Khan videos, learning, and reinforced misconceptions

Relevant: http://news.ycombinator.com/item?id=2429522 ("Khan Academy: the bad").

This reminds me of my old chemistry teacher, we used to enjoy watching his demonstrations because half the time they didn't work. Excuses would be made about a bit dirt must have been in the test tube or out of date chemicals etc.

But it made the lesson interesting (we wanted to see it fail), watching a well made video is less engaging than seeing a live demonstration.

Am I the only one thinking that having a good presentation alone is not enough to learn automatically? You need to practice what you learn to make it sink in.

In other words: it depends on the individual student to practice. Just looking at the teaching method and ignoring that factor is not enough imho.

EDIT to clarify: Criticizing something but ignoring a potentially big factor is not enough.

This resonates with the study discussed earlier this year that less legible study materials were actually recalled better:

http://bps-research-digest.blogspot.com/2010/12/harder-to-re...

Interesting, but it doesn't seem to control for the possibility that study materials presented in a subtly different way are recalled better. (I'd imagine Arial is used a lot in schools...)