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The Big Energy Gamble

Classroom Activity

Activity Summary
Students conduct an energy audit to determine how much carbon dioxide their family is releasing into the atmosphere and then make recommendations for minimizing their family's carbon footprint.

Learning Objectives
Students will be able to:

  • understand the units of power and energy.

  • determine the cost of running various household appliances.

  • find the amount of carbon dioxide emitted for different types of energy consumption.

  • determine ways of reducing energy consumption and carbon dioxide output.


Multimedia Resources

Additional Materials


Earth is no stranger to climate change. Throughout its history, the planet has undergone periods of warmth and icy cold. There is a growing concern that human activities are contributing to a new breed of climate change that will have devastating effects on the human population.

The problem is an increase in global temperatures, thought to be caused by an increase in greenhouse gases. While these gases—like carbon dioxide, water vapor, and methane—are normally present and necessary to help keep the planet warm, an increase in their concentration is contributing to a rise in global average surface temperatures. Some scientists believe that this increase is due to greenhouse gases produced through human activities.

In the United States, three-quarters of human-generated greenhouse gas emissions are due to energy use, mostly in the form of carbon dioxide emissions from burning fossil fuels. According to the U.S. Environmental Protection Agency, more than half the energy-related emissions comes from large stationary sources such as power plants, while about a third comes from transportation. The U.S. government is working to slow the growth of emissions and to encourage other countries to do the same.

Students and their families can make changes in their own lives and habits to slow the growth of emissions in the United States. In this activity, students consider how much energy they use every month and what they might do to reduce their own CO2 output.


Before the Lesson

  1. Bookmark the NOVA Program Clips page.

  2. Make copies of the Your Energy Audit and Carbon Dioxide Emission Inventory handouts for each student.

The Lesson

  1. Play the video clip from NOVA's "The Big Energy Gamble" program. The clip features the efforts of actor Ed Begley and science educator Bill Nye to make their houses more energy efficient. After students have viewed the clip, ask them if they have ever heard the term "going green." Explain that going green means taking steps to curb harmful human-induced effects on the environment. While more individuals like Begley and Nye are making changes in their personal lives, companies are also taking steps to make their buildings greener. Organize students into teams and have them research what a building needs in order to be certified as a green building. Draw on the board a large illustration of a building (showing a side view with several floors) and have students make notes on the illustration about what can be done to make the building more environmentally friendly.

  2. Ask students if they know where the energy they use on a daily basis comes from. (When students say "the gas station" or "the electric company," ask them to go further. Where does the gas that is delivered to the gas station come from? Where is the power plant that produces the electricity? What type of fossil fuel or nuclear source is transformed into the electric energy?) Explain to students that energy is power usage over time. Power is measured in watts. Electrical energy usage is usually measured in kilowatt-hours (kWh—a kilowatt-hour is when 1000 watts is used for 1 hour).

  3. Bring in several electricity bills or find a sample to use (NSTAR provides a sample online). Review the bill with students. What is charged for in the bill? (There is usually a charge for energy consumption and one for energy delivery.) Does the charge for a kilowatt-hour remain the same throughout the year? (Charges for kilowatt-hours usually vary throughout the year depending on how much energy a household uses or whether the energy is being delivered during a time of year when energy is in high demand. In addition, costs usually vary by region.) In which months does the family use the most electricity? (Many families use more electricity during the summer months.) What might be the reason for this? (Increased air conditioning use is one reason.)

  4. Tell students they will now calculate how much it costs to run a TV all night for a month. To estimate the appliance's energy use, have students use the following formula (students should find out how much a kilowatt-hour costs in their community):

    Power (Watts) × Time (Hours) = 1 Kilowatt-Hour / 1000 Watts
      = Daily Kilowatt-Hour (kWh) Consumption
    Daily kWh Consumption × Cost per kWh = Energy Use Cost
    If a 200-Watt TV were left on 12 hours and each kWh costs 10 cents, the cost to run the run the TV for all night for one month would be $7.20 (200 Watts × 12 Hours × 0.001 = 2.4 Kilowatt-Hours; 2.4 Kilowatt-Hours × $0.10 per Kilowatt-Hour = $0.24; $0.24 × 30 days = $7.20).

  5. Give each student the two handouts—Your Energy Audit and Carbon Dioxide Emission Inventory. Have students collect the information on how much energy each family uses each month in terms of transportation, electricity, and space and water heating. Help students complete their tables when they return to class.

  6. After students have completed their tables, have each student create a pie chart that reflects the amount of usage per family member across the categories. Have a class discussion about students' charts. What percent of each family member's total carbon footprint was due to: a) transportation, b) heating, and c) electricity? (Generally, up to a third or more of energy expenditures are for heating and/or cooling.) What commonalities and differences can be seen across students' charts? What might account for the differences? Why might actual energy usage differ among family members?

  7. Start a class blog that includes some Web sites that offer ways to improve energy efficiency (see Links & Books for suggestions). Have students first look at the Web sites you list and then post ideas for changes they and their families could make. Ask each student to provide information about how much of a decrease in CO2 emissions would be achieved yearly (every kWh saved means that the power company releases one less kilogram of CO2 into the atmosphere).

  8. After all students have blogged, discuss with them how this activity has influenced their thinking about their own energy use. Have students design a plan for reducing their carbon footprint, and challenge them to implement their plan.

  9. As an extension, have students do a case study of their school's energy use and suggest changes for improvement.


Use the following rubric to assess students' work.



Needs Improvement

Energy Audit and Reduction Suggestions

Students complete all parts of the audit and complete the energy audit table. Students come up with four viable suggestions for reducing their carbon dioxide output.

Students complete most of the parts of the activity, but at least one item in the table is missing. Students can name two ways to reduce their carbon dioxide output.

Students do not complete the assignment. At least one major section is missing. Students are unable to think of any ways they can reduce their carbon footprint.

Links and Books

Consumer Guide to Home Energy Savings
Features tips for what to do to make a home more energy efficient today, this week, this month, and this year.

Energy Efficient Homes: Easy Steps to Improving Your Home's Energy Efficiency
Includes tables for no-cost and low-cost energy changes.

Energy Hog
Features a game that allows students to learn where energy is being used most in a home and how to use energy wisely.

How to Make Your Home More Energy Efficient
Provides an article outlining a variety of ways to seal leaks and improve insulation to make a home more energy efficient.

Your Home
Offers tips from the U.S. Department of Energy for lowering electrical use, reducing the energy that appliances consume, improving home energy efficiency, proper insulation and air sealing techniques, and more.


The "The Big Energy Gamble" activity aligns with the following National Science Education Standards.

Grades 5-8
Physical Science

• Transfer of Energy

Science and Technology
• Understanding about science and technology

Classroom Activity Author

Jeff Lockwood taught high school astronomy, physics, and Earth science for 28 years. He has authored numerous curriculum projects and has provided instruction on curriculum development and science teaching methods for more than a decade.

Teacher's Guide
The Big Energy Gamble

Interactive NOVA Program Clip (1 segment, 4m 33s)

Koch Foundation