Just how fabulous is Desmos.
Following up on last Friday’s lesson, I had the kids create their own “Des-man” on Desmos. I showed them these simple sketches and gave them the minimum requirements:
The face and mouth must be parabolas.
The eyes and nose must be linear equations.
Not only did this reinforce concepts like slope, y-intercept, and coefficients, but it also gave us a chance to talk about domain and range in a natural, visual way.
Here are some things I heard around the room:
Oh, I get this now! I see what changing this number does!
Oops, I made his face too wide!
His smile is crooked. But I think I’ll leave it because he looks cool that way.
Ha! I see my mistake—I said x had to be greater than 4 but less than 2. Silly me.
I want the eyes to be oval shaped. My plan is to make two parabolas opening into each other.
Can we work on this in 6th period too?
When I saw two students had made circles for faces, I knew they’d pulled those from the Desmos gallery—since we haven’t learned circle equations (and won’t in Algebra 1). I reminded them of the minimum requirements but told the class they were welcome to copy and modify equations to add other features—like hair or facial hair.
(I said whiskers, and Lexi corrected me: “Whiskers? On a man? You mean beard or mustache?” People don’t have whiskers? Good to know.)
I made my own Des-man with elliptical eyes and tweeted it. The good folks at Desmos responded. So cool.
This activity gave us a lot of mileage. When instruction is minimal and student engagement is high, you know something good is happening.
And if you missed it, check out the launch of Daily Desmos, brought to us by Michael Fenton and inspired by Dan Anderson. It’s about three weeks old now.