Expert Insights

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 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 changed my method of teaching to be a team-based learning approach where in fact as teams they are responsible to each other within the team for their level of engagement or for what they put into that team and if they don’t put in what the team thinks is useful then they get marked on that, their peers mark them on how much they’re contributing to the team’s goals.  So rather than me as the educator saying you need to do this and you need to do that, in fact the system is such that as a team they’re responsible for a certain outcome and the team must achieve that outcome and so they need to work together.  For the students who don’t put in as much as the team expects of them then there is peer pressure to increase their level of input and their engagement and if the students don’t then the team members get a chance to reflect upon that and give them a sort of team work score.

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 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. 

I think we’ve all sat in lectures and gone, that was dreadful, so we learned quite a lot from understanding how not to do it as well as how actually to do it.  And of course the key is preparation and organisation..... whenever I go into a class knowing that I am beautifully organised, that gives you that extra confidence to project and to present, and you come away with that feeling that you know that the class has gone well and you’ve got the information across to the students in the way that you wanted. 

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.’

Anonymous

Ions and ionic chemistry are essential to life and just about everything they will run across.

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.

It’s continuous learning.  I mean, what I used to try to say to students when I taught the acid-base stuff I’d say ‘look there are only about six types of problems and if you can solve one of them you can solve them all because they’re all the same.’ But what you’ve got to be able to do is look at the question and say to yourself ‘this is one of those types of questions therefore this is the way I should think about approaching it.’  So take the question, dissect it, decide what you’re being asked to do, decide what information you’re given, and then say ‘yeah that’s one of those types of questions, this is the way I should go about solving it.'  If you can get that across to them, that it’s not a new universe every time you get a question, it’s simply a repeat universe of the same type of question... But many students tend to look at each problem as a new universe and start from the beginning again.  Many students don’t see that there is a limited number of problems that can be asked on a certain topic.

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