Gas station without pumps

2015 June 19

Teaching as public speaking

Filed under: Uncategorized — gasstationwithoutpumps @ 21:57
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“Dean Dad” recently wrote a post Confessions of a Community College Dean: When Public Speaking Works Best, in which he talked about the advantages of improvised talks over highly prepared ones:

My best moments as a speaker have consisted of a layer of improvisation on top of a prepared framework. The words were substantially ad-libbed, but in a context that had been thought through in advance. Having the safety net of a clear framework, the knowledge of where I was going, and the security of knowing that the worst that could happen wouldn’t do permanent damage, made it possible to follow the muse of the moment. I could improvise knowing the direction I wanted to go, and having faith that I’d get there one way or the other.

That is my usual modus operandi for giving talks or class lectures. I start by figuring out what I want to cover and (sometimes) in what order, and make sure I understand the material thoroughly.  There have been a couple of times when I’ve had to give lectures on material I’m not completely comfortable with, and the results are not really satisfactory.  I know that there are people who can give scripted lectures from prepared PowerPoint slides on stuff they don’t really understand, but I can’t—I have to have the stuff really solid in my head. (Which is not to say that I never pass on mis-information—I have sometimes realized after further study that I’ve been teaching a simplification that is incorrect.)

My best classes usually have no more than about 5 words of lecture notes, reminding me of the topic of the day—the entire performance is improvised off of those notes, together with lots of “audience participation”—getting the students to ask questions and come up with partial solutions.  Such talks do not use prepared slides, but blackboard/whiteboard or live coding (for programs like gnuplot, where the concepts really rely on seeing what the program does with various scripts).  I also get a lot of digressions in the best classes, when students ask about what really interests them, rather than what I have prepared.  If the digressions are valuable and I know enough to go in that direction, I’ll take them.  If I don’t know enough, I’ll usually put the students off until the next lecture, so that I have time to do some reading.

I have, once, given a talk with a carefully written-out script (see Video of Designing Courses talk), when I had a very short time slot to present a large amount of material. The results were OK, but not as good as the longer, slower improvisational presentation I use in classes.


  1. The textbook I use for my senior stats course is the best book I have ever used. It is actually readable by the students. It comes with a really slick set of PowerPoint slides. I use the slides when there is a picture or formula I want to show but there is no way I can lecture from the slides. I look at the previous section and the next section in the book and use that as my outline. Canned lectures are guaranteed to put high school kids to sleep. My classes are small enough that I can actually converse with my students during the class (the reason I was happy to quit teaching at the university level). If I run short of time I make them read the book. For some reason hs kids think the book is just for weight or to occupy locker space.

    Comment by gflint — 2015 June 22 @ 16:21 | Reply

  2. Agreed on that blog post’s value. Scripted talks also come off as if you don’t know what you are talking about, and have to read them. I saw one talk where you could tell it was being read from the “notes” side of the PowerPoint that the presenter could see, and I lost all faith in the competence of that (nationally known) speaker. Just phoning it in. Might not have even written the speech!

    I prepare class the same way, although I will sometimes have data for an example in there. But you do have to know what you are doing! The only downside I see is that the students come to believe that you have some sort of God-like knowledge of everything, which isn’t necessarily good. They need to see how YOU figure it out to realize that they can do it themselves.

    Regarding time, I learned when participating in debate that you can operate an internal clock that fits everything that needs to be said into the alloted time even when working extemporaneously — but that takes a lot of practice. Those effortless TED talks are not made by someone who just walks up on the stage!

    Comment by CCPhysicist — 2015 June 25 @ 21:24 | Reply

    • A lot of my extemporaneous talks are intended to show students how I approach and solve problems, rather than giving them polished solutions. (I used to call this “live-action math”.) I think it is instructive for students to see a professor fail at something, then immediately go about debugging it. So the failed EKG demo, where I replaced a loose wire and stuck on new EKG electrodes to get a working demo, was a good use of 5 minutes of class time, even though it was not as slick as a demo that worked first time.

      I don’t always manage to fit in everything I want to say—in part because I almost always have more to say than the time permits, and know that going in. I try to get to the most urgent stuff first.

      Comment by gasstationwithoutpumps — 2015 June 26 @ 02:25 | Reply

      • Absolutely. My comment about time was for a prepared talk, not class, and one where you can see a time prompt.

        Like yours, my talking points are in order of importance. If I end up spending a half hour instead of 15 minutes on some active learning exercise and come up short, I just draw a line on my list to indicate where I left off. There is always another day!

        BTW, your article and these comments remind me that we should probably tell our students when we are just winging the solution (and how we can do it with only one cue on where to start) and when it is rehearsed. Both can look like magic, perhaps even making them think they can never do the same, but both are within reach of any student. I’m always reminded of that when a former student shows me what they are working on for a senior engineering class as if I know what they are talking about!

        Comment by CCPhysicist — 2015 June 27 @ 15:30 | Reply

  3. I have always done the chalk-and-talk style, without notes. I think about what I will do in class and make sure I go through all the derivations and whatnot beforehand, but then in class it’s just me with the white board and markers. I draw fairly well, which is a skill I use abundantly in my lectures.

    I don’t like PPT and never use it in class. Of course I have to give research talks off of slides, but I always hate preparing them. I make sure I have the first 2-3 slides well rehearsed, and then I just improvise from there (once you are past the grad student or postdoc stage, you end up giving too many talks for it to even make sense to practice the whole talk; who has the time?)

    And there is definitely such a thing as overpreparation. A few years ago I was tasked with giving a talk on behalf of a collaboration within a large NSF-funded centers grant; the talk was part of a site visit for the grant renewal. It was challenging to present everyone’s work in detail, but also fun. However, my collaborators insisted on many, many practice sessions and lots of input. By the time I gave the talk, I was completely sick of it, it didn’t look as what I wanted but has suffered from too much input (there is such a thing). I think I did a good job objectively, but I felt I did a horrible one at the time. I personally think the talk was more fun when I did the first dry run than 15 practice-and-input sessions later. Having a speaker who’s sick of the talk they are about to give is not a recipe for a good presentation.

    Comment by xykademiqz — 2015 June 25 @ 21:45 | Reply

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