Expert Insights

I remember when I was taught this, that the only definition we were given was Le Chatelier’s actual definition, or his principle, and I remember reading that language and going geez, that’s really hard to follow as a student, so I used to always try and present that and then break it down in to a more simple sort of version that I thought would be easier to understand.

When you think of things in terms of energy you can represent energy … energy can be modelled as a particle, as matter.  It can be modelled using waves and then trying to talk about how we would use each model as it's appropriate for a particular situation.  It's the sort of things we observe might dictate which model we use to explain it, by recognising that in each case there is another model but perhaps just not as useful.  So maybe it goes back to just trying to show that everything that we do is a model, every model has its upside and its downside and that we usually only use a model that’s as detailed as it needs to be for the particular concept that you're trying to get across.  If you want to get across a concept of a car to someone who has never seen a car you don't probably show them a Ferrari or a drag racing car.  Maybe you show them a Lego style block and we do the same thing with our scientific models as well.  I guess trying to get across that idea that this is the model that we're going to use but it can be a lot more complicated.  I don't want you to think it's as simple as this but it's appropriate under the circumstance.  So I guess I spend a lot of time talking about things as models when I'm talking about quantum mechanics.  Our treatment in the first year, which is where I cover it, a little bit of second year but I don't take a mathematical detail treatment of quantum mechanics.  Someone else does that, so I really bow to them. So most of mine is non-mathematical, just simple mathematics and mainly conceptual type of stuff.  I guess some of the things I try and do to illustrate the differences between the models and the way that we use them is to ask questions in class that might be postulated in such a way that you can't answer it if you're thinking about both models at the same time.  So the one I like is where I show say a 2s orbital and the probability distribution of that node in between.  I talk about things that … there's one briefly, this plum pudding model which they all laugh about.  When you look at this 2s model there is a probability and a high probability, relatively so, that the electron can be inside the nucleus, if you think about it in particle terms.  Then talk about the nodes and so on and how they arise in quantum mechanics and so on and then ask questions like if the electron can be here and here but it can never be here how does it get there?  ...  I try and get across maybe the bigger picture, everything we're going to do from this point on (because we do this fairly early in first year)  - everything is going to be a model.  Nothing is going to be right.  Nothing is going to be wrong. Nothing is going to be exactly the way it is.  Everything will be just a model. You'll hear us saying things like ‘this is how it is’ or ‘this is what's happening’.  But really you need to interpret that as ‘this is a model and this is how this model is used to explain this particular phenomenon.

Try to show students that the fundamental form of matter is energy. Then that this can be represented as particles with mass or as waves (wave functions). Then try to show them that we use the model particle/wave that best helps us understand different phenomena. In class I often do this by asking questions about wave mechanics in particle terms. eg. If a 2s orbital has a node how can the electron pass accross it? Then explain to them the limitations and advantages of each approach.

We do an awful lot of focus on teaching but realisticly, authentic assessment that actually engages the student, that’s a tougher ask... I set a lot of essay type assignments. I think we ought to do more of that in science.  But when I started doing this I used to get very poor results and it’s taken me a little while to realise that the students weren’t understanding what the questions was.  They didn’t understand what I meant by compare and contrast or discuss or argue for this.  So increasingly now I use workshops to actually spend time with the students unpacking, what is this essay assignment about?  What am I actually asking you to do?  What do you need to think about? And not assuming that they know how to write an essay.

Too often I think students and others think that analytical chemistry is just that measurement step.  When you use the AA, when you use the ... and doesn’t take into account, well all of the other stuff, what’s the actual problem you’re trying to solve?  What are you actually trying to do, sampling, measurement, validating your results? Because only then when you’ve got a result, only then does it actually become information.

Students see equations and panic. Students struggle to transfer mathematical knowledge to chemical situations. Students silo knowledge and find it hard to relate concepts to actual systems.

I don’t like to be in a position where I’m stood at the front talking for 50 minutes. I like to be a in a position where I’m engaging with students, where they’re engaging with each other, where there’s a buzz, where there’s things happening, and it’s an active environment.

So my approach to teaching is that I want students to be actively engaged with the material throughout the lectures, all the tutorials, all the workshops or whatever, and so I’m not giving didactic lectures, I’m not using lots of PowerPoint slides.  I’m giving them information. I’m describing things to them, but then I give them lots of examples and lots of things to do, lots of activities to do. 

The difference between chemistry as it happens in a flask, chemistry as we show it on paper or in a textbook and helping students to understand that these are representations and they're conceptual frameworks that we use to understand our discipline and so helping them put those two pieces together.

We all spend a certain amount of our class time going through definitions and jargon and getting students up to speed with the basic area and now that’s material which I take out of the class and put online and let students read and understand that in their own time before they come to the class.

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