Using Percent to Reduce Your Carbon Footprint


Jamie Dicks

Unit Title:

Using Percent to Reduce Your Carbon Footprint





Estimated Duration:

16 Days

Unit Activities:

Activity 1: Hook Essential Questions and Guiding Questions

Activity 3: Percent Background Information

Activity 4: Challenge and Post Assessment

Background Knowledge: 

Students need to have an understanding of equations, expressions, and variables.  


July 2014

The Big Idea (including global relevance)

Energy conservation is a topic that is becoming increasingly important as our nonrenewable resources are dwindling and energy costs are going up.  It is imperative that students learn ways to reduce their carbon footprint while also saving money in the process.  As students learn the basics of percentages, they will make calculations, using the percent equation, to discover the cost of various energy conservation practices.  

The Essential Question

How can we decrease our carbon footprint?

Justification for Selection of Content

In 7th grade, students are required to learn the percent equation and make percent calculations, including percent increase and decrease.  Energy conservation is a globally relevant topic that is important to the livelihood of all students which can easily be analyzed using percentages and the percent equation. In addition, energy-saving devices can be tested for effectiveness by calculating percent increase and decrease.  

Unit 5

As seen in the above data, my class has shown lower percentages in above-proficient scores in this category.  This is evidence that this content is something that requires more focus in my classroom.

The Challenge

Design a solar water heater that shows the highest percent increase in temperature.

The Hook

Students will calculate their carbon footprint.  

Teacher's Guiding Questions
  • What is a solar water heater?
  • How do you make a solar water heater?
  • How do you find percents?
  • How do you calculate percent increase?
  • How can we decrease our carbon footprint?
ACS (Real world applications; career connections; societal impact)

A – Energy Conservation

C – Environmental Engineer

S – Reducing your carbon footprint

Engineering Design Process (EDP)

Students will be led through the engineering design process as they design a solar water heater that shows the largest percent increase in water temperature.  

Unit Academic Standard

7.RP.3. Use proportional relationships to solve multistep ratio and percent problems. Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.

Understand that rewriting an expression in different forms in a problem context can shed light on the problem and how the quantities in it are related. For example, a + 0.05a = 1.05a means that “increase by 5%” is the same as “multiply by 1.05.”

Unit Activities

Lesson 1: Hook and Pre-Assessment (2 Days)

Activity 1: Hook, Essential Questions, and Guiding Questions (1 Day)

o    Hook - calculate carbon footprint

Activity 2:Pre-Assessment (1 Day)

(assessment not included due to copyright issues)

o    Pre-Assessment/Survey

Lesson 2: Using Percents (14 Days)

Activity 3: Percents Background Information (8 Days)

Digits 3-1 The percent equation (copyright Pearson) (1 Day)

Digits 3-2 Using the percent equation (copyright Pearson) (1 Day)

o    Additional practice and activity using percents with energy conservation (1 Day)

Digits 3-3 Simple interest (copyright Pearson) (1 Day)

o    Simple interest practice (1 Day)

Digits 3-4 Compound interest (copyright Pearson)  (1 Day)

o    Compound interest practice (1 Day)

Digits 3-5 Percent increase and decrease (copyright Pearson) (1 Day)

Activity 4: The Challenge and Post Assessment (6 Days)

o    Challenge: Create a water heater with the largest percent increase in temperature (3 Days)

Digits 3-6 Markups and markdowns (copyright Pearson) (1 Day)

Digits 3-7 Problem solving(copyright Pearson)  (1 Day)

o    Post-Assessment (1 Day)

Where the CBL and EDP appear in the Unit

Lesson 2 Activity 4


Students often have trouble with the difference between the part and the whole

Students sometimes believe that the percent cannot be over 100 or that the part must be smaller than the whole

Additional Resources
Pre-Unit Assessment Instrument


Post-Unit Assessment Instrument


How to Make This a Hierarchical Unit

In order to make this a high school unit, you could calculate the efficiency of the solar water heater compared to just a container of water sitting outside in the same conditions. Students would have to do higher-level calculations in order to accomplish this. Students could also create systems of equations to see when two different water heaters will reach the exact same temperature. .


Create equations and inequalities in one variable and use them to solve problems.Include equations arising from linear and quadratic functions, and simple rational and exponential functions.


Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales.


Represent constraints by equations or inequalities, and by systems of equations and/or inequalities, and interpret solutions as viable or nonviable options in a modeling context. For example, represent inequalities describing nutritional and cost constraints on combinations of different foods.

How to Make This a Hierarchical Unit

How to Make This a Hierarchical Unit