Energy – Names, Stores, and All That


If you’ve found this blog then you probably know that the way Energy is taught has been under discussion, and that the wording required by the Physics GCSEs has been changed for first teach 2016.

If you want help with this change then your starting point should be the IoP because as far as I can tell this new wording is their baby, and they do provide plenty of online as well as face to face support:

There are also teachers starting to blog their ideas about how to convey the change to your students, one that caught my attention recently was by Neil Atkin:

Teaching Energy – The ‘New’ Approach with Stores and Pathways

I’d also suggest that you sign up to because there are plenty of people on there who will help.

The aim of this blog is, however, not to help, but rather to question the whole point of the change. I know that from a regulatory point of view it is a battle that has been lost, at least at GCSE level, but that doesn’t mean that we all have to line up and cheer.

So why do I object, is it just because I’m a curmudgeon for whom change is difficult? Well true as that might be, I hope it isn’t the only reason. I’ll start with one concern, and I can expand out to others if anyone is interested.

Before I start I guess I should nail my colours to the mast. I think that the idea that kids construct mental models of the world (Piaget) which they add to, or (very rarely) replace, in response to science lessons has a lot of value in explaining kids’ understanding of science.

Prior to first reading about the changes on TalkPhysics I hadn’t really given the way we teach energy much thought; we introduce the names in Year 8 and use them to frame the ideas that Energy is a Physics topic with Physics language that differs from everyday language and that Energy must be conserved. We do some questions with regard to efficiency, talk about perpetual motion machines, do one efficiency experiment and that’s it, we don’t think about it again until we can start to quantify Energy at the end of Year Nine, start of Year Ten. OK so we lament the rather silly questions where they have to write out the transformations. At best those questions are trivial, at worst they encourage the kids to think that the amount of energy dissipated via sound is as significant as that via heat.

Having named the types we go on to Thermal Physics, and it is here that we have to engage in a fight to break their preconceived models – in particular that Thermal Energy is a thing. We all know the “Explain Convection” “Heat Rises, Sir”  problem. If you were able to ask any nineteenth century Physicist I’m sure they’d tell you just how seductive the “Caloric” heat as a fluid model is. I suspect that naïve versions of Caloric are just the models which many of today’s kids construct for themselves, try as we might to oppose it.

I actually think that the names help with this. If heat is Thermal Energy, but Thermal Energy can just as easily be Kinetic Energy or Electrical Energy, then a mental model of heat as a fluid becomes just that little less tenable.

It is here, I think, that the differences between my impression of kids’ thinking and the “Stores and Pathways” (hereafter S&P) advocates’ impressions begin to strongly diverge. One of the arguments made against the names approach (hereafter Names) is that it leads to the kids believing that each of the named energies is a different physical thing. I’m not convinced that ours give it that much thought, and isn’t that something that can be minimised through the teacher’s emphasis? Of course, if the S&P advocates are right then Names hasn’t helped because if Thermal Energy is a separate thing then it can have a separate physical manifestation (i.e. be a fluid) from the other energies in a mental model of the world. But if their model is to be consistent doesn’t it require a whole set of pathways creating to explain how one physical manifestation of an energy type transforms itself into another?

If you have seen those pictures of vats of yellow fluid that accompany this topic then you have probably seen where I am going with this.

Energy is abstract. The S&P advocates continually emphasise the idea, which they give Feynman’s authority to, that it is just an accounting tool. Kids don’t like abstract ideas, you don’t have to be a died in the wool Piagetian to know that they shy away from them. What is the IoP sanctioned response to this when teaching abstract ideas like Energy or Electricity? Offer an analogous model. Anyone who has ever been to IoP training has probably passed a rope loop hand to hand to represent electrons in a circuit. And what is the model in this case? Vats of yellow liquid.

So the S&P advocates oppose Names in part because it gives a reality to the “accounting tool” that is energy, and then back this up with pictures of energy as a yellow liquid.  How can they not see that they are reinforcing the very problems that everyone already has – getting away from the fluid model of heat and getting away from the idea that energy is a thing? They even provide pathways from one vat to another so if you were worried that your yellow fluid has to have different properties when it is Thermal rather than say Kinetic you have a mechanism for change.

And don’t get me started on the thought that those pictures surely have to give the kids – that there will come a point when the stores are filled – and what happens then? When I asked this on TalkPhysics the implication was that I was a bit dim for not realising that the tanks drawn in the pictures were not real, well possibly, but I’m not 13 with a dislike of Physics.






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