THE POWER OF SOLAR. Lesson 7 Wind Turbine

Transcription

1 THE POWER OF SOLAR Lesson 7 Wind Turbine Overview: Students will explore sources of energy, renewable and nonrenewable resources, and forms of energy through a systems approach. This lesson includes a hands- on science investigation in which students build and operate wind- powered s. An informational passage and diagram are used to support learning from the activity. Objectives: 4- PS3-1 Use evidence to construct an explanation relating the speed of an object to the energy of that object. 4- PS3-3 Ask questions and predict outcomes about the changes In energy that occur when objects collide. 4- PS3-4 Apply scientific ideas to design, test, and refine a device that converts energy from one form to another. 4- ESS3-1 Obtain and combine information to describe that energy and fuels are derived from natural resources and their uses affect the environment. Identify basic forms of energy. Identify the sun as the energy source of light and heat on earth. Identify earth resources and materials that come from the environment to meet the needs and wants of humans. Identify parts of a system and explain how it may not work as planned if a part is missing. Describe how tools and machines extend human capabilities in science and technology. Background Information: Natural resources are the sources of energy for electricity generation. Coal, oil, and natural gas are fossil fuels and nonrenewable resources because it takes millions of years for them to form. Solar, moving wind, moving water, and biomass resources are examples of renewable resources. All sources of energy used to produce electricity require energy conversion to change their original form of energy to electrical energy. One way to describe electricity generation is through a systems approach. A simple system consists of inputs, processes, and outputs. Inputs are the resources you put into the system. Processes are the actions that occur in the system. In an energy system, processes are often burning a source of energy or turning a. Outputs are the results of the system. In this case, it is electricity. Biomass and fossil fuels come from plants. Their original form of energy is chemical. Because it is stored energy, it is a form of potential energy. The chemical energy has to undergo a process, such as burning the energy source, to convert it to a form of kinetic energy that can be used to generate electricity. In the case of most electricity generation, the biomass or fossil fuel is burned, heating water and turning it to high- pressure steam that turns a steam to rotate the shaft in an electric generator to produce electricity. On the other hand, some renewable sources of energy, such as moving wind and moving water, are already in a form of kinetic (moving) energy. Typically, the mechanical International energy Technology of moving and wind Engineering and water Educators directly turn Association a to rotate EbD- TEEMS the shaft NextGen: in an electric Grade 4 generator. Solar energy is different than the other sources of energy. A photovoltaic solar cell absorbs

2 the radiant (light) energy from the sun and converts it to electrical energy. Materials: Copies of the "Energy Systems" handout Copies of the "Making a Wind Turbine" blackline master Each student needs his or her STEM notebook and a pencil. 1 fan For each group: Card stock (half of a file folder) Scissors Compasses Protractors Rulers Plastic drinking straws 10-12" Wooden skewers String approx. 50 centimeters Masking Tape 1 meter 1 washer Teacher Preparation: Make one copy of the "Energy Systems" handout and "Making a Steam Turbine" blackline master for each student in the class. In order to save time distributing materials, it is recommended that all of the materials required to make a be placed in a bin or box for each group in advance: 1 pie pan, 1 pair of scissors, 1 compass, 1 protractor, 1 ruler, 1 plastic straw, 1 wooden skewer, a rubber band, and tape. Each group will also need an unopened soup can. Set up a "power plant" station in a location in the room where there is an outlet and a table or counter. This is where the source of steam should be located and where students will test their s. Safety Concerns: Skewers and compasses are sharp, discuss safe handling. Teacher Procedures: 1. Introduce the concept of an energy system by explaining to students that they will work in teams to build a wind-powered working model. 2. Distribute a copy of "Making a Wind Turbine" to each student. Demonstrate the process that students will use to make the model. 3. Place students in groups of four. 4. Distribute to each group: 1 piece of card stock, scissors, a compass, a protractor, a ruler, 1 plastic straw, 1 wooden skewer, string, a washer, and tape. 5. Instruct students to follow the directions carefully and construct a model of a. Provide close supervision during this part of the activity and circulate as students work. Provide guidance to groups that need assistance or have questions.

3 6. Once models are constructed, students will test their models with the fan. They may need to modify their design for where the tape is attached at the end of the skewer so that the string will wind up properly. 7. As groups finish building their models, have students test their s using the fan at different speeds. 8. Students will make observations of how the speed of the fan affects the energy that the produces. 9. Distribute a copy of the "Energy Systems" handout to each student in the group to read. The group should read the passage together and discuss it as they read to collectively make sense of the information. 10. When all groups are finished constructing their models and reading the passage, invite each team to test its steam-powered at the "power plant" station. (Setup recommendations are provided in the Teacher Preparations section of this lesson.) 11. As each team is at the "power plant" station testing its, ask students: "What is the input of the energy system, what is the process, and what is the output?" (The input is the wind, the process is the wind turning the, the output is the energy being transferred to the string to wind up the washer.) 12. Instruct students to record the terms "system," "," "source" (of energy), "fossil fuels," "kinetic energy," and "potential energy" in their STEM notebooks and Word Detective graphic organizers. Students should complete the Word Detective chart for each of the vocabulary terms. This could be completed in class or as a homework assignment. Extensions: Expand upon the idea of a system. Have students brainstorm additional natural and technological systems in their daily lives. Provide students with a systems diagram that has an input, process, output, and feedback loop. Ask students to identify these components in the systems that they brainstormed. This activity could also focus exclusively on energy systems. Students could research sources of energy and learn about the specific components of their energy systems to generate electricity, heat, or even the motion of a vehicle. Have students build another using a different design or materials. ASSESSMENT: To reinforce learning and as a formative assessment, have students participate in a kinesthetic energy systems activity. Give each student a card that lists one of the following words or phrases: coal, oil, natural gas, corn ethanol, soy ethanol, wood, moving water, moving wind, solar, chemical energy (x2), mechanical energy (x2), radiant energy, burned to heat water to produce steam (x2), turn a (x4), absorbed by solar cell, electricity (x5). Instruct students to read their card and then circulate around the room to find partners with cards that will help them form an energy system that includes an input, processes, and an output. Remind students that depending on their source of energy, one or two forms of energy and one or two processes may be part of their system. When all students have formed systems, call on groups to share the systems they have formed. After the first round, collect the cards, shuffle them, distribute new cards to students, and play again. Repeat.

4 Making a Wind Turbine 1. Using a compass, ruler, and protractor measure and draw a 10-cmdiameter circle with a pencil on your card stock. Cut out the circle. 2. Fold the circle in half, then fourths, then eighths. Open the circle back up. Each angle should measure Place a quarter-sized object in the center of the circle and trace it. This will be the guideline for where to cut the blades. Cut 8 blades by cutting along the 8 fold lines, to within 2 cm of the center. Make sure not to cut all the way to the center. When finished cutting, use the point of a sharp pencil to poke a small hole in the center. 4. Bend each blade gently up on one side so that all blades are curved up in the same direction. Don t over-bend the blades. Just bend them to give them a curve or twist. You may need to make adjustments to the blades when you use your. 5. Set up the system by sliding the blade on the wooden skewer about 4-5 centimeters from the blunt end and taping it in place. Tape may be needed on both sides of the blade to securely attach it to the wooden skewer. 6. Slide the straw over the wooden skewer. 7. Attach a string to the end of the skewer and tie a small washer at the other end of the string. 8. Use tape or other materials to create a system that allows the string to roll up on the end of the skewer causing the washer to wind up. 9. Hold the wind in front of a fan so that the will spin and roll up the string lifting the washer.

5 Energy Systems The electricity that you use in your home came from a source of energy. But, it did not come from the source of energy directly. Instead, a natural resource was collected, processed, and its energy converted into electricity. In an energy system to generate electricity, the natural resource is called an input. An input is something that you put into a system. The energy system also has processes, such as burning an energy source or turning a. A process in a system is an action. Finally, in an energy system, there is an output, such as electricity. An output in a system is the final result. The flow chart below shows five energy systems used to produce electricity. Energy Source Fossil Fuel Coal Oil Natural Gas Biomass Corn Ethanol Soy Ethanol Wood Solar Moving Wind Moving Water Potential Energy Form Chemical Chemical Process Burned to heat water to make steam to turn a Burned to heat water to make steam to turn a Kinetic Energy Form Mechanical Mechanical Radiant Mechanical Mechanical Process Absorbed by solar cell

6 Electricity, the movement of electrical charges through a conductor, is generated. Energy resources can be categorized as renewable or nonrenewable. Renewable resources can be easily replenished through natural cycles. Plants, wood from trees, sunlight, wind, and water are all examples of renewable resources. Nonrenewable resources Open Coal Mine Photo by Iain Thompson CC BY- SA 2.0 cannot be easily replenished through natural cycles. Natural gas, oil, coal, and other minerals are examples of fossil fuels that are nonrenewable resources. Fossil fuels were produced deep underground over millions of years from ancient plant and animal life that was trapped and pressed between layers of earth. Both renewable and nonrenewable resources can be inputs in an energy system. Energy is found in many different forms and can be changed from one form to another. Forms of energy used in electricity generation include chemical, mechanical, radiant, thermal, and electrical energy. Chemical energy is the only one that is considered a Potential form of energy. Potential energy is stored energy that is not in motion. Mechanical, radiant (light), thermal (heat), and electrical energy are all forms of Kinetic energy. Kinetic energy is in motion. When a natural resource is used to make electricity, its energy is has to be converted from one form of energy to electrical energy. In an energy system, the processes of burning a source of energy or turning a are common ways to convert one form of energy to electrical energy. The electricity that is generated is the output of the energy system.