Re: Problem with a problem

[Science Lab1 <emigh@COMMNET.EDU>]

Then I am clearly a dolt, I thought it was fun.  And although the
problem itself really is "poorly specified" (actually overspecified, so
I did it numerically, while doing the general solution led to a well
duh! if you do not see the easy answer to begin with),  I can see only
one interpretation that is actually physical (the others are
mathematical or logical artifacts).  This always leads to good
discussions in my class (which is why I am going to use it).  Among
other things, in this case, the discussion will touch on why you should
usually solve problems in general first to understand the physics.

Could I specify it better?  Probably (at least I hope so).  I also read
Leigh's problem and remember doing essentially that problem when I was
taking physics, but I do not know why he would claim the answer to be
"intrisically interesting" or even more interesting (its a pencil
falling over for Pete's sake), though I think it is a very good problem
to test students.

Recently we did a problem involving a train accelerating up a hill. The
students were given grade of track, force of friction, and starting
velocity and ending velocity.  From this they were to calculate how far
the train traveled.  What a dull thing to look for, but the actual
process of solving it (conservation of energy) and what other results
you could then develop are very interesting indeed.  The students asked
me for another problem with a similar "surprise solution".  For many of
us (and certainly myself) it is the game itself that is interesting and
not the results.  One test I took asked us students to find the allowed
excitation states of a weather balloon exposed to monotonic sounds at
differing frequencies.  The results were rather disappointing (except
when you think of the thousands of ways you could break the balloon with
sound), but the process needed to discuss the problem is still
interesting to me 25 year later.

And tol be blunt, I find ideal gas problems inherently boring and why
would I care what the maximum theoretical compression of an ideal gas is
under various conditions (unless more pressure would result in a phase
change to a plasma or a degenerate gas, but I would be more interested
in the phase change itself).  On the other hand I am sure my dad would
be very interested in the problem. But of course, I need to know my way
around ideal gasses to understand the "interesting stuff", like plasmas
and degenerate gases.


David Emigh

Joseph Bellina wrote:

> Hi Leigh,
> I have to ask.  What makes a problem intrinsically interesting?
>
> cheers,
>
> joe
>
> On Thu,
> 18 Nov 1999, Leigh Palmer wrote:
>
> > Rick has already told you how to solve the problem. I will point
> > out that there is more than one solution to this poorly specified
> > problem. My principal objection to it, however, is that it is a
> > *stupid* problem. What is the point of doing this calculation?
> >
> > I think that good problems in physics should motivate students to
> > solve them because the result will be intrinsically interesting.
> > This one isn't. The result I fear most is that the student will
> > go away from the only physics course she takes thinking that this
> > is what physics is.
> >
> > Thus endeth the sermon.
> >
> > Leigh