helping students think like scientists

By Alison Campbell 09/02/2011

Today I was involved in a session on ‘large-group teaching’, run by our Teaching Development Unit. (Secondary teachers can probably skip this post as most likely what I’m going to talk about is pretty much routine for you.) Why? Well, there’s a fairly common perception that ‘the’ model to use in large first-year science classes is the bog-standard lecture: an academic discourses on a particular topic & students take notes. I accept that this may be seen as a bit of a caricature & I do know that not everyone teaches this way, but it is the way that most lecturers of my generation were taught & we do tend to model that sort of thing.

Anyways, back to the chase. What do I see as a ‘large’ group, an average lecture size? Well, Waikato is a smallish institution so my ‘large’ classes have around 200 students in them. But I need to say up front, I don’t think there’s actually much difference in how I teach a class of 20 and a class of 200. Maybe it takes a bit more planning with a large class, but the same techniques work with both.

When you’re on my side of the lectern it’s worth identifying, up front, the things you want your students to get out of your teaching. I see myself as educating my students in the broadest sense – that means I want them to take the information, the concepts, the ideas, the perceptions of how science works & how it sees the world, and fit them into the personal intellectual framework that lets them make sense of the world (the keynote at an e-learning symposium I attended last week called this framework a ‘schema’). To me, when I’m working with students, what I’m hoping for is that I’m helping them incorporate those new data points, & the new way of thinking I’m presenting, into their personal schema.

So I’d like to think that my lectures are exciting, sometimes, and entertaining, sometimes, and engaging – hopefully all the time, because I believe that students are more likely to make meaningful learning connections if they’re engaged with the material. But I want more than that.

I want them to interact (with each other, with me, with the ideas they’re encountering), because that too makes it more likely that meaningful learning is going to take place.

I want them to participate, because if you’re actively participating in a class you’re far more likely to be thinking about what’s going on & engaging with all the ideas flying around, & making sense of them – and maybe changing some of your existing conceptions about the world. Because, after all, education should be transformative, taking you from one state of knowledge (in the broadest sense) to another.

I want them to learn a darn sight more than ‘the facts’. (I can’t think how often I’ve heard someone say, “oh that’s all very well, but if you do those things you must be missing out an awful lot of facts.”) What are the most important things we want students to gain from a paper, or a program of study? In science (at any level), one of the aims surely has to be to gain an understanding of what science is, how it’s done, & why it’s such a powerful tool for gaining an understanding of how the world works? In which case, it’s not enough to tell students about science & to fill them up with facts (many of which will probably be dropped from short-term memory storage as soon as the exam is past); we have to give them opportunities to practice doing science, & thinking like scientists, for themselves, & to fit their new knowledge & understanding into the long-term storage of their personal intellectual framework.

So how do you do this in a class of 200 or more? That’s really what I was asked to talk about – but in the light of what I’ve just said, what do you think would be my preferred approach? Yep, the seminar participants got to do the things I was advocating. A couple of examples:

In about the third lecture I’ll give in the next semester, I ask the class to consider why I think it’s important for them to know something about plants. Why are plants so important to the very existence of life on earth? Part of this includes looking at a graph which up until now (& thus failing to practice what I preach!) I’ve basically just talked about. This year I’ve decided to put it up on screen & ask the students to tell each other what it means – challenging their comprehension, giving them the opportunity to interpret & explain data presented in this particular way. So I showed it to my colleagues & said right, go to it, why are plants so important to life on earth? What’s going on in the graph? What evidence is there for your interpretation?

The graph looks a bit like this, although it has other information on it, including uptake of O2 first by marine rocks & later by terrestrial surfaces:

Well! I had to interrupt after 3-4 minutes so that we could come back as a group & discuss this. It was a good reminder for me that I needed to check that everyone in my first-year class is familiar with the conventions of how graphs are drawn & read, & for my ‘class’ of colleagues I really should have reminded myself that none were biologists & most weren’t scientists! But on the other hand, because this was completely new stuff for most in the room, they found it interesting & really got involved with working out what the graph was about & how to explain what they were seeing. Yes, this will take longer than me standing up in front of my first-years & expounding on the graph, but which approach do you think is going to result in a better-quality learning experience?

And another example to leave you with; again, what I’m trying to do with this one is to get students to look at things through a scientific lens; to ask questions, design hypotheses; consider how to test these. This time it’s from a lecture on reproduction.

When you look around the animal kingdom, you’ll find that for a great many species, individuals don’t live long beyond their prime reproductive years. Mayflies are probably an extreme example: after a mad orgy of reproductive activity that lasts only a few days at most, all the adults die. (They’re not called Ephemeroptera for nothing!) Now, in evolutionary terms this makes sense – once you’ve successfully passed your genes on, from an evolutionary perspective it doesn’t really matter too much if you’re run over by a bus the next day (or the mayfly equivalent thereof). But take a look at primates (the group of mammals that includes monkeys, the other apes, & us) & you’ll see something different. Many primates do live past their prime reproductive years.

The questions I pose – for you now, as I did for my colleagues today – are: why? What sort of selection pressures might lead to some primates living well past their reproductive years, to become grandparents? And, once you’ve made an hypothesis about this, how would you test it?

0 Responses to “helping students think like scientists”

  • “why? What sort of selection pressures might lead to some primates living well past their reproductive years, to become grandparents? And, once you’ve made an hypothesis about this, how would you test it?”

    I would start by considering any possible benefits to the survival of groups (or individuals within the groups) that would not exist otherwise, e.g. is there something that those long-lived primates contribute that nobody else does, or that others only contribute in a limited manner? My first thought would be some form of experience or experiences that only come(s) with time/age. Social aspects such as being able to assist with children in monitoring their health, predator awareness, etc.

    I would test this theory initially but very roughly by considering observations that others had made to see whether this was too far out or whether it was worth pursuing by careful observation of primate communities in their “natural” habitat.

  • When I did this exercise with my colleagues last week they came up with a couple of hypotheses. One was the learning one you suggest, Sam :) The other was that having grandma around to do the childcare freed mum up to forage more widely & thus obtain more resources. They don’t have to be mutually exclusive. After a bit of discussion the group tended towards the second, which is something you could test by looking at the long-term survival of young primates who did, & didn’t, have grandmas. (My first-years are a bit more bloodthirsty – last year they suggested killing off all the grandmas in one ‘tribe’ of primates & comparing that with a group that was left alone…We went on to talk about why this was NOT a good thing to do.)

  • Alison, your first years scare me. I’m glad you would have provided them with some information about science and ethics.

  • Oh yes, carpe diem & all that! Srsly, I suspect that it wouldn’t be just ‘my’ first-years. I doubt that there’s a huge amount of discussion of ethics in your average high school bio class, although some might arise when they’re studying biotechnology. So if you offered any first-year bio class that sort of scenario, I’d be willing to bet that someone would come up with the same answer as my lot did last year.

  • Alison, I think I rather like your first years 😉

    My favourite, rather unusual, test of the grandmother hypothesis has to do with the X-chromosome and would probably take more than a lecture to explain…

    Paternal grandmothers are guaranteed to provide an X-chromosome to their granddaughters (since the X goes to her son, can’t recombine in him and is passed to his daughter) and guaranteed to not pass on her X to any grandsons (since her son must have passed on his Y-chromosome). So, gene for gene, paternal grandmothers are closer to their grandsons than granddaughters.

    Maternal grandmothers always have 50% of their X-chromosome genes represented in both grandsons and granddaughters ( or, more correctly, a 50% chance for each gene.)

    Now, if the grandmother hypothesis is true, and we think menapause evolved as a way for non-reproductive females to further their genes, then we can predict that paternal- and maternal-grandmothers will behave differently with respect to male and female grandchildren.

    Specifically, boys ought to better when cared for by maternal grandmothers (who have some X-relatedness) and girls ought to do better when cared for by paternal grandmothers (who have 100% X-relatedness). Amazingly, when you look at statistics from pre-industrial cultures from across the globe you can see just the pattern, males out-surviving females when maternal grandmothers were around, and females out-surviving males when paternal grandmothers were in the household:

    Fox, M., Sear, R., Beise, J., Ragsdale, G., Voland, E., & Knapp, L. (2010). Grandma plays favourites: X-chromosome relatedness and sex-specific childhood mortality Proceedings of the Royal Society B: Biological Sciences, 277 (1681), 567-573 DOI: 10.1098/rspb.2009.1660

    We used this paper in our Journal club last year, and I think it was probably the most fun paper we had a go at dissecting.

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