[Phys-L] Re: Energy is primary and fundamental???

[jbellina at SAINTMARYS.EDU (jbellina)]

Back to the pedagogy.

I can think of few concepts that are more difficult to deal with than
acceleration.  If an energy first, or momentum first approach would
allow one to avoid acceleration, so go back to Newton original idea
about force and momentum change, I think it would do a great service.
Of course one would have to check carefully that the sort of conceptual
understanding that John Clement calls for is indeed there.

joe


On Aug 11, 2005, at 4:54 AM, Todd Pedlar wrote:

> Jim Green wrote:
>
> > I find myself wondering what has come over the list.  Do we really
> > want to
> > debate whether the fellow who smacks you on the nose has applied a
> > "force"?  If there is anything real in his galaxy, that is real.
> >
> > But "energy"???  For Pete's sake energy is an invention!  It certainly
> > isn't "primary and fundamental"  We wander around saying that "light"
> > is
> > photons or maybe waves or maybe a beam.  Also inventions.  Yes
> > photons got
> > Einstein a prize, but they are not "real"  All these  concepts are
> > useful
> > -- They help us solve some practical problems.-- but they are not
> > real.
> >
> > If we try to teach that they are "primary and fundamental,"  we do our
> > students a great disservice..
> I agree.  I'm really not sure I grasp the motivation for creating a
> course
> that treats Energy as "fundamental".  In some ways, as a particle
> physicist,
> I agree that energy is a fundamental quantity.  However, I fail to see
> any
> pedagogical advantage in trying to introduce what is really a rather
> abstract
> topic in the opening stages of a course.  I have a hard enough time in
> a
> traditional ordering convincing some students that gravitational
> potential
> energy actually exists - I can't imagine beginning with energy topics,
> without
> having grounded them in understanding position, velocity and momentum.
>  I
> say this with potential physics majors in mind in a calculus based
> class!  I
> certainly wouldn't dream of thrusting this concept at the outset on
> students in
> an algebra-based course for science majors or worse on students in a
> non-science majors course!
>
> The fairly recent article in The Physics Teacher on the origin of
> potential energy
> contained (I think) a very nice discussion that is relevant to our
> discussion. I
> honestly think, with Jim and Ludwik that any conceivable advantage to
> an
> energy-first method would be outweighed by rather ponderous conceptual
> disadvantages.
>
> My 2 cents, for what it's worth.
>
> Todd
>
> --
> ______________________________
> Todd K. Pedlar
> Assistant Professor of Physics
> Luther College
> pedlto01@luther.edu
Joseph J. Bellina, Jr. Ph.D.
Professor of Physics
Saint Mary's College
Notre Dame, IN 46556