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Re: free fall data repost


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From: John Gastineau <gastineau@mindspring.com>

Spoken as a true Luddite.

I couldn't disagree more. I think that this is a prescription for turning
off yet another generation to physics, and for continuing teaching
practices that appear to be inferior as judged by the literature.

A couple of standard references: "Learning motion concepts using
real-time
microcomputer based laboratory tools," Thornton and Sokoloff, AJP vol 58
p
858

"The effect of real time lab graphing on learning graphic representations
of distance and velocity," Brassel, JRST, vol 24, p 385ff.

These both showed that students doing kinematics experiments who had to
do
more traditional style analysis learned LESS than those who had real time
computer graphing tools. The physics is in the interpretation and
understanding of the graphs. Drawing graphs is important too, but it is a
separate skill.

I'm not sure I can fully agree with this last paragraph. First, the
assessment of having learned more or less is subjective based on exactly
what was tested. I would suggest that being able to MAKE a graph either
from data or even a description of motion is also an important part of
understanding the physics, and if the studies quoted didn't test this
ability (they may have, I don't have quick access to the papers) then I
might not fully agree with the interpretation that MORE or LESS was
learned. As an example of what I mean, I asked my third semester class to
graph velocity versus time for a free-falling object both falling in a
vacuum and falling through air. Everyone (sample size = 9) could do the
latter having seen the graph in a modeling experiment the day before (the
computer drew the graph), but 3 of the 9 couldn't get the first one right,
having not seen this graph recently. My main point is that I would not
totally separate drawing graphs from the interpretation and understanding
of graphs and therefore the physics.

Rick