# Desmos Polygraph

I’ve used Polygraph from the Desmos team in my Algebra 1 class twice now. The first time was right after we returned from winter break, with the intention of reviewing vocabulary of linear functions (this was the linear functions version of Polygraph). I didn’t set up the activity very well with my students, so I don’t think they really understood what they were supposed to be doing. They kept picking either the horizontal or vertical lines, so their opponent didn’t really need to do anything to guess the line.

The second time I did Polygraph, we did the parabola version. This was after my introduction to quadratics, which was very heavily focused on graphing. This time, I knew what I needed to say to my students to introduce them to the activity before throwing them in. (One problem – I was waiting for part of the class to finish a quiz, so I didn’t say any of this out loud. I posted it on the board and had them read the instructions.)

First, I introduced it by reminding them of the game “Guess Who” that it’s based on. I reminded them that the object of the game is to stump your partner – you win if they DON’T guess the person you picked! This also means that the person who is asking questions needs to think of good questions to ask, so they can tell similar-looking parabolas apart. I did also explain that my intention for this activity was for them to review the vocabulary that they had learned for parabolas.

Then, while they were playing, I did two things that I think we’re most helpful for achieving my goal of using this activity productively. One: I “kept score” on the board. I wrote the word “Winners” on the board, and recorded a student’s name every time a game ended. If the student did not guess the right parabola, the picker won, and if the student did guess correctly, then the guesser won. Adding this level of competition created an environment when students really wanted to pick graphs that would stump their partner.

Two: I posted a list of Awesome Questions! on the board. I had a blank PowerPoint slide open and typed questions that I saw that used the vocabulary I wanted to see, and were actually helpful for differentiating between graphs. One advantage of this was that I provided some positive feedback to students who were meeting my expectations (without me needing to say anything out loud, as I still had students finishing quizzes). The other major advantage to this strategy was that other students who were struggling had some guidance for what kinds of questions they should be asking. After I posted one of two questions, all of a sudden I had a bunch of students using the direction the parabola opened to help them eliminate a bunch of graphs! They just hadn’t thought of this strategy on their own and needed some assistance.

When I do this activity again (and I do plan to use it a few more times to reinforce the parabola vocabulary that we will continue to be reviewing for most of the semester) I will make sure to introduce the activity with clear expectations, and I think I will use the competitiveness of my students again. I might even offer to use the game to award a quiz score, to help provide even more motivation to “win”. (I didn’t offer any incentive last time, and they were still quite competitive, letting me know when they had won and asking for their names to go on the board. Although next time I think I’ll have them write their own names on the board.) I also really liked what happened when I started highlighting good questions. It never ceases to amaze me how much positive feedback influences my students.

## 3 thoughts on “Desmos Polygraph”

1. Shaun Errichiello

I love using this move: “After I posted one of two questions, all of a sudden I had a bunch of students using the direction the parabola opened to help them eliminate a bunch of graphs! They just hadn’t thought of this strategy on their own and needed some assistance.”

Just wanted to let you know that I am planning this out now and might have forgotten to do this had you not posted it.

2. Patty Stephens

Thanks for sharing your experience! I’m sharing the Polygraph activities with teachers in a PD session on Thursday and will definitely share your suggestions.

3. Joe

I did a lo-fi version with printed cards, for a group of 4-6th graders, and another of 7-9th graders. I found that with each group, after a few rounds, they discovered that you can hone in on the other player’s choice efficiently by focusing on the location of the image on the card. The lesson gravitated to binary search algorithms, and how you can always find an item from among a list of 16 in 4 guesses.

While that was cool, it wasn’t what I was going for. I wanted to see their language for describing the images evolve. And it would feel dogmatic to make it “illegal” to mention the image’s placement on the card – feels like not allowing them to be clever. I ended up having to make up another activity on the spot, that evoked some precision of language.

Anyone else run into this problem?

The next time I do it, I’m going to scramble the images so the order is different for each student, and add the rule that you can’t show your copy of the card during the game.