A thoroughly sporadic column from astronomer Mike Brown on space and science, planets and dwarf planets, the sun, the moon, the stars, and the joys and frustrations of search, discovery, and life. With a family in tow. Or towing. Or perhaps in mutual orbit.

How not to, um, be too bad

One of the main things that you might convince yourself of if you walked around classrooms at almost any high powered research institution – including my own institution – is that the ability to do something well and the ability to teach that thing well are totally unrelated. It’s not that there are not good teachers in these places – every place has some outstanding teachers – but you would never be able to predict who is going to be one of the good ones by looking at a CV or noting how famous the person is as an academic.
We all know this to be true.
So I was particularly amused the other day when I got an invitation to give a talk about how to be an effective teacher.
“I have no idea how to tell someone how to be an effective teacher,” I protested.
“But you’re such a good teacher you must know how,” I was told.
First rule of effective teaching: don’t assume that someone who is good at something knows how to teach it. Particularly if that thing is teaching.
I couldn’t really get out of it. Last year I won Caltech’s Richard Feynman Prize for Outstanding Teaching, which is a flattering shot of confidence that perhaps I am doing something right in my classroom, but along with the prize comes some responsibilities. Last fall I had to talk to a group of graduate students about how to be an effective teaching assistant (“Don’t overestimate how organized your professor is”) and I had to give a talk at a graduation lunch on a topic of my choosing (“Why it’s OK to feel like an impostor”). I have to speak at the big dinner before graduation this year (haven’t started thinking about that one).Talking about effective teaching was one of the things I had to do.
Three weeks before the talk I was asked for a title. I had not, of course, even begun to think about what I was going to say (Second rule of effective teaching: know what you intend to say). Jokingly, I suggested “Teaching: How not to suck,” knowing that they would not actually use such a rude title. So, of course, they did. And then they plastered signs with the title all around campus.
Such a shockingly rude title led to a higher-than-usual interest in hearing what I had to say. Plus there was free food. The lecture hall was relatively full. Sadly, though the talk itself kind of sucked (Third rule for effective teaching: don’t raise expectations unrealistically).
I did end up with a few things to say; I just didn’t say them in an organized coherent enough way to have it be useful to anybody who was in the audience. But being forced to think about how to describe effective teaching did give me time to come up with a few general principles, of which some have already been stated. Here are a few more:
Fourth rule for effective teaching: have a thin skin. Students always like professors who care, but they rarely understand exactly what that caring really means. Yes, it is important to me that I teach effectively and students learn what I think they are supposed to be learning and they’re not bored. But I also have a very thin skin. To be short (and rude): I hate to suck. I really really hate to suck. And, believe me, sometimes I do. Students out in the audience of large lecture halls think they are very clever about surreptitiously falling asleep without being noticed. I always notice. There are days when I lecture and I simply know it is not going well. I am not clear; I ramble; I say things in the wrong order. And when I leave the lecture hall I feel simply awful. And I go back to my office and think “I do not want this to ever happen again” and I work hard on the next lecture. But not really because I am a magnanimously caring, but because my skin is too thin to have this happen too many times.
Fifth rule of effective teaching: lecturing is bad. I am fairly convinced that lecturing is one of the least effective ways of transmitting information ever invented. We lecture because that is what the monks did in the medieval times before they had books or computers or videos, and no one seems to have really thought very hard about whether or not this makes any sense anymore. So why do it? I challenged my audience during my talk to come up with any reasons they could think of for why lecturing might be useful. They had three thoughts: (1) It might be entertaining; (2) It might aid memory; and (3) It might aid comprehension.
Is any of this true? Who knows! But simply asking them the question totally changed the dynamic of the lecture. They were no longer passive recipients of wisdom from me, but active participants in trying to figure out what was going on. The change in the room was obvious. People sat up in their chairs; eyes were opened; hands were raised. And all of this means, I think, that brains were engaged. They will remember this part of the lecture more than any other part, and when they stand up in their own classes to give lectures perhaps they will think to themselves “why am I lecturing” and they will at least be thoughtful about what they are doing.
The point, of course, was to demonstrate that lecturing is bad. Engaging is good. I do think that a classroom section can be entertaining and aid memory and aid comprehension, but I think that this rarely happens when I stand and deliver a one-way lecture. If it’s one way it might as well be a video, which is significantly more efficient.
Sixth rule of effective teaching: humbly remember your days of ignorance. I teach a class on geology. Conveniently, I know very little geology. I thus relate quite strongly to my students who are seeing these concepts for the first time. I actually think that it would be very clever to require that introductory classes are taught by relative outsiders to the field.
Seventh rule of effective teaching: never ever go late. All students will hate you even if you are the most informative and entertaining person in the world. Fifty minutes after the start, not a single person still wants to be around. The same is true here, thus I end.


  1. lecturing isn't a bad way to teach. It;s bad lecturers that are the problem. You seem to see teaching as 'transmitting information' judging by your first rule of teaching.; Its so much more than that. Lecturing is part of the diet we should all use and be fed. Its about guidance, translation of material, enthusiasm and maintenence of motivation. If you can do it right, lecturing is absolutely superb as part (notice, PART) of a teaching and learning package

  2. Your post made me smile. Nicely stated.