Re: [Phys-l] Independent Variables

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

> I agree with all who are suggesting it would be best to abandon the
> terms independent variables and dependent variables.  And when John
> Denker advised that "you should gather the villagers, get some torches
> and pitchforks, and march on the state offices" this is certainly what
> needs done.

I don't think there is anything wrong with the terms.  They are used in
math, so using them in physics is not a bad idea.  But the totally rigid
application of rules regarding them is the problem.  There are certainly
rules which are rigid such as "plot A vs B" gives an exact command as to how
to plot data.  The idea that you set some variables and that others respond
is a very important concept that students need to acquire.  I see all too
often that this has not been acquired.  Such students do not understand
equations and that an equation generally has at least 1 variable, and often
more than 1.  So they have trouble even starting an equation.  When you ask
them to write and equation for the velocity, they should at least write V=,
but even that often eludes them.  One wonders what the math teachers are
doing.  Many teachers do not acknowledge that sometimes there is a blurred
distinction between the in/dependent variables, and that graphing rules
based on them can be violated for very good reasons.

As to the state standards, yes, we should get them changed.  But many
textbooks still have the same misconceptions in them, so it is not just the
standards.  Then of course there are the many teachers who take a rigid
point of view with respect to factoids.

Many teachers say, yes, the "scientific method" is not the only one, but it
is a scientific method.  The problem with this is that it is taught as a
series of steps and the students do not experience inquiry.  They still post
it on the wall, despite the fact that I tell them that it is not correct.
However, this idea is also falsely put forth by some of the scientific
literature.  There are many papers which follow the hypothesis, experiment,
conclusion with confirmation/denial of the hypothesis.  The fact that this
sequence may not have been what actually happened in this order is never
evident.

Teachers have been taught this so they continue to promote it.  And of
course there are so many factoids in standard texts that it is much easier
to just test factoids rather than try to promote understanding and inquiry.
One of my favorites is the stress that state standards place on the 3
classes of levers, at the expense of having student develop proportional and
compensational reasoning.

John M. Clement
Houston, TX