Energy Efficiency World Teacher's Guide
Page 9: Energy Efficiency Helps the Environment
Objective: To explain how energy use affects the environment and how energy efficiency reduces these impacts.
Background/Discussion: There are environmental impacts from all energy resources. Most of the energy we use comes from fossil fuels like coal, oil, and natural gas. When these fuels are burned, carbon dioxide is released. Carbon dioxide is one of the greenhouse gases that are increasing in our atmosphere. Renewable energy sources also have an effect on the environment. For example, burning biomass also releases carbon dioxide (although less than fossil fuels). Manufacturing solar cells results in pollutants that must be specially disposed of. And the construction of dams for hydropower facilities changes the ecosystem of the rivers they are built and affects the animals and plants that live there. So no matter where your energy comes from, using it efficiently helps the environment.
Word Game Solution: Trees can help people save energy. In summer, tree shade can keep your home and car cool so you don’t have to run your air conditioner as much. And in winter, trees can block cold winds so your heater doesn’t have to work as hard.
Interesting Statistic: Over one year’s time, one acre of mature trees removes the same amount of carbon dioxide from the air as is produced by driving a gasoline-powered car 26,000 miles.
Page 10: You’re Getting Warmer…
Objective: To help students understand how the greenhouse effect works.
Background/Discussion: Greenhouse gases make life on earth possible—without them, the planet would be much colder. The problem is that their concentrations have increased due to human activities. Natural sources of greenhouse gases, like volcanoes and animals, used to be in balance with natural absorbers of those gases—especially trees and oceans. But humans burn so much fossil fuel now that we release more carbon dioxide than natural absorbers can handle. Recent research shows that the concentration of carbon dioxide in our atmosphere is indeed increasing and as a result the earth’s weather patterns, ocean levels, and habitats are changing. This phenomenon is known as global warming or climate change.
Experiment: Students’ predictions, observations, and conclusions will vary. Answers to #6 should include the observation that the ice in the covered jar melted faster because the plastic wrap kept the temperature in the jar warmer. Students should explain that the plastic wrap holds in heat just as the clear greenhouse gases trap the earth’s heat. Ask students what kind of energy melted the ice cubes. (Radiant energy.)
Pages 11 and 12: Save Energy at Home and at School
Objective: To offer students age-appropriate tips for reducing home and school energy use.
Background/Discussion: Explain that just as each slice of the pie is a piece of the whole, each type of home energy use shown in the pie chart on page 12 represents a percentage (or portion) of the total home energy use. Students may require help labeling which energy uses go to which slices of the pie, as several percentages are similar. (The grey slice at the top is Refrigerators 5%; the green slice at the top left is Home Electronics 7%; the yellow slice just below the green slice is Lighting 10%; and the grey slice at the bottom is Other Appliances 16%. The large teal slice is Heating and Cooling 49%.