Linear Relationship Project: Modeling the Environmental Impact of a Lifestyle Change

I wanted to create an authentic opportunity for my Algebra students to model something mathematical from their lives. While playing around with a site about carbon emissions from food, I landed on the idea of having everyone model the impact of a lifestyle change on their carbon emissions or their water use. My dream is to have all of their math projects this year focused on the theme of human impact on the environment.

*I did not have as much time to develop this project as I would have liked…it was definitely a bit of an experiment, but, then again, that’s kind of what teaching is, right?

Project Launch:

My students’ 6th and 7th grade science teachers were very passionate about climate change, so I knew they were well-versed in the idea of greenhouse gases.

I introduced the project with the following prompt and gave each kid an index card to write on. After a few minutes, many of them shared their questions out loud.

Some questions:

How will we use math to study human impact?

What will the units of measurement be?

I wonder if humans have a more positive or negative impact on the environment.

I wonder how many animals have gone extinct.

Next, I asked them to spend 8 minutes or so looking over the graphs on this website which display a wide variety of data about CO2 emissions and to be prepared to share what they noticed or learned.

Our discussion about the graphs highlighted the disproportionate impact America has had on global carbon emissions, which lead perfectly to the project:

I explained that I wanted them to pick a lifestyle change that they could realistically make that would decrease either their carbon emissions or their water usage. (California is in a drought and we’ve been asked to reduce our water use by 15%.)

Students brainstormed, in pairs and then as a class, by creating webs about how they contribute to greenhouse gas emissions and use water.

Lastly, everyone filled out an index card with their idea for a lifestyle change that they could investigate. I included my example.

Day 2:

I did a think-aloud to model my process for developing my model. It went something like this: “So I want to figure out how much of an impact it will make if I bike to work three days a week instead of driving every day. What do you think I might need to do to figure this out?” Kids shared a few ideas, like figuring out how much gas I use, and how far away school is, and what the carbon emissions are for driving. I continued, “Yes, I think you are right about that. Hm, I also have consider all of the other ways that I contribute to carbon emissions, so that I can see the big picture and compare the reduction from biking to the other carbon emissions I’m responsible for.”

I explained that I did some research and found this pie chart. I decided that to keep my model from getting too complicated, I would only include emissions from travel. I then listed all of the ways that I travel: commuting to work, flying to NY twice a year, errands once per week, and camping trips 2 or 3 times a year.

Next, I did some research on the carbon emissions from flying versus driving and found that planes emit significantly more carbon, so for my model, I chose to focus on my commutes and my flights to the East Coast.

Finally, I shared my two equations and my graph.

The class got to work.

Handout: Students used this handout to help think through and plan their models:

Google Slide Presentation: Then, they completed this slideshow about their lifestyle change.

Here is the project from one of my students. This student, like many others, focused on reducing showering:

Successes/failures and ideas for next time:

While creating the graphic organizer, I really struggled with how much scaffolding to provide for students. I wanted to keep it open-ended so they could truly develop their own way to model the problem, but I also wanted to give the project some structure and hoped to ensure a certain level of success.

Even after seeing their work, I remain a bit torn. I think next time, I would either make the project more open-ended and truly let kids develop their own models – even if they are more simplistic – OR be more clear upfront about how the model should show the impact of the lifestyle change over the course of a year and how the y-intercept should represent the yearly total of other carbon emissions/water use.

Another change I would make is having kids work in groups. It was hard to support so many kids working on such individualized projects. They did help each other, but I wasn’t able to meet with everyone during class.

I think this project has a lot of potential; there are so many rich discussions to have, particularly around the choices we make when creating a model and how we can best interpret our graphs/equations in a real world context.

Please let me know if you do something similar and have or make a more awesome version.

Always happy to hear from readers!