I don’t remember when I first used the idea of breaking down a demonstration for students by having them follow the POE format:
- Predict what will happen
- Observe what actually happens
- Explain it in context
I think a lot of science teachers used this before – or even without – referencing the ideas of Michael Bowen, who explains the approach in this video. He wasn’t the first, but I tracked down the link via the site of the National Science Teachers Association in the US. There are several papers available there, for example this from a decade ago about hypothesis-based learning, which makes explicit the difference between a hypothesis and a prediction. It’s easy to see how these steps link nicely with a 5/7Es planning method. But I think it’s worth adding some steps, and it’s interesting to see how it might have developed over time. How students cope with these stages is an easy way to approach formative assessment of their skills in thinking about practicals, rather than simply doing them.
Please note – I’m sure that I’m missing important references, names and details, but without academic access I simply can’t track original papers or authors. My apologies and please let me know what I’m missing in this summarised family tree!
PEOE: I think this because…
To stop students making wild speculations we need to involve them in a conversation justifying their predictions. I suppose this is a first step in teaching them about research, to reference their thoughts. I find this needs guidance as many students mix up the two uses of explain; the derivation of their prediction and the link to accepted theory.
PODME: Recording what we observe
I got this from Katy Bloom (at York SLC, aka @bloom_growhow) I think after chatting at a TweetUp. I’m paraphrasing her point: in Science it’s not enough simply to observe, we must also share that observation. This can take two forms, Describing in words and Measuring in numbers. The explanation then becomes about the pattern rather than a single fact or observation. Bonus points to students who correctly suggest the words qualitative and quantitative for the observations here!
PBODME: My current approach
I’ve tweaked this slightly by making the first explanation phase explicit. The display is on the wall and students can apply this (with varying degrees of success) from year 7 practicals with burning candles to year 13 physics investigations into gamma intensity affected by thickness of lead shielding.
- Prediction of outcome
- Because of hypothesis based on life experience, context or research
- Observation using senses, measuring devices
- Description in words of what typically happens (sometimes as commentary during practical)
- Measurement using appropriate units, with derived results and means where needed
- Explanation of results, patterns, anomalies and confidence
Is it getting ungainly? Having this structure means students can see the next step in what they are doing, and are hopefully able to ask themselves questions about how to develop a practical further. I suppose you could argue that the original POE approach is the foundation, and these stages allow us to extend students (or ideally allows them to extend themselves).
PBODMEC: Why does it matter?
In many ways, the natural next step would be about Context – why should we care about the results and what difference do they make to what we know, what we can do or what we can make?
I plan to follow up this post with the printable resources (wall display and a student capability checklist) but they’ll have to wait until I’m home. In the mean time, I’d welcome any thoughts or comments – especially any with links to other formats and their uses in the school science lab.