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[Phys-L] Re: Goals of the Introductory Course

On 03/23/05 15:00, Joseph Bellina wrote:
Sadly, I don't believe the ability to solve a problem or set of
problems, no matter has carefully crafted, will tell you if students
understand the content.

That is self-contradictory.

No, it is not because understanding content does not imply the ability to do
problems. One can understand NTNs 3rd law and still not be able to access
it when needed to do a problem. See Mehl's thesis for evidence.

I can't think of a "concept" that means anything
outside the context of using the concept to solve
problems ... preferably real-world problems, as opposed
plug-and-chug make-work problems.

There is lots of data, not just the FCI which
strongly suggests that students can solve the problems at the end of the
chapter and not understand the conceptual content.

That's OK, because it accuses only the end-of-chapter
problems, not problems in general.

The FCI is nothing more than a set of "carefully crafted"
problems ... yes, different from the usual end-of-chapter
plug-and-chug problems, but still just problems.

Again this is not really true. The FCI provides suggestions for wrong
answers, or distractors, which problems do not inherently do. And the
distractors have been carefully chosen to cleanly discriminate students who
have misconceptions vs students who don't. The FMCE does the same thing,
but by including all possible answers. Problems are inherently far messier
and require skills which do not relate to the concepts.


| What good assessment problems have to avoid is
| being structured exactly like example problems in the
| books--such that memorized algorithms can be used to solve
| them. This takes some effort, but it is not all that
| difficult. Now how well students fare with such questions.......;-(

And these are exactly the kinds of problems that tend to earn you low
marks in student opinion surveys

Well, that depends.

Mostly it depends on whether the students can _handle_
the assessment problems. If they have been trained
on a steady diet of chug-and-plug problems, then
!pow! they get hit with an exam full of problems
that play by different rules, then they really do
have something to complain about.

But remember this sub-thread started from the idea
of working backwards from the exam. Construct an
exam that assesses what you care about. Then
your task is clear: teach them what they need to
know to meet that goal. If the text doesn't teach
them anything but plug-and-chugging, get a better
text, and/or supplement it like crazy.

This brings up the question of how to actually construct such an exam. We
have been constructing exams for generations that we thought were doing
this, and the evidence is that we have failed. This is precisely because we
have been raised on a diet of plug and chug problems, and have not been
taught how to make problems and questions that actually assess what we want
the students to learn. Also physicists in general have not been trained in
the necessary psychology to be able to understand why students are having
problems, and how to remediate them. College teaching has in general been
an amateur activity.

I am not at all convinced that kids intrinsically prefer
plug-and-chug problems and abhor conceptual thinking.
Here's some rough evidence: Go to the neighborhood
bookstore. I predict you will find a goodly number
of _puzzle_ books (far outnumbering the physics books).
These puzzles commonly require out-of-the box thinking.
I think most kids have an innate attraction to this.
Indeed there is reason to suspect that the typical
educational process stifles this. when it should be
encouraging it.

Yes, but how many children actually buy those books? After being given some
of these books, how many children actually work the puzzles? One important
fact to consider is that when children are confronted with a contradictory
event, the common reaction is to dismiss it as an aberration, or even not
perceive that it is contradictory. As a result they do not improve their
thinking ability. By the time students get to college or HS they have been
fed such a huge diet of facts many of which were rote memorized and do not
make sense that they will approach physics that way. One of my students
asked me if I was serious about having a course where rote memorization and
forgetting after the test was not going to be rewarded. He got the point
and was surprised to encounter a course which was different.

If you want to look at whether students like to think out of the box find
out how many read science fiction, or Scientific American. BTW crossword
puzzles are often not really thinking outside of the box. They actually
have a large set of standard answers and questions that you can learn to

John M. Clement
Houston, TX
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