Re: form and function

[John Denker <jsd@MONMOUTH.COM>]

At 08:58 AM 10/24/00 -0600, Dewey Dykstra, Jr. wrote:
> Is it a central issue which physics shares with all the other sciences?
>
> 3. The teacher understands the concepts of form and function.
>
> Is this an important subject matter theme in physics?  How would you
> assess teacher or student knowledge of this standard?

Here's how I'd approach it:

Physics comprises a number of sub-fields, including
  *) theoretical physics
  *) experimental physics
  *) applied physics, including
        -- biophysics
        -- optoelectronics
        -- etc.

... and in addition the physics teacher is called upon to teach the
introduction to fields such as electrical circuitry and mechanical engineering.

It's not clear to me how "form and function" applies to theoretical
physics, but in all the other areas it seems reasonable enough.  Examples:
  *) Physics lab: apparatus is put together in forms related to function.
  *) Biophysics: enzyme systems generally didn't just happen;  they are
        there for a reason.
        Lehninger speaks of "the molecular logic of life".

I don't think it is necessary to burden the syllabus with multi-hour
lectures on "form and function" -- but instead it would be good to keep the
principle constantly in mind, to remark on it when appropriate, and to use
it to filter out foolish homework problems.

We've seen applications of (and violations of) the principle on this list.

The circuit John Mallinckrodt posted doesn't just have a "form" containing
four capacitors;  such circuits have a "function", which needs to be
discussed.  And to the extent that the form is ill-matched to the function,
it is a foolish circuit and a bad thing to inflict on students.

I have similar feelings about the Cenco "dissectable capacitor".  What is
its function?
 -- Surely it doesn't illustrate the concept of "capacitor" that I want
students to have.
 -- Is it supposed to illustrate something about static electricity and
charge separation?  Then why not study an electrophorus or Wimshurst
machine instead??
 -- Or is it supposed to illustrate that lots of things can go wrong if
you have a poorly-designed experiment with lots of uncontrolled variables?

        If you don't know where you are going,
        it doesn't matter which road you take :-)