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Re: [Phys-l] Order of Topics (Was: Re: What comes first, the equation or the explanation?)



And experts do NOT follow a linear path. The research shows that experts
make many mistakes, but they recognize blind alleys and correct themselves.
They are willing to go back and thing things in a different fashion.

Of course the equation is generally dictated by the concept, so the concept
has to come first. But when the concept is not the correct one to use,
experts change the approach. So in classical physics which concept is used
for a particular problem, energy, kinematics, or momentum to name the major
ones. Sometimes you have to use all 3. Experts often have a gestalt which
they use and which may not be explainable at first. But then they find a
way to justify it conceptually.

Some of the successful research based programs have the students conciously
pick the concept first. The Minds on Physics program does exactly that and
an independent evaluator found that students exhibited more expert like
problem solving behavior.

Novices generally just pick the equation first, and then try to use it. But
they often pick the wrong one and use it anyway. This has been reinforced
by many textbook authors.

John M. Clement
Houston, TX

At 8:44 PM -0500 12/21/11, ludwik kowalski wrote:

On the other hand, as John D. emphasized several years ago--I am
nearly certain it was him--one proceeds from what is known
to what is
unknown. This implies linearity; topics are not chosen randomly. The
sequence of topics is essentially the same in all textbooks.

But that doesn't mean the the order is either logical or
pedagogically correct. Mostly the order of most textbooks today is
historical, in the sense that "that's the way it's been done since
time immemorial, so we're not going to rock that boat." Several
altered topics orders have been tried, notably the Berkeley physics
series and Chabay and Sherwood's more recent effort, but none of them
has changed the preference for the traditional approach.

I know that this is a rather radical shift from the original thread,
but linearity doesn't imply logic, and, while a written text does
tend to imply linearity, ot doesn't necessarily imply logic of order
and so may well not make the subject any clearer to the confused
student. JD is correct in how he portrays the progress of
knowledge--from the known to the unknown--but there are many things
known that can serve as stating points and many routes from there to
the unknown, some more productive than others.