- I can critically examine photographs and identify details of competing design solutions based on the priorities and constraints of the problem.
- I can weigh the efficiencies and inefficiencies of different systems to meet human energy needs.
This information is not for classroom content, but to prepare teachers for the photographs, activities, and potential questions from students.
Any system designed to capture energy for work has associated criteria and constraints that are defined by a variety of factors. Consideration of scientific principles and other relevant knowledge may limit possible solutions. For example, extracting, processing, transporting, and using fossil fuels have environmental impacts. Hydroelectric and nuclear power plants create risks and benefits for a region. Renewable energy sources, such as wind turbines, solar panels, and biofuel production, have production costs and demands and require space. Costs and requirements change as technology advances but are often limited by geographic constraints or situations.
In this activity, students will focus on one of the energy sources highlighted in the second activity. Students will use photographs showing different systems designed to capture, store, and transfer wind energy to analyze different design features of wind energy systems, thinking about the environmental factors involved in different solutions. Small group and class discussions will consider the design benefits of different systems that take advantage of energy sources. Students will have the opportunity to apply engineering design strategies to locations and situations in their own community.
Begin the Activity
- Rulers, pencils, and paper
Give students a photograph to work on, possibly in pairs. (Optional: Start by making a diagram, as in Energy Systems, to show the flow of energy in the system in the photograph.) Show the energy flow from the source through the processing equipment to a specific use, such as a home, car, or school.
Next, consider the space required for the energy-capturing system in the photograph. If the photo has an associated scale, for example 1 cm = 5 m, calculate the dimensions of the energy-capturing system. If the photo does not have an associated scale, use a familiar item in the photo (such as a person or vehicle) to estimate the dimensions. For example, use an average height of 170 cm per person, or guess that a tree might be 5 or 10 meters high to calculate the length and width of solar panels or wind turbines.
Have students look at the background features of the photographs and note the general geographical features and the expected climate of the region.
As a class, share the footprint—the dimensions—of each energy-capturing system. Discuss the amount of space required for the different systems as well as requirements.
Thinking about the space and other requirements, discuss the advantages and disadvantages, such as environmental impact, risks to the surrounding community, sustainability of the energy source, or aesthetic impact. For example, if this system were installed in your state or region, what ecosystems might be affected? What else might the space be used for?
Note: Using the activity results, students will be able to discuss the space requirements. For the other features, they could generate hypotheses about advantages and disadvantages of the energy-harnessing systems, such as the sustainability of a system that requires a steady supply of wind or sun, or complaints that people might have about the aesthetics of various systems. For a more in-depth activity, have students choose one of the systems and research its advantages and disadvantages more fully.
Using the estimates from Part 1, based on the photos of the solar array and wind turbine, have students go outside and plot or map out their estimates of the size of the energy-capturing systems. Back in the classroom, have students discuss and identify factors besides size that would be required to using the systems in their community.
In this part of the activity:
- Students work in pairs or small groups to analyze different wind turbine and blade designs and discuss possible reasons for the different design components.
- Student teams select a possible local site for installing a wind energy system and identify the relevant environmental factors to be considered.
- Student teams create a model of a wind energy system with a design based on real local data.
Give students photos of wind turbines. Based on the variety of designs shown in the photos, have students make one or more models that explore options for blade design and turbine structure. After they have sketched or described their own models, have the students research and design a option that might work locally. (Option: An Internet search might find directions for building and testing a mock wind turbine.)
Questions to Consider
Look at the background features of all the photographs.
- What general geographical or climate features do you see?
- Where in the United States or in the world might this type of energy-capturing system work well?
- Is the system suited for developed or developing countries?
- Would this be a good option for your community? Why or why not?
Compare the advantages and disadvantages that the class came up with for the energy-capturing systems in the photographs to the pros and cons of the predominant systems in your area. Do you think your region has the optimal energy option? Why or why not? (Interactive maps and tables from the U.S. Energy Information Administration can answer questions about energy capacity and consumption in different regions and by different sources. See References and Further Reading.)
What sources of energy are we not yet using effectively? What is needed to use or improve our use of these energy sources?