To compare and contrast different energy sources and the trade-offs of using them.
Students at this age should know about renewable energy sources, such as the sun, wind, and geothermal, as well as nonrenewable energy sources, such as fossil fuels. They should have a solid working knowledge of renewable and nonrenewable energies before doing this lesson.
While the motivation and first part of the development cover the basics of renewable and nonrenewable energies, the Science NetLinks lesson Energy Sources and Use offers a more in-depth refresher or introduction to the basics of renewable and nonrenewable energies. We recommend that you consider starting with Energy Sources and Use if your students have not covered the topic of energy yet.
The basics of energy are a good springboard for exploring the issues and trade-offs surrounding energy that will be covered in this lesson. One specific example: students at this age (and before doing this lesson) should know the special conditions under which fossil fuels are created and therefore can reason that these fuels are not easily replaced. Issues like this one are the main focus of this lesson.
Elementary school age is when children start to practice and apply their decision-making skills, particularly in grades 3-5. When making decisions, often students will come across the pros/cons of a situation and the trade-offs involved. Gaining an understanding of the concept of social trade-offs may be one of the most important components of a comprehensive education. (Benchmarks for Science Literacy, p. 164.)
This lesson will encourage students to examine the trade-offs involved in our use of energy, a topic they will likely revisit throughout their lives.
This lesson is built around an interactive called Power Up! in which students choose how to power a city. They will have to choose between various energy sources, taking into account the trade-offs between cost and the environmental impact of each choice. Discussions before and after the game will examine the various options and what students may want to take into account when making their decisions.
You may want to visit these sites in order to prepare for this lesson:
For a review of energy, the various sources, and how we use it in our everyday lives, have students use their Power Up! student esheets to go to and read Renewable Energy and then Nonrenewable Energy on the Energy Information Administration's Energy Kid's Page. These pages will help (re)familiarize them with the different types of fuel energy.
If students have preceded this lesson with the Energy Sources and Use lesson (as suggested in the Context), students should still read the assigned pages, but you may want to skip or adapt the first four questions.
Note: If you have students who are energy savvy, and/or in the higher grades, you may want to assign them to read the first page of the Energy Kid's Page and to click on all the words underlined on the first page to refresh their knowledge. Just be aware that this would increase the amount of reading substantially; the deeper into the site they venture, the more technical the vocabulary becomes.
Follow up with these questions:
- Which energy sources are renewable? (Renewable energy sources include solar, wind, hydro, biomass, and geothermal.)
- What does renewable mean? (It means fuels or resources that can be easily made or renewed.)
- Which energy sources are nonrenewable? (They include oil, natural gas, coal, and nuclear.)
- What does nonrenewable mean? (It means that the resource cannot be easily made or renewed. We can use up nonrenewable resources.)
- Is one type of energy better than the other? (Here you will be able to gauge what sort of training your students may already have. For instance, they may automatically say that renewable energy is better because it is less harmful to the environment. You may want to press them and ask, "Well then why don’t we use them?" to get them thinking beyond what they already know before the lesson starts.)
- Which energy sources do you think are the best to use? (This is a great lead in to the interactive, namely because students have not yet delved into the trade-off aspect of energy sources yet. They may have set ideas about what is best at this point in the lesson, but may have different ideas at the end of the lesson.)
To complete this section of the lesson, hand students the Pros and Cons of Powering Up student sheet. Then, have students use the Power Up! student esheet to guide them through the development of the lesson.
Students should first read Renewable Energy vs. Fossil Fuels, on the Energy Quest site, which gives a good overview of the two categories of energy and the pros and cons of each.
After they are done reading, ask students (you may want to write the answers on the board so that students can see the contrasts):
- What are the pros (benefits) of renewable energy? (They include less pollution or harm to the environment, there are seemingly endless supplies, and there seems to be plenty of them.)
- What are the cons (drawbacks) of renewable energy? (The relatively high upfront cost and land space are some drawbacks. The article does not do a comparison of dollars per kilowatt hour between say solar and coal, so you may want to mention that the article says wind energy is less than 5 cents per kw hour and solar is 20 cents. Electricity today costs approximately 5 cents per kw hour and comes from various sources depending on where one lives, but most comes from a combination of fossil fuels. When considering fossil fuels, though, one also needs to take into account the environmental costs—such as cleanup and pollution prevention.)
- What are the pros of nonrenewable energy? (Some pros include the relatively low upfront cost and our society is already "set up" for these fuel sources.)
- What are the cons of nonrenewable energy? (Some cons include the harm to the environment and a limited supply.)
- Do you think that the low cost of nonrenewable energy would continue to be low if we started to run out? (Answers will vary.)
Now, students are instructed to go to the next part of the development, an online interactive where they are supposed to collect the right combination of power plants to bring the city up to full power. Students will have several energy sources from which to choose and they'll need to decide the best combination for their city, taking into account the cost and impact on the environment and community.
In the directions, we suggest that students always pick the choice with the lowest environmental impact for one game. For another, to always select cheaper choices. This will help isolate the consequences of their choices. (If time is an issue, you may want to time students 10 to 15 minutes for the interactive.)
As students do the interactive, put the teacher sheet overhead up in the front of the classroom. This will allow students to figure out how to win a game, by seeing the numbers, and will work as an aid as you ask them these questions:
- When you choose a certain energy plant, what do you have to consider? (Students will realize that they have to balance environmental impact and economic efficiency. You may want to let students elaborate on their thoughts here.)
- What are the consequences of your choices? (Students may talk about a certain game or the one you thought had the best results. Really focus on the word consequences and try to lead in to "trade-offs." For instance, choosing coal may not be great for the environment, but it may be cost-effective, this is a trade-off.)
- List some of the trade-offs in choosing certain power plants. (You can use the overhead here to show that cheaper energy has a higher impact on the environment.)
- With a game that you won, were you able to pick the kind of power that you think your city SHOULD have? Why or why not? (This may bring up all sorts of interesting thought processes that students have. Some students may have become solely concerned with finding a way to power the city. Others may have wanted to choose more renewables, etc.)
- Do you think that when people choose certain energy sources there are unexpected consequences? (Students may relate this question to their own experience with the interactive such as in the question above, or they may come up with scenarios. See if they have an understanding of the third benchmark this lesson addresses: that even if decisions are made thoughtfully and a lot of thought is given to the pros and cons, the outcomes may still be unexpected. This does not mean that the outcome has to be negative.)
As directed on the student sheet, instruct students to write a proposal letter intended to be read to the citizens of the city, which explains how their city will be powered. It's important that the proposal explains why students made the power plant choices they did. They can use these guidelines:
- Address the letter to the Mayor and the citizens of the city.
- Describe each power plant to be used.
- Describe the advantages of each power plant. Include any disadvantages, but be sure to make a case for why each power plant is a good choice, even with disadvantages.
Students' proposal letters should demonstrate that they have an understanding of the three benchmarks.
The Energy Story, in its entirety, is 20 chapters long and covers just about everything. Students may opt to check out the table of contents (at the bottom of the front page) and skip to certain aspects of energy in which they are interested.
The Secret Lives of Energy is a Community Science Action Guide. It specifically focuses on whether or not oil should be drilled for in the Antarctic. This is a good follow up to the lesson because it not only focuses on energy, but is very pro/con/trade-off oriented.
The state of Pennsylvania has an electric choice program where people are able to choose their electricity suppliers. There are many choices throughout the state, some offer renewable energy at greater cost, others are cheaper and offer only coal-powered electricity. If your students are in the older grades and/or research savvy, you could assign them to explore this site and report back what they have learned and what kind of electricity they would choose.