Re: heat, centrifugal force, etc.

[Rick Tarara <rtarara@SAINTMARYS.EDU>]

Almost all students come to their first (real) physics courses (H.S. and/or
Intro-level College) as Aristotelian thinkers.  I'm going to venture an
educated guess that most people on this list are Newtonian thinkers.  A
minority here really think in terms of 20th Century Physics.  The majority
_know_ that Newtonian gravity has been superseded by General Relativity,
that the mechanics of the small and fast are best handled by Relativistic
QM, that in the 'real' world friction, viscosity, turbulent flow, etc., etc.
complicate our simple models, but in the end, we still think about everyday
actions, macroscopic objects and interactions in Newtonian terms.  The goal
of MOST intro courses is to try and pull students from their Aristotelian
conceptual framework into a Newtonian framework and then (and only then) to
at least inform them that 21st Century physics requires yet another paradigm
shift by identifying the problems with the Newtonian world.

As evidenced by such diagnostics as the Force Concept Inventory (as overused
and flawed as it is), this is a VERY DIFFICULT task.  It can take a full
year of work to begin to break down student pre-conceptions about their
world to the point where they can start to build the Newtonian model and
incorporate it into their own thinking.  IMO, what we have really learned
from PER is that the Newtonian viewpoint is much more difficult for most
students to understand than we previously believed (being the 'chosen few'
who 'got it' quickly).  I don't know that the (in)famous Hake plot really
proves anything more than if you design a curriculum and techniques to
directly address student difficulties with the Newtonian model you will be
more successful than if you simply (and quickly) present the Newtonian model
as 'fact', then proceed to use it to do some simple physics.

The point here is that I am supporting Bob in that the basic goal of HS and
intro-College courses is (and IMO should be) getting students to understand
the Newtonian view of nature and to hopefully incorporate this into their
own world view.  Forays into more modern views of nature must be limited in
order to spend the time and energy necessary to break Aristotle's strangle
hold on the student mind.  Once the student HAS successfully made the
transition from Aristotelian to Newtonian thinker, then those few destined
to become physicists will be prepared for the next paradigm jump.  It is
sufficient for the others to know that such a jump is necessary to get to
today's understanding of physics.

If someone has a successful approach that can move students from their
Aristotelian conceptual framework all the way to a truly modern (21st
Century) framework in one course, I'd be happy to rethink this position.

Rick

*********************************************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, Indiana
rtarara@saintmarys.edu
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----- Original Message -----
From: "John S. Denker" <jsd@MONMOUTH.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Thursday, December 12, 2002 6:45 AM
Subject: Re: heat, centrifugal force, etc.


> Bob Sciamanda wrote:
>
> > [1] Included as part of the
> > teaching of Newtonian mechanics are an appreciation of its historical
> > position, its limitations as an early model, and anticipatory glimpses
of
> > its successors. [2] But I don't think we should teach modern physics
> > as if GR
> > and QM  sprang from nothing yesterday. [3] We owe it to our students
> > and to
> > Newton, Lagrange, Euler, et al to give the Newtonian model a full
> > hearing on
> > its own merits and limitations.  [4] This is how our race came to GR
> > and QM;
> > give modern students a chance at the same fulfilling experience.
>
> Hmmmmm....
>
> A) I completely agree with [1] and [2].  But that's not a
> sufficient basis for the conclusions [3] and [4], and it
> certainly doesn't justify teaching students that centrifugal
> force doesn't exist.
>
> Recently my nephew's high-school football coach used
> the term "centrifugal force".  My nephew and a classmate
> corrected him, telling him there was no such thing as
> centrifugal force.  I had to explain to the kids that
> the coach had used the term entirely correctly.  The
> kids find it amusing that in this case at least, the
> coach has the physics right and the physics teacher
> has it wrong.  The kids find it less than amusing that
> they have to remember that they are required to speak
> of centrifugal force in one class and forbidden to
> speak of it in another.
>
> B) Mentioning a little (!) bit of the historical context
> of scientific discoveries has its place, but history
> is verrrry far from being a reliable guide as to what
> to teach or even what order to teach it in.
>
>   -- Our race came to astronomy via Mars-the-god-of-war and
>      Venus-the-god-of-love.
>   -- Our race came to electromagnetism via luminiferous ether.
>   -- Our race came to medicine via leeches and homeopathy.
>   -- Our race is coming to civil rights via feudalism,
>      racism, and sexism.
>   -- Etc. etc.
>
> Yes, I want my students to be aware of such things, but
> it would not be "fulfilling" to require them to retrace
> those steps personally, to learn and then unlearn every
> bit of foolishness our race has ever come up with.
>
> C) The typical physicist is not qualified to teach the
> history of physics.  The way the "historical" development
> of science is typically taught is a gross distortion of
> the actual history.  Kuhn had something to say about this.