Top tips for chemists teaching physics

Most learners start by studying all three sciences together but they can find science confusing when similar ideas are treated differently by the different disciplines. One reason for this is that each discipline values different ways of thinking – something chemistry teachers need to consider when teaching physics. 

Take energy, for example. In physics, energy is a quantitative model used to track and constrain change, whereas in biology, energy helps explain processes, such as respiration releasing energy from glucose.

Teaching outside our specialism needs us to think differently, too. In this article, I’m sharing some themes that capture what is distinctive about physics, alongside tips to help chemistry (and biology) teachers develop this way of thinking when they’re teaching physics.

In chemistry, there is a focus on entities and mechanisms, such as particles, structures and interactions. Physics places great emphasis on how knowledge is constructed and tested, and physicists routinely make assumptions and strip away complexity to focus on what matters most. For learners to get to grips with physics, they need to develop ways of thinking, such as defining systems, reasoning quantitatively and critiquing models. 

The universe is enormously complex, so taking a simple approach can feel uncomfortable for students and teachers alike. Objects are reduced to point masses moving on frictionless surfaces in uniform fields. Simplifications make models powerful and reusable, but they can also make physics feel unrealistic. So, when teaching physics, explain to your students what has been left out and why. Resist the temptation to add detail that obscures rather than clarifies.

Maths can get in the way of intuition and make science ideas harder to understand. Some students can manipulate formulas fluently yet lose sight of the physical meaning behind them. In chemistry, calculations often follow conceptual understanding. In physics, maths frequently is the conceptual structure.

Treat formulas as relationships between quantities, not as tools to substitute into. When teaching Hooke’s law, show practically that a stiffer spring requires greater force to extend it by 1 cm. Show qualitatively that F = ke makes sense, and thatF = k/e does not (extension requires a greater pull, not less). Simple quantitative questions, such as ‘what happens if the force is doubled?’, encourage students to reason about constraint and proportionality. Students will experience physics as predictive and trustworthy, rather than as arbitrary rules.

Physicists organise their thinking around ideas, such as conservation, equilibrium and limits. Conservation laws for energy, momentum and charge give students something that must remain the same, even when the details of a situation are unfamiliar. This stabilises reasoning and allows students to rule out impossible outcomes before focusing on mechanisms.

‘This model works well … for now’

Patterns recur across different contexts. An electron accelerating in an electric field has similarities with a mass falling in a gravitational field. Orbital models apply from atoms to planetary systems. When you teach physics, explicitly draw attention to these patterns and similarities by asking, ‘What is playing the same role here?’ or ‘Where have we seen this structure before?’. This helps students see physics as a coherent discipline rather than disconnected topics.

Although it is tempting to present physics as rules that simply work, do not give learners the impression that physicists already have all the answers. In fact, physics explanations are empirical, reasoned, testable and always open to revision.

In the physics classroom, you can make this explicit through careful language. Phrases such as ‘this model works well … for now’, ‘this captures the essential behaviour’ or ‘we are ignoring effects that matter later’ help students understand why a model is useful without implying that it is final. Acknowledging limitations helps learners see physics knowledge as durable and open to improvement.

What’s next?