Re: brightness vrs. power

[brian whatcott <inet@INTELLISYS.NET>]

At 05:50 7/7/00 -0400, Robert wrote:

> Back in May, this list had a discussion regarding Ohm's Law and the
> resistance of light bulbs.  I posted a question on the following series
> parallel configuration:
>            /-----X------X-----\
>       -----                    -------
>            \-----X------X-----/
> vs. a single configuration:
>       ---------------X----------------
>
> ...I reaffirmed my belief that beginning students (who
> assume R is constant) will guess that the four lights *together* will be
> brighter than the one alone ...

> Robert Cohen

I am downcast that a person carrying out a difficult
and demanding role (which in some cases can remain
in the memory of students a lifetime later, for better
or sadly for worse) should remember the words of my evil
twin brother, for even a day, far less a month, if they
take away from his passion.

Even so (without being quite certain which one of us is
in present command of the keyboard) I do not refrain from noting
that Robert shares a character with many of his worthy
colleagues on the list - that he may externalize the student
body's performance under his direction from his leadership.

 I recall an idealized conception of the teaching role as that
of 'tutor'.   In this heavenly schema, one is commissioned to
cultivate the skills, talents and imaginations of one's students
 in the chosen field of study.

  If one's charge is unamenable to chalk and talk, one exhibits
the lives of physicists. If one cultivates no fertile patch this
 way, one visits a working lab. If this is unavailing, one asks
for paintings, poems, line drawings, word pictures of physical
concepts.  If math modeling will not light the flame then
experimental construction may yet. In a word, one does what is needful.

 The patron will understand (one hopes) that not all precious stones will
polish to a brilliant in the same way, and that a symmetrical gemstone
has been subjected to 'brutage' to knock off the obtuse corners.

 There is room for baguettes and roses D'Anvers and couronnees too.
    And to labor the metaphor far too hard, it is the impurity
that colors the allochromic gem.

 In this conception of physics, the student would be the center of the
entire universe. There is no a nor c grade, but only a more difficult,
or more convenient tutorial path to a certain student understanding
of the field.


Let me be the first to say:  ...I am sincerely glad I am not at
the receiving end of this whole homily.
Is there a lion-hearted saint alive who could actually make any of
this happen, I wonder?


Ah..hem, back on topic - what about if we connect some negative
temperature coefficient thermistors in series parallel:
am I confident I could predict the relative dissipation vs a
single component? No, I guess not.



brian whatcott <inet@intellisys.net>
Altus OK