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Re: [Phys-l] independent variables, or not



I was having a conversation the other day about this very issue with a middle school teacher who has a PhD in biology. What I found interesting is that this person had never heard of the phrase "plot A vs. B". I've found that my students aren't familiar with the phrase either and just passed it off as poor preparation. However, might it be a phrase only used in physics or only some scientific fields?

Robert A. Cohen, Department of Physics, East Stroudsburg University
570.422.3428 rcohen@esu.edu http://www.esu.edu/~bbq

On 01/13/2012 11:07 AM, LaMontagne, Bob wrote:
Suppose you go to a local stream and measure the temperature and the
speed of flow of the water. A plot of temperature vs time has an
obvious dependent and independent variable - because you are in
control of the time. Likewise for flow speed vs time. But suppose you
decide to plot the two variables temperature and speed of flow against
each other - which is dependent - which is independent?

Unless you have deliberate control over the choice of one of the
variables, I don't really see where dependency and independency enter
the choice of axes. I simply state to my students that the expression
"plot A vs B" has a standard interpretation of A on the vertical axes
and B on the horizontal.