Khan Academy and online learning

Two math professors critique the Khan Academy in the video below. See also the excerpted Chronicle article.

An earlier post on online learning and the future of higher education.


 

Chronicle of Higher Education: ... Khan Academy is a collection of video lectures that give demonstrations of mechanical processes. When it comes to this purpose, KA videos are, on the average, pretty good. Sal Khan is the main reason; he is approachable and has a knack for making mechanical processes seem understandable. Of course, his videos are not perfect. He tends to ramble a lot and get sidetracked; he doesn’t use visuals as effectively as he could; he’s often sloppy and sometimes downright wrong with his math; and he sometimes omits topics from his subjects that really need to be there (LU decomposition in linear algebra, for example). But on balance, KA is a great resource for the niche in which it was designed to work: giving demonstrations of mechanical processes. ... 

This is not to say that Khan Academy can’t play a useful role in learning calculus or some other subject. I don’t deny that mechanical skill is important for getting to the higher-level cognitive tasks. But mechanical skill is a proper subset of the set of all tasks a student needs to master in order to really learn a subject. And a lecture, when well done, can teach novice learners how to think like expert learners; but in my experience with Khan Academy videos, this isn’t what happens — the videos are demos on how to finish mathematics exercises, with little modeling of the higher-level thinking skills that are so important for using mathematics in the real world. So the kinds of learning objectives that Khan Academy videos focus on are important — but they’re not enough.

I tried out a couple of Khan Academy videos on my kids recently and I thought they were reasonably effective. Khan is not as precise as a real math professor but he gets the message across.

Small nitpick: he referred to negative numbers as "smaller" than positive or less negative numbers (e.g., -100 is "smaller" than 1), which is I think confusing and even a bit misleading. I think he should have used "less than" rather than "smaller". If you are familiar with complex numbers then you'll probably tend to think in terms of a magnitude (big vs small) and an orientation (with negative numbers along the theta = pi direction), so that -100 is not really small (in magnitude) relative to 1. Presumably Khan learned complex analysis at some point in his education (although maybe not, he went to MIT ;-) IIRC he started out wanting to do physics.