In the Dark

Making use of this Bank Holiday Monday morning to tidy up some things on my computer I realized I had bookmarked this short clip of Richard Feynman answering a question about teaching. I clearly intended to blog about it at some point but forgot to do so, so I’m correcting that now.

Feynman was of course a renowned lecturer both for university students and for public audiences. I think one of the things that made him so successful is that he liked talking about his subject and liked being the centre of attention; people who like neither of those things are unlikely to make good lecturers!

But the thing that really struck me about what he says in this clip is near the beginning where he says he thinks the way to approach teaching is “be chaotic” to “use every possible way of doing it”. Now some of us are occasionally chaotic by accident, but I think there is a great deal of truth in what he says. I also agree with him when he says “I really don’t know how to do it..” I don’t either

If you start from the premise that every student is different, and will consequently learn in a different way, then you have to accept that there is no one unique style of teaching that will suit everyone. It makes sense therefore to try different kinds of things: worked examples, derivations, historical asides, question-and-answer sessions, and so on. And we shouldn’t rely exclusively on lectures: there must be a range of activities: problems classes, tutorials, supplementary reading, etc. With a bit of luck the majority of your class will find something that stimulates and/or enlightens them.

The point about using every possible method at your disposal has become especially relevant now that we have had about 18 months’ experience of online teaching. I feel very strongly that we should make recordings of lectures routinely available to all students, not as a replacement for the “live” experience but to add to the set of resources a student can draw on. The same goes for other things which came into regular use doing our online period, such as printed lecture notes (again, not as a replacement for a student’s own notes but as a supplement).

I think it also helps to acknowledge that what you can actually achieve in a lecture is very limited: you shouldn’t be simply trying to “deliver” material for later regurgitation. You should be pointing out the particularly interesting aspects, explaining why they are particularly interesting, and what things students should follow up in private study where in textbooks and on the net they will find yet more different ways of approaching the subject.

After over thirty years of teaching have come to the conclusion that the main purpose of university education is to convince students that their brain is more than simply a memory device, i.e. that it can also be used for figuring things out. I’m not saying that a good memory is worthless. It can be extremely useful and memory skills are important. I’m just saying that the brain can do other things too. Likewise, examinations should not be simple memory tests. Sadly school education systems seem to be focussed on coaching students passing exams by rote learning.

We see particular evidence of this in physics, with many students afraid to even attempt to solve problems they haven’t seen before. One infers that they passed exams by simply memorizing answers to questions very similar to those on the paper. Our job is to remove that fear, not by pretending that physics is easy, but by giving students the confidence to start believing that they can do things that they previously thought were too difficult. In other words, university education is often about undoing some of the limitations imposed on students by their school education.

Back to lecturing, there are some obvious basics which lecturers need to do in order to teach competently, including being prepared, talking sufficiently loudly, writing clearly (if relevant), and so on. And of course turning up at the right theatre at the right time. But there are also those things that turn mere competence into excellence. Of course there are many ways to lecture, and you have to put your own personality into what you do, but the main tips I’d pass on to make your lectures really popular can be boiled down into the Three Es. I add that these are things that struck me while watching others lecture, rather than me claiming to be brilliant myself (which I know I’m not). Anyway, here we go:

Enthusiasm. The single most obvious response on student questionnaires about lecturing refers to enthusiasm. My take on this is that we’re all professional physicists, earning our keep by doing physics. If we can’t be enthusiastic about it then it’s clearly unreasonable to expect the students to get fired up. So convey the excitement of the subject! I don’t mean by descending into vacuous gee-whizz stuff, but by explaining how interesting things are when you look at them properly as a physicist, mathematics and all.

Engagement. This one cuts both ways. First it is essential to look at your audience, ask questions, and make them feel that they are part of a shared experience not just listening to a monologue. The latter might be fine for a public lecture, but if a teaching session is to be successful as a pedagogical exercise it can’t be passive. And if you ask a question of the audience, make your body language tell them that it’s not just rhetorical: if you don’t look like you want an answer, you won’t get one. More importantly, try to cultivate an atmosphere wherein the students feel they can contribute. You know you’ve succeeded in this when students point out mistakes you have made. On the other hand, you can’t take this too far. The lecturer is the person who is supposed to know the stuff so fundamentally there’s no symmetry between you and the audience. You have to be authoritative, though that doesn’t mean you have to behave like a pompous schoolmaster. Know your subject, explain it well and you’ll earn respect without needing to bluster.

Entertainment. As I said above, lecturing is very limited as a way of teaching physics. That is not to say that lectures don’t have a role, which I think is to highlight key concepts and demonstrate their applicability;  the rest, the details, the nuts and bolts are best done by problem-based learning. I therefore think it does no harm at all if you make your lectures fairly light on detail and (with reason) enjoyable as pieces of entertainment. By all means introduce the odd joke, refer to surprising examples, amusing analogies, and so on.  As long as you don’t overdo it, you’ll find that a bit of light relief will keep the attention levels up. A key element of this is spontaneity. A lecture should appear as if it develops naturally, in an almost improvised fashion. Of course your spontaneity will probably have to  be very carefully rehearsed, but the sense of a live performance always adds value. A lecture should be a happening, not just a presentation. Lecture demonstrations also play this role, although they seem to be deployed less frequently  nowadays than in the past. Being a showman doesn’t come naturally to everyone, and the audience will know if you’re forcing it so don’t act unnaturally, but at the very least try to move about. Believe me, watching a lecturer drone on for an hour while rooted to the spot is a very tedious experience (especially on a video recording). You’d be surprised how much difference it makes if you can convey at least the impression of being alive.

On this last point, I’ll offer a few quotes from a physicist who definitely knew a thing or two about lecturing, Michael Faraday. First, his opinion was that the lecturer should not be

…glued to the table or screwed to the floor. He must by all means appear as a body distinct and separate from the things around, and must have some motion apart from that which they possess.

Conventional wisdom nowadays suggests that one should take breaks in lectures to stop students losing concentration. I’m not sure I agree with this, actually. It’s certainly the case that attention will flag if you persist with a dreary monotone for an hour, but  I think a lecture can have a natural dynamic to it which keeps the students interested by variation rather than interruption. Faraday also thought this.

A flame should be lighted at the commencement and kept alive with unremitting splendour to the end…I very much disapprove of breaks in the lecture.

Finally, here is one of my all-time  favourite physics quotes, Faraday’s take on the need for lectures to be entertaining:

..for though to all true philosophers science and nature will have charms innumerable in every dress, yet I am sorry to say that the generality of mankind cannot accompany us one short hour unless the path is strewn with flowers.

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