Expert Insights

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

Students see equations and panic. Students struggle to transfer mathematical knowledge to chemical situations. Students silo knowledge and find it hard to relate concepts to actual systems.

We do an awful lot of focus on teaching but realisticly, authentic assessment that actually engages the student, that’s a tougher ask... I set a lot of essay type assignments. I think we ought to do more of that in science.  But when I started doing this I used to get very poor results and it’s taken me a little while to realise that the students weren’t understanding what the questions was.  They didn’t understand what I meant by compare and contrast or discuss or argue for this.  So increasingly now I use workshops to actually spend time with the students unpacking, what is this essay assignment about?  What am I actually asking you to do?  What do you need to think about? And not assuming that they know how to write an essay.

I want them to get the big picture about what analytical chemistry is about in terms of solving an analytical chemistry problem.  They need to know the big picture rather than just focussing on the measurement step.

I like to approach chemistry as a different language, because it used symbols to convey ideas across, but they are not the reality.  When we draw a little stick structure, alcohol does not exist as I’ve just drawn it, it’s a representation.

I remember when I was taught this, that the only definition we were given was Le Chatelier’s actual definition, or his principle, and I remember reading that language and going geez, that’s really hard to follow as a student, so I used to always try and present that and then break it down in to a more simple sort of version that I thought would be easier to understand.

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.

[Analytical chemistry] is probably one of the things that’s easiest to tie back to their own experiences.  Because it’s very easy to link the idea of the importance of chemical measurement, is actually pretty easy to get across. You just talk about what is sports drug testing, road side testing, when was the last time you went to the doctor to get a path test.  These are all forms of analytical chemistry.  So I have a significant advantage over some people [teaching other topics] in being able to imbed it in their experiences.  Everybody has some kind of experience we can draw on to say, yeah that’s analytical chemistry.  The difficulty is of course to ensure that misconceptions don’t creep in.

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 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.

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