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Re: [Phys-l] Graphing algebraic equations



This problem starts in the high school where the math teacher requires a graphing calculator but invariably fails to instruct them how to interpret the graphs they get. Students never have to actually draw a graph until they get to my physics class where they have to draw the resulting data on graph paper for some newtonian mechanics lab, such as displacement v time or velocity v time and they can't figure out which variable goes on the x axis and which goes on the y axis. They eventually can place the *dots* on the graph, but then can't figure out how to draw the curve. (They want to connect all the dots even though actual data often doesn't follow a pure curved pattern. Then I bring out "Mimi and Fifi", my French curves, and teach them how to show a smooth best fit curve. They have never seen a French Curve set before and probably never will, because when they go to the math class again they are right back to the calculators. They also cannot interpret or interpolate from the given curve and often can't place the proper interval of data on the axes. (In the beginning they all want to put the actual data numbers which gives a nice straight line) In the end, they think I am a throwback and that they will probably never have to do what I have instructed about graphing. So, they get to you and have become addicted to the easy way out... using the caucluator and the heck with what it all means!.

Marty

ps: BTW, I tell them that in high school physics I the only calculator they really need is a $12 TI-30. Most of them can't use 99% of the functions on the TI-85's anyway!


On Mar 22, 2010, at 1:19 PM, Dr. Richard Tarara wrote:

Are other people seeing problems with this--students ability to sketch
graphs of algebraic expressions? This year is the worst I've seen. The
context is primarily in doing Gauss' Law for spheres and cylinders and
wanting a field versus distance graph. I'm getting a lot of nonesense even
after we've done numerous examples (and pure gibberish the first time this
is asked). [We're talking about Chemistry and Engineering students with
pretty solid calculus backgrounds.] I'm wondering if this might not be
partly due to graphing calculators--they've graphed many functions but never
internalized what shapes go with what functions. Again--is this an
isolated observance or are others seeing this too?

Rick

***************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN
rtarara@saintmarys.edu
******************************
Free Physics Software
New multi-input energy simulator--plays similar to the Montana State analog
computer.
www.saintmarys.edu/~rtarara/software.html
*******************************

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