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

[pedlto01 at LUTHER.EDU (Todd Pedlar)]

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