### July 15-19, 1996 - Swarthmore, Pennsylvania

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## Mathematical Golf

Eric Sasson has written some GSP Sketches to simulate this activity. (Need help in setting up Sketchpad as a helper application for your browser?)

Disguising mathematics as recreation, Wednesday afternoon Mike DeFoe set up some miniature golf greens in the classroom and puttered around for a bit...

Seriously, this is an activity that Mike does in his classroom when studying reflections. The greens were rectangular in shape (using two walls and two boards), and had paper cutouts to indicate the hole and the ball. There were obstacles, so that you had to be creative to get the ball in the hole. In our case, this meant bouncing the ball off two walls in order to maneuver around the obstacle and sink it.

The trick to the whole thing was to figure out where to aim your shot. In class, Mike makes this golf activity one of the questions on the next test, and says that those who want to guess before figuring it out risk losing 10 points if they miss! Very encouraging, I suspect, and keeps the students on the task at hand.

So with string and pieces of paper, we figured out (we hoped!) where we'd have to aim to get the correct bounces off the walls. Once we'd marked a spot on the board, we took turns aiming for the spot (a challenge in and of itself) and seeing if we could make the shot. Some of the groups figured it out fairly quickly and spent their time honing their accuracy. Others spent a lot of time working out the solution and then talking about generalizations.

The illustrations show a couple of ways to approach this.

Mike gave several tips for dealing with this activity in the classroom. One, if you're the teacher and you want to talk, walk around and take all the balls :-) Two, since this is a 5-point question on Mike's test, if a student wings the ball across the room or just hits it really hard, he or she doesn't even get to try that question on the test. And three, beware of floors that aren't level!

- Annie Fetter

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## Method 2

- drawings by Sarah Seastone