To look at different energy resources, where they come from, what they produce, and the trade-offs of using them.
By this age, students will know what energy sources are and for what energy is used. They can discuss the various renewable (sun, wind, geothermal, and biomass) and nonrenewable (fossil fuels such as oil, coal, and natural gas) sources of energy. They also should be very familiar with the process in which fossil fuels were formed and, therefore, their limited supply.
This lesson uses an interactive called Power Up! in which students are challenged to power a city by choosing different types of power plants. The challenge is to stay within a budget and to keep harm to the environment within a certain parameter.
The interactive emphasizes two aspects of this lesson: that electricity comes from a variety of sources and that different energy sources have different consequences for the environment. Prior to doing the interactive, students will read a short article on electricity, partly so that they can personally relate to the lesson, and also to point out that this "power" comes from various energy resources. After the interactive, students will visit two situations that will present issues and trade-offs surrounding the energy resources, oil and coal.
The concept of trade-offs should show up in every part of the curriculum. Student decision making in the classroom and in other situations should help them learn the inevitability of trade-offs and the need to take benefits and costs into account in any proposed action. (Benchmarks for Science Literacy, p. 164.)
You may want to read/visit these sites in order to prepare for this lesson:
To get students excited about this lesson, explain to them that for this lesson they are the ones in charge of the electricity grid for their town. They have to learn about how the electricity gets made and then gets to their homes, the different sources of electricity, and the trade-offs associated with each energy source.
Have students use their Energy Resources and Trade-Offs student esheet to go to and read Electricity, an article that describes the different sources from which electricity comes and how it gets from those primary sources to a person's home. Ask these questions (students can record answers to these questios on the Energy Resources and Trade-Offs student sheet):
- What energy sources does electricity come from?
- (The main sources listed in the article are coal, natural gas, and nuclear fission. Certainly, wind, solar, and hydro also make electricity.)
- Is electricity easy to move around? Why or why not?
- (Electricity can move through wires over great distances before it is even used. If students want to elaborate on the process, that is fine.)
- Once electricity gets to its destination (likely someone's house), what kinds of work and devices use electricity?
- (A lot of things: light, heating/cooling, television, etc. Encourage students to talk about how dependent we are on electricity.)
- Do you think certain primary sources of energy used to make electricity harm the environment?
- (This is not in the article, but rather is leading into the development. If students aren't sure, ask whether or not they think burning coal harms the environment. They may know that harm is done, but they may not know exactly what it is, and that's fine. It will be covered in the development of the lesson.)
- If you were to run a power plant that made electricity, what primary source of energy would you use?
- (This is an interesting place to gauge what students think is best. If they lean toward fossil fuels, ask about the environmental effects, like burning coal. If they lean toward renewable energy, ask why we don't use it already if it is better. This is just to get students thinking about trade-offs.)
This section of the lesson starts with on an online interactive activity where students are supposed to build the right combination of power plants and 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 possible impact on the environment and community.
After students are done with the interactive, discuss these questions:
- Is it possible to power up a city and not harm the environment?
- (The answer is basically no, even with renewable energy there is ultimately some damage to the environment. At some point, students will need to realize the need for compromise and that compromises result in trade-offs.)
- Do you think the trade-off of harming the environment is worth buying less expensive power plants?
- (Answers will vary. Encourage students to explain their answers.)
- Are there other trade-offs that you noticed when investing in power plants for your city?
- (Answers will vary. Encourage students to explain their answers.)
- Who do these trade-offs affect? You personally, the city as a whole, or people beyond the city?
- (It may be interesting for students to realize that what seems to be good for a whole city, society, or group, may not necessarily be what they want personally. For instance, it may be better for society to use renewable energy, but what if individuals have to pay more? You and your students may be able to come up with several scenarios like this one.)
- What if you changed the trade-off, for instance, spent more money to do less harm to the environment, OR did more harm to the environment to have cheaper utility rates? What would the outcomes be?
- (This may also have many of the same answers as the former question.)
- Are the outcomes of your decisions for powering up a city all good?
- (Another interesting point. Environmental harm is done, regardless of the power plants chosen and so, students may realize that there is a major compromise involved in our use of energy resources.)
Now have students write a paragraph where they consider this example: since electricity can be transmitted efficiently great distances, could you build the polluting plants way out in the middle of the desert and then distribute the electricity to the cities on the coast? What are the trade-offs for that scenario?
So far, students have focused on the trade-offs involved in buying power. The assessment will broaden their understanding of energy resources and how the trade-offs start from the very beginning of finding and extracting these resources. They will be asked to read a few articles. The articles cover the impact mountaintop mining has on its surrounding community and the possibility of drilling for oil in the Arctic.
These short articles by no means give a full picture of how humans research and obtain most of the resources in the world. There are innumerable situations all over the world, each with its own trade-offs. And many corporations combat the negatives with positives.
The articles, on the other hand, will get right to the point of the trade-offs involved in the process. They also will give students an opportunity to understand that different resources are obtained and distributed differently, as one benchmark states.
We encourage you to read these sections from the PBS NOW series, The Cost of Coal, along with your students:
Then, students should read these two short articles about drilling for oil in the Arctic:
Once students have gone through these articles, they can use the Comparing Coal and Oil student sheet to write a two-page essay comparing these two energy resources. They should make these points:
- The general differences of the resources, such as how they are obtained and distributed.
- How obtaining these energy resources (in these two situations) can have an impact on the environment.
- Any trade-offs that have already occurred, or could occur in the future, regarding the two situations about which they have read.
- Whether or not the trade-offs are between desirable possibilities or outcomes.
You can extend the ideas in this lesson by using these Science NetLinks lessons:
In light of the BP oil spill in the Gulf of Mexico on April 20, 2010, students may be interested in learning more about this event. They can view live feeds of the spill below the surface by going to Oil Spill in the Gulf - Live Cam.