Your Friday Five

Here are five activities authored by Desmos users, polished by Desmos Teaching Faculty, and recently added to the search pool. (Plus one bonus activity!)

Crazy Conics Can Create Creativity

At Desmos, we have a soft spot in our hearts for tasks with multiple right answers; the opportunities for creative minds to express their alternative viewpoints. We are also fond of needless alliteration. In both of these spirits, Richard Seitz brings us this delightful precalculus activity that challenges students to graph five conic sections—each going through their choice of exactly one of two points.

Introduction to Parallel Lines

Speaking of creativity (but not alliteration), remember the name Bob Lochel. This is a teacher who is going places—and taking the rest of us along with him, hopefully. In this activity, he takes us (and by us, I mean students and teachers of algebra and geometry) on a sweeping tour of Philadelphia and the coordinate plane. (Actually, considering the weather impending there, it’d better be a street-sweeping tour….or a snow-plowing tour…)

Anyway, y=mx+b, sliders, hidden folders…Bob brings this all to bear in service of summoning slopes. Perhaps he’ll consider changing his name to Lucky?

The Discriminant of a Quadratic Function

Mrs. Belman focuses her attention like a laser on the discriminant of a quadratic function. Using hidden folders and graph exhibits, this activity has students manipulate the discriminant, and then notice what happens to the roots. Conjectures are made and tested. Math happens.

Maybe you and your class will get so fired up about discriminants that you’ll want to generalize to the discriminant of a cubic (did you even know cubics HAD discriminants?) If so, Shelley Carranza has just the ticket … er activity…for you.

Polygon Challenges

Hidden folders are key for Paul Jorgens’s Polygon Challenges. Here’s a triangle, Paul challenges his (and your) Algebra students, I bet you’ll enjoy drawing it and coloring it in using inequalities and domain restrictions!

Nice work, Paul. How about throwing a few hexagons in the mix next time?

If you want to add hexagons (or anything else!), just duplicate Paul’s lesson, and edit your new version until it’s the lesson of your dreams! (Instructions for duplicating existing activities are available here.)

Correlation and Regression

Finally, Andrew Knauft asks the question, What is the effect of a single point on a correlation coefficient? Then through the magic of movable points, he challenges students to explore several possibilities and to answer that question for themselves.

File these five (plus one) activities away wherever you keep your lesson-planning ideas, and report back to us on how they go.