Energy
Energy and Thermal Physics

An opportunity for change

Blog for IOP RESOURCES

Where this series has come from

I have had many discussions about energy over the years and know that these discussions are usually, to say the least, uncomfortable. So, in starting this series, I am bursting with caveats and caution.

The first caveat is that the overriding aim of this series is to be helpful; I will be discussing ways in which I think energy discussions can be improved and I will highlight a number of concerns with the prevalent paradigm. But that is not to be critical of individuals.

Secondly, this is not about banning specific words. I hope it is more about taking the opportunity to consider the pictures that those words paint and how we can make those pictures as helpful as possible to children coming to energy ideas for the first time.

Thirdly – and at the very least – it is an opportunity to have a look at the new energy statements in the Revised National Curriculum and consider the implications for what is now required (and also what is no longer required) in the energy topic.

Where it is going

The changes in the revised National Curriculum can be summarised as there being a move towards:

  1. energy as a quantitative tool rather than energy being a substance
  2. explanations that explore processes rather than rely on energy
  3. start and end points in energy analyses
  4. quantifiable terms
  5. heating (as a process) rather than ‘heat’ as a substance
  6. differences as the cause of change
  7. dissipation and ideas from the second law

Each of these is to be welcomed and each one provides an opportunity for talking about energy in a more helpful way. I will work through these opportunities in this series of postings.

Some personal comments

When I started teaching in the mid 1980s, there were articles and discussions about the teaching of energy. There was concern about the use of the words ‘transform’ and ‘convert’ when talking about ‘types’ of energy. But these concerns was part of a broader unease: that the existing paradigm gave energy substance and suggested that energy made things happen by being interconverted between different types. However, discussions about reframing the way we talk about energy had little impact in classrooms – mainly because official documents continued to insist on types, transformations and energy’s causal powers; to the extent that, at one point, the QCA documentation specified that there are 9 types of energy. I’ll call this the ‘9 types’ paradigm.

It was with some relief, then, that, in 2006, I was introduced to the approach advocated in the Institute’s SPT resource. We will return to that later but it is worth saying that it is an approach I strongly support but did not develop. It is also an approach that works with the statements in the revised National Curriculum (at both Key Stage 3 and Key Stage 4) and also the GCSE criteria – which determine how Awarding Organisations have to present energy ideas in their specifications. So, after decades of having official documents that have hobbled innovation and improvements, we now have official documents that support a more helpful (in my view) approach to talking about energy.

IMO and mainly IMHO

I have thought about all these issues quite a lot over the years. I don’t have all the answers but, as you will see, I do have some views. I won’t preface every single one with ‘IMHO’, but please take that as read.

A gentle introduction to concerns

So, there are positive moves. But I do need to dwell momentarily on some negatives and discuss why some of us are troubled by the prevalent ‘9 types’ paradigm. In the following examples, please do think about what picture is being painted of energy, the role that energy is playing in the explanation and whether either of those is helpful.

Here are some examples of how the 9 types paradigm manifests itself in the media:

  • The steam [from a volcano vent] is converted into energy and transported to Europe via a 1,200-mile sea-floor cable. (The London Paper)
  • Carbonaceous matter is converted to heat or other forms of energy (a physics magazine)

And then in slightly more official documents:

  • Energy makes things happen (ASE Big Ideas)
  • The moving pencil uses kinetic energy (QCA)
  • The bulb lights because energy flows from the battery to the bulb (Sophie, Year 9, KS3 SATs sample responses)

In all of the above, I would suggest that energy is given some substance – so much so that steam and coal can be converted into energy (1). The substance can flow and it is used up to make things happen. Additionally, the use of energy-based terminology is employed to make the explanation sound a bit more scientific. But, in fact, explains away the actual processes and mechanisms that are what really ‘make things happen’ (2). There are ambiguities (3) and even spurious ‘types’ of energy that have been invented to fit into the paradigm (4). The most deceptive of these is ‘heat’ or ‘heat energy’(6).

A harsher development of some concerns

The examples above were, perhaps, from easy targets. However, they a mirrored – or even developed – by the language that is used in the study of the sciences up to 16. All of these examples are from GCSE text books or exams:

  • The useful energy input of a food processor is electrical energy and its useful energy output is kinetic
  • Some of the energy released by the Sun is converted into electrical energy
  • A microphone converts sound energy to electrical energy
  • Machines are noisy. They transfer energy and some of the energy is transformed into sound
  • Energy is the capacity to do work
  • Green plants capture light energy and use it to grow
  • The cells in animals and plants all use energy for the jobs they do.
  • Chemical energy from hydrocarbon fuel is converted into motion
  • It is a striking example of a chemical reaction producing heat and work.

Again: energy is presented as a substance (that exists and can flow); it is ‘released’ and ‘produced’; it is converted and does useful jobs.

Above all, the examples state (or imply) that it is used up. Yet, we also tell children that energy is conserved.

And finally... the second law

So, on top of all the concerns about the 9 types paradigm, we are presenting students with an incomplete (and paradoxical) picture of an energy that is both conserved and runs out. It’s not altogether surprising because people’s everyday language often implies that energy is used up. However, we should try to get it right in science lessons. And that means addressing students’ experience – generally and through the language they hear: that something useful is used up to make things happen (fuels, food etc) (6).

However, whatever it is that runs out, it is not energy; and this distinction can be made through discussing ideas relating to the second law of thermodynamics  – ideas that are accessible and, perhaps, whose time has come (7). Certainly, the revised National Curriculum provides some opportunities to talk about the second law – so maybe we should; and I will return to this towards the end of the series.

Next steps

In this introductory posting, I have highlighted some concerns, hinted at how they might be addressed through the way we talk about energy and suggested that the revised National Curriculum will not hinder that rethink and may even help it.

Attached is a summary document that lists the concerns (labelled 1 to 7), summarises how they might be addressed and links them to opportunities in the National Curriculum statements.

I will explore the opportunities in more detail over the course of this series of posts.

Energy
appears in the relation ΔEΔt>ℏ/2 ΔQ=mcΔθ E=hf E ∝ A^2
has the special case Photon Energy
is used in analyses relating to Emission/Absorption Spectra Phase Change
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