Expert Insights

They [students] reveal great misunderstandings about the molecular world. So the difficulties and limitations are as a result of not spending sufficient time on getting them to think about this world, and spending too much time on doing. You know, we’ve got to spend some time, but you can’t spend too much time, I think, on a lot of the ideas that we do teach, and doing calculations and things that, really, no one else does. It’s really something that’s done almost like it’s make-work-type stuff.

They struggle with the language of chemistry.  So we sort of need to teach them the process and how to work out how to do these things.  We know that their tendency is just to attempt to memorise reactions.  Whereas if we can teach them to derive … find out what the nucleophile and the electrophile is then all they have to do is draw a curly arrow from the nucleophile to the electrophile, rather than trying to work out what the reaction is itself. 

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.

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.

I think to get the students to straight away mark for somebody else what they’ve just done and then to mark or take part in the marking of two other versions of the same thing is really powerful.  So it’s not so much me directly finding out what they do and don’t understand but using methods by which they can diagnose for themselves.  I haven’t got this, she has, or yep I have got most of that, she hasn’t, and I can see where she went wrong.  Very powerful, very powerful indeed. 

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.

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.

You're learning a new language as well as new concepts. There's lots of vocab, so terms like electrophile and nucleophile and many others. So learning the language, learning the code that we use, the curly arrow code, and then starting to apply that in half a dozen or a dozen or so different contexts, different reactions.

Many years ago, lecturers only had one style, you know they just wrote on the blackboard, actual blackboard with chalk.  That was the only style.  They just talked... That’s all I knew so that was fine and so I thought, well I’ll just continue that and the students weren’t understanding what I was saying and explaining and I thought, oh hang on what’s going on here?  This is the way I was taught.  Come on, it should work.  So, yeah I think it would be good if someone told me that at the start, but as I said because I’d end up doing my Diploma of Education that opened my eyes to that and that’s when I started to utilise different strategies and I appreciate that not everyone is going to understand one way of, my teaching way.

I use a lot of eye contact. The people in the back row are not anonymous, you know.  Make sure you’re talking to them and make sure that you see them.

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