Expert Insights

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 think personally the quicker the students can see that holistic approach to chemistry the better... Because that’s when they start to realise how cool it is.

I guess what every educator deals with is needing to find out what preconceptions there are at the start of the unit and then correct those and then keep on top of those throughout the course.  For example I get students who use the word particle and the word droplet interchangeably. Whereas to an expert, a particle is something that is made of a solid material and a droplet is something that’s a liquid material.  Students use those interchangeably so they may be talking about a suspension of solid materials but then they use the word droplet because they think it’s interchangeable with the word particle. Or vice versa, they might be talking about an emulsion and they talk about particles where they should be talking about droplets.  So because they’ve heard these phrases before in first year... the importance of using exactly correct terminology hasn’t been reinforced.

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.

I have one slide where I'm first demonstrating how we use curly arrows and that shows an arrow going in a particular direction from a nucleophile to an electrophile and emphasising that the arrow shows electrons moving - so it's got to start from where they are.  There has to be some electrons there for them to move.  So the whole screen goes black and comes up with a little orange box of 'never do this' which is an arrow starting from an H+, which has no electrons. The dramatic emphasis that the whole room goes dark and then it's just up there.

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.

They [students] expect to either succeed or fail immediately or very quickly on particular problems. They do not see the process as a learning process.

This understanding builds students' knowledge about the basic structure of matter which stimulates them to think in sub-microscopic level that provides the fundamental understanding for further chemistry learning.

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.

Students from high school might understand that vinegar for example is a weak acid compared to hydrochloric acid, but they never knew why. And you could then show them that with equilibrium, this is why. And all of a sudden they’re, 'oh, I’ve always known that I shouldn’t spill HCL on my hand, but I can spill vinegar on my hand and put it on my fish and chips'... Those sorts of moments can really... the students go ‘oh wow.’

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