About physics and teaching

Using Videos to Help Learners

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The media attention garnered by Khan Academy has inspired considerable debate about the efficacy of using videos to help learners.  Some have taken criticism of Khan’s videos (such as this well-reasoned piece from Frank Noschese) as equal to saying videos are incapable of helping students learn. Sal Khan has personally commented on the subject, and at one point challenges others to post better videos. He also gets a little testy later on in the comments, suggesting directly that his critics think video is useless as a learning medium. Yet I think it’s what happens in the video that is important. The fact that video is the medium is quite secondary. The secondary nature of the medium is totally lost on most of the fawning press Khan Academy gets. “It’s video! OMG! It’s a revolution!” Yes. Gag.

I think video can be useful for helping learners. I’d like to set forth here how, when and why I use video (or want to use it more… I’m pretty new at this).

Individualized feedback:

I mark up student work like everybody else. That is, I give written feedback. I am often unsatisfied with my own written feedback, because 1) my writing is messy, 2) the page gets crowded, 3) I am too impatient to fully explain what the student is missing and 4) I suspect my written feedback is often not studied by my students. An alternative that I have used is to write only very limited feedback, scan the student work, then make a quick screencast, pointing at the mistake on the scanned document with my voice-over expounding on what has gone wrong. I can even ask questions of the student, rather than just give the correct answer.

Why do all this when my students and I live nearly on top of each other? The reason is I can quickly knock out four or five short screencasts in the evening before bed or in the morning before class in about the same time it would take to set up a series of short conversations with the kids. And the students tend to watch the videos and then ask really good questions later. These videos do not replace the student-teacher interaction, they make it simpler and often make it deeper when the face-to-face happens.

Mechanistic Instructions:

I make short videos showing how to do things like redrawing a vector with its tail on the tail of another vector, reproducing the magnitude and direction accurately using a protractor. Simple, right? Anyone should be able to do that. At least that’s what I thought until I realized many students were flailing around, unable to translate words and still pictures into action. I’m getting ready to make a video showing students how to use a scale on the page to measure the magnitude of a vector. And how to use a protractor correctly. These are all things that I want my students to be able to do on the summer homework I just sent them. Without the videos, I know that I get a lot more confusion and less learning, just because some very simple steps have not been explained. Sure most would figure it out by themselves, and most actually will! This is a back-up plan for the minority that need it.

How are these videos different from Khan Academy videos? They are different because they closely match the way I want to teach vectors. They are not designed to give any deeper understanding about vectors, they are designed to address small steps that are fairly mechanical in nature. The videos are customized to my style to a degree that a video made for millions can’t be. And the subject matter is chosen to address small problems that I know students will have, based on my in-class experience.

Once this past year, a student had a problem that I didn’t have time to address. She had forgotten how to use scientific notation and this was holding her back. She had learned scientific notation before, but was rusty. I sent her to Khan Academy (even though I cringed a bit at the way negative exponents were explained). Here is what I consider a legitimate use of Khan Academy videos: the student already knows the content, but needs a refresher. If the student were learning scientific notation for the first time, I would not want to present the algorithmic approach that Khan uses (even though he claims to “explain the why,” I find most of his videos very much “do this, then do that” algorithms with little meaning), but for my student who needed a quick refresher, this was the quickest way for her to get it. If I had an extra thirty minutes that day (and they coincided with her extra thirty minutes), a live session with me would have been better, but we got the job done with the help of Sal Khan.


Occasionally I make a longer video (or pen-cast) that shows me walking through a tough problem. I do this so the students have a model of solid problem-solving that they can review as many times as they want. I emphasize that just watching a video (or a live lecture) of a problem being solved by someone else will not result in understanding. But the video gives the students a way of getting immediate feedback when I’m not around. This is how we achieve deep practice if I’m not actually in the same room as them.

Can Khan Academy provide this kind of video? I guess it could, but it doesn’t. Maybe it can’t. My problem-solving videos may only work for students who start their solutions from fundamental principles and then move to a determination of what models apply. Other teachers use different approaches… I wouldn’t suggest students outside my school would get a great deal from my videos. Maybe they could, but I won’t insist they could. My students get to where they can understand my videos by developing their own understanding in the lab. If a student went from Sal Khan’s kinematics lectures to my problem-solving videos, I’m pretty sure they would be confused.

Flipping the Classroom:

More on this later, but I haven’t figured out how to do the flipped classroom all that often. I use Modeling Instruction, where the students are already doing in class what proponents of the flipped classroom are advocating. The uses of video mentioned above do save some class time, but it’s not as if I’m giving video homework every night. Or even once a week. I think of using video as a way to be more efficient. Maybe there’s more… I’ll work on it. I am gradually using video more and more, though.

Do you have more ways of using video? Leave a comment!

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Written by Mark Hammond

2011/06/11 at 12:25

5 Responses

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  1. Great post, Mark, it really hits me in stride. I do a lot of screencasting, some for a whole class but a ton for individual students. Just yesterday a student emailed with a question about a project and I started to type a reply. After about 5 words I realized it would be much easier to make a screencast. So I did and she tells me that now she gets what I mean (I have a suspicion I wouldn’t have been so clear with just words). What I do in those situations is very similar to what I would do on my chalkboard or on a piece of paper if the student were in my office.

    When it comes to giving feedback on papers, I started to use screencasts with the thinking that I could talk faster than I could write (in red ink, no less). While that’s true, it turns out that I spend easily as much time (if not more) per paper but I know that I’m giving much more complete feedback. In the past I might have a statement like “move this paragraph” written (in red) whereas now I can really talk about why it doesn’t belong where it is. My full workflow is this: Read papers on the bus ride home. Mark them with cryptic symbols for my eyes only. Then, back in my office the next day, I pull up their pdf and hit record. I look at the paper copy and find those places that need some feedback. I’m pretty pleased with how it’s going but very pleased with the progress my students are showing in their writing.

    Andy "SuperFly" Rundquist

    2011/06/15 at 11:14

  2. [...] Mark Hammond’s Using videos to help learners [...]

  3. I’m with Andy on this, you hit on some great uses. I also make extensive use of videos (or screencasts as some prefer) and I use them consistent with your mentions. Where I haven’t used them is in the feedback loop you describe. I’ve been perplexed for years on how to effectively give constructive criticism on the lab reports I get from my junior and senior (college) physical chem lab students. Sometimes, I need to give extensive suggestions, too much to write. I try to arrange meetings but it’s a challenge getting a group of three scientist/.engineering students together with all their labs and projects. I will definitely start banging out some comments on Jing – really great idea. I got a hint of this while going over Andy’s web yesterday. I’ve felt alone using these tools for years – it’s great to see there are others out there trying their best to reach out and make contact with more of their students. I believe this task is much more challenging for college than K-12, and as the enrollment of the college grows, even more challenging. All of these tools have a place, and there isn’t one that is the revolution. Thanks for a useful post.


    2011/06/17 at 13:45

  4. Oh! About problem solving – I was hired by one of the big text publishers to make, specifically, problem solving videos for the website that accompanies one of the big college chem textbooks. These are not just problems at the end of the chapter – they are set aside as multi-concept problems that are really quite impressive in what they hope to accomplish. To do the problem, a first year student often will have to pull together 5-6 different and unrelated concepts from earlier chapters. These problems gave no hint as to what concepts are used, where they could be found – in some cases, they were challenging for this PhD chemist to solve. So – the videos were meant to be about process, rather than the mechanics you mention. I had to do the mechanics, too but the hardest part of the instruction was trying to reveal how a working chemist does her job – that of solving problems using the tools in the chemistry bag. I just finished the job and I am not sure if they are useful. I think I am going to put one or two up on my blog to get some feedback. I feel this is the next big use of video – can we use a process like this to teach problems solving. I am certain problem solving is better learned in an apprenticeship situation but does video work at all? I don’t know but I do believe we can do a lot of work in this area for those who are interested.


    2011/06/17 at 13:52

    • In the problem-solving section, this is exactly what I was trying to describe: taking a big ol’ bear of a problem and letting the students in on my thinking as I puzzle it out. Like you, I’m not sure how worthwhile it is. But this year I did a few such videos and I had two students tell me that upon watching the video for the umpteenth time, they finally noticed the ONE THING that they weren’t doing. And identifying that one thing they were glossing over made the entire unit fall into focus. So I guess they helped those two kids for sure. But note that it took them many viewings to catch the thing that they were glossing over or ignoring. I’m not sure that even one-on-one I could have identified that one thing. But it took students willing to spend time, dig deep and think hard. Maybe anything we do to make the student spend time, dig deep and think hard is worth it.

      Mark Hammond

      2011/06/17 at 17:19

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