Expert Insights

I know it's hard for them to 'suspend reality' and just accept a concept. They grasp for real life examples or metaphors which make sense to them. Students don't like the concept of something that can shift/change. They like one answer which is set and that's it, right or wrong - not 'shifts to the left/right'.

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 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. 

I think it’s a key teaching topic, also because it’s teaching students to look at data and to interpret data, to assess which part of that data is going to get them to the answer and which part is exquisite detail that they can come back to later on. 

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.

In the workshops, the workshop idea as we run them is that you are out and about and amongst the students all the time in those groups, seeing what’s going on in the groups, seeing how they’re answering their questions.  They have set questions on sheets that they work through in groups and the groups of three just get one set.  They’re all working on them together and you’re moving in and out and around among the groups and seeing how they’re going.  In that circumstance you can quickly, having looked at three or four of your eight different groups, figure out where a particular issue would be and then that can be addressed on the board, it can be addressed with models or something like that.

Difficulties are having to relearn something that they thought was true from school and not understanding the evolving nature of science. New knowledge is easier to assimilate than changing old knowledge.

The concept of a continuum is, I think, really important in chemistry and… what I see is that students come up with this issue of things being black or white.  They struggle with this concept of the in between stuff.

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.

In the lab it comes out in a variety of ways.  It comes out most commonly when the student gets to actually start doing their calculations and you ask them to relate that back to what they’ve actually physically measured.  And when they start doing those sorts of things you realise there’s a bit of a misplaced idea here or a misconception that you can deal with there.

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