Re: [Phys-l] Independent Variables

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

Unfortunately some of these concepts are extremely difficult for lower level
thinkers.  But examples and teacher discussion will not do the job.  Instead
a learning cycle approach with guided inquiry on the front end is much
better.  It has to be done over and over again with various experiments.

Voting schemes, a la Mazur, where the situation is proposed on the board,
and students vote on it can be very helpful.  As a matter of fact students
should brain storm the variables in a physical situation and vote on the
roles of the variables before an experiment.

Incidentally this is precisely where most physics classes fall down.  By
lecturing and using the usual cookbook experiments students never learn to
design experiments in any fashion.  But this is what the syllabus is asking
for, design of experiments.  And it can not be learned by the traditional
methods.  According to most accounts Modeling is much more successful at
doing this, but probably Workshop Physics would also have a higher success
rate.

John M. Clement
Houston, TX

> Ludwik,
>
> you wrote
>
> > > Why do you really want to deal with this issue?
> > > Ludwik Kowalski
>
> Not a bad question!  The syllabus that I teach states,
>
> "A student:  justifies the appropriateness of a particular investigation
> plan:
>
> 11.2 plan first-hand investigations to:
> a) demonstrate the use of the terms 'dependent' and 'independent' to
> describe variables involved in the investigation
> b) identify variables that needed to be kept constant, develop strategies
> to ensure that these variables are kept constant,
> and demonstrate the use of a control"
>
> It is highly likely that these concepts will be tested in some form or
> other and so I have some concern about whether my students can meet the
> syllabus requirements.  The wording of the syllabus also means that I
> cannot use substitute terminology except as an explanatory note, as the
> students will be tested using the syllabus language.  The final
> examination
> is a state test that I have no control over.
>
> Despite using some examples and discussing "cause and effect", a number of
> students still identify the variables back to front.  That is, they are
> calling the dependent variable "independent" and the independent variable
> "dependent".