Tuesday, January 21, 2014

Quick Curriculum Note: Introducing Polar Coordinates

I introduced polar coordinates today by blindfolding one student at a time, sending her out of the room, and drawing a point on the blackboard. While the student was out, I picked someone to guide the blindfolded kid to the point. They were allowed one sentence. I brought the kid in, put her finger at the center of the board, and then she got her instructions.

Roughly speaking, there were two types of directions:
  1. "Take 5 steps to the right, and then move your finger up a foot."
  2. "Move your finger diagonally from the center for a foot."
There's some technique involved in picking points that will provoke the sorts of responses you'll want. To get talk of "diagonals," keep your point near the center of the board so that no steps are really involved. (Why? It's harder to measure inches than steps, so kids go for directions and angles.)

3 comments:

  1. I think this is a brilliant idea! I think another way you could modify it would be to make a mark on the floor and have the students direct the blindfolded student to the mark.

    This could force them to use words like "rotate"

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  2. I tried a similar conversation with respect to vector notation once.I was not clever enough to think of the blindfolds, but I did ask to describe how to get from point A to point B. I was surprised by how reluctant my students were to talk about directions like 5 left and 3 up. This was a struggle, they wanted to talk about angles which would have been great for a polar chat. I wish I had remembered that experience about two weeks ago when my Calc gang tackled polars.

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