It’s been a while since I’ve blogged about a math-specific activity.  But today, I spent the better part of 5 hours creating a Polygraph Activity with scatter plots on Desmos, and it was a ton of crazy math fun.  Here is the link if you’d like to use it. 

It’s kind of like the game Guess Who, but with mathematical concepts like parabolas, quadrilaterals, and systems of equations.  It’s relatively easy to make one of these activities, but incredibly complex and time-consuming to create a good one.

Christopher confirmed my inclination:

https://twitter.com/Trianglemancsd/status/626896794782408705

Bob and Michael had some helpful thoughts:

Here’s what I came up with for my scatter plots:

 

I had my husband field test it for me.  He used language like “mostly linear” when eliminating graphs but then seemed to focus on how many points are in each quadrant.  I took out the axes to see if that solves the problem but I’m worried that might make the graphs indistinguishable to students.

 

What I learned:

• The Math:  By first experimenting on StatKey (thanks @rockychat3), I was able to determine the effect on the line of best fit when maneuvering points.
• The Logistics:  The only window available is -5 to 5.  I had to edit most of my graphs to fit in that space.  Also, intermediate saving is not currently available so ensuring your graph inputs are ready to go is helpful.
• The People: I’m never short of completely humbled when I reach out for help with something on twitter.  Thank you everyone for your input.