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Exploring Photovoltaics

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Teacher Guide Hands-on investigations to teach secondary students how electricity is generated using photovoltaics and other solar systems. Students will explore the variables affecting photovoltaic cells.

Pri Ele

Int

Grade Level:

Sec Secondary Subject Areas: Science

Language Arts

Social Studies

Technology

Math

NEED Mission Statement The mission of The NEED Project is to promote an energy conscious and educated society by creating effective networks of students, educators, business, government and community leaders to design and deliver objective, multi-sided energy education programs.

Permission to Copy NEED curriculum is available for reproduction by classroom teachers only. NEED curriculum may only be reproduced for use outside the classroom setting when express written permission is obtained in advance from The NEED Project. Permission for use can be obtained by contacting info@need.org.

Energy Data Used in NEED Materials NEED believes in providing teachers and students with the most recently reported, available, and accurate energy data. Most statistics and data contained within this guide are derived from the U.S. Energy Information Administration. Data is compiled and updated annually where available. Where annual updates are not available, the most current, complete data year available at the time of updates is accessed and printed in NEED materials. To further research energy data, visit the EIA website at www.eia.gov.

Teacher Advisory Board

Teacher Advisory Board Constance Beatty Kankakee, IL

Robert Lazar Albuquerque, NM

La’Shree Branch Highland, IN

Melissa McDonald Gaithersburg, MD

Jim M. Brown Saratoga Springs, NY

Paula Miller Philadelphia, PA

Mark Case Randleman, NC

Lisa Cephas Philadelphia, PA Nina Corley Galveston, TX Samantha Danielli Vienna, VA

Monette Mottenon Montgomery, AL

Mollie Mukhamedov Port St. Lucie, FL In support of NEED, the national Teacher Advisory Board (TAB) is dedicated to developing, Shannon Donovanimproving, and promoting standards-based, effective energy curriculum, training, and outreach. NEED thanks these individuals forRItheir support and collaboration. Greene, Cori Nelson Winfield, IL Amy Schott, M.Ed, NBCT Jennifer Mitchell-Winterbottom, Jennifer Davis, M.Ed Adebisi Babayemi, M.Ed, NBCT Michelle Garlick M.Ed, WT Raleigh, NC Pottstown, PA Long Grove, IL Cincinnati, OH Bowie, MD Don Pruett Jr. Kristin Slota, M.Ed Mollie Mukhamedov Michelle Garlick, M.Ed La’Shree Branch Puyallup, WA Yardley, PA Port St. Lucie, FL Cary, IL Highland, IN Michelle Gay Brandon Staton Cori Nelson Daphne, AL Nancy Gifford, M.S. James M. Brown, NBCT, CEM, BOC Judy Reeves Thomasville, NC LA Hinckley, IL Saratoga Springs, NY Harwich, MA Lake Charles, Jennifer Trochez Maclean, M.Ed, NBCT Erin Gockel, M.Ed Judy Reeves Nancy Gifford Karely Carlos, M.S. Lake Charles, LA Los Angeles, CA Farmington, NM Lodi, CA Harwich, MA Libby Robertson Matthew Reis, PhD Scott Valenta Mark Case, M.S. Greg Holman Chicago, IL Paradise, CA Chía, ColombiaErin Gockel Winfield, IL Randleman, NC Melissa King, MLIS Craig Richard,Farmington, M.Ed Lisa Cephas, M.Ed NM Amy Schott Philadelphia, PA Gaithersburg, MD Atkinson, NH Raleigh, NC Libby Robertson Nina Corley Paula Miller, M.Ed Robert Griegoliet Chicago, IL Galveston, TX Philadelphia, PA Naperville, IL Tom Spencer Hallie Mills, EdD Greg Schanne Samantha Danielli, M.Ed Chesapeake, VA Philadelphia, PAEric Havel Sammamish, WA Vienna, VA Oakland, CA Jennifer Trochez MacLean DaNel Hogan Los Angeles, CA Tucson, AZ NEED Teachers eventually must retire from the classroom, but many remain engaged in their communities and with NEED curriculum, training, and Wayne Yonkelowitz outreach activities. NEED thanks these individuals for their continued support and collaboration. Greg Holman Fayetteville, WV Paradise, CA Constance Beatty Melinda Forist Barbara Lazar, M.Ed Robert Lazar Don Pruett, Jr., M.Ed Wayne Yonkelowitz,

NEED TAB Emeriti

Kankakee, IL

Wellfleet, MA

Albuquerque, NM

Alburquerque, NM

Barbara Lazar Albuquerque, NM

Puyallup, WA

M.Ed, NBCT, Milken Educator Fayetteville, WV

Exploring Photovoltaics Teacher Guide

www.NEED.org

Exploring Photovoltaics Teacher Guide

Table of Contents  Exploring Photovoltaics Kit 6 PV panels 12 Digital multimeters 6 Breadboards 48 Alligator clip jumper wires 1 Bag of LEDs and resistors 6 Alligator clips, 5” long 24 Ping pong balls 1 Teacher Guide 1 Student Guide

The NEED Project thanks Generac for their generous support of the development of our solar curriculum and the students who will explore solar energy in our programs throughout the year.

Standards Correlation Information

Materials

Teacher Guide

Rubrics for Assessment

Answer Key

Expected Outcomes

Solar Energy Bingo Instructions

Solar Energy in the Round

Photovoltaic Cell Master

PV Ping Pong Simulation Instructions

Digital Multimeter Master

Enlarged LED Master

Workable Wiring Schematic Master

U.S. Solar Resource Map Master

Solar Space Heating

Solar Energy Bingo Sheet

Solar Energy in the Round Cards

Evaluation

Exploring Photovoltaics Teacher Guide

www.NEED.org

Standards Correlation Information www.NEED.org/educators/curriculum-correlations

Next Generation Science Standards This guide effectively supports many Next Generation Science Standards. This material can satisfy performance expectations, science and engineering practices, disciplinary core ideas, and cross cutting concepts within your required curriculum. For more details on these correlations, please visit NEED’s curriculum correlations website.

Common Core State Standards This guide has been correlated to the Common Core State Standards in both language arts and mathematics. These correlations are broken down by grade level and guide title, and can be downloaded as a spreadsheet from the NEED curriculum correlations website.

Individual State Science Standards This guide has been correlated to each state’s individual science standards. These correlations are broken down by grade level and guide title, and can be downloaded as a spreadsheet from the NEED website.

Exploring Photovoltaics Teacher Guide

www.NEED.org

Materials ACTIVITY

MATERIALS IN KIT

ADDITIONAL MATERIALS NEEDED

PV Ping Pong

Ping pong balls

Simple Solar Circuit

PV Panels LEDs Digital Multimeters Alligator clips

Working with PV Panels and Breadboards: Build & Test Your Circuit

PV panels LEDs Breadboards Resistors

Light sources*

Set Up Multimeter 1 & 2

PV panels LEDs Breadboards Resistors Digital Multimeters Alligator clip jumper wires

Light sources*

Verify Solar Module Similarity

PV panels Digital multimeters LEDs

Light sources*

Light Intensity

PV panels Digital multimeters LEDs Resistors

Breadboards Alligator clip jumper wires Alligator clips, 5” long

Dim light sources* Moderate light sources* Bright light sources* Rulers

Angle of Incidence

PV panels Digital multimeters LEDs Resistors

Breadboards Alligator clip jumper wires Alligator clips, 5” long

Light sources* Protractors Rulers

Shading a PV Panel

PV panels Digital multimeters LEDs Resistors

Breadboards Alligator clip jumper wires Alligator clips, 5” long

Cardboard or cardstock Tissue paper or other translucent material Bright light source* Rulers Pencils

Surface Temperature

PV panels Digital multimeters LEDs Resistors Breadboards

Alligator clip jumper wires Alligator clips, 5” long

Bright light source* Watertight, clear plastic bags Plastic containers with ice baths Thermometers Hair dryers (students can share 1 or 2) Rulers

A Step Further

PV panels Digital multimeters LEDs Resistors

Breadboards Alligator clip jumper wires Alligator clips, 5” long

Light sources*

Flashlight Colored tape Sticky name tags or cardstock Resistors Breadboards Alligator clip jumper wires

Alligator clips (additional) Bright light source* Tissue paper or other translucent material Cardboard or cardstock

*See note on page 6 regarding light sources.

Exploring Photovoltaics Teacher Guide

www.NEED.org

Teacher Guide Grade Level Secondary, grades 9-12

Note This unit focuses on solar energy as it relates to photovoltaic cells and electricity. For information on solar energy and heating, you may wish to copy the Solar Space Heating article on pages 28-29 for your students to read.

: Internet Resources American Solar Energy Society www.ases.org EIA Energy Kids www.eia.gov/kids Energy Information Administration www.eia.gov Interstate Renewable Energy Council https://irecusa.org/ Interstate Renewable Energy Council Solar Career Map www.irecsolarcareermap.org Lawerance Berkeley Lab Tracking the Sun emp.lbl.gov/tracking-the-sun NEED’s Solar Energy Awesome Extras www.NEED.org/resources/solarmaterials Solar Energy Industries Association www.seia.org

The Exploring Photovoltaics unit focuses on how solar energy is used to generate electricity with photovoltaic cells. The student informational text has information on photovoltaic cells, as well as concentrated solar power, and emerging solar technologies.

Time Five to six 45-minute class periods

2 Unit Preparation Familiarize yourself with the Teacher and Student Guides, and with the materials in the kit. Be sure you read the informational text in the Student Guide and understand the information associated with each activity you choose to conduct. NOTE: Many of the images, diagrams, and masters within the Teacher and Student Guides can be found in full color in the digital PDFs. It may be helpful to share color versions of these elements with your students. Download the PDFs for free at www.NEED.org/shop. Collect the materials that are not included in the kit. See the materials list on page 5. It is suggested that you test the equipment and read the operating manuals prior to instruction. Set up six stations, each containing two multimeters, one PV panel, two LEDs, one 100-ohm resistor, one 68-ohm resistor, six alligator clip jumper wires, one 5” alligator clip, one breadboard, and either a reflecting lamp or access to direct sunlight. NOTE: These panels may work with many light sources, including (but not limited to) incandescent, LED, sunlight (direct or through a window), and even a smart phone flashlight. Be sure to test your light sources ahead of time to ensure they function with these panels.

@Notes about Circuits and Breadboards BREADBOARD USE The curriculum kit designed to accompany this curriculum guide provides breadboards for students to use to connect their circuits. The main advantage is the ease with which components can be connected or disconnected to each other. If you are not familiar with breadboards, we highly recommend that you work through the activities in the student guide to diagram your layout and connect the entire circuit as described, testing your circuit as you go. If you have difficulty getting the LEDs to light, the troubleshooting tips below may help.

U.S. Department of Energy, Solar Energy www.energy.gov/solar

LEDs must be connected in the correct orientation (polarity) with respect to the power source (solar panel) in order to light. Make sure they are both facing the same way, and if they still do not light, pull them both out of the breadboard, rotate 180°, and re-insert them.

U.S. Department of Energy, Solar Energy Technologies Office www.energy.gov/eere/solar/solarenergy-technologies-office

The LEDs will not light if the digital multimeter measuring current is not switched on. Make sure the digital multimeter connected in series with the load is turned on to 20 mA DC.

U.S. Department of the Interior Bureau of Land Management www.blm.gov/programs/energyand-minerals/renewable-energy/ solar-energy

&Background

Make sure the holes you are using in the breadboard to connect components are they themselves connected. The end of the first component must be in a set of connected holes as the lead of the next component. See Breadboards and How to Use Them, Student Guide page 25, for more information. The Workable Wiring Schematic master can be found on page 26 for the activities in this unit. If you do not have enough time for students to spend planning and deciding as a team how to connect elements in the breadboard, or if you are having trouble yourself, feel free to consult it or copy and distribute it as needed.

Exploring Photovoltaics Teacher Guide

www.NEED.org

SERIES AND PARALLEL CIRCUITS Many physical science teachers may decide to use solar energy as a way to teach their students about series and parallel circuits. We have not included circuits in this curriculum guide because its intended objective is to learn about the factors influencing photovoltaic output. We do recognize that the PV panel in the curriculum kit can be used to teach students the basics of DC circuits. There is one caveat we wish to bring to your attention: The panels contained in the kit may not behave as expected. When two similar DC power sources are connected in series, the voltages should be additive. When connected in parallel, the currents should be additive. However, you may find that connecting Module 1 and Module 2 of this PV panel provided does not behave as expected when connected in series. Connecting the two modules in parallel will probably produce a higher current, though it may not be completely additive. Connecting the two modules in series may produce a higher voltage, but our experience has been that the increase is not significant nor does it behave as expected. You may need to experiment with various loads of different types to get the desired results. The provided LEDs and resistors, when connected as specified in the Student Guide, will allow your students to test the different variables and get the expected results based on those variables. CONNECTING MODULE 1 AND MODULE 2 The fastest way to connect the modules of your PV panel is to make the connection through the breadboard using alligator clip jumper wires. However, the ends of the wires on the PV modules may have smaller amounts of soldered metal exposed, or after prolonged use become difficult to insert into the breadboard. If the modules need to be connected in another way, consider using a short alligator clip wire (5” provided in kit) to fasten Module 1 and 2 together. The photographs on page 26 show one way to connect the components and get a working, functional solar-powered circuit, provided the LEDs are in the correct orientation, sufficient light is striking the panel, and the meters are turned on. There are many, many more ways the circuit can be connected through the breadboard that will work. This photograph is intended to be a reference or guide to assist you and your students, should you have limited time to conduct the activities.

@ Solar Modules and LEDs If you are using this curriculum guide with PV panels different from those in the kit, keep in mind that your panel may not produce the same current or voltage as the ones pictured in this guide. One LED must have at least 3 volts to light, and 2 LEDs in series must have at least 6 volts. Keep in mind that dimmer lights may not allow your PV panel to produce the needed voltage to light both LEDs. You may choose to allow your students to determine a workable solution by simply telling them one LED needs at least 3 volts, or if your time is limited, you may need to direct them to remove one LED from the circuit and move the other components on the breadboard so they are all connected. You can get a general idea of the capability of the solar panel you are using by connecting it directly to a digital multimeter and measuring its voltage output, or by consulting the packaging or labeling that came with it.

@Science Notebooks Throughout this curriculum, science notebooks are referenced. If you currently use science notebooks or journals, you may have your students continue using them. A rubric to guide assessment of student notebooks can be found on page 9. In addition to science notebooks, student worksheets have been included in the Student Guide. Depending on your students’ level of independence and familiarity with the scientific process, you may choose to use these instead of science notebooks. Or, as appropriate, you may want to make copies of worksheets and have your students glue or tape the copies into their notebooks.

Exploring Photovoltaics Teacher Guide

www.NEED.org

Activity 1: Introduction to Solar Energy  Objective Students will be able to describe how a PV cell converts radiant energy into electrical energy.

 Materials 20-25 Ping pong balls Flashlight Colored tape Sticky name tags or cardstock Photovoltaic Cell master, page 21 PV Ping Pong Simulation Instructions, page 22-23 Solar Energy Bingo, page 18 (optional) Solar Energy in the Round, page 20 (optional) Student Guide, pages 4-16, 21

2 Preparation Make copies of the master and prepare any interest grabber activities you plan to use (Solar Energy Bingo or Solar Energy in the Round). Preview the facilitation instructions for PV Ping Pong. Gather the supplies and set up the simulation supplies in an open area as described.

Procedure 1.

Have students read the solar energy informational text on pages 4-16 of the Student Guide, or assign as homework. Students should answer the review questions on page 21 of the Student Guide.

(Optional) Play Solar Energy Bingo and/or Solar Energy in the Round as an introductory activity to gauge students’ comfort with solar energy vocabulary. These activities may also be used as formative assessments throughout the unit.

Review and discuss a PV cell and its function with the class using the Photovoltaic Cell master.

Assign students to roles and run the PV Ping Pong Simulation.

Using the answer key on page 16, discuss answers to the review questions with students.

Activity 2: Simple Solar Circuit & Background There are some circumstances where a full-blown investigation of all the factors affecting solar panel output, a discussion of voltage, current, resistance, and power, or the use of breadboards is not necessary or practical for your classes. In those cases, this simple solar circuit activity can quickly inform students of how a PV cell works and how a solar system is affected by shading and angle, so they have a basic understanding of the most significant limitations on solar systems. This activity also makes a great introduction to the panels and multimeters prior to the subsequent investigations that are slightly more involved.

 Objectives Students will be able to connect a simple circuit with a solar panel. Students will be able to explain how shading affects solar panel output. Students will be able to explain how tilting a solar panel away from its light source affects output.

Exploring Photovoltaics Teacher Guide

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 Materials 6 Solar panels 6 LEDs 6 Digital multimeters 9 Alligator clips Lamps or bright light sources (sunlight through a window is acceptable) Cardboard or cardstock Tissue paper or similar translucent material Photovoltaic Cell master, page 21 (optional) Digital Multimeter master, page 24 Enlarged LED master, page 25 Student Guide, pages 22-24

2 Preparation Gather all materials and create six stations, each containing a PV panel, an LED, a digital multimeter, 3 alligator clips, a lamp/light source, tissue paper, and cardboard. The kit includes alligator clips and jumper wires, but you may need to supplement with additional clips, depending on your set-ups. Preview the activity yourself, connecting a circuit to anticipate issues students may have. Make copies of the student activity for each student and prepare copies of the masters you will use to project. Preview NEED’s multimeter set-up videos for sharing with the class: Setting Up a Digital Multimeter: https://youtu.be/vka8yjWVzpk?si=Lj6dFM4J4YJKmQjA Reading Current and Voltage on a Digital Multimeter: https://youtu.be/O1eFJKlHhM0?si=Z6W61H0kUqh42XC9 Decide if you will have students answer the Conclusion questions individually or as a class. Divide students into groups of no more than three individuals.

Procedure 1.

Review how a PV cell is set up and how it works, projecting the master from the previous activity if helpful. Explain that students will be connecting a very simple solar circuit to understand the most basic factors affecting solar panel output.

Project the Digital Multimeter master. Hold up a multimeter from the kit and demonstrate how and where the leads connect and which setting to use on the dial. Alternatively, you may show the YouTube videos on multimeter setup and readings (see links above).

Demonstrate the solar panel, showing students the red and black wires. Important: If your panel has more than one module, instruct students to use the red and black wires for just one module. Show them which two wires you would like them to use.

Project the Enlarged LED master, pointing out that there are two leads, and one lead (+) is longer than the other. Explain to students that an LED must be connected in the correct way to light. If the LED does not light when they have their circuit assembled, they should invert the connection of the LED. This is typically the first troubleshooting step if students are having issues.

Allow students time to complete the activity.

Have students reconvene as a class to discuss the Conclusion questions.

Exploring Photovoltaics Teacher Guide

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Activity 3: Build & Test Your Circuit & Background This activity introduces students to breadboards and setting up a circuit using a breadboard and a solar panel as the power source. Students will begin by learning how breadboards are structured and plan their circuit using a paper schematic diagram and symbols. Once they have planned their circuit, they can assemble and test it. After testing, students are then encouraged to test a parallel circuit design before testing a series circuit. However, the parallel circuit design can be used as an optional extension. It is addressed first in sequence prior to the series circuit, as students will continue working with their series assembly in subsequent activities and thus, does not require disassembly and reassembly going forward.

 Objectives Students will be able to distinguish between a series circuit and a parallel circuit. Students will be able to successfully connect a circuit using a breadboard.

 Materials 6 PV panels 6 Breadboards 6 100-ohm resistors 6 68-ohm resistors 12 LEDs Lamps or light sources Workable Wiring Schematic master, page 26 (optional) Student Guide, pages 25-31

2 Preparation Gather materials and assemble supplies into six stations for students. Each station should contain at least 1 PV panel, 1 breadboard, 2 LEDs, and 1 of each resistor. Decide if you will be sharing the visual of the wiring schematic or allowing your students to learn the connection basics and create their wiring plan on their If using, prepare a copy to project of the Workable Wiring Schematic master. Decide if you wish for students to assemble and test both series and parallel circuits. Parallel can be done as an option/extension, as the remaining variable testing activities explore the PV panel using a series circuit design. Make copies of the pages you will use from the Student Guide for each station, or for each student. If working indoors, assemble stations near your lamps/light sources. If working outdoors, ensure proper space is available for students to work in direct sunlight, and students can transport supplies outside easily.

Procedure 1.

Distribute copies of the Breadboards and How to Use Them, Connecting and Using a Solar Panel, How Light-Emitting Diodes (LEDs) Work, and Planning Your Breadboard Circuit worksheets on pages 25-29 of the Student Guide.

After students have reviewed the worksheets, allow them time to first work individually and then in small groups to plan the way they will connect the components on the breadboard. Be prepared to stop and hold a class discussion on breadboards and circuits if students are struggling.

After planning their breadboard circuit, it is helpful to check their designs and provide feedback on paper. Review student designs on Planning Your Breadboard Circuit worksheets. If the breadboard layouts are accurate, ask the students to build their circuit on the breadboard, including 2 LEDs and 2 resistors.

Distribute copies of the Build & Test Your Circuit: Parallel and Build & Test Your Circuit: Series on pages 30-31 of the Student Guide, if using both activities, and allow students sufficient time to read through the instructions.

If desired, see the instructions for Build & Test Your Circuit: Parallel to power the circuit and test it for the first time. Again, be prepared to review or lead a discussion on how the breadboard works if students are still having difficulty. If you plan to have students work only with a series circuit, skip to Step 6.

Exploring Photovoltaics Teacher Guide

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After successfully powering their breadboard in parallel, students should follow the instructions in Build & Test Your Circuit: Series to rewire their breadboard. The remaining activities are written as if the solar panel is wired to the breadboard in series. Students should be be able to transition into the variables testing activities without making changes to their circuit.

Problem Solving Check that the power (+) and ground (-) rail are connected to both the circuit and solar panel. LEDs have 2 “legs”. The long anode (+) should connect to the power (+) rail. The short cathode (-) should connect to the ground (-) rail. Resistors do not have direction and can be connected in the circuit at any point. Electrical components should only connect between rails and terminal strips. They should never be connected to the same terminal strip. Terminal strips should be used like wires to connect between components. If a component is connected to the same terminal strip in two places, the component will be bypassed, and the circuit will be shorted.

Activity 4: Set Up Multimeter 1 and 2 – Voltage and Current & Background Before beginning variables tests, it is important for students to be able to measure the output of their panels when wired in circuits. This activity provides a step-by-step approach with diagrams for students to practice wiring the two multimeters needed to measure voltage and current in their circuit with accurate readings. Voltage is measured in parallel, while current is measured in series.

 Objectives Students will be able to explain current and voltage as they relate to DC circuits. Students will accurately wire a digital multimeter into a photovoltaic system. Students will measure the voltage and current within a photovoltaic system. Students will be able to successfully connect a circuit using a breadboard.

 Materials 6 PV panels 6 Breadboards 6 100-ohm resistors 6 68-ohm resistors 12 LEDs Lamps or light sources 24 Alligator clip jumper wires (“male” prong end) 12 Digital multimeters Digital Multimeter master, page 24 Workable Wiring Schematic master, page 26 (optional) Student Guide, pages 22, 32-33

2 Preparation Gather materials and assemble supplies into six stations for students. Each station should contain at least 1 PV panel, 1 breadboard, 1 multimeter, 2 LEDs, 1 of each resistor, and 2 alligator clip jumper wires. If working indoors, assemble stations near your lamps/light sources. If working outdoors, ensure proper space is available for students to work in direct sunlight, and students can transport supplies outside easily. Prepare a copy of the Digital Multimeter master and/or preview NEED’s multimeter set-up videos for sharing with the class: Setting Up a Digital Multimeter: https://youtu.be/vka8yjWVzpk?si=Lj6dFM4J4YJKmQjA Reading Current and Voltage on a Digital Multimeter: https://youtu.be/O1eFJKlHhM0?si=Z6W61H0kUqh42XC9 Make copies of the pages you will use from the Student Guide for each station or for each student.

Exploring Photovoltaics Teacher Guide

www.NEED.org

Procedure 1.

Distribute copies of Connecting and Using a Solar Panel, Set Up Multimeter 1: Voltage, and Set Up Multimeter 2: Current on pages 27 and 32-33 of the Student Guide.

Ask students to wire the first digital multimeter using the instructions in Set Up Multimeter 1: Voltage. The first multimeter will be wired in parallel, directly into the same power (+) rail and ground (-) rail as the circuit.

Have students use the digital multimeter to measure the voltage when the solar panel is covered and uncovered.

Ask students to then wire the second digital multimeter using the instructions in Set Up Multimeter 2: Current. This multimeter will be wired directly in series, into the same path as the circuit. Students can refer to the 3-step diagram in the instructions. This diagram shows the easiest way to wire a multimeter in series.

Have students use the digital multimeter to measure the current when the solar panel is covered and uncovered.

Problem Solving The voltage multimeter must be wired to the same rails as the solar panel and circuit. Check that the power (+) and ground (-) rail are connected to both the circuit and solar panel. The current multimeter must be wired in series. The best way to accomplish this is to disconnect the circuit from the power (+) rail and bridge the gap using the multimeter’s leads. This will force the current through the multimeter and makes the multimeter part of the circuit itself.

Activity 5: Exploring Variables That Affect PV Panel Output  Objectives Students will be able to explain how light intensity, angle of incidence, shading, and surface temperature impact PV panel output.

 Materials 6 PV panels 6 Breadboards 12 Digital multimeters 12 LEDs 6 100-ohm resistors 6 68-ohm resistors 48 Alligator clip jumper wires (“male” prong end) 6 5” Alligator clip wires (clip ends) Lamps or light sources - dim, moderate, and bright Rulers Protractors

Cardboard or cardstock Tissue paper or similar translucent material Watertight plastic bags Plastic tubs Ice water Thermometers Hair dryers Digital Multimeter master, page 24 (optional) Workable Wiring Schematic master, page 26 (optional) Student Guide, pages 34-43

2 Preparation Gather materials for the six basic stations for students as listed above and used in Activity 4. Add the clip wires, and extra supplies as needed for each variable testing activity you aim to complete. Some students may not require all the alligator clips and jumper wires provided in the kit. Extras can be provided to promote exploration and multiple options. Consult the materials list chart on pages 5-6 for a breakdown of what items are needed for each variable test. If materials and time are limited, you may opt to have groups each work with a different variable (light intensity, angle of incidence, shading, and temperature), and have them jigsaw/report their findings to the class. Review wiring plans, schematics, and multimeter instructions if needed from Activities 3 and 4. Setting Up a Digital Multimeter video: https://youtu.be/vka8yjWVzpk?si=Lj6dFM4J4YJKmQjA Reading Current and Voltage on a Digital Multimeter video: https://youtu.be/O1eFJKlHhM0?si=Z6W61H0kUqh42XC9 Make copies of the pages you will use from the Student Guide for each station or for each student.

Exploring Photovoltaics Teacher Guide

www.NEED.org

Procedure 1.

Distribute copies of Verify Solar Module Similarity, Light Intensity, Angle of Incidence, Shading a PV Panel, and Surface Temperature (pages 34-43) from the Student Guide.

Make sure students understand that for each of these activities, they should be using both modules of the panel, connected in series to each other. Demonstrate or display the schematic master, should students need a reminder.

If necessary, review with your students how a protractor is used.

When students have finished their investigations, discuss their results. Reference the expected outcomes, if necessary, listed on page 17 when discussing these results.

Activity 6: Further Exploration and Discovery  Objective Students will be able to make and test a hypothesis with respect to simple PV panel output.

 Materials PV panels Breadboards Digital multimeters LEDs 100-ohm resistors 68-ohm resistors Alligator clip jumper wires (wire end) Alligator clip wires (clip ends) Lamps or light sources–dim, moderate, and bright Digital Multimeter master, page 24 (optional) Workable Wiring Schematic master, page 26 (optional) A Step Further activity, Student Guide, pages 44-45

2 Preparation In this activity students will need to combine into larger lab groups and re-distribute supplies. If necessary, pre-assign groupings and determine how materials will be split amongst the groups. Most groups will require 1 light source, 2 PV panels, 4 multimeters, 4 LEDs, 2 of each resistor, 2 breadboards, and 12 jumper wires. Review wiring plans, schematics, and multimeter instructions if needed from previous activities. Setting Up a Digital Multimeter video: https://youtu.be/vka8yjWVzpk?si=Lj6dFM4J4YJKmQjA Reading Current and Voltage on a Digital Multimeter video: https://youtu.be/O1eFJKlHhM0?si=Z6W61H0kUqh42XC9 Make copies of the student worksheet for each student.

Procedure 1.

Distribute copies of the student activity page and describe the challenge.

Put students into groups and facilitate materials redistribution as needed once students formulate their hypotheses and plan their tests. Allow students time to complete their work.

When students have finished their investigations, discuss their results. Ask students how their work mimics the way commercial photovoltaic panels are constructed. If you have easy access to a solar system, take students to it or show them photographs of it and have them try to determine how the solar cells inside one panel are connected.

Exploring Photovoltaics Teacher Guide

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 Unit Extension Activities 1. Career Exploration Have students review the list of careers from the Student Guide found on pages 17-19, and read the Career Profile on page 20. Discuss the careers with students or allow them time to further investigate any career that is interesting to them. Download and play NEED’s Energy Career Enigma to allow students to explore energy industry careers. The guide and digital file are available for free at www.NEED.org/product/energy-career-enigma. Download Energy Career Excursion from www.NEED.org/product/energy-careers-excursion-free-pdf-download and conduct one or more of the activities to allow students to explore careers and develop soft skills useful in the workplace. 2. Can Solar Meet Your Electricity Demands? Have students analyze their electricity usage and peak sun hours to determine whether solar energy can meet their demands. Students should use their own electric bill to determine their family’s electricity usage. If they do not have access to an electricity bill, students can use the national average of 855 kWh a month for electricity consumption. Have students complete page 46 of the Student Guide. A full page U.S. Solar Resource Map is included on page 27 of this guide and on page 47 of the Student Guide. For color maps and more information about solar resources in the U.S., visit the National Laboratory of the Rockies website at www.nrel.gov/gis/solar.html. As a further extension, have your students analyze the payback period in cities that have different peak solar hours than your city. 3. Your Solar-Powered Cabin Have students work in pairs or individually to power “Uncle Ed’s” cabin on pages 48-49 of the Student Guide. Have students present or discuss their plans with the class. 4. Data Collection Download NEED’s Schools Going Solar guide from www.NEED.org/product/schools-going-solar-free-pdf-download for data collection activities for solar installations. 5. Site Visit If your city or school district have a solar system installed, arrange for your students to visit the site to observe the installation, noting its azimuth, angle of tilt, and connections visible on the back. Ask the official who oversees the array to meet with your students to talk about the system and how it is benefitting the community or school district. Have a professional solar systems installer come into your class to talk about the different components of a system and discuss the different ways they can be installed for residential and commercial customers. 6. Solar Space Heating Read the text on solar space heating or instruct students to read it for homework from pages 28-29 of this guide. Hold a design challenge where students must design and/or build a solar collector that reaches a certain temperature, holds temperature, or other parameters. A simple version of this challenge is for students to build a pizza box solar oven. Download the activity instructions at www.NEED.org/shop.

Evaluation and Assessments There are a variety of assessment opportunities provided in this module. These include: Conduct the Solar-Powered Cabin activity as an assessment. Revisit the Review Questions on page 21 of the Student Guide. Play Solar Energy Bingo or Solar Energy in the Round as review activities before an assessment. Instructions can be found on pages 18-20. Evaluate student work and group work using the rubrics on page 15. Evaluate the unit with the class using the Evaluation Form on page 35.

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Rubrics for Assesment Inquiry Explorations Rubric This is a sample rubric that can be used with inquiry investigations and science notebooks. You may choose to only assess one area at a time, or look at an investigation as a whole. It is suggested that you share this rubric with students and discuss the different components.

SCIENTIFIC CONCEPTS

SCIENTIFIC INQUIRY

DATA/OBSERVATIONS

CONCLUSIONS

Written explanations illustrate accurate and thorough understanding of scientific concepts.

The student independently conducts investigations and designs and carries out his or her own investigations.

Comprehensive data is collected and thorough observations are made. Diagrams, charts, tables, and graphs are used appropriately. Data and observations are presented clearly and neatly with appropriate labels.

The student clearly communicates what was learned and uses strong evidence to support reasoning. The conclusion includes application to real life situations.

Written explanations illustrate an accurate understanding of most scientific concepts.

The student follows procedures accurately to conduct given investigations, begins to design his or her own investigations.

Necessary data is collected. Observations are recorded. Diagrams, charts, tables, and graphs are used appropriately most of the time. Data is presented clearly.

The student communicates what was learned and uses some evidence to support reasoning.

Written explanations illustrate a limited understanding of scientific concepts.

The student may not conduct an investigation completely, parts of the inquiry process are missing.

Some data is collected. The student may lean more heavily on observations. Diagrams, charts, tables, and graphs may be used inappropriately or have some missing information.

The student communicates what was learned but is missing evidence to support reasoning.

Written explanations illustrate an inaccurate understanding of scientific concepts.

The student needs significant support to conduct an investigation.

Data and/or observations are missing or inaccurate.

The conclusion is missing or inaccurate.

Culminating Project Rubric This rubric may be used with the extensions or for any other group work you ask the students to do.

CONTENT

ORGANIZATION

ORIGINALITY

WORKLOAD

Project covers the topic indepth with many details and examples. Subject knowledge is excellent.

Content is very well organized and presented in a logical sequence.

Project shows much original thought. Ideas are creative and inventive.

The workload is divided and shared equally by all members of the group.

Project includes essential information about the topic. Subject knowledge is good.

Content is logically organized.

Project shows some original thought. Work shows new ideas and insights.

The workload is divided and shared fairly equally by all group members, but workloads may vary.

Project includes essential information about the topic, but there are 1-2 factual errors.

Content is logically organized with a few confusing sections.

Project provides essential information, but there is little evidence of original thinking.

The workload is divided, but one person in the group is viewed as not doing a fair share of the work.

Project includes minimal information or there are several factual errors.

There is no clear organizational structure, just a compilation of facts.

Project provides some essential information, but no original thought.

The workload is not divided, or several members are not doing a fair share of the work.

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Answer Key STUDENT GUIDE REVIEW QUESTIONS 1.

Identify and explain the nuclear reaction in the sun that produces radiant energy. Smaller nuclei fuse together to form larger nuclei. During the process, some of the matter is converted and emitted as radiant energy.

Define renewable energy. Explain why solar energy is considered renewable. Renewable energy sources are resources that are continuously replenished by nature and never run out. Fusion reactions that power the sun will release energy for billions of years to come.

Explain why a car parked in the sun becomes hot inside. Light passes through the windows of a car and is absorbed by the interior fixtures, where it is transformed and trapped as thermal energy. The car is a solar collector.

Why is a solar cell called a PV cell? What does the word photovoltaic mean? A solar cell is called a PV cell because it uses light or solar energy to create electricity. “Photo” refers to light and “volt” refers to electricity.

Explain the conversion efficiency of a PV cell. How efficient are PV cells today? Conversion efficiency is the proportion of radiant energy the cell is able to convert to electricity. Current PV cells convert approximately 13-30 percent of the radiant energy striking them into electricity.

How do new thin-film technologies compare to conventional PV cells? New technologies and designs have produced conversion efficiencies as high as 46 percent, but with limitations to their uses.

Explain briefly how a PV cell converts radiant energy into electricity. PV cells are made of a semiconductor doped with materials that are electron rich or electron poor. The most common materials are silicon doped with phosphorus and boron. The phosphorus doped layer is the n-layer and the boron doped layer is the p-layer. When the two layers are in contact with each other, electrons move from the n-layer to the p-layer and an electric field is formed. Radiant energy of the correct wavelength is absorbed by electrons and the move back into the n-layer, seeking to shed the excess energy. A conducting wire allows the electrons to travel away from each other and complete a circuit, generating an electric current.

Do PV modules produce AC or DC current? Which type of current do most appliances use? What device converts DC to AC current? PV modules produce direct current. Most appliances and electronics require alternating current to run. An inverter changes DC power to AC power.

Define current and voltage and give the unit used to measure each. Current: the number of electrons flowing through a section of wire in one second, measured in amperes (Amps, or A) Voltage: the potential of an electron to jump a gap between charged plates, measured in volts (V)

10. Which area of the United States would be most advantageous for installing a utility-scale solar system? Use evidence in the text to support your answer. Answers may vary slightly, but in general the southwestern US, with the highest annual solar irradiance, is most advantageous. The argument can be made that its high summer temperatures render it less favorable. 11. Are photovoltaic systems better or worse for the environment when compared to a thermal power plant using natural gas as the fuel? Justify your answer with evidence from the text. Answers may vary, but some arguments may be as follows:

Better for the environment

Worse for the environment

No carbon emissions

Require large amounts of land for same electricity generated

Renewable fuel

Not able to operate all the time, so other sources of energy are needed to supplement

Make no noise when in operation

Full-time use requires energy storage, and the minerals for batteries must be mined

Almost maintenance-free, so energy is not needed to maintain them

Manufacturing PV technologies can harm the environment

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Expected Outcomes SOLAR INVESTIGATIONS Verify Solar Module Similarity, Student Guide, pages 34-35 Question: Should similar PV modules within an array vary significantly in electrical output under similar conditions? Conclusion: Each module should produce similar, though perhaps not identical, results.

Light Intensity, Student Guide, pages 36-37 Question: How does light intensity affect the electrical output of a PV array? Conclusion: The greater the light intensity, the higher the electrical output.

Angle of Incidence, Student Guide, pages 38-39 Question: How does the angle of incidence of the light source affect the electrical output of a PV array? Conclusion: The greater the angle between the panel and light source, the less the electrical output.

Shading a PV Panel, Student Guide, pages 40-41 Question: How does covering different parts of a PV panel affect its electrical output? How does the opacity of a material covering a PV

panel affect its output? How does the amount of the PV panel being covered affect its output? Conclusion: The more parts of a PV panel that are covered, the less the electrical output. The greater the opacity of the material covering the panel, the less the electrical output. The greater the amount of shade on the panel, the less the electrical output.

Surface Temperature, Student Guide, pages 42-43 Question: How does surface temperature affect the electrical output of a PV array? Conclusion: The greater the surface temperature of the panel, the less the electrical output.

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Solar Energy BINGO Instructions Solar Energy Bingo is a great icebreaker for a NEED workshop or conference. As a classroom activity, it also makes a great introduction to an energy unit.

2 Preparation 5 minutes

Time 45 minutes Bingos are available on several different topics. Go to www.NEED.org/resources/ energy-bingo-games to check out these resources for more bingo options! Biomass Bingo—Energy Stories and More Change a Light Bingo—Energy Conservation Contract Coal Bingo—Coal guides Energy Bingo—Energy Games and Icebreakers Energy Efficiency Bingo— School Energy Managers and School Energy Experts Hydropower Bingo— Hydropower guides Hydrogen Bingo—H2 Educate Nuclear Energy Bingo— Nuclear guides Oil and Natural Gas Bingo— Oil and Natural Gas guides Science of Energy Bingo— Science of Energy guides Wind Energy Bingo—Wind guides

Get Ready Duplicate as many Solar Energy Bingo sheets (found on page 30 of the Teacher Guide) as needed for each person in your group. In addition, decide now if you want to give the winner of your game a prize and what the prize will be.

Get Set Pass out one Solar Energy Bingo sheet to each member of the group.

Go PART ONE: FILLING IN THE BINGO SHEETS Give the group the following instructions to create bingo cards: This bingo activity is very similar to regular bingo. However, there are a few things you’ll need to know to play this game. First, please take a minute to look at your bingo sheet and read the 16 statements at the top of the page. Shortly, you’ll be going around the room trying to find 16 people about whom the statements are true so you can write their names in one of the 16 boxes. When I give you the signal, you’ll get up and ask a person if a statement at the top of your bingo sheet is true for them. If the person gives what you believe is a correct response, write the person’s name in the corresponding box on the lower part of the page. For example, if you ask a person question “D” and they give you what you think is a correct response, then go ahead and write the person’s name in box D. A correct response is important because later on, if you get bingo, that person will be asked to answer the question correctly in front of the group. If they can’t answer the question correctly, then you lose bingo. So, if someone gives you an incorrect answer, ask someone else! Don’t use your name for one of the boxes or use the same person’s name twice. Try to fill all 16 boxes in the next 20 minutes. This will increase your chances of winning. After the 20 minutes are up, please sit down and I will begin asking players to stand up and give their names. Are there any questions? You’ll now have 20 minutes. Go! During the next 20 minutes, move around the room to assist the players. Every five minutes or so tell the players how many minutes are remaining in the game. Give the players a warning when just a minute or two remains. When the 20 minutes are up, stop the players and ask them to be seated.

PART TWO: PLAYING BINGO Give the class the following instructions to play the game: When I point to you, please stand up and in a LOUD and CLEAR voice give us your name. Now, if anyone has the name of the person I call on, put a big “X” in the box with that person’s name. When you get four names in a row—across, down, or diagonally—shout “Bingo!” Then I’ll ask you to come up front to verify your results. Let’s start off with you (point to a player in the group). Please stand and give us your name. (Player gives name. Let’s say the player’s name was “Joe.”) Okay, players, if any of you have Joe’s name in one of your boxes, go ahead and put an “X” through that box. When the first player shouts “Bingo,” ask them to come to the front of the room. Ask them to give their name. Then ask them to tell the group how their bingo run was made, e.g., down from A to M, across from E to H, and so on.

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Now you need to verify the bingo winner’s results. Ask the bingo winner to call out the first person’s name on their bingo run. That player then stands and the bingo winner asks them the question which they previously answered during the 20-minute session. For example, if the statement was “can name two renewable sources of energy,” the player must now name two sources. If they can answer the question correctly, the bingo winner calls out the next person’s name on their bingo run. However, if they do not answer the question correctly, the bingo winner does not have bingo after all and must sit down with the rest of the players. You should continue to point to players until another person yells “Bingo.”

SOLAR ENERGY BINGO ANSWERS A.

Has used a solar clothes dryer

Knows the average conversion efficiency of PV cells

Knows the nuclear process in the sun’s core

Can explain how solar energy drives the water cycle Knows how plants convert solar energy into chemical energy

Has used a photovoltaic cell

Rides in a solar collector

Uses passive solar energy at home

Has seen a solar water heater

H. Can explain how solar energy produces wind L. Has cooked food in a solar oven

N. Knows the energy conversion that a PV cell performs

Can explain why dark clothes make you hotter in the sun

M. Can name two advantages of solar energy

Has hung clothes outside to dry

Owns solar protection equipment

13-30%

Fusion

In electromagnetic waves (or transverse waves)

Car without tinted windows is a solar collector-like a greenhouse

Sun heats the Earth’s surface unevenly-hot air rises and cooler air moves in

Allows sun to enter through windows for light and heat-has materials that retain heat (masonry, tile, etc.)

ask for location/description

Solar energy systems do not produce air pollutants or carbon dioxide, minimal impact on environment, sun’s energy is free

radiant energy to electrical energy

Dark colors absorb more radiant energy and turn it into thermal energy

Sunscreen, sunglasses, etc.

Sun evaporates water in lakes and oceans, water vapor rises and becomes clouds, rains to replenish

I Photosynthesis

Knows how radiant energy travels through space

ask for location/description

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ask for description

Solar Energy in the Round Solar Energy in the Round is a quick, entertaining game to reinforce vocabulary and information about solar energy and photovoltaics.

Grades 5–12

2 Preparation

Get Ready Copy the Solar Energy in the Round cards on pages 31-33 onto card stock and cut into individual cards. Make an additional copy to use as your answer key. These pages do not need to be cut into cards. Have the Exploring Photovoltaics Student Guides or NEED’s Secondary Energy Infobooks available for quick reference. Infobooks can be downloaded from www.NEED.org/product/energy-infobooks.

5 minutes

Get Set

 Time

Distribute one card to each student. If you have cards left over, give some students two cards so that all of the cards are distributed.

10–20 minutes “In the Round” guides are available on a variety of topics. Explore more fun “In the Round” examples at www.NEED.org/shop! Coal in the Round—Coal guides Conservation in the Round— School Energy Managers, School Energy Experts Energy in the Round—Energy Games and Icebreakers Forms of Energy in the Round—Science of Energy guides Hydrogen in the Round— H2 Educate Oil and Natural Gas Industry in the Round—Fossil Fuels to Products, Exploring Oil and Natural Gas

Have the students look at their bolded words at the top of the cards. Give them five minutes to review the information about their words.

Go Choose a student to begin the round and give the following instructions: Read the question on your card. The student with the correct answer will stand up and read the bolded answer, “I have _____.” That student will then read the question on their card, and the round will continue until the first student stands up and answers a question, signaling the end of the round. If there is a disagreement about the correct answer, have the students listen to the question carefully looking for key words (forms versus sources, for example) and discuss until a consensus is reached about the correct answer.

Alternative Instructions Give each student or pair a set of cards. Students will put the cards in order, taping or arranging each card so that the answer is directly under the question. Have students connect the cards to fit in a circle or have them arrange them in a column.

Uranium in the Round— Nuclear guides

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MASTER

Photovoltaic Cell

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PV Ping Pong Simulation Instructions &Background Solar energy can be used to produce electricity without any chemical reaction. This process, known as the photoelectric effect, allows electrons to be ejected or emitted from the surface of a material when photons of light strike the material. Solar panels, or photovoltaic cells, are the devices we use to collect radiant energy from the sun and turn it directly into electricity to power our homes, schools, and businesses. This process, however, can be somewhat mystifying to students. In this simulation, students will act as the layers of a solar cell within a solar panel, photons of light, and electrons on the move.

 Materials 20–25 Foam or tennis balls Flashlight Colored tape Sticky name tags Photovoltaic Cell master, page 21

2 Preparation Set up two lines of tape on the floor for students to stand on. The lines should be facing each other with a few feet between them. Create a circle behind one of the tape lines. This will be the photon home. Write out name tags for each of the roles. This can also be done by the students once roles are assigned. You may choose to get “fancy” giving name tags or props that resemble roles as well (i.e. N-layers = N, P-layers = P, Photons of light = a flashy item, etc.).

Procedure 1.

Show students examples of graphics, videos, or animations of how a PV cell works. Some good examples include: PV Interactive Infographic, SaveOn Energy: www.saveonenergy.com/how-solar-panels-work/ Brown University Sci Toons: www.youtube.com/watch?v=UJ8XW9AgUrw

Assign students to roles.

Ask the P-layer students to stand on one line and the N-layer students to stand on the other line so that they are facing each other. Tell them the P-N junction is between them. Have the students on each line hold hands “wiring“ themselves together.

The electrical load(s) should stand at one end of the two lines. Students on the end of each line should hold hands with the electrical load, forming an open loop from P-layer through electrical load and on to N-layer.

Ask the photons to congregate in the photon circle, their “light source”.

Give each N-layer student a ball. Tell students these are electrons. P-layer students should have none but should want to receive them.

Explain to students that the N-layer has a higher concentration of electrons than the P-layer, and the electrons migrate toward the P-layer. When you signal, photons must leave the light source circle and tap a P-layer student on the shoulder. They should then return to the circle and repeat the process. Explain that now, an electric field exists between the N-layer and P-layer.

Describe to students the process that occurs when sunlight reaches a photovoltaic cell. Photons reach the P-layer, energizing electrons. The energized electrons move through the conductive lines on the PV cell through the circuit to do work. When a P-layer student with a ball feels a tap, he or she should frantically wave their arms to indicate readiness to accept a ball (electron).

When N-layer students see the P-layer students across from them wave their arms, they should toss their electrons to the P-layer students, who will catch them.

10. Explain that the electrons transfer the energy they received from the photons to the circuit. When the electrical load student receives an electron, they should turn on their flashlight and yell “WOOO HOO,” and turn it off as they pass the electron to the other side. 11. Explain that electrons returning to the N-layer will again move into the P-layer as they did at the start of the simulation. As electrons come to the N-layer from the load, they should immediately be tossed to the P-layer again. 12. Simulate darkness by having photon students sit in their circle, not moving. P-layer students should stand, holding electrons, ready to receive photons.

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PV Ping Pong Simulation and Roles N-layer students – 17

Photon students – 10 Ball

P- layer students – 17

Electrical load students – 1-2

photon circle

Movement of Electrons (balls)

STEP 2

P-Layer

STEP 3

STEP 4 STEPS 1, 5

Electrical load

N-Layer 1. 2. 3. 4. 5.

N-layer passes electron to P-layer Photon strikes P-layer P-layer passes electrons toward load Electrons power load and return to N-layer N-layer passes electron to P-layer again; when simulation ends, P-layer should have electrons.

Extensions Have students determine how they would extend the simulation to include more solar arrays and devices into the circuitry. Have students write a description of how PV cells work. Have students design a simulation to showcase how a concentrated solar power (CSP) facility operates.

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MASTER

Digital Multimeter DISPLAY

V ---

DC VOLTAGE

1000

OFF

200

2000 µ

200 m

20 m

2000 K

200

RESISTANCE

200K B

B E

10 20K

NPN PNP

AC VOLTAGE

200µ

20 2000 m

ROTARY SWITCH

750

200

Ω

hFE 2000

DC CURRENT

200

DIGITAL MULTIMETER

A ---

10A max unfused

10ADC VΩmA 750VAC

10A JACK FOR RED (NOT USED)

1000VDC 200m A max

VΩmA JACK FOR RED

COM

500V max

COM JACK FOR BLACK

Directions DC Voltage (

)

1. Connect RED lead to VΩmA jack and BLACK to COM. 2. Set ROTARY SWITCH to highest setting on DC VOLTAGE scale (1000). 3. Connect leads to the device to be tested using the alligator clips provided. 4. Adjust ROTARY SWITCH to lower settings until a satisfactory reading is obtained. 5. With the solar modules or array, the 20 DCV setting usually provides the best reading.

DC Current (

)

Set up

1. Connect RED lead to VΩmA jack and BLACK to COM. 2. Set ROTARY SWITCH to 10 ADC setting. 3. Connect leads to the device to be tested using the alligator clips provided. Note: The reading indicates DC AMPS; a reading of 0.25 amps equals 250 mA (milliamps). 4. With the solar modules or array, the 20mA DC setting usually provides the best reading.

Reading YOUR MULTIMETER MIGHT BE SLIGHTLY DIFFERENT FROM THE ONE SHOWN. BEFORE USING THE MULTIMETER READ THE OPERATOR’S INSTRUCTION MANUAL INCLUDED IN THE BOX FOR SAFETY INFORMATION AND COMPLETE OPERATING INSTRUCTIONS.

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MASTER

Enlarged LED epoxy case emitted light LED chip

anode lead

cathode lead

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MASTER

Workable Wiring Schematic Diagram 1 depicts a common way to connect opposite power (+) and ground (-) rails. This is a reference for how students could wire the circuit before connecting the multimeters. There are many ways for students to connect these 4 components, so there may be variety in the final circuits. Since students are wiring the circuit in series, the order of the LEDs and resistors does not matter. If the circuit does not light, students should check the orientation of their LEDs and check that terminal strips are utilized accurately. Diagrams 2 and 3 show the zoomed in and out images of one way to connect the two digital multimeters to the solar panel and circuit. These photographs are intended to be a reference or guide to assist you and your students, should you have limited time to conduct the activities. The voltage multimeter should always be wired in parallel, directly to the power (+) and ground rails (-). The current multimeter is wired directly into the circuit, and acts as a bridge between the power (+) rail and the first electrical component. DIAGRAM 1

DIAGRAM 3

Module 1 Wires

Voltage Multimeter

Module 1 Wires

Resistors

LEDs

LEDs Current Multimeter

Module 2 Wires

DIAGRAM 2

Circuit/Load Solar Panel

Voltage Multimeter Wired to the power (+) and ground (-) rails, in parallel to the panel and circuit.

Current Multimeter Wired as part of the circuit, in series.

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MASTER

U.S. Solar Resource Map Annual Average Solar Concentration

Note: Alaska and Hawaii not shown to scale Data: National Laboratory of the Rockies

5 to 6

4 to 5

3 to 4

Less than 3

LOW

Annual Average Solar Concentration (KILOWATT-HOURS PER SQUARE METER PER DAY) HIGH

More than 6

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Solar Space Heating Space heating means heating the space inside a building. Today, many homes use solar energy for space heating. There are two general types of solar space heating systems: passive and active.

Passive Solar Homes In a passive solar home, the house itself operates as a solar collector. A passive home does not use any special mechanical equipment such as pipes, ducts, fans, or pumps to transfer the heat the house collects on sunny days. Instead, a passive solar home relies on properly oriented windows and is designed with added thermal mass to store and release heat. Since the sun shines from the south in North America, passive solar homes are built so that most of the windows face south. They often have few or no windows on the north side. A passive solar home converts solar energy into heat just as a closed car does. Sunlight passes through a home’s windows and is absorbed in the walls and floors. Materials such as tile, stone, and concrete are often used, because they can store more heat than wood or sheetrock. To control the amount of heat in a passive solar home, the designer must determine the appropriate balance of mass in the floors and walls with the admission of sunlight.

Passive Solar Home SUMMER SUN

WINTER SUN Overhang creates shade HEAT CIRCULATION

STORAGE OF HEAT IN THE FLOOR AND WALLS

South

North

PUEBLO DWELLING

Windows let in the sunlight, which is converted into heat when it is absorbed by the walls and floors. The mass stores the heat from the sun and releases it when the air temperature inside drops below the temperature of the mass. Heating a home by warming the walls or floors is more comfortable than heating the air inside a home. Additionally, the doors and windows can be closed to keep heated air in or opened to let it out, to keep the temperature in a comfortable range. At night, special heavy curtains or shades can be pulled over the windows to keep the daytime heat inside the home. In the summer, awnings or roof overhangs help to shade the windows from the high summer sun to prevent the home from overheating. Passive homes are quiet, peaceful places to live. A well-designed passive solar home can harness 30 to 80 percent of the heat it needs from the sun. Many passive homeowners install equipment such as fans to help circulate air to further increase the comfort and energy efficiency of their homes. When special equipment is added to a passive solar home, it is called a hybrid system.

Image Credit: John Mackenzie Burke via Wikimedia Commons

Many indigenous Americans, like the Pueblo in the Southwest, used passive solar designs when building their homes.

ACTIVE SOLAR HOME

Active Solar Homes Unlike a passive solar home, an active solar home uses mechanical equipment such as pumps, blowers, and PV cells to convert radiant energy to thermal energy or electricity. Pumps and blowers allow for greater control of when, where, and how much of the collected heat from the sun gets used. This equipment delivers the heat from where it is collected to where it is needed.

Image Credit: Kristian/Adobe Stock

Active solar homes use mechanical equipment such as PV cells, pumps, and blowers to harness the sun’s energy.

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Storing Solar Heat

MATERIALS THAT RETAIN HEAT WELL

The challenge confronting any solar heating system—whether passive, active, or hybrid—is heat storage. Solar heating systems must have some way to store the heat that is collected on sunny days to keep people warm at night or on cloudy days. In passive solar homes, heat is stored by using dense interior materials that retain heat well—masonry, adobe, concrete, stone, tile, or water. These materials absorb surplus heat and radiate it back into the room when the air temperature is lower than the surface temperature of the material. Some passive homes have walls up to one foot thick. In active solar homes, heat may be stored in one of two ways—a large tank may store a heated liquid, or rock bins beneath the house may store warm mass. Houses with active or passive solar heating systems may also have furnaces, wood-burning stoves, or other heat sources to provide heat during long periods of cold or cloudy weather. These are called back-up systems.

Solar Water Heating

Masonry

Concrete

Adobe

Stone

SOLAR WATER HEATER

Solar energy is also used to heat water. Water heating is the second largest home energy expense, costing the average family more than $300 a year. Installing a solar water heater can save 50 to 80 percent of your water heating bill, depending on which type of back-up system you have, where you live, and how much hot water your family uses. A well-maintained solar water heating system can last around 20 years, longer than a conventional water heater. A solar water heater works in the same way as solar space heating. A solar collector is mounted on the roof, or in an area of direct sunlight. It collects sunlight and converts it to heat. Solar water heaters then circulate the fluid to the home. Passive solar water heaters rely on gravity only to make this happen. Active solar water heaters rely upon pump systems. In an active solar water heater, When the fluid in the system becomes hot enough, a thermostat starts a pump. The pump circulates the fluid through the collector until it reaches the required temperature, called the set point. Then the heated fluid is pumped to a storage tank where it is used in a heat exchanger to heat water.

Image Credit: Zikri/Adobe Stock

Passive Solar Water Heater Batch collector

The hot water may then be piped to a faucet or showerhead. Most solar water heaters that operate in cold climates use a heat transfer fluid similar to antifreeze that will not freeze and damage the system. Today, millions of homes in the U.S. use solar heaters to heat water for use in household activities or swimming pools.

Hot water to house

Spigot drain valve (for cold climates)

Bypass valves Cold water supply

Solar storage/ backup water heater

Passive solar water heaters work best in areas where temperatures rarely fall below freezing. They also work well in households with significant daytime and evening hot water needs. This image depicts a passive solar water heater, as it does not use a pump and relies upon gravity for circulation. ©2026 The NEED Project

Exploring Photovoltaics Teacher Guide

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SOLAR ENERGY BINGO Knows the nuclear process in the sun’s core

Rides in a solar collector

H. Can explain how solar energy produces wind

Uses passive solar energy at home

Has seen a solar water heater

Has cooked food in a solar oven

N. Knows the energy conversion that a PV cell performs

Can explain why dark clothes make you hotter in the sun

Owns solar protection equipment

ME NA ME NA

E NA M

NA M

ME NA

NA NA

ME NA

Knows how radiant energy travels through space

Knows how plants convert solar energy into chemical energy

Can explain how solar energy drives the water cycle

M. Can name two advantages of solar energy

Knows the average conversion efficiency of PV cells Has used a photovoltaic cell

NA M

Has used a solar clothes dryer

Exploring Photovoltaics Teacher Guide

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IN THE ROUND

I have energy.

I have the speed of light.

Who has the two major gases that make up the Who has the form of energy that sunlight is sun? converted to when it is absorbed by the Earth?

I have hydrogen and helium.

I have thermal energy.

Who has the process in which very small nuclei Who has the color that absorbs more sunlight are combined into larger nuclei? than other colors?

I have nuclear fusion.

I have the color black.

Who has the form of energy emitted into space Who has a system that captures solar energy by stars and the sun during fusion? and uses it to heat spaces or substances?

I have radiant energy.

I have a solar collector.

Who has the amount of time it takes the sun’s Who has the process of using the sun’s energy energy to reach the Earth? to heat buildings?

I have solar space heating.

I have eight minutes. Who has 186,000 miles per second?

Exploring Photovoltaics Teacher Guide

Who has a home that relies on orientation and construction materials to capture the sun’s energy for heating interior spaces?

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IN THE ROUND

I have chemical energy.

I have a passive solar home.

Who has a home with solar collectors and other solar equipment to heat it?

Who has the process that traps the sun’s energy in the atmosphere and makes life on Earth possible?

I have an active solar home.

I have the greenhouse effect.

Who has the energy source produced by uneven heating of the Earth’s surface?

Who has the process plants use to convert radiant energy into chemical energy?

I have wind.

I have photosynthesis.

Who has organic matter that has absorbed energy from the sun?

Who has evaporation, condensation, and precipitation driven by energy from the sun?

I have biomass.

I have the water cycle.

Who has the energy sources that can be replenished in a short time?

Who has an object that can be used to cook food on a sunny day?

I have renewables.

I have a solar oven.

Who has the form of energy that is stored in fossil fuels?

Exploring Photovoltaics Teacher Guide

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IN THE ROUND

I have concentrated solar power. Who has the Greek word that means light?

I have silicon. Who has the device that nearly 2 million U.S. homes use to increase the thermal energy in their water?

I have solar water heater.

I have photo. Who has tiny bundles of energy from the sun?

Who has the direction solar collectors should face in the U.S.?

I have photons.

I have south.

Who has the form of energy directly produced by solar cells?

Who has a major reason that capturing sunlight is difficult?

I have electrical energy.

I have solar is spread out.

Who has the technical word that is abbreviated as PV ?

Who has the only renewable energy source that is NOT produced by the sun’s energy?

I have photovoltaic.

I have geothermal.

Who has the element that is a semi-conductor used to make PV cells?

Who has the ability to do work or cause a change?

Exploring Photovoltaics Teacher Guide

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Youth AWards Program for Energy Achievement

Youth Energy Conference & Awards

NEED’s annual Youth Awards Program for Energy Achievement rewards students for their efforts in energy outreach and student leadership.

The NEED Youth Energy Conference and Awards gives students more opportunities to learn about energy and to explore energy in STEM (science, technology, engineering, and math).

The Youth Awards Program is great for all schools—new to energy education, or veteran. Projects and outreach completed for the program provide opportunity for enrichment and engagement, as well as an opportunity for your students, classroom, and school to shine. Youth Awards projects can be completed by afterschool/out-of-school time programs, community groups, and even families!

The annual June conference has students from across the country working in groups on an Energy Challenge designed to stretch their minds and energy knowledge. The conference culminates with the Youth Awards Ceremony recognizing student work throughout the year and during the conference. For More Info: www.NEED.org/youthenergyconference

What’s involved? Students and teachers set goals and objectives and keep a record of their activities. Students create a digital project to submit for judging. In April, digital projects are uploaded to the online submission site.

Check out: For more information and project submission details, we invite you to visit https://youthawards.NEED.org. Be sure to explore the site to view past winning projects and garner inspiration!

Exploring Photovoltaics Teacher Guide

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Exploring Photovoltaics Evaluation Form State: ___________

Grade Level: ___________

Number of Students: __________

1. Did you conduct the entire unit?



Yes



2. Were the instructions clear and easy to follow?



Yes



3. Did the activities meet your academic objectives?



Yes



4. Were the activities age appropriate?



Yes



5. Were the allotted times sufficient to conduct the activities?



Yes



6. Were the activities easy to use?



Yes



7. Was the preparation required acceptable for the activities?



Yes



8. Were the students interested and motivated?



Yes



9. Was the energy knowledge content age appropriate?



Yes



10. Would you teach this unit again? Please explain any ‘no’ statement below



Yes



How would you rate the unit overall?



excellent



good



fair



poor

How would your students rate the unit overall?



excellent



good



fair



poor

What would make the unit more useful to you?

Other Comments:

Please fax or mail to: The NEED Project

8408 Kao Circle FAX: 1-800-847-1820 Manassas, VA 20110 Email: info@need.org

Exploring Photovoltaics Teacher Guide

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