Thursday, October 21, 2010

Talk about Algebra: Variable Types and the Mythbusters

First:  I did remind students not to try anything from this video at home.  I said it, they said it, I said it again.

Now, on with the discussion.

Due to the MEAP testing this week,* some classes got a little off from others.  We did our review as planned in 6th hour but with a little extra time and many many student questions on Dependent vs Independent variables I thought it was time to tap my favorite TV Show:  Mythbusters.

The myth we watched and discussed was one that had to do with how much of a fire ball would be created by pouring water onto a grease fire.  The Mythbusters were experimenting with different materials, different pans, and different ammounts of water with the intent to try to create the largest ball of fire possible.  This worked prefectly with our discussions of Independent and Dependent variables in class.

For example, in the "mini" experiement (linked below) they varied the size and shape of the pan to see what was the effect on the fireball.  In this case the "Shape of the Pan" is the Independent Variable (the input) and the fireball height was the Dependent Variable (the output).  If we were to draw a graph, we'd plot the shape along the bottom of the graph, and the height of the graph, convienently, would be along the side, literally showing the height.

Now to be fair, Domain and Range is problematic for students as well.  Domain is the set of values for the Independent Variable, and Range is the set of values for the Dependent.  For this experiment it'd look like this:

D = {wok, sauce pan, stovepipe}
R = {20ft, 22 ft}  (or some similar numbers)

*I never understood why the MEAP didn't liscence the Road Runner as it's mascot.

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