In my college trig class I’ve been hinting at the unit circle for a while. Earlier this week, students learned the angles of the unit circle. Today, the coordinates were introduced. I used an idea from an article given to me by the one and only @veganmathbeagle. The article is from the February 2014 article of the Mathematics Teacher, My Favorite Lesson: the Human Unit Circle submitted by Maureen MacInnis.
So, I wanted to do this outside in the fresh air with some sidewalk chalk, but this winter (#worstwinterever) would not allow that. (The parking lot was an ice skating rink this morning.) Thankfully, we have a large locker commons area.
I wrote up 32 cards, one for each x- and y-coordinate on the unit circle (x’s pink and y’s blue.) Students picked up 1-2 cards on the way to the commons and were instructed to “find their match” and “plot the ordered pair” on the coordinate grid taped to the floor. After some struggling (and remembering the special right triangles we solved for warm up), they successfully re-created the unit circle. Success.
Then we made like Autobots and rolled out… the x- and y-coordinates to show the cosine and sine curves.