Towards a concept and inquiry-based DP Physics

Why “towards?”

The subject guide tell us

“Conceptual understanding is always a work in progress—it is continually being developed and refined.” (IB Diploma Physics Guide, p.17)

Indeed. Since I (Paul) started to teach and write for this most recent DP Physics course, I have been thinking a lot about how to make concepts more visible and so more powerful across the course. But I have had this nagging feeling that something is missing – which I naturally interpret as something I am missing in my preparation and teaching of the programme. I think what I am missing is what these concepts are.

The Guide mentions three overarching (better perhaps, ‘underpinning’) concepts: energy, particles and forces (Guide p.18) But these are so general they have little explanatory power in my day-to-day teaching (“oh, look, here are some particles sticking together because there's a force, I wonder if energy has been transferred?”) And anyway, what do they mean? 

Let's take energy as a concept. Labelling energy as ‘that which is transferred between stores when work is done through a process’[1] dodges the conceptual question. To put it differently: if energy is to be used as a concept, what general set of attributes do we need to identify in order to understand a process in terms of energy transfer?

In his Lectures in Physics (Volume I) Richard Feynman memorably stated “In physics today, we have no knowledge of what energy is,” but he goes on to frame energy in terms of conservation, “… a numerical quantity which does not change when something happens … an abstract thing in that it tells us something does not change." I try to explain to students that they can think about energy as a sort of book-keeping quantity, a balance sheet for before and after a process happens.

So conservation seems to be a key concept here. So is work - understood as a measurable change in conditions that a process causes, such as in position or temperature. Another would be systems (whether open, closed or isolated.) And so on.

In turn this suggests to me that there is a set of disciplinary concepts that we ought to think about when writing and teaching for DP Physics, even though they are not spelled out for us in the Guide. To me, this is much more than a pedagogical exercise. Students will construct understanding of these concepts through the course and in doing so they will naturally see links and connections, how one part of the course makes sense of another. For example, from energy and momentum they will see the concept of conservation reappear with angular momentum, charge, and ultimately that conservation laws enable us to ‘model’ properties in quantum mechanics such as ‘spin’ even though we can’t make much sense of them physically.

In fairness, the Guide does outline something like this approach (p.17-18) and notes that the five organizing themes are conceived to group content around the three ‘big’ concepts of particles, forces and energy. The question is, how do we leverage these conceptual ‘categories’ in our teaching of the topics?

Why inquire?

Even in the context of DP Physics – a prescribed syllabus that is largely assessed by summative examinations – we can make space for students to ask questions. We can devise learning activities that structure and guide their inquiry such that through those questions they construct conceptual understanding. One way that the Guide proposes is through the guiding questions for each topic:

“The purpose of these guiding questions is to promote inquiry: they are therefore not straightforward and best answered once the associated understandings have been acquired. Teachers and students are encouraged to create their own guiding questions based on the content of units of study.” (p18)

The given guiding questions for each sub-topic are quite applied, e.g. C1: “What makes the harmonic oscillator model applicable to a wide range of physical phenomena?” This guiding question certainly encourages transfer of their understanding of SHOs to new contexts. However, my colleague Danny Doucette points out that the guiding questions can’t really function as prompts to student inquiry within the topic – since making sense of them requires understanding of the topic. It is odd then that they are positioned at the top of each unit.

In any case, by the time we reach p.26 (‘Syllabus format’), the concepts seem to have vanished from view. The ‘Understandings’ for sub-topics are really learning objectives and define content.

Perhaps students should develop their own concept statements, but this seems a big ask.

As we develop unit planners on our site, I would like to try to frame each of the sub-topics in terms of a set of fundamental concept statements which, taken together, tell us what Physics does. This will involve a sort of reverse-engineering from the topics given in the Guide that makes sense of why we might want to understand that content. Those concept statements would then guide us in making choices about the learning experiences (activities) we devise for our lessons. I would like to call this ‘inquiry-flavoured conceptual learning’, probably it sits somewhere between ‘structured’ and ‘guided’ inquiry in the spectrum.

These concept statements would then be the starting point – the basis – for our units of inquiry.

Here are some possible examples (not intended to be exhaustive for the given topics):

I wonder if our subscribers have any other concept statements, or better ones than these?

[1] Although better than earlier iterations, in which energy was treated as though it were a substance that magically changed ‘form’. See for example Tracy, “Energy in the New Curriculum” (Energy in the New Curriculum | IOPSpark) and Millar, R (U. York 2005) Teaching about Energy, and BEST teacher notes ibid.