Expert Insights

I think it’s a key teaching topic, also because it’s teaching students to look at data and to interpret data, to assess which part of that data is going to get them to the answer and which part is exquisite detail that they can come back to later on. 

So I think we just, I used to give them, perhaps, 10 minutes to work on a problem, now I probably only give them two or three minutes.  I find that concentrates them and prevents them just talking about the State of Origin or whatever it is that’s on their mind.  We just need to keep changing the activity, rather than have extended activities... we want them to chat, but I think human beings won’t sit and chat about quantum mechanics for more than two or three minutes, they’ll get onto what they want for lunch.  So it’s that balance.

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.

So, just to make them do some work, and made them think about the ideas themselves.  Talk amongst themselves about it.  I think that just too much of me in the lecture just washes over them after five to 10 minutes.  So they just need to have a break, think about the problem, do a couple of problems, talk amongst themselves... that seems to help, with both the variety of students in the class, but also just keeping them engaged.  Keeping their attention.

It is vitally important for their understanding of chemistry that they understand that molecules are three-dimensional things and that they have a spatial requirement in that they have a shape of their own and that shape will change.  They can't do higher level manipulations without an understanding of three-dimensional nature of molecules.

So the first thing that I really stress that people do, is that they actually go and watch some classes.  I think that’s the most important thing.  When they’re coming straight out of a post doc, or they’re coming straight out of the Research Centre, and then, they’re told they’re going to be lecturing 300 first year students, they’ve got to go and sit in the back of the lecture theatres for a few weeks.... when I came over from the UK to here, and the class sizes are about three or four times as big, it was just a real help to be able to see what worked and didn’t work  – how little time the students were on task in quite a few lectures.  Where the lecturer would just be talking and be oblivious to this.  I think people just learn a lot by seeing good things, but they also learn a lot by seeing quite bad things going on.

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.

We teach way too much stuff.  We teach way too much stuff that we used to teach because students didn’t have the resources available to them that they’ve got now.  I mean if you look at the resources - they’ve got textbooks, they’ve got electronic media, they’ve got Sapling. They can do the problems in their own time in a guided way with something like Sapling. We don’t have to do it, all we’ve got to do is give them the framework to solve the problems.  And I think we often misunderstand how much we should give them because I think we underestimate the value of letting them solve problems in a guided way with things like Sapling.  And I think, you know, in the old days we’d just do problem after problem after problem, which is as boring as anything.

The actual curly arrow mechanisms are in a way themselves cartoons, how they map to the reality in the way that a Micky Mouse might map to real life.

I think for a lot of people, before they started chemistry, especially if they haven't done any chemistry before, they've got no real understanding of the difference between macroscopic things and microscopic and atomic sized things. We all know how important that distinction is.

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