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Re: [Phys-l] "Looking up" results on a graph



On 01/12/2012 01:48 PM, Folkerts, Timothy J wrote:
Students (especially at high school or lower college levels) often have
a hard time deciding which variable to plot along the bottom of a graph.
A very simple memory aid suddenly occurred to me today -- "looking up"
the answer on the graph.

On 1/12/2012 8:21 PM, John Denker wrote:
There is a fundamental reason why it is hard for students
(or anybody else) to decide which variable to plot in which
direction. The reason is: In most cases, it doesn't matter!

True. However, I think it's useful for students to learn the convention
of plotting the independent variable on the horizontal axis and the
dependent on the vertical axis. The science doesn't care how we
represent it, but following the convention makes it easier to
communicate our findings with each other.

Part of the reason I don't personally need a mnemonic for which axis is
which is because pretty much every plot I've ever worked with over
several decades depicts y as a function of x and not the other way
around. I feel that one of my responsibilities is to turn out students
who not only understand the physics, but who can make themselves
understood easily, and part of that involves being able to understand
and follow the conventions.

Conventions may be broken, but it is generally unwise to do so
capriciously or out of ignorance.

--
Jeff Bigler
Lynn English High School, Lynn, MA
"Magic" is what we call Science before we understand it.