— Sal Khan’s videos have found a big niche, proving they’re needed and appreciated, and yet,
— Sal’s videos can be deadly dull when he makes us watch him drawing and labeling x- and y-axes etc. I wonder, how does he get away with this stuff? The explanation has to be partly in my first point, but also that
— Sal has mastered his subject matter and we’re patient with him because we know he’ll make sense of it.

So I see the collaboration with Vi Hart as very productive: take a video by Sal that sounds as if he just whipped it off while waiting for the clothes to dry, and cover the subject matter using the visual appeal and verbal fluency that Vi has, and all of the more boring presentations can be made exciting and fun.

Students aren’t always going to recognize their deficiencies with the content, nor will they necessarily benefit from the example given in the video, which is why it’s important that we spend time dissecting the videos to see how a teacher would actually use them to support student scaffolding and development.

KA might be good for some people, like: 1) a home-schooled student whose household no longer could teach her beyond geometry, 2) a student whose teacher has such a heavy accent that listening to his lectures is painful, 3) an adult learner who needs a refresher course on free radidals, 4) an incompetent and lazy teacher who thinks Khan is god, 5) someone (maybe I) perusing the site because there’s an impressive collection of videos.

Vi, however, is kickass cool. She’s a musician! I really enjoy her videos, and my students do too. I’ve shown three Vi Hart videos (Wind and Mr. Ug, Binary Hand Dance, and Pi is [Still] Wrong) — all at the end of the unit. Vi’s work is entertainment, not lesson planning.

I had never uttered one word about KA to my staff, but our Superintendent (teaching a small elective class), Special Ed teachers, and a few parents have used KA as part of their “curriculum.”

There’s definitely a market for Vi and Sal — the Bill and Melinda Gates Foundation thinks so.

However, even with division, I think the KA assessment tool has a lot of room for improvement. I liked the fact that one of the problems I got was: 792 divided by 8. This keeps me alert because I am sometimes rewarded with problems like this that can be done quickly with mental math. Unfortunately, when I asked for hints on 792 divided by 8, I was guided through the standard alogrithm. To me, you have not mastered this sort of division unless you can recognize when mental math is the better approach, can use an algorithm quickly and accurately, and can recognize when to use division in a word problem.

If your students are like mine, many of them that can give an explanation for something (how division works) don’t actually understand it all that well. There is a video on Keith Devlin’s blog showing a girl seemingly able to explain how place value works. On further probing, it becomes clear she doesn’t understand at all.

Define “mastery.” You’re on the right path with your thinking, but I think that your comment is too broad to take on all of the concepts covered by Khan. Here’s an example – I’ve got some students that can clearly explain how division works, but for the life of them, can’t compute it fluently. If I tie the mastery achievement to a speed badge and independently check for conceptual knowledge, that mastery badge begins to mean a little more.

Also yes the Khan Academy video should only be shown at the end. That’s what I put in my post and what I stand by.

Why couldn’t they have Vi working through some math doodling similar to Veritasium’s break down of science videos (in that they include correct and incorrect methodology)?

The students could then work through some KA problems, and only then would they be able to access the KA video on the topic.