H.S. Solar Energy: Solar Powered Cars

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1 D R I G r e e n P o w e r P r o g r a m G r e e n B o x H.S. Solar Energy: Solar Powered Cars Created by: Learning Cycle 5E Lesson Based upon and modified from Roger Bybee* (1990) *Bybee, R & Landes, N. (1990). Science for life and living: An elementary school science program from Biological Sciences Curriculum Study (BSCS). American Biology Teacher. 52 (2)

2 Solar Powered Cars Next Generation Science Standards (NGSS) Physical Science: HS-PS1-4. Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy. HS-PS2-6. Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials. HS-PS3-2. Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as a combination of energy associated with the motions of particles (objects) and energy associated with the relative positions of particles (objects). HS-PS3-3. Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy. HS-PS3-5. Develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction. HS-PS4-1. Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling in various media. HS-PS4-5. Communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information and energy. HS-PS1-5. Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs. Earth Science: HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems. Background Knowledge Teacher: The following background knowledge is from the National Research Council. A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas. Washington, DC: The National Academies Press, Through this lesson students will be able to take the information gathered from previous lessons in the Green Box to build solar cars. Working collaboratively in teams, students will work to build the fastest, most effective solar car from kits. They will build and refine their solar cars within given restraints to convert one Solar Energy Green Box: Lesson 5 Solar Powered Cars 2

3 form of energy into another form of energy. In this case the cars will convert solar energy, to electrical energy, to mechanical energy to ultimately move the solar cars. Students will also explore engineering concepts throughout this lesson as well. Electric power generation is based on fossil fuels (i.e., coal, oil, and natural gas), nuclear fission, or renewable resources (e.g., solar, wind, tidal, geothermal, and hydro power). Transportation today chiefly depends on fossil fuels, but the use of electric and alternative fuel (e.g., hydrogen, biofuel) vehicles is increasing. All forms of electricity generation and transportation fuels have associated economic, social, and environmental costs and benefits, both short and long term. Technological advances and regulatory decisions can change the balance of those costs and benefits. Although energy cannot be destroyed, it can be converted to less useful forms. In designing a system for energy storage, for energy distribution, or to perform some practical task (e.g., to power an airplane), it is important to design for maximum efficiency thereby ensuring that the largest possible fraction of the energy is used for the desired purpose rather than being transferred out of the system in unwanted ways (e.g., through friction, which eventually results in heat energy transfer to the surrounding environment). Improving efficiency reduces costs, waste materials, and many unintended environmental impacts. In this lesson students will be building and refining cars powered by solar cells (solar cells are human-made devices that capture the sun s energy and produce electrical energy). They will also be drawing designs for solar cars of their own invention. The engineering design process begins with the identification of a problem to solve and the specification of clear goals, or criteria, that the final product or system must meet. Criteria, which typically reflect the needs of the expected end-user of a technology or process, address such things as how the product or system will function (what job it will perform and how), its durability, and its cost. Criteria should be quantifiable whenever possible and stated so that one can tell if a given design meets them. Student: A. Prior Standards: a. MS.Structure and Properties of Matter b. MS.Chemical Reactions c. MS.Energy d. MS.Engineering Design e. MS.Waves and Electromagnetic Radiation A. Life Experience: Students may already have experience with solar cells being used in other technology. Students use solar cells in calculators, they might Solar Energy Green Box: Lesson 5 Solar Powered Cars 3

4 Time 90 minutes notice them on construction signs, on their homes or they may have neighbors that use them. Students are also very familiar with cars and the fact that their parents constantly have to fill the cars with gasoline (a fossil fuel). Materials List Solar Car PPT Student Guides Building a Solar Car Worksheet Solar Car (1 per group) Safety Procedures Please refer to the instruction manual of the solar car kit. Also, if working outside in the heat, make sure students don t get too hot or sunburned. Engagement After reviewing Slide 2 with the list of objectives for the class, ask students if they have ever seen a solar panel. Ask where they have seen them. Ask students if they know how a solar cell works. Show students Slide 3 including the video ( that explains how solar cells work. This is a brief and quick video and may need to be watched twice. After checking for understanding, show Slide 4 which explains again in simple terms how a PV cell works. Ask students what they would use solar energy for? Ask students if they think solar energy could power a car. What would be some challenges and/or benefits to using this technology to power a car as opposed to using gasoline? This line of questioning transitions into the Exploration activity. Exploration 1. Have students gather in groups of It is up to the teacher s discretion to share the instructions from the kit manufacturer or not. Show this YouTube for the how-to assemble video: 3. Students will need to collect one kit per group and copies of the worksheet Building a Solar Car. On this sheet students record the process of building Solar Energy Green Box: Lesson 5 Solar Powered Cars 4

5 and refining the solar car, the challenges they faced, the solutions they found and the final outcomes. 4. Once students have their materials, students can either stay inside the classroom or outside (preferred method) to build the car. 5. Students can continually refine and test cars. Explanation 1. Were you able to make your car more efficient? How? 2. How did the sunlight affect the performance of your car? Why? 3. Explain the different forms of energy that were used to make your car work? What was the main source of energy that was used to power the car? 4. What was your group s process for identifying and resolving any engineering issues? 5. How did the solar cell make electricity? Scientific Vocabulary: Photovoltaic effect: The creation of voltage or electric current in a material upon exposure to light. Solar cell (also called a photovoltaic cell): An electrical device that converts the energy of light directly into electricity by the photovoltaic effect. It is a form of photoelectric cell (in that its electrical characteristics e.g. current, voltage, or resistance vary when light is incident upon it) which, when exposed to light, can generate and support an electric current without being attached to any external voltage source, but do require an external load for power consumption. Engineering: Engineering (from Latin ingenium, meaning "cleverness" and ingeniare, meaning "to contrive, devise") is the application of scientific, economic, social, and practical knowledge in order to design, build, maintain, and improve structures, machines, devices, systems, materials and processes. The discipline of engineering is extremely broad, and encompasses a range of more specialized fields of engineering, each with a more specific emphasis on particular areas of technology and types of application. Atom: The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. Elaboration Students can take time either in class or at home to complete their Student Guides. In their Student Guides students will be asked to draw a diagram of the solar car that their group built. Students will need to identify the different parts of the solar car. They will then need to design and draw plans for a solar car of their own invention. Once again students will need to identify the different parts of the car. Solar Energy Green Box: Lesson 5 Solar Powered Cars 5

6 Students will need to explain how their model is more effective and efficient than the one they built. Evaluation Formative: Qualitative Data As students work with their cars constantly ask why and how. Why their solar module is angled that way? Why is the motor necessary? Why is it (or isn t it) working? How they plan to identify and solve problems? How is the solar (or PV) module creating electricity? How is it getting the energy to make electricity? How are the wheels being made to move? Your line of questioning will be fueled by the students and their successes and challenges. Summative: Quantitative Data Students will be handing in their Building a Solar Car worksheet as well as their diagrams. Rubric: Comprehensive list of challenges and solutions: 25 Solutions based on understanding of how PV cells work: 25 Overall understanding of how the solar car works: 25 Understanding of the different types of energy used to make the car work: 25 Creative and innovative car design of their own invention (adding 2-3 new features): 25 Understanding of transfer of energy: 15 Clean-up Students will need to take apart their solar cars and return the parts to their corresponding kits in an organized and careful manner so as not to break the parts for the next class. Students need to return all materials and supplies to where they were originally for the next class. If it is the last class of the day, have students collect all materials and return to the Green Box. Closure Review Slide 9. Review some of the most common challenges and solutions that the students discussed during their presentations. Ask students to share some of their new designs. Solar Energy Green Box: Lesson 5 Solar Powered Cars 6

7 Adaptations for ESL, Special Ed, or G.T. Not applicable. Management Strategy There is one main activity in this lesson that requires students to move around the classroom and/or outside. Students should exercise a good amount of independence and critical thinking and engineering skills. To keep students on task, remind them of time limits and of the critical objective to make their solar car actually work. Go over the Building a Solar Car worksheet and the Student Guide beforehand letting students know how their work will be assessed. As students will be working in groups throughout the lesson, talking over the chatter is not recommended. Engage in low-profile intervention of disruptions and continually move about visiting different groups and asking the questions listed in the Evaluation section. Solar Energy Green Box: Lesson 5 Solar Powered Cars 7