Expert Insights

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.

When we’re teaching ideas in chemistry, I liken it to hacking your way through a forest.  It’s all this detail.... and you can’t expect students to do the hard work of fighting your way through the forest or the jungle, unless they have a global view of where they’re going. What I mean by that is, the other factors that influence the way I teach intermolecular forces, is that I keep going back to applications in the real world.  How is it that geckos can crawl up a wall, and almost sit on the ceiling without falling off?  How is it they’re able to stay there with gluey legs or what?  But the interactions between their feet and the ceiling are just, how could they maximise the attractions between the molecules in their feet, and the molecules in the ceiling? So what I’m trying to do all the time is to show applications, powerful, interesting, hopefully, and engaging applications of the ideas that are important. So, for students to engage and to feel, ‘well this is worth hacking my way through the jungle of detail to be able to understand it’, is to zoom out and show them how this topic relates to all of the other topics.  It’s called scaffolding, and it’s a very, very important idea. So, the other factors are essentially the incredible number of other applications of this idea... that the power of an idea is its explanatory power, and when they can see just how important an idea is, in being able to explain all sorts of phenomena, they might be willing to care about it more.

So I think we just, I used to give them, perhaps, 10 minutes to work on a problem, now I probably only give them two or three minutes.  I find that concentrates them and prevents them just talking about the State of Origin or whatever it is that’s on their mind.  We just need to keep changing the activity, rather than have extended activities... we want them to chat, but I think human beings won’t sit and chat about quantum mechanics for more than two or three minutes, they’ll get onto what they want for lunch.  So it’s that balance.

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.

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 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.

I think what I try to get students to see is that we use models and you use a model, while it works. Then when it doesn’t work you develop a more sophisticated model, and what we’re doing now is developing a more sophisticated model of the structure of the atom, of bonding between atoms. So they find that difficult, the fact that you’re putting aside the model you used previously and developing a more sophisticated one. I think that’s something, it just knocks their confidence a bit. I think we’ve got to convince them that, actually, what your teachers told you at school wasn't wrong, it’s just that this is more sophisticated, that science is all about building models to explain reality.

You're learning a new language as well as new concepts. There's lots of vocab, so terms like electrophile and nucleophile and many others. So learning the language, learning the code that we use, the curly arrow code, and then starting to apply that in half a dozen or a dozen or so different contexts, different reactions.

It’s something that needs to be reinforced, it’s not that you taught it in this unit for three weeks, we are over it. It’s something that keeps coming back, and that you can possibly reintroduce it, with not much change to your teaching. Not every single time, but every now and then remind the students, ‘remember, you still have to think about stoichiometry and limiting reagents’.

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. 

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