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Re: force

I wonder if it is really that linear. One of the points Arons and
others have made very vigorously is that it is not necessary to cover
each topic in absolutely exhaustive detail before moving on to the
next, that a cycling back with successive refinements approach yields
greater benefits.It seems logical, then, that intricately linked
ideas such as force and acceleration should be developed in tandem
rather than in succession. If you have two tools, you can fix more
broken things than you can if you have only one. If a student is
still thinking of acceleration as another species of velocity, then
you can point out that this is inconsistent with the result obtained
from Newton's Laws in the case of a ball on the end of a string
whirling in a circle. Now we can work on resolving the inconsistency.
A state of cognitive dissonance is an opportunity to learn; in this
case, there is a strong motivation to look at how directed motion
changes because clearly there is *something* gumming up the works
here -- one thing you know is inconsistent with another thing you
know. Two floodlights tend to cast fewer shadows than a single one.

As I mentioned from, the heart of the matter, for me, is getting students
to understand directed motion, and how it changes. If they can recognize
that, then you have a chance at getting them to understand the notion of
force as cause for those changes.


Paul J. Camp "The Beauty of the Universe
Assistant Professor of Physics consists not only of unity
Coastal Carolina University in variety but also of
Conway, SC 29528 variety in unity. --Umberto Eco The Name of the Rose
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