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Richard Hake
Posts:
1,205
From:
Woodland Hills, CA 91367
Registered:
12/4/04


Kahn's Video Lectures on Acceleration and Newton's Second Law
Posted:
Mar 15, 2012 8:02 PM



Stimulated by "Re: Khan Academy on Sixty Minutes" [Hake (2012)], I went into the Kahn Academy <http://www.khanacademy.org/> and looked at two videos:
1. "Acceleration" at <http://bit.ly/wycpxX>, and
2. "Newton's Second Law" <http://bit.ly/xqoW4X>.
These consist of Kahn's blackboard solutions of algorithmic exercises to find:
(1) the acceleration "a" of a Porsche, given the change in its velocity v during a change in time t; and
(2) the acceleration "a" of a block, given its mass m and the force F acting on the block.
There's little attempt to lead students to a *conceptual* understanding of either acceleration or Newton's Second Law. There's no emphasis on *operational* definitions of velocity, time, acceleration, force, or mass. Kahn appears to be (a) oblivious of physics education research, and (b) simply repeating in a traditional way the cookbook stuff he learned at MIT in passivestudent lectures.
I note that there's a 68post thread "Khan Academy: Math instruction goes viral" on the MathEdCC at <http://bit.ly/FOoNt6> which contains, among other things, negative comments on Kahn's math video on averages at <http://bit.ly/AaMkpu>.
For example:
a. Guy Brandenberg (2011) wrote: "That is one of the worst lessons on stats and averages I have ever seen. . . . He acts like the important part is the computation itself. He gives no reason WHY we should add the numbers up then divide. . . . . . And people pay him money? And think he's doing a great job?. . . . He's about as bad as John Saxon."
b. Domenico Rosa (2012) wrote: "I have not seen many of Khan's videos, and his style of teaching is significantly inferior to the teachers that I had in the public school system in the factory city of Everett, MA. My point is this: All the hits that his videos are getting are indicative of the hunger for direct instructiona fact that has been completely missed by the media pundits who have been giving him so much exposure."
Richard Hake, Emeritus Professor of Physics, Indiana University Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands President, PEdants for Definitive Academic References which Recognize the Invention of the Internet (PEDARRII) <rrhake@earthlink.net> Links to Articles: <http://bit.ly/a6M5y0> Links to SDI Labs: <http://bit.ly/9nGd3M> Blog: <http://bit.ly/9yGsXh> Academia: <http://iub.academia.edu/RichardHake> Twitter <https://twitter.com/#!/rrhake>
REFERENCES [URL's shortened by <http://bit.ly/> and accessed on 15 March 2012.] Brandenberg, G. 2012. "Re: Khan Academy: Math instruction goes viral," on the OPEN! MathEdCC archives at <http://bit.ly/FOpC53>. Post of 7 Sep 11:01 PM to MathEdCC.
Hake, R.R. 2012. "Re: Khan Academy on Sixty Minutes" on the OPEN! AERAL archives at <http://bit.ly/zsYxUk>. Post of 15 Mar 2012 10:59:140700 to AERAL and NetGold. The abstract and link to the complete post are being transmitted to several discussion lists and are also on my blog "Hake'sEdStuff" at <http://bit.ly/yapt2S> with a provision for comments.
Rosa, D. 2011. "Re: Khan Academy: Math instruction goes viral," on the OPEN! MathEdCC archives at <http://bit.ly/z2qEml>. Post of 12 Sep 1:59 PM to MathEdCC.



