Saturday, January 12, 2008

Human Ellipse

Earlier in this winter January week in Texas with 60 - 70 temperatures, I was staring out my classroom window and remembering one event in my high school years. I don't remember the class/teacher/activity-purpose. All I remember is that one day we got to go OUTSIDE during class. This memory has lasted 26 years or so. So I related this to my 6th period class, and after their clamoring I promised we'd do something mathy outside some day.

Well, we started conic sections this week, and Friday was going to be a wee bit disrupted from other things, so I thought we'd go outside for part of the class and build a human ellipse to start off the unit. I had a long stretch of nylon yellow rope that I tied into a loop. Two students were the foci, one student was the pencil. Those 3 were inside the loop. The foci stayed fixed, and the "pencil" moved around while keeping the rope taut. The rest of the students were the "pencil traces" and moved to the "pencil's" spot after she left it.

We made 3 or so ellipses and I prompted them first each time about what they thought would happen if the foci moved in or out. We discussed circles. We got some sun. I think they have a sense of the ellipse properties now for when we get to them.

5 comments:

  1. MathTeacher446:45 PM

    This post was so funny because just this past week I discussed building a human parabola using the defintion of the points being the same distance from a focus and directrix. Maybe I'll do it next year....I doubt we'll be going outside in MA though! :)

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  2. Anonymous6:52 PM

    Oooh! I tried to think how to do that effectively, and didn't follow through with it. ... Can you do it in a hallway or something? I'm guessing y'all are not wearing shorts and t-shirts now.

    Ms. Cookie

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  3. MathTeacher447:25 AM

    I was going to use my room if I could....or maybe next year I'll try for the gym. I think maybe I would use the scenario of a back wall being the line and me being a fixed point and putting students equidistant from both. I ended up doing a smaller scale demo on the white board with a car parked at the fixed point (one kid asked if it was a ford focus, which I loved!) a street (the line) that their friend would park somewhere on. If both people walked the same distance to meet, where are their possible meeting places? The kids thought it was pretty good. Next year I'm going to jazz it up a bit with better car graphics, etc.

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  4. Anonymous10:40 AM

    Ford Focus ... tee hee. That's smart doing it inside, then maybe if your tiles are uniformly 12"x12" you could use that as a type of ruler.

    Ms. Cookie

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  5. Ahh this is so neat!

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