Re: Physics First

[dykstrad@varney.idbsu.edu (Dewey Dykstra, Jr.)]

> > It is safe to say that Piaget is _not_ the framer of these particular
> > 'facts;' (1) that proportional reasoning is required to learning
> > "meaningful, even conceptual, Physics" and (2) that proportional reasoning
> > is "not normally achieved in the ninth grade."  Piaget's work in
> > understanding the origins of knowing was not about limitations.
>
> > Dewey
>
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> I never meant to say that Piaget said that proportional thinking was needed
> for Physics understanding, that is my own observation and one that I hold to.
> One can teach about Physics and even get some rote understanding and problem
> solving (if it is a familiar problem) with out proportional thinking but ....
> As for when that normally happens, he may not have limited it but he did
> place it on a maturation spectrum. Most ninth graders I have taught are not
> there, many are getting ready to blossom.

I was getting at two issues.  One is the one you mention. The other is
about the supposed limitations implied by Piaget.  Although your original
statement left wide open the possibility that Piaget said something about
physics teaching, I expected you did not mean this, but it is not clear
that others understand that Piaget did not specifically address physics
teaching.  As to the second point, it is still a gross misunderstanding of
Piaget's work to suggest that it is about or implies limitations.

As to the suggestion that Physics understanding requires proportional
thinking, well, this leaves an extremely thin collection of topics and none
at the beginning level of the students conceptually, if one insists on a
formal notion of proportionality as opposed the qualitative one the
students ALREADY HAVE.  I AGREE ultimately at some level proportional
reasoning comes up in most topics of physics, esp when it becomes
appropriate to use formal mathematics.  BUT, this is several steps BEYOND
where most jr hi students begin, or for that matter most non-science majors
in college, conceptually.

There is plenty of material at the foundations of conceptual development
which _does not require_ specifically proportional reasoning.  Even one of
the central issues in Newtonian physics: net force results in acceleration,
does not in the first stages of initially constructing such an idea require
proportional reasoning either in constructing notions of acceleration that
are different than their everyday notion of acceleration or in deciding
that a net force results in an acceleration.

Sure they use a type of proportional reasoning:  if x is bigger then so is
y, but they ALREADY are in good possession of this qualitative level of
proportional reasoning.  The more formal level of proportional reasoning
which is entailed in mathematical proportionality:  if x is 3.7 times
bigger then y is 3.7 times bigger, IS NOT INITIALLY NEEDED.  Sure if you
want to take the students further, then the issue comes up, but for MANY
students there is NEITHER time NOR is it appropriate to go on to this level
of formal proportionalities in a particular course.

In almost every area of phenomena in physics the first logical steps that
students take from their initial conceptions of the phenomena require NO
MORE than the qualitative notion of proportionality that they ALREADY HAVE
down to at least the 6th grade in my direct experience.  I can give more
examples in motion, forces, electricity, light and heat.

As long as we insist that we never step beyond the bounds of these
formalisms when we teach physics we are doomed not to reach a majority of
the population.  The profession of physics suffers and the broader society
of which we are members and to which we have some obligations is not well
served.
> ken

Dewey

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Dewey I. Dykstra, Jr.                   Phone: (208)385-3105
Professor of Physics                    Dept:  (208)385-3775
Department of Physics/SN318             Fax: (208)385-4330
Boise State University                  dykstrad@varney.idbsu.edu
1910 University Drive                   Boise Highlanders
Boise, ID 83725-1570                       novice piper
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