Re: Fields etc

["Van E. Neie" <ven@PHYSICS.PURDUE.EDU>]

> Electrons in the broadcaster's antenna oscillate and due to the Coulomb
> force cause the electrons in the antenna on my car to oscillate.  I can
> talk about "radio waves", but I know there  is nothing "real" there.  No,
> William, I don't think of radio waves as being real.  In some circles, even
> the electrons are thought not to be "real" in this sense.
How can we argue with that?   Can we say that anything is "real"?  Objects
(or concepts, whatever) consist of qualities and qualities exist only in
the mind.  So in a sense, the whole observable universe is simply a product
of the imagination.  I can sit here typing on my computer and feel the
keys, see the screen, hear the clack of the keys, etc., but is it real?
All of these sensations are ultimately processed in my brain.  I have no
way of knowing whether these are real or what "real" means.  But I'll go
ahead and use the term, because I think that most of the time, my listeners
are aware of what I mean when I say it's real.

In our communications with each other, we often say things that
grammatically are incorrect, but for the sake of avoiding sounding awkward,
we go ahead and say it anyway.  Well, "everybody does it," so what's the
harm?  The harm is a degradation of the language, a loose playing with the
rules.   I hear lots of complaints on this thread about incorrect physics,
but rarely do I hear criticism regarding incorrect use of the language.

Someone on this list about a year or so ago presented us with Thumb's
Postulates.  I lost the reference, so I'd like to know who it was.

        Postulate 1:  It is better to solve a problem with a crude
approximation and know the truth, plus or minus ten percent, than to demand
an exact solution and never know the truth at all.

        Postulate 2:  An easily understood, workable falsehood is more
useful than a complex incomprehensible truth.

It is the second postulate that I find a bit more than tongue-in-cheek.
Many concepts in physics are quite complex and virtually incomprehensible
to the beginning student.  So we often use "workable falsehoods" to get the
essence of what we're trying to convey.   And my guess is that a student
can lead a full and fruitful life without knowing the "truth."

I recall being a part of the community that got really hung up on the
mass-weight thing. " No, no--kilogram is a unit of mass!  The can of beans
doesn't WEIGH 1 kg, it has a MASS of 1 kg.  It WEIGHS 2.2 lbs (or is it 2.2
lb-masses?) "   Unless the student is trying to work out a problem in a
physics class using Newton's Second Law, does it really matter?  Most
people say they want to lose weight, but don't they really want to lose
mass?  Does it really matter what they mean?

Just some thoughts.  You may kindly disagree.






------------------------------------------------------------------------------
Van E. Neie                                      ven@physics.purdue.edu
Dept of Physics                                 PH:  (765) 494-5511
Purdue University                          FAX: (765) 494-0706
1396 PHYS Bldg
W. Lafayette, IN 47907-1396

"[Those] who have an excessive faith in their theories or in their ideas
are not only poorly disposed to make discoveries, but they also make very
poor observations."

---Claude Bernard  1865