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Richard Hake

Posts: 1,104
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

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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 passive-student lectures.

I note that there's a 68-post 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 instruction--a 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!
AERA-L archives at <http://bit.ly/zsYxUk>. Post of 15 Mar 2012
10:59:14-0700 to AERA-L and Net-Gold. 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.