Expert Insights

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.

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

So my approach to teaching is that I want students to be actively engaged with the material throughout the lectures, all the tutorials, all the workshops or whatever, and so I’m not giving didactic lectures, I’m not using lots of PowerPoint slides.  I’m giving them information. I’m describing things to them, but then I give them lots of examples and lots of things to do, lots of activities to do. 

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. 

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 culture in the chemistry department was always lots and lots of content.  And that’s changed now because you don’t need it, because they can find it another way, but you’ve got to give them the framework to understand the content.

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.

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.

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.

At the start of every class my standard thing was ‘can you see me, can you hear me, can you see the slide?’ I would always look up the back for someone to put their hand up and always I would never talk to the front row. I’d always talk middle and back row and if someone was talking in the back row I’d pick them up and say ‘hey you, be quiet’ and then they know that I’ve seen them.

So you’ve got to focus on the whole class not just the people at the front - the people at the back as well.  Because sometimes smart people sit at the back as well, not just the dummies who want to get out. You’ve got to make sure you know everyone in the class.  And the surprising thing is that most kids sit in the same place every lecture.

So you can actually recognise where they are and who they are.  You don’t know their names but there’s a pattern in the way they sit.  You’ve just got to be aware of that.  So the trick is to embrace the whole class with your - you know physically, just with your eyes and and the way you talk.  You know, when you wave your hands, wave it to the back row. Make sure they’re involved.

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