Expert Insights

I think what I try to get students to see is that we use models and you use a model, while it works. Then when it doesn’t work you develop a more sophisticated model, and what we’re doing now is developing a more sophisticated model of the structure of the atom, of bonding between atoms. So they find that difficult, the fact that you’re putting aside the model you used previously and developing a more sophisticated one. I think that’s something, it just knocks their confidence a bit. I think we’ve got to convince them that, actually, what your teachers told you at school wasn't wrong, it’s just that this is more sophisticated, that science is all about building models to explain reality.

So, it’s helping to bed down analysis, problem solving, doing the sort of detective work to get to an answer.  And the students also seem to quite enjoy having material presented to them in that way - here’s a spectrum, what do you think the structure is, because it’s a more active form of learning as well.  So I find I enjoy teaching it, and they respond well in terms of, they keep coming in and asking me for additional problems to practise on which is clearly evidence that they feel it’s challenging them.

I find it [teaching] enjoyable, and I think that if you’re enjoying teaching something then your passion and desire and enjoyment gets transmitted to the students.  It’s not necessarily easy to teach, but it’s satisfying and generally we want to inspire them to increase their level of intrinsic motivation to want to continue to study chemistry.

So you shouldn’t be rigid, you shouldn’t be rigid in what you’re going to do.  It’s always stunned me that people say you should know where you start a lecture and where you’re going to finish, and if you get to that point and you finish ten minutes early you then should just finish.  I’ve never worked on that principle.  I never know where I’m going to start because I never know where I’m going to finish, right.  So where I finished the lecture before is where I start the next day, I haven’t got a set content.  If a student asks me an interesting question and I get the feeling that they want to know that answer I’ll go off for five or ten minutes or three or four minutes answering it, and if I don’t get to the end of where I thought I was going to get to, too bad I’ll do it next time.  So you go with the flow, you don’t go with a rigid thing ‘I’ve got to get through these 15 slides today and if I don’t the world will end,’ because it won’t.

I find that some students pick up what the mole concept is from the idea of grouping numbers of things that are every day size. 

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.

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.

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.

Chemistry is a different language so I try to approach it that way by explaining the ideas behind symbols.

When we’re teaching ideas in chemistry, I liken it to hacking your way through a forest.  It’s all this detail.... and you can’t expect students to do the hard work of fighting your way through the forest or the jungle, unless they have a global view of where they’re going. What I mean by that is, the other factors that influence the way I teach intermolecular forces, is that I keep going back to applications in the real world.  How is it that geckos can crawl up a wall, and almost sit on the ceiling without falling off?  How is it they’re able to stay there with gluey legs or what?  But the interactions between their feet and the ceiling are just, how could they maximise the attractions between the molecules in their feet, and the molecules in the ceiling? So what I’m trying to do all the time is to show applications, powerful, interesting, hopefully, and engaging applications of the ideas that are important. So, for students to engage and to feel, ‘well this is worth hacking my way through the jungle of detail to be able to understand it’, is to zoom out and show them how this topic relates to all of the other topics.  It’s called scaffolding, and it’s a very, very important idea. So, the other factors are essentially the incredible number of other applications of this idea... that the power of an idea is its explanatory power, and when they can see just how important an idea is, in being able to explain all sorts of phenomena, they might be willing to care about it more.

Pages