Sunday, June 29, 2014

Video lectures


Video lectures vs live lectures
Advantages
* You can watch them anytime you want (e.g. when you are most alert)
* You can watch them pretty much anywhere you want (e.g. on the bus on your smartphone)
* You can pause and repeat part of the lectures.
* You can watch all or some the lectures again and again (e.g. while doing a homework problem or  preparing for an exam).
* Good video lectures are short (max 7-10 minutes) and focussed on one specific topic.
* As a teacher you can't "get behind" on your lecturing.
* Video lectures free up valuable class time for discussion, e.g. using peer instruction.

Disadvantages
* Students cannot ask questions right away.
- In most large courses this is practically impossible anyway.
- In my experience questions occur very infrequently, even in smaller courses.

* If you use your lectures to inspire and motivate students that is probably better done live
- While students enjoy such lectures, there is no evidence that they learn more from them than "boring" lectures.

* Students won't watch the videos
- I really recommend "reading" quizzes
- Students also skip your live lectures.

Video lectures vs assigned reading
* If your lectures (or some of them) are basically repetition of the textbook, just assigning the reading instead of making the video lectures. Make sure they read it using "reading" quizzes

* Another alternative to making videos are detailed lecture notes, if you have them already.  If you don't, making video lectures is much faster than writing detailed lecture notes.

Powerpoint vs chalk-board (pen-cast) lectures
For live lecturing students tend to favor chalk-board lectures over Powerpoint lectures, because the pace of chalk-board lectures tends to match that of note-taking.  The relatively slower pace of chalk-board lecturing also means that fewer new concepts are introduced during lecture.

In the case of video lectures these differences largely disappear.  Students can pause and repeat Powerpoint video lectures. Pen-cast lectures (the video equivalent of chalk-board lectures) are no longer restrained by the available lecture time and can cover just as much as Powerpoint lectures.

It it telling that it is possible to view Powerpoint video lectures on the on-line platform Coursera at 1.5 or 2 times the regular speed. There seems to be no demand for slowing the Powerpoint lectures down!

I tend to make Powerpoint video lectures rather than pen-casts because I often present rather complicated equations or diagrams that are laborious to write or sketch by hand. However, if I want to demonstrate some thought process (e.g. solving a problem) then I use pen-casts.

In any case, I always give students access to the Powerpoint slides or the handwritten notes I base the video on. It is much faster to read these notes than to watch the video. If the written material is clear, there is no need to view the video.

Good video lectures
* The optimal length is about 7 minutes
* One specific topic per video
* At least one multiple choice question per video
* Students can handle no more than 7 such videos (new topics) per lecture period.

You can see some examples video lectures that I made here.

Making the videos
Here is how I make Powerpoint video lectures and pen-casting video lectures.

This post is part of an ongoing series of post on teaching tools and tips collected here.

This work is licensed under a Creative Commons Attribution 4.0
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