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Hello, reader! If you intend to post a link to this blog on Twitter, be aware that for utterly mysterious reasons, Twitter thinks this blog is spam, and will prevent you from linking to it. Here's a workaround: change the .com in the address to .ca. I call it the "Maple Leaf Loophole." And thanks for sharing!

Tuesday, June 9, 2009

Target Practice

Ever see a student "graph" something by obviously just sort of copying the general shape he sees on his graphing calculator window? Come on, you know you have. Making a nice graph is a tedious procedure for an adolescent. Invariably someone is just going to wing it.

Exasperated with saying "plot points and draw a smooth curve" over and over, I hit on an analogy that sticks. I've never seen such pretty hand-drawn graphs as this year.

This is pretty famous on the Internet, and maybe you have seen it:


It is supposedly located in the men's bathroom in Amsterdam's Schiphol Airport. See the irregular black spot? That's a housefly painted on the porcelain.


Why on Earth would they do that? Because your aim improves when you have a target. The flies keep the bathroom cleaner for longer. In my search for images, I even found that a company is marketing a sticker called "the urinal fly."

What this has to do with graphing, of course, is in my exhortation for students to plot points before sketching a curve. After telling the story, now I can say, "Remember the urinal flies in Amsterdam? Give yourself a target." From my notes:

Now that is some explicit direct instruction! I'm a fan of the book Made to Stick, but aside from the six key principles simplicity, unexpectedness, concreteness, credibility, emotions and stories, I think they should add a principle for communicating with teenagers: grossness.

Ooh! Maybe next time I will find some housefly clipart in the Smart Notebook gallery and use them to plot points.