Re: Beichner's book

[John Clement <clement@HAL-PC.ORG>]

> Hi.
> Well, I'm fully prepared to hear the chins hit the
> desktops and the whispers of "Joe's an idiot" when I
> say this, but I don't care. Here goes. Traditional
> kinematics has GOT to go! It's the "bane of introductory
> physics instruction" (Paul Hewitt's quote, not mine). It's
> boring to teach, and it's more boring to sit through as a
> student. There' s no useful physics there either (cue the
> dropping chins). All of the results of traditional
> kinematics can be derive much more elegantly from
> conservation principles. Break with tradition and trash
> traditional kinematics and start with dynamics from day
> one.

Obviously Joe is not an idiot, but there are some things that have to be
considered.  Being able to derive results by other means does not mean that
students actually understand the results.  There is some evidence that
students have to understand acceleration well before they can understand the
idea of force.  Dewey can provide data for this.  As a matter of fact you
can not assume, because the students are budding engineers that they
understand position, velocity, or acceleration.  The fact that rate of
change is "taught" in calculus does not mean that they understand or can
apply it.  I might make an exception for "Workshop Calculus", a
collaboration with Priscialla Laws.  I heard she copyrighted the word
Workshop.

Worse yet some of the students will not be able to reliably apply
proportional reasoning.  This will presumably be a minority, but there will
still be some.  I agree with John that having a section with just
underpinnings is probably not wise.  The ideas in that section should be
judiciously brought out when they are needed and well motivated.

BTW while Hewett is a wonderful author and illustrator, there is no evidence
that courses based on his books have higher FCI/FMCE gain than other
traditional courses.  I have some reports that his books achieve
conventionally low gain. It may be possible that he achieves high gain in
his own courses, but alas he has not published any gain figures.    His
comment is correct, but it may be a necessary bane.  There is to my
knowledge currently no data that shows high gain for courses which omit the
traditional kinematics, and all courses that do achieve high gain include
kinematics.  I would say that omitting kinematics would be a gamble.  It may
be possible to move it to a different spot in the sequence, but that is of
unknown benefit.  Without trying the sequence in a course it is impossible
to judge any possible merit.

I would be tempted to keep a more traditional sequence with interactions and
force following kinematics because they mesh so well.  On the other hand
momentum might work if a somewhat historical treatment is used.  In either
case interactions need to be considered as possibly a separate section.
Really in the end what counts is how the sections fit together and it is
impossible to judge this until each section is written.

In a sense a text is uncharted territory because there are no research
comparisons between just texts in physics.  All of the comparisons are
between activity based courses or interactive lectures and conventional
courses.  The only way to find out if the book works is to field test it
with various teachers who report their pre and post test data.  The best
information for effectiveness of texts can be found in JRST.  There have
been a number of studies involving particular types of texts, but I have
only read some of them.  The one tidbit that I do have is that refutational
text can be effective in promoting conceptual gain.  I would also carefully
examine "Minds on Physics" because it apparently is capable of promoting
expert like problem solving.

John M. Clement
Houston, TX