"There is no one way"

Wednesday, March 17, 2010

Kinesthetic Radians

(Previous kinesthetic posts: Pascal's Triangle, Graphing, Distance.)

If radians are introduced strictly with a formula, the meaning of the word is difficult to grasp for many students. Some years ago, I learned two tricks from a colleague, which I'll share here:

- Tell students that "radian" is short for "radius angle".

- A one-minute kinesthetic activity: ask students to pair up with someone of roughly the same height. Student O will be the center of the circle, and stretch out an arm, which will be the radius. Student P will stand at that distance from O, and hold an arm out in a curvy way along the (unfortunately invisible) circle. Student O then stretches out the other arm towards student P's hand, thereby showing a central angle of one radian. (Of course, the point is not accuracy, which would be impossible to achieve, but to hammer home the point that a radian is a radius angle.)

If you have other ideas for kinesthetic activities, I'd love to hear them!

--Henri

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