Re: [Phys-l] Physics First

["John Clement" <clement@hal-pc.org>]

Unfortunately the term "abstract thinking" is often not well defined.
Abstract thinking abounds even in young children.  Piaget studied specific
tasks which are markers of what he called "formal operational" reasoning,
and these are often absent at ages 10+ and always absent before then.  But
at each age there are types of abstract thinking.  Indeed all thinking is in
a sense abstract because it depends on using pictures you have in your mind,
that you have created.  As a matter of fact memory is very abstract because
the picture you have of an event is actually created by you from a few
facts, and with background filled in by what you think is plausible.

The conceptual physics course should more properly be called a low math
course.  But there is no evidence that the general Hewitt approach actually
improves understanding of physics concepts.  And yes, equations are so
powerful that students learn to just plug in and give answers whether they
make sense or not.

But students are capable of drawing deductions and sharpening their powers
of observation and thinking, even at age 10+.  Shayer & Adey demonstrated
this with Thinking Science, which pushes up students on the Piagetian tasks.

So if you wish to teach kinematics to students in the lower grades, you use
motion maps, graphs, and verbal descriptions, but delay the introduction of
equations until they can solve problems using maps and graphs.  Students in
the lower levels can understand many "abstract" concepts, but they have to
be introduced by suitable labs or simulated experiences.

One of the important factors is getting them to predict answers using the
information they have, before doing experiments.  In other words they have
to use hypothetico-deductive reasoning.  This type of reasoning has been
shown by Lawson to be the basis for most human reasoning.  Indeed he has
confirmation that induction proceeds by application of HD reasoning, so in a
sense induction is not a separate form of reasoning.

The big problem at the lower age is that they will have extreme difficulty
dealing with concepts involving things they can not see even with aid of a
microscope, such a molecules and evolution.  Lawson has shown that there is
a "level" above "formal operational" which is important to understanding
such things.  This is precisely why physics is difficult, because it deals
with things you can not see such as acceleration, force, momentum...
However many of these can be made more "seeable" by such devices as motion
maps.

Indeed there are now reports from the Modelers that students are better
problem solvers if they are first taught to use maps and graphs, and only
later allowed to use equations.  This has also been the focus of the UMPERG
group at U. Mass Amherst, which sadly is now breaking up as various faculty
scatter to other places.

Students us hypothetico-deductive reasoning in everyday life, and then
expect to memorize and regurgitate in math in science.  A good conceptual
physics course needs to break the mindset.  They need to begin to solve
problems using reasoning rather than just following rote procedures.  So
conceptual physics needs to be taught in depth with multiple representations
for a limited number of topics, and not cover the entire canon of physics.

John M. Clement
Houston, TX


> When people say that students are not ready to do abstract thinking as
> Freshmen, then recommend that they take Conceptual Physics as freshmen
> instead of a math-based course, does that sound strange?  (It may be my
> geriatric state of mind.)  Isn't conceptual physics exactly the abstract
> part??  (As opposed to plugging numbers into equations.)  Isn't the
> problem
> we all have teaching physics teaching the concepts??  Because they are
> abstract??  I'm not sure I get this.
>
> Wes