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Re: Teaching methods (was "Homework...")



OK, you used the word understand. This means that the students should be
able to look at a situation and use NTN1 to analyze it when appropriate or
they should be able to identify cases of NTN1. This is a tall order, and is
generally not possible in 1 class. Students have to interact with many
cases of NTN1 and also interact with many cases where it does not apply.
Both the FCI and FMCE have questions that probe some aspects of this.
Generally conventional lecture gives small improvements on those questions.
If you are to confine yourself to 1 class then one of best treatments would
be the Thornton, Sokoloff ILD on NTN1 & 2. It is actually a scripted lesson
which incorporated discovery, discrepant events, peer instruction and some
observations by the instructor. It produces good gain on the available
standard evaluations.

Part of the problem of NTN1 is that students do not really believe that
balanced forces can still result in constant velocity. This is demonstrated
quite nicely with the use of opposing pushes provided by fans. The low
friction carts glide on the track with almost no change in speed. Students
are challenged to first predict and then are given the answer by means of a
demo. Finally a student is asked to explain it. At the end of each lesson
the instructor provides bridging examples which are designed to produce feed
through of the lesson. This latter idea is also used by Shayer and Adey in
Thinking Science.

One of the important features of the lesson is that student's must predict.
The time between the prediction and the experiment must not be too long or
the results will be degraded. This is now explainable by some recent
psychology research. Memories are not stored photographically and are
actually stored in a skeletal form which you flesh out upon recall. In
addition recent research shows that they can be fairly static until
recalled. At which point you store them again. During this "refresh" cycle
it is possible to modify or even falsify the memories. The predict part of
the cycle brings up the imbedded idea, and it is possible to modify it by a
quick demo. In such a fashion it is possible to actually convert students
to a more Newtonian oriented way of thinking.

This method is very closely organized by the instructor and includes a
variety of things including some teacher talk. It is also very well
researched. Alas, it does not work as well for non "formal operational"
learners, but neither do other methods. Lawson has shown that concrete
operational thinkers generally are not as ready to give up their
misconceptions.

John M. Clement
Houston, TX



Let me present a friendly, straightforward challenge to opponents of
traditional physics teaching. Although the challenge calls for only
a thought experiment, it may end up being almost as valuable as some
of the educational research being cited in this discussion. No
sarcasm intended. ;-)

Suppose my goal is to take a classroom full of beginning physics
students and have them understand Newton's first law of motion after
one class period of instruction.

I can lecture and do a few demos, or I can use any other
"discovery/engagement" alternative to conventional teaching.

I assert that the "discovery/engagement" approaches won't have a
prayer. Unless I drop some VERY salient, counterintuitive hints
(which amount to lecturing), my students are not going to discover
Newton's 1st law for themselves. Aristotle couldn't do it. Galileo
did it only after months (years?) of contemplation and experiment.

Newton's 1st law is TOUGH. It seems to contradict everyday
experience, and it's IMPOSSIBLE to test in the laboratory because we
can never achieve Fnet = 0.

Isn't most of the interesting stuff in physics quite a bit like this?
Isn't most of physics so counterintuitive to most people that
"discovery" is highly problematic? "Discovery" either takes too much
time or it requires sneaky hints that amount to a reversion to
conventional teaching.

Wanting to understand,

-Tucker
--
***********************************
Tucker Hiatt, Director
Wonderfest
P.O. Box 887
(39 Fernhill Avenue)
Ross, CA 94957
hiattu00@usfca.edu
415-577-1126 (voice)
415-454-2535 (fax)
http://www.wonderfest.org

Truth is a great flirt. - Franz Liszt
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