Turn Off the Faucet!: Exploring with Linear Models

Sometimes I still have to tell myself that I'm a math teacher, not just a language arts teacher. But last week it felt for realsies when I wrote my own math lesson plan: a hand washing experiment

Every unit I try to do a hands-on project to reinforce the importance of the math we're learning and to help the students see how much they know. We had just finished a unit on linear models and all of the different things you can predict. A few years ago, we used this to explore the leaky faucets on our campus and to get the school district to replace one. But now we didn't have any leaky faucets, so we needed something new to explore. 

I started exploring all of the different ways we waste energy on a regular basis. Did you know that PG&E has a whole analysis of your bill with energy-saving tips? We looked at YummyMath's lightbulb and toilet activities, but I really wanted something that my seventh graders had power over. And they needed to be able to do it with a sub since I'd be away at a conference. 

Enter hand-washing. Seemed perfect for the amount of sniffles I hear in my class on a daily basis. Did you know that the CDC now recommends that you sing the Happy Birthday Song TWICE through while you scrub your hands? That's a ton of water waste while you scrub your hands! 

My students did a great job exploring this task together and asking each other for help if there was a step that they didn't understand. I'm happy to report that they completed the experiment and the math without me there to guide them. Afterwards, we were able to debrief, and they helped me clarify a few of the different points. As I looked at them, for example, I realized their final measures were in mL, which have very little meaning to them. We decided it would be better to convert it into L or 2L since that's something they can picture a little better. We added a screencast of my favorite way to change between measures in the metric system so we could better understand the data. In addition, they helped me clarify the directions in different places. I can't wait to try it with next year's class! 

Take a look and let me know if you have any advice. And if you decide to use it with your class, let me know what you think!