Energy Language Thoughts Part 4
Parts 1 (Introduction), 2 (Pathways/Processes) and 3 (Stores) are all available and will help make this more useful. Please continue to comment, on whichever post seems most relevant, if you’ve any queries or suggestions. Thanks to those who have already done so.
The IOP guidance begins by taking snapshots before and after an event and describing the changes to various possible associated stores. The alternative is to think about the physical processes – which will be variably familiar to students, depending on age – and thinking about the effect they have on parts of the system. YMMV.
The famous energy circus can be used, but be cautious! Some make much clearer examples than others. In most cases you will need to be very specific about the start and end points you wish the students to consider. I recommend checking out the SPT guidance. In particular, the ‘one step at a time’ diagram shows why chains of energy can cause problems. The suggestion there, which I endorse, is that you:
- start with the idea of fuels ie chemical stores
- make clear that fuels limit effects, they don’t by themselves cause the effects
- give high, hot and stretched objects as equivalents, but as they’re clearly not fuels we associate them with
- gravitational, thermal and elastic stores respectively
I’d suggest looking at your energy circus for clear demonstrations of these to begin with. Next would come a kinetic store, probably as an endpoint. A gyroscope or Newton’s cradle is a nice example of a kinetic store which lasts long enough to be plausible.
Approaches to consider
You could have a first round to develop some basic ideas, then a second with more complex snapshots (either more than one store involved at the end, or the same kind of store but associated with different objects).
Have students identify just the stores to begin with, discuss them as a class, then come back and add descriptions for the processes. This could be split between lessons; that way you can provide correct stores in the second lesson and concentrate on processes. In some cases, such as the classic filament bulb, two similar pathways will be needed.
- From: thermal store of filament
- Via: heating by visible radiation, heating by IR radiation
- To: thermal store of air in the room
If you want them, here are energy-circus-cards as pdf (includes example and blank cards)
Provide sets of laminated cards with stores, and arrows for the descriptions of processes. Labelled arrows are of course an option, but be aware of limitations and I’d include some blanks.
Again, cards-for-energy-v3 as pdf to save you a few minutes.
An extension could be to suggest measuring equipment and/or units for the relevant stores in each situation. If returning to these examples at GCSE, then recall of the equations are the natural next step.
Consider including actual photographs for some situations that cannot be easily reproduced in the lab; this would be a good way to introduce some examples from biology and chemistry. A food chain in biology might, for example, be described so:
- From: chemical store of lettuce
- To: chemical store of rabbit
- From: chemical store of rabbit
- To: thermal store of rabbit, kinetic store of rabbit, chemical store of fox
- From: thermal store of rabbit, kinetic store of rabbit
- To: thermal store of air
For chemistry, exothermic reactions will involve heating by particles and/or heating by radiation pathways. If the material explodes (which in my experience is the preferred result) then there is some kind of mechanical working too, yes? Be prepared for questions about state changes; the best approach is that latent heat means the thermal store is not only identified by the temperature change. Which, yes, is a complication.
It’s probably worth adding notes – mental or otherwise – to the other science topics so you can remind students of the new language. If you have particular queries, drop me a line in the comments or, for a more considered answer, join in with the discussions on TalkPhysics.
This seems like a good chance to consider the Big Ideas in Science Education. Which should be up anyway, somewhere, but it’s always nice to have a reminder.
Exams and Textbooks
This is where I must admit defeat. I know – in fact I started the first post in this series with this point – that teachers want to know what will get marks and what won’t when it comes to the exams. Sadly, I don’t know. At least one board used the old language in the sample papers originally made available. The list of stores is not consistent between boards, though I hope that makes more sense after Part 3. And so on.
I’m sure we’ll all be happier once we see more examples of possible questions, but I’m not involved much with the boards so I have no insight. My advice – which isn’t official IOP guidance, nor is it specially informed – is that if your students can explain the mechanisms behind the transfers, they shouldn’t need to worry about the language, either pathways or processes. For the stores, it’s probably more important that they can identify the equations that are relevant and be able to do the maths – that, of course, hasn’t changed! I’ve recently discovered that Richard Boohan is putting together some materials; I shall be watching with interest.
Whether students will be penalised for talking about light energy, sound energy, electrical energy – that I don’t know. I also don’t know how much emphasis will be placed on this language by those marking biology and chemistry questions. So I’m not much good, really. Sorry!
Last appeal for comments, feedback, criticism… please let me know what you think of these four pieces. At well over 3000 words I appear to have accidentally written an essay. I hope that if you’ve waded through it, you feel it was worth your time. Please do give me a shout if there’s something I can do to improve the time spent vs time saved ratio.
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