# Monthly Archives: April 2015

## 3D Graphing

I saw this cool idea as an intro to graphing. The problem for me is that I switch between classrooms almost every period of the day, and even my Precalculus classes are in different classrooms!

I tell my students (especially my Chemistry & Physics students) that I’m not a science teacher–I’m a math teacher pretending to be a science teacher. So when I see ring stands, I don’t see a tool that goes along with a Bunsen burner or a titration set. Instead, I see a tool to help students understand 3D!!

I gave each student their own ring stand and device to attach to the ring stand (either a test tube holder or ring), and I gave them an equation: x+y+5z=0. We talked about whose ring stand represented which x & y values, and they figured out the z value from their values and the equation.

After attaching the test-tube holder at that z-value, we spread out the ring stands in their appropriate positions, and I tied string around the test tube holders to show how the equation gives a plane.

I placed paper on the string to help them view the plane even further.

We then graphed a second equation answer the question “what if I made the y value negative??” Our equation: x-y+5z=0. Our result is the blue paper.

This model helped them understand that the planes intersect in a straight line. Next up we need to figure out what that line is using our system of equations!

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