# Estimating OUR Carbon Footprint

## Summary

This is a three-part algebra activity focusing on food-related carbon dioxide emissions. Part 1 of the activity sets the context by examining how dietary choices impact carbon emissions. Part 2 explores the impact of population growth and per capita carbon emissions on emissions at the national level. Part 3 examines how freezing national carbon emissions at the 2015 level impacts per capita consumption when the population continues to grow.

## Learning Goals

This activity exposes students to key quantitative reasoning and mathematical modeling concepts and skills such as interpreting units, computing with large numbers, making and using assumptions to derive mathematical models, making projections, and considering the validity of model results in context.

It also highlights how mathematics can be used to explore current issues of civic importance and make decisions that have direct impacts in the lives of people.

## Context for Use

This activity was written for use in high school algebra and pre-calculus courses. It is also appropriate for use in introductory-level college mathematics courses such as college algebra or mathematics for liberal arts.

## Description and Teaching Materials

The entire activity (Parts 1-3) consists of a set of Student Handouts (Acrobat (PDF) 463kB Mar6 15). The activity is self-contained within these worksheets and includes references for all data used in the activity.

## Teaching Notes and Tips

**Time Requirements:**

Parts 1 and 2 of the activity together present the main ideas of the activity and instructors may choose to have their students work only these two parts. Based on our experience using this activity in sections of college algebra, Parts 1 and 2 together require approximately one hour of class time when students work in small groups of 3-4 students. Part 3 of the activity is an optional extension which requires approximately an additional one hour of class time.

**Structuring In-Class and Out-of-Class Work:**

Although all three parts of the activity may be worked in class, instructors may assign any or all parts as homework. For example, an instructor might assign Part 1 as a pre-class writing assignment, Part 2 as an in-class activity, and Part 3 as a post-class homework assignment.

## Assessment

Students will make mathematical mistakes in the course of working through the activity. If not addressed some mistakes will lead to significantly different outcomes, causing students to misunderstand key aspects of carbon footprints. For this reason, instructors need to consider carefully how they will assess their students' learning.

Instructors are encouraged to incorporate both formative and summative assessments as students are working through the activity. For example, students might give short oral reports to the class summarizing their work on different segments of the activity to obtain feedback from peers and instructor. If the activities are being completed as in-class group activities, instructors can also visit each group periodically, ask students to summarize their most recent findings, and give them opportunities to ask questions. Instructors might consider allowing students to revise their incorrect work for partial credit. If time permits, instructors are encouraged to have a concluding discussion. Students may report out to the class on their findings, summarize the key points or questions raised in the activity, or discuss possible extensions of the activity.