Making a teaching video is much harder than it appears. My Q*Bert video was built out of 30 second chunks and many, many retakes. Even then I had to do some sound editing of ‘well’ and ‘um’ and so forth. I don’t have this problem teaching to students in person (even if I’m doing most of the talking) because I can always pause; “dead air” isn’t nearly as deadly. Salman Khan’s use of continuous takes at 8+ minutes is quite a feat.
Video is not just spoken text. Salman doesn’t fully utilize the video format, but he wouldn’t be able to be so prolific otherwise. Even so, what he does is non-trivially different from text. Consider Why Gravity Gets So Strong.
Here’s a shot of the video early on…
… and here’s a shot later.
In a book format one could have a diagram that is progressively developed (but often is not for space concerns), but even given that in the video there is focus and movement going on that gives a more tactile sense of mass that a static image cannot convey.
Video cannot utilize student response the same way as other forms of interaction. I had several points in my Q*Bert video with requests to pause, because it was intended for front-of-classroom use by a teacher. However, some students have seen (and used) it solo. While I did receive one email inquiring about the puzzle at the end, the number of students working alone that paused the video in the middle when prompted I estimate roughly between zero and zero.
Hence, saying “let’s think about this” and giving several minutes wait time is not plausible. (I do have some ideas for how I might get students more willing to pause and may incorporate them in my upcoming video, but I don’t have high odds that they will work.)
Salman Khan cares getting students to understand why things work more than he is alleged. His Slope and Y-intercept intuition video, for instance, shows off an interactive applet that students can use to explore. Even taking a non-interactive portion of the site, like Proof: log a + log b = log(ab) nets a quote like:
What I actually want to do is stumble upon the logarithm properties by playing around. And then, later on, I’ll summarize it and then clean it all up.
Of course, optimally, we’d like the students to discover things and clean them up for themselves. That is asking for something different than a video (or at least how we normally think of video, presented linearly). Even then, for the students who worked through an exploration on their own but still didn’t get it, it’s nice to have a video leading through the same logic as a backup.
Now, it’s not to say there aren’t issues, but some of the bobbles and mistakes — at one point fixed by a pop-up box on Youtube, but I believe that video has been remade now — come through more as humanity and charm rather than obscuring factors.
I can hardly claim speed-recording as many lectures as Salman Khan has allows him to fully utilize the video format. There’s all sorts of dynamic aspects of design that would help with presentation, but they are of course time-intensive. It’s like complaining about Wikipedia and recommending Scholarpedia instead for all work. Scholarpedia only has a fraction of Wikipedia’s content and in all likelihood a particular topic X will not be found in Scholarpedia. It’s only usable as a resource in reverse: looking at the index and reading from there.
Still, in many topics, Khan’s not the only game in town. A common sorted index akin to how The Online Books Page sorts books would be welcome. Khan has a consistent quality that makes him usable; random Youtube choices often lead to some extraordinarily dull math videos. Competition between videos needs to open up in a coherent way that students can navigate; this will push in some better lessons in the gaps Khan has.
Example: By all rights, Dr. Taton’s videos should have more views than they do, try say–
However, I’m not going to blame Salman for getting famous and being dubbed The Messiah of Math and so forth. Critiques should be measured and backed by solutions: there’s a chance here to build something new.