Dot Physics

Videos and traditional lecture

I see that Doug at Nanoscale Views has fond memories of the hit show The Mechanical Universe. If you have never seen this show, it is quite excellent (even if old).

Perhaps the best thing about The Mechanical Universe is that it might be the best that traditional lecturing can provide. Oh, I know it isn’t quite the same. Students can’t ask questions while watching a video. But the main point is that if you want to go with some type of traditional lecture style format for a class, you would be hard pressed to do better than this. Or maybe something similar – there are other good video lectures out there.

I, for one, do not think traditional lecture is the best way to go. Mainly, I think this because I don’t want to be replaced by a video. Fine. Then what do I do in class if I don’t lecture. I like to think of the lecture as opportunities to ad value to the textbook. Here are some ideas:

  • First, I expect students to read the textbook. If I just go over what is in the textbook in class as a lecture, why would they read it?
  • If all I did was to let them ask questions and I answer them – that wouldn’t be too bad. That is something that a textbook can’t do – at least not yet.
  • Ok, I lied. Sometimes I do go over stuff in the book. But I expect the students to have read it first – and then I just go over the super-complicated ideas. If the students have already wrestled with these ideas, a lecture can be helpful.
  • Clicker questions. These are awesome. The students are obviously engaged when doing student-response questions. Win-win.
  • Practice problems. In a smaller class, letting students do a practice problem can be very useful. They can help each other and they can ask me questions. Another variation is to let them work on problems in groups and then present their solutions to the class (on a $2 presentation board)

Now that I think of it – I have another problem with The Mechanical Universe. It is these “morphing equations”. If you don’t remember them, let me show you a sample. Suppose they are talking about the momentum principle. Here is a starting equation and a sequence of screen captures. (I couldn’t find an embedable video of this)

i-e04cdde4a4fbe7fc8360c34596cdc9b7-2010-08-17_sta.jpg

i-411608e72d1359cf3544ba27bd0f3e25-2010-08-17_morph_2.jpg

i-a1e6b7bebdf38db884a7f5d03280c160-2010-08-17_m_3.jpg

i-db526903d1fa8502af6cd92a17036515-2010-08-17_m_4.jpg

I see what they are trying to do. They are trying to mathematically manipulate these expressions to show something. I get that. The problem is that this looks magical. And perhaps there are people out there that feel this is some sort of magic. Not Harry Potter type magic, but magic in the sense that they couldn’t do this. Maybe there is no way around this problem for these videos.

The other problem I had with the morphing equations is that they would do something I hate. They would “move” a variable from one side of the equation to the other and put it on the bottom. This drives me nuts (although some would say I am already nuts). The problem is that students often fail to understand the sacredness of the equal sign. It means “these two things are equal”. So, to maintain equality, you must do to one side what you do to the other side. The end result is that it LOOKS like a variable moved to the other side, but it didn’t. (Here is a slightly more detailed version of my equal sign rant)

In looking for an example of the morphing equations, I found a couple of other things to complain about with the Mechanical Universe. So, it is not perfect. This is probably similar to the Buck Rogers series. When I was a kid, this show was awesome. However, when I re-watched it as an adult, I realized I should stop watching it before it ruins my childhood memories.

Comments

  1. #1 Frank Noschese
    August 17, 2010

    I had a physics professor who did “morphing equations” on the chalkboard. The students called it “proof by erasure.” Not very helpful.

    I think Walter Lewin’s lectures are way better then the Mechanical Universe. His excitement and passion are infectious. Here’s a video of some of Prof. Lewin’s best lines: http://www.youtube.com/watch?v=raurl4s0pjU

    Anyway, I worry that videos like these promote the “transmission model” of teaching and learning. What are your thoughts?

  2. #2 Rhett Allain
    August 17, 2010

    @Frank,

    I don’t really think of these as just transmission type learning, instead I would consider it to be a video version of the textbook. Maybe that is a good thing, maybe it is bad. Good that students can perhaps understand some of the material despite their reading problems. Bad in that they don’t get to practice their reading comprehension.

  3. #3 Mark Hammond
    August 18, 2010

    Right now I’m liking the idea of short mini-lecture videos for my students. I had several realizations that pushed me toward this idea:
    1) I watched a colleague in the Spanish department show how he teaches first year Spanish without using English. It was a 40 minute sample class. I drifted off at least 4 times, even though I was interested! I realized that my students can’t be expected to pay attention to every second of every lecture. Not even close.
    2) As an experiment, I gave into student pleas to “work a problem on the board,” but then took up their notebooks to see what they had written. At least a third of them had major mistakes that rendered their notes totally useless for studying. These are high-achievers, too!
    3) I listened to a very nice lecture by Lee Smolin on iTunes, and I found myself backing up periodically when I had missed a point (drifted off again… I know what you are thinking… I was never tested, because, compared to my brother, I have plenty of attention span). The rewind button gives videos a leg up on live (how often are the questions you get in lectures due to students actually missing a step here and there?).

    Thus, the main advantage that I see to having videos of 10 minute lectures is that the kids can spend 15 minutes with it and actually get the attempted transmission. Admittedly, it is transmission, but that is, in itself, not necessarily a bad thing. The trouble with “teaching by transmission” is that it is exceptionally inefficient. One reason (certainly not the only one) that transmission is inefficient is the attention problem, or the “I missed that step, darn” problem.

    I’ve been looking for lectures that I like. I like Physics Classics, as they are more explanations that go along with experiments. Lewin’s lectures are nice for me, but they are long, at least for assigning a lecture for homework. And they are a bit complex for a high school sophomore. I, too, dislike morphing equations. What I have done is to buy a SmartPen and create “pencasts” showing the algebraic “moves” that my kids are having trouble with. I really like my SmartPen. Check them out (LiveScribe.com). I’ve also made some videos with my Flip camera this summer when students ask questions on summer homework. It’s a bit more work to get set up, but in the end, it’s easier answering their questions than trying to do so in an email.

    I also make screencasts of me talking through student work that I have scanned and have sitting on my screen. I point at stuff and tell them a bit about what they are missing. I can usually go over a test in a 3-5 minute video, without having to match up schedules and hope neither of us forgets, etc. I ask the students to at least watch the screencast before they set up a meeting with me, thus we can start out our meeting with at least a little bit done already. Often the screencast puts them on the right track.

    I think it was Bob Beichner at NCSU who put some video lectures up as a resource. Students who actually used the videos reported significantly higher use of the textbook. It may be that a student who will go use outside (and non-required) resources is more likely to also use the book… I don’t know. Or viewing the lecture spurred them to go read?

    Mark

  4. #4 Rhett Allain
    August 18, 2010

    @Mark,

    I really like your experiment #2 (collecting the notebooks).

  5. #5 Sili
    August 18, 2010

    The problem is that students often fail to understand the sacredness of the equal sign. It means “these two things are equal”. So, to maintain equality, you must do to one side what you do to the other side.

    I’ve only been teaching for 1½ week and this already drives me nuts as well.

  6. #6 ankara halı yıkama
    August 18, 2010

    is transmission, but that is, in itself, not necessarily a bad thing. The trouble with “teaching by transmission” is that it is exceptionally inefficient. One reason (certainly not the only one) that transmission is inefficient is the attention problem, or the “I missed that step, darn” problem.

    I’ve been looking for lectures that I like. I like Physics Classics, as they are more explanations that go along with experiments. Lewin’s lectures are nice for me, but they are long, at least for assigning a lecture for homework. And they are a bit complex for a high school sophomore. I, too, dislike morphing equations. What I have done is to buy a SmartPen and create “pencasts” showing the algebraic “moves” that my kids are having trouble with. I really like my SmartPen. Check them out (LiveScribe.com). I’ve also made some videos with my Flip camera this summer when

  7. #7 Stephanie Chasteen
    September 3, 2010

    I’m always amused by how posts about whether lecture is useful always get lots of comments. I think this is something that we’re all struggling with as we realize that interactive methods are so important.

    I think that transmissionist techniques — like lecture and video — have their place. To quote Dan Schwartz, “There is a time for telling, but not too soon”. In other words, we can’t really create all our own knowledge, we do want the “sage on the stage” to set it straight for us at some point, but that transmission doesn’t make sense to us if we haven’t struggled with it in some way, through (for example) clicker questions and pre-reading, as you do Rhett.

    Here’s a nice post by my co-author SidneyEve Matrix, who argues that the didactic lecture and the interaction part can be seen as two aspects of a classroom experience: http://theactiveclass.com/2010/04/15/eventness-partitioning-the-lecture/

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