You are trying to decide what popcorn containers to select for a school movie night.

For the four types, calculate:
1) Volume
2) Surface Area
3) Cost per Cup of Popcorn (hint: you’ll need to find out some more information).

The challenge: come up with new popcorn containers that hold the same volume but have less surface area (so they cost less to produce).

Authentic Movie Night: The small plastic tub costs \$1.99. It measures 5.25″ across the top and is 5″ tall. The large plastic tub costs \$2.99. It measures 7″ across the top and is 7.25″ tall.

Pop-open Popcorn: These cardboard tubs have dimensions 4″W x 8″H. They come in packages of 100 for \$22.99.

Movie Time Red: This square plastic tub is 7” by 7” and costs \$9.99.

The kids figured out that they had to find the number of cubic inches per cup, so I showed them how to do the conversion by typing it into Google.

Some kids figured out to take the second tub and turn it on its side so that the opening would be on the long side (holding the exact same volume but removing a bunch of the cardboard).

I liked this activity for having students manipulate real-world shapes and present their work in front of others. Some groups in one class didn’t get to this challenge activity because they needed more time practicing volume calculations, so they served as judges for choosing the best modifications to the popcorn boxes.

• ### Marshall Thompson

I like this very much. I am thinking of an extension of this idea where students would be given x amount of square feet of tagboard or poster paper and asked to produce containers from that material. We could grade them on maximizing volume from the surface area (paper) given. Could even grade them on maximizing profit if we set some price parameters…

…you got me thinking…many possibilities…thank you!

• ### Appetite for Instruction

Thanks Marshall! I like the idea of building the containers too, and the profit dimension!

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