# Geometry: Which Pasta Does Mueller’s Want You to Buy?

So, I’m walking through Publix about a week or two ago, and I noticed this:

Mueller’s makes both regular length and pot-sized pasta.  Since I’m giving a presentation next week involving problem based instruction in the geometry classroom, I saw this as an opportunity excuse to develop a new geometry lesson (I really miss teaching geometry sometimes).  So, I started talking to my co-presenter and asked her to help me develop something useful for us to present with.

My co-presenter is a first year teacher and I quickly found out that she’s not very familiar or comfortable with problem based instruction.  Since she’s my mentee, I thought it would be a good idea to develop a lesson with her and then team teach in her classroom.

So we started with the question: Which would Mueller’s rather you purchase?

Her student’s sat there and started at me for a few moments.  I encouraged them to talk with each other and figure out how they could answer the question.  Two minutes later, we discussed what they wanted to compare and what questions they had for us:

They were insightful.  The only thing they didn’t ask about (that I was expecting) was a question about shipping.  My mentee and I quickly steered the conversation toward packaging costs.  So, her students wanted some measurements:

I made up the cardboard cost…maybe I can get Mueller’s to give me that info.

Given that this lesson was given during a point in the curriculum that has nothing to do with surface area, they did okay with calculations.  I was surprised to see that 3 or 4 out of the 8 groups thought that volume was the appropriate measurement to use (rather than going straight to surface area).  After some quick conversations, most were right on track.  Ultimately, the most difficult calculation was converting the cost from square inches to square centimeters.

The calculations bear out that the pot sized pasta is cheaper to package.

I’m encouraged that my mentee is interested in continuing to create lessons like these.  I’m taken back a bit that this isn’t the norm in most classrooms.  I have to find a way to keep encouraging my colleagues to keep bettering themselves and their students.