Defining physics: what’s in, what’s out?

Starch granules under the microscope.

In this month’s Physics World, Peter Main and Charles Tracy debate how physics should be defined. It’s a tricky issue if you want to do better than the old adage: “if it moves it’s biology, if it smells it’s chemistry and if it doesn’t work it’s physics”. As physicists we know that’s not good enough.

The view that Sam Edwards, a former Cavendish Professor expressed (as many others have) that “physics is what physicists do” can be a useful defence to doubters, as I’ll explain below, but it also begs the question. It is particularly hard to apply when physics is done in departments other than those with the name of Physics, departments where people might not want to identify themselves too loudly as physicists. Main and Tracy certainly don’t want physics to be defined by subject areas, which is often done, and instead come up with a list of ‘big ideas’ to define the way physicists think, including causality, reductionism and universality.

These issues matter as the debate over what should be in the National Science Curriculum continues and as the IOP works hard to increase the uptake of A-level Physics, particularly targeting girls who remain in a small minority among A level candidates. Even at university, there are significant issues over what should be taught; very often this comes down to subject area much more than the notion of ‘big ideas’. For instance, the 2008 Wakeham Review identified some things that weren’t being taught as much as they would have liked:

– concern remains as to the health of physics departments in terms of the selectivity that all but the largest have exercised with respect to their research portfolio…

– it is essential that students continue to be exposed to areas of the subject which are particularly applicable in the 21st century such as biophysics/medicine….

– physics students in many departments get regrettably little exposure,if any, to modern soft matter physics and biophysics.

In the wake of the Wakeham Report, the IOP sent a questionnaire to physics departments to try to establish how many of them did actually teach anything that could be deemed to be ‘biological physics’. Of the 14 responses, eight said they did teach something along those lines (although in some cases it seemed to be medical physics, which is actually rather different) and six said they taught nothing that fitted the category.

On the back of those responses, strengthened by the fact that whether departments answered yes or no they mainly seemed to think some additional help with teaching material would be beneficial, the IOP set up a Teaching Biological Physics Project. This project, of which I am the director, is charged with producing material that can be freely used by departments and lecturers in the way that suits the local teaching structures best. Much of our material, written by a group of researchers from various UK departments, is already accessible – have a browse! But there are a few outstanding items before what we are calling ‘phase 1’ is complete; at that point, watch this space as there may be a follow-up blog to announce completion.

So much for teaching. What about research in this subject? Things have come a long way from the time when, as a young lecturer working on starch structure, I was told by another former Cavendish Professor, the late Brian Pippard, that “things have come to a sad pass when people at the Cavendish study starch”. He was clearly defining what he thought wasn’t physics, and starch came into that category for him. I believed then (and of course still do) that he was wrong. I was using the tools of physics, in this case small angle X-ray scattering, to analyse hierarchical patterns of packing within the starch granule.

I suspect that for Pippard, the material was just too messy and complex for him to be able to imagine finding simple, universal ideas. Recall that universality was one of the ‘big ideas’ that Main and Tracy identified as defining physics. It would probably have surprised Pippard to find I had published a paper entitled ‘Universal features in the structure of the starch granule from different botanical sources’ in 1993. Yes, universality exists even in something as messy as a bit of a plant! That is why I felt, at the time, the defence Sam Edwards definition of physics gave me was useful. I’m a physicist so I’m doing physics. Unfortunately, as a (relative) youngster I didn’t actually feel up to challenging Pippard to his face; anyhow I was just too gobsmacked by his remark to be able to respond quickly enough with any coherent words.

Physics has evolved a long way since that conversation. The community researching biological problems from a physics perspective has steadily grown and we have a strong sense of identity, not least through the IOP’s subject group in Biological Physics which came into being in 2007. This new group arose largely as a response of the IOP to the EPSRC’s 2005 International Review of Physics, which highlighted the lack of any such subject group in the UK. But have the Research Councils kept up with that evolution? I’d suggest the answer is, at best, a somewhat qualified ‘yes’.

Last year the EPSRC issued a call for a Grand Challenge Network in Understanding the Physics of Life and the launch meeting of the group that ‘won’ the call was held at the start of April. This meeting, which was very oversubscribed, will be followed by a series of 3 plenary meetings; the first of these will be on the Physics of the Living Cell and will be held in Sheffield in July. (Registration has recently opened for the meeting.) Further meetings later in the year will be on Synthetic Biology and Multicellularity. The EPSRC is obviously hoping that through this Grand Challenge some focussed questions can be identified that the community see as priority areas and collectively want to address.

However, the answer to my question about whether the Research Councils have evolved appropriately to cope with the changing research community can only be a partial yes, because there remains the problem of gaps between Research Councils. At the launch meeting of the Network, the EPSRC’s Andrew Bourne made it very clear that EPSRC could only fund future projects growing out of the network that sat within the physical sciences; they would not fund the biological component. How truly interdisciplinary projects would be properly funded to answer the wide-ranging questions that ‘understanding the physics of life’ will inevitably throw up is therefore not at all clear to me. The cracks between Research Councils down which interdisciplinary proposals fall is a long-running beef of mine, which I’ve written about previously and many others in the community have spoken out about it too. Maybe the IOP’s project can patch up the teaching in our undergraduate courses, but something far more radical within RCUK than simply a patch is required to solve the researchers’ problems.


Athene Donald

Professor Dame Athene Donald is a Professor of Experimental Physics and Master of Churchill College. Her research is in the general field of soft matter and physics at the interface of biology; she has published over 250 papers in these fields. In recent years she has become heavily involved with policy issues, ranging from chairing the Royal Society’s Education Committee to chairing the Scientific Advisory Council of DCMS.She served on University Council (2009-14) and was the University’s Gender Equality Champion (2010-14). She is currently a member of the Scientific Council of the ERC and a former Trustee of the Science Museum. As well as various prizes from the IOP and Royal Society, she won the 2009 L'Oreal/Unesco Laureate for Europe award.

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