Quadratic Motion Project

Math 2 is starting a unit about quadratics. Eventually they’ll be doing the standard solving quadratics stuff but first we’re familiarizing ourselves with parabolas. I remembered seeing this awesome art installation and wanted to try and recreate it. After all, whenever something gets thrown in the air, its motion is quadratic – that’s just math! Theirs didn’t turn out quite the same as the ones at the art museum, but we achieved the intended effect.

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I’m not sure what materials they had to work with at the Mustang Art Gallery, but in my class we were taping ping-pong balls to fishing line and dowel rods. There were some pitfalls with things getting tangled and un-taped, but my favorite mistakes were a little bit more process-oriented. To figure out the placement of the ping-pong balls, students plotted their quadratics using some type of grapher, either a calculator or Geogebra. I told them to decide what y-value the dowel rod was and find the distance from that to each point. This one has the dowel rod at y=5:

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Geogebra will just measure that distance for you. You can also just subtract whatever the point is from whatever the dowel rod is, which led to this interesting mistake here – can you figure it out?

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I think that the 2 points that should have been farther down were where the parabola crossed to be under the x-axis. For the example above, it’s pretty clear that 5 – 4 = 1 [C], and 5 – 2 = 3 [D]. It’s also entirely possible to get 5 – -2 = 3 rather than 7 [A].

The visual should make it clear that the math is off, but the frustration inherent in re-taping may have been a disincentive in fixing it.

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3 thoughts on “Quadratic Motion Project

  1. I love this project! I wish I could come to class with your students!! I can’t believe how cool this whole idea is! I’m going to have to look at all the other installations Ana Soler has done—I’m now a fan!
    Would it work with styrofoam balls like the ones we use for Christmas decorations? Then you could thread the fishing line through the ball with a needle and tie a loop around the ball to position it, instead of taping it. I may have to try this at home!!

    • Thanks : ) The original installation is amazing, I’m sure she’s worth looking into. Styrofoam would be so much better, I will definitely try that next year – poor kids worked so hard only to watch the little ping-pong balls drop to the floor! Thanks for the idea.

  2. Pingback: Arts and Sciences Festival | Multiple Factors

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