomes less important. The prompts disappear. The questions become less familiar.
And the pupil starts doing the thinking.
Sources used
Education Endowment Foundation – Improving Secondary Science
EEF guidance on effective secondary science teaching, including the use of scientific models, misconceptions, practical work and supporting pupils to become more independent learners.
Education Endowment Foundation – Metacognition and Self-Regulated Learning
Guidance on explicitly teaching pupils how to plan, monitor and evaluate their learning, including teacher modelling and thinking aloud.
Education Endowment Foundation – Worked Examples
EEF material on using worked examples, faded examples and self-explanation to support pupils before gradually moving towards independent problem solving.
Department for Education – National Curriculum in England: Science Programmes of Study
Used for the curriculum context around physics, mathematical skills, scientific understanding and the use of models within school science.
AQA – GCSE Physics 8463 Specification
Used for GCSE Physics mathematical requirements, working scientifically, practical assessment and examples of the ways pupils are expected to use representations and mathematical skills.