Desmos makes noise!

Desmos makes noise. I let my class know that I remember making graphs tat could be heard, to help people with visual impairments understand what graphs “look like” but with sound. I had forgotten how to do it, but sure enough my grade 10s figured it out within 5 minutes and were exploring what parabolas sounded like. At this point I knew we could either stick to my lesson plan (and have it be derailed every 30 seconds by a “noisy parabola”) or to just go with it, and explore graphs in a very different way than I had ever done with a class.

We used the graph y=(x+2)(x-5) as our starting point and listened to the graph.

It makes a static noise as it traces part of the graph. We had to replay it a few times to figure out when the sounds changed (static is when the graph is below the x axis, negative y values). It make a brighter sound for part of the graph, we figured out when that happens (positive x values). We then figure out how to make the static sound longer or shorter by changing what’s in the brackets. Students made connections to how the factors control where the parabola crosses the x axis (the goal of my lesson) but achieved in a different way than anticipated.

We looked at how there could be a whole family of parabolas that crossed the x axis at the same spots (we added an “a” value and then used a slider to show how the graph changes as the “a” is positive and negative, big and small, and of course we ended up animating it).

We made connections between factored form and standard form, and looked at what information from each equation is shown on the graphs.

There were some connections made between how factored and standard form are different ways of describing the same relationship, similar to how we can describe area or dimensions of an algebra tile rectangle.