On June 28 David Dockstader posted this,in the thread on tidal bulges:
"Now the question is what do we do as educators? What do we teach? The tidal
bulge model is useful and does give a kind of a global average of the tides.
It explains pretty well such things as changes in the moons orbit. It is
simple and easy to understand. However, it isn't very useful for planning
kayak trips in coastal areas, and naive reliance on such a simple model could
easily result in death by drowning. When this comes up in intro physics,
astronomy, geology, etc. should we issue a disclaimer and explain that this
simple model is highly modified and complex at the local level and explain
qualitatively some of the factors that create these modifications? I've never
done this, but it does seem like a good idea.
Isn't this a problem with most of what we teach in physics? We present simple
models of ideal situations as if they came from God on gold tablets and spend
very little time of the limitations of these models or the modifications of
these models which may be necessary when trying to apply them in the real
world. In some cases this means we just clutter up kids heads with useless
information, but it also leads to real misconceptions about science...."
Ruth Chabay and Bruce Sherwood are giving a talk at the Summer AAPT meeting
which addresses your question, David. Read their abstract on page 104. It
says that "modeling is the important physics, while the work assigned to
the student is mostly formula manipulation. This contributes to the typical
view that physics consists of a large set of magic formulas." Chabay and
Sherwood say that, rather than our traditional approach of making the
idealizations and approximations for the students, the students themselves
should be engaged in explaining real phenomena in messy contexts. Students
practice this by simplifying real-world situations, by making
approximations and idealizations of real phenomena. Chabay and Sherwood
will give examples of homework problems designed to do this.
The modeling method of high school physics instruction emphasizes student
construction of models from real world phenomena, too. In modeling
instruction, students learn that the solution to a problem is a model, not
a number. The modeling method has been shown to be quite effective, and it
is unifying because the physics course is structured into a small number of
basic models.
So, to sum up, don't make models for the students; rather, guide them into
modeling activities. After all, making models is at the heart of what
scientists do.
Cheers,
Jane
Jane Jackson, Prof. of Physics, Scottsdale Comm.College (on leave)
Box 871504, Dept. of Physics, Arizona State Univ., Tempe, AZ 85287-1504.
phone:(602) 965-8438 fax: 965-7331 e-mail: jane.jackson@asu.edu
Modeling Workshop Project: http://modeling.la.asu.edu/modeling.html