Putting the magic in the machine since 1980.

Tuesday, May 12, 2009

Screencasting is Better than Lecturing

Many years ago when I was an undergraduate, in the late 80's, I watched many of my lectures on the TV in our dorm room. Like many other schools at the time, MIT had its own cable channels that it delivered to the dorms. For several of the large classes there would be the standard lecture one could attend in person, but also a second lecture, by a second professor, that was designed solely for the camera. This TV lecture was filmed by a camera that was fixed to the ceiling pointing down to a pad of paper on which the prof. wrote. All we could see was his hand writing on the piece of paper, with occasional cuts to a head shot of him. The TV lectures then played on a continuous loop, 24/7, on the various cable channels. They were very popular with students. I even vaguely remember some drinking games constructed around them. They were the original version of the MIT Open Courseware.

Flash forward to the present and now we all can afford the technology to do even better. Thus, this last semester I decided to use online screencasts instead of real world lectures in my 242 (web applications) class, you can see the screencasts here. I followed a now somewhat established model of having the students see the lectures at home and then class consisted of hands-on exercises. I was then able to provide each student with one-on-one help in doing the exercises (these exercises were not quizes and I provided as much help as needed to get it done). This model works very well. Of course, it probably only works with small classes. I had 9 students in the class.

The feedback I received from the students was positive. Some of the main lessons I learned are

  1. Students that already know most of the material did not watch the videos, instead they read the slides and other material I provided. These are probably the same students who would show up to class and spend all their time facebooking or somesuch. So, I think I saved them some time.
  2. The rest of the students do watch the videos and find them useful. Students new to the material will go back and re-watch parts. They all really love the fact that they can watch at any time.
  3. Having in-class exercises is critical as they tell me exactly how much each student knows and they drive home the message that you cannot learn how to program by watching a lecture: you have to practice. Without these exercises it is likely some students would have waited until the last day before a homework is due to practice, at which point it is impossible to get the homework done so they would have copied it. This would just increase the number of students who cannot program.
  4. On the technical side, I used Camtasia ($299, free trial) to record the lectures and posted them to vimeo. I learned that (a) I have to eliminate the background buzzzz noise one always gets when recording as it gets really annoying (Camtasia lets me do this by pressing a button) (b) programming screencasts have to be in HD (1280x720) as regular resolution makes it really hard to see the text, only vimeo let me host HD videos at a reasonable price ($60/year).
  5. I also bought the Bamboo Pen Tablet so I could freestyle draw on the slides. This worked fairly well, but my handwriting is even worse on the videos than in real life because I have not gotten used to writing on the pad while looking at the screen. Still, I think it helped for explaining some ideas.

Screencasting is better than lectures in that it allows students to proceed at their own pace. This is a significant advantage in CSE where we have such a large variance in the skillset of students. Still, it should be paired with even more one-on-one student contact. In effect, the teacher (or TAs, if you have them) becomes a tutor for every student in class.

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