Re: Setting up problems

["QUIST, OREN" <OREN_QUIST@SDSTATE.EDU>]

There was an old "Far Side" cartoon by Gary Anderson where some poor bloke
had obviously died and gone to hell.  The devil was watching from around the
corner, flames and smoke etc. etc.  Anyway, he was in a library and the
books were all labeled Story Problems, Story Problems, and More Story
Problems.  (If anyone knows where this cartoon might be available, I would
like a copy for my classes)

Thinking is work, hard work.  And students need to exercise their thinking
skills.  Story problems are mental calisthenics.  If students would work as
hard at their thinking skills as hard as athletes work on calisthenics,
physics classes could go much better.

Oren Quist, SDSU

-----Original Message-----
From: Jack Uretsky [mailto:jlu@HEP.ANL.GOV]
Sent: Thursday, October 09, 2003 1:00 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Setting up problems

        Will I ever get tired of saying this?

        There is essentially nothing in modern algebra textbooks that
suggests that the purpose of algebra is to make problem solving easier.
"Word problems" in a modern high school math course is an unpleasant
excursion, lasting about two weeks, from unrelated exercises in the
mechanics of symbol manipulation.
        In other words, Rick, the problem starts with math teaching.




On Thu, 9 Oct 2003, Rick Tarara wrote:

> I'll go beyond what Joe and Ludwik have said and that Jack 'suggests'.
Most
> of our students cannot reason 'algebraically'.  Here they can't (at least
> don't) reason that since the kinetic energy is proportional to the mass
and
> the gravitational potential energy is proportional to the mass, then the
> actual mass is not needed to compare the two energies for a particular
> object.
>
> I can provide the equation--say that for centripetal acceleration or for
the
> Gravitational force and ask how the acceleration or the force changes if
we
> double the distance (or radius).  To MANY, MANY students, this is like
> asking them to translate Aristotle from the original Greek.
>
> Can we, should we, be teaching basic Algebra in our physics course?  Or
> maybe it's not the Algebra, just a lack of critical thinking skills.   ??
>
> Rick
>
> *********************************************************
> Richard W. Tarara
> Professor of Physics
> Saint Mary's College
> Notre Dame, Indiana
> rtarara@saintmarys.edu
> ********************************************************
> Free Physics Educational Software (Win & Mac)
> www.saintmarys.edu/~rtarara/software.html
> Energy 2100--class project
> www.saintmarys.edu/~rtarara/ENERGY_PROJECT/ENERGY2100.htm
> ********************************************************
> ----- Original Message -----
> From: "David T. Marx" <dtmarx@ILSTU.EDU>
> To: <PHYS-L@lists.nau.edu>
> Sent: Thursday, October 09, 2003 10:04 AM
> Subject: Re: Setting up problems
>
>
> > Perhaps I can get the topic back.
> >
> > I just came from my class and had a discussion with the class after a
quiz
> on work and energy.
> > Students commonly state, "I know the concepts.  I have them memorized."
> >
> > They also are demanding the kind of "plug and chug" problems they have
> grown accustomed to doing.
> > One example problem from the quiz:
> > _____________________
> >
> > A roller coaster starts from rest at the top of an 18-m hill.  The car
> travels to the bottom of the
> > hill and continues up the next hill that is 10.0-m high.  (a diagram of
> the situation is given with
> > the problem)  How fast is the car moving at the top of the 10.0-m hill,
if
> friction is ignored?
> > ______________________
> >
> > Students can tell me, if I give them the mass, what the potential energy
> is at each location.
> > The fact that the mass isn't given really makes them crazy.  They do not
> even know how to start the
> > problem without it.  During the quiz I told them that the mass isn't
> needed and that they should
> > proceed by considering what exactly is going on and write down the
> appropriate equations.
> > In class I did a few examples for conservation of energy after a few
> examples on potential energy
> > and kinetic energy separately.  In talking about conservation of energy,
I
> used the example of the
> > bob sled sliding down a hill.  At numerous points on the hill, I wrote
> down the kinetic and
> > potential energies of the car and showed that the total is constant.
> >
> > Students describe their difficulty as "understanding the definitions,"
> "being able to calculate
> > quantities," but not being "able to apply the concepts" to solving a
> problem.
> > > I don't understand how this fits into the preceding dialogue.  It
seems
> to
> > > take the phrase "rlated equations" out of the context in which it had
> been
> > > used.
> > >                                 Regards,
> > >                                         Jack
> > >
> > >
> > > On Wed, 8 Oct 2003, Bernard Cleyet wrote:
> > >
> > > > "I think, Bob, what people were responding to is the part about
> > > > 'have them look at the related equations'".
> > > >
> > > >
> > > >
> > > > OK here's related equations:
> > > >
> > > > The generalized solution for numerical modeling of two dimensional
> > > > orbits is:
> > > >
> > > > Q(i) = AX(i)(x^2 + y^2)^B     where to model the earth:

--
"Don't push the river, it flows by itself"
                                Frederick Perls