Thursday, December 19, 2013

Service Learning - Terracycling meets Math

At my school I am in charge of all of the school's terracycling. If you're not familiar with terracycling, check it out! The down and dirty of it though is that this company takes things that normally couldn't be recycled and "upcycles" them into new products. AND they pay you for the trash. My school collects juice pouches, empty glue sticks & bottles, empty tape dispensers, Solo cups, used toothbrushes, floss containers and toothpaste tubes, and with the help of Diane over at Fifth in the Middle, we collect used writing tools (markers, pens, etc.) 

It's a big job! All of the waste needs to be sorted and packaged for shipping. But the good people at Terracycle want to receive the waste in batches that meet minimum shipping requirements. Each item on our list has different requirements. So I posed a seemingly simple "exemplar's style" math problem to my kids..."How many of _____ does it take to equal the minimum shipping requirements?" I provided scales, pencil and paper, and waste products, they did the rest. 

If you haven't heard of the Exemplar's math program, I'll sum it up. It's basically a way of teaching kids to solve complicated multi-step word problems. Kids are expected to use pictures (diagrams), numbers, AND words when showing their work. Their work can be assessed by the complexity of their answers and the method they used to solve the given problem. 

This problem required them to figure out that they aren't going to be able to just weigh out 21 pounds of Capri-sun pouches. Especially because the scales I gave them measured in either grams or ounces. They needed first to determine the conversion between the different units to pounds. Once they did that they basically determined a ratio for each item (10 pouches = 2 oz.) and went from there to determine how many units it took to make a pound, and finally the number of pounds for the shipping requirement of the item. Phwew!

I had the kids write their numbers anonymously under the different headings to see how close the answers were. We had a great discussion about all of the factors that might have caused different groups to get slightly different (or in one case a VERY different) answers. We canceled out the unreasonable answers and then found the mean.

We decided those would be reasonable amounts to collect before checking the weight to see if we'd collected enough to ship. We agreed that this would be an excellent example of when you'd use rounding up to be on the safe side. 

It was awesome as a teacher to have my kids working together on the solution to a real life problem, while having them critically thinking and doing advanced math skills. Multiplication, division, ratios, finding the mean...these are 3rd graders we're talking about. They didn't have calculators, and they didn't complain even ONCE about doing the math. They were invested in discovering the answers. They need to know how much trash to collect before we can ship it after all!

My terracycling service learning project doesn't stop here though. Later in the year we'll determine how much waste we shipped, how much we got paid, and then we'll write persuasive pieces trying to convince each other how we should spend the money on helping various charities. All while helping the environment! 

What service learning projects do you have going on in your schools? I'd love to hear about them!

I hope everyone has a wonderful holiday break!


  1. I love this! Such great real-world problem solving! Let me know if you need more labels :) Hopefully you'll get the check for the June ones soon!

  2. I love this! I must share this with the math teachers at my school!!

    Thanks for sharing this wonderful post!

    Mind Sparks


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