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KEEP: Solar Tilt Investigation

Exploring the Effect of Sun Angle on �Solar Panel Electricity Generation

KEEP: Wisconsin’s K-12 Energy Education Program - www.uwsp.edu/keep

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KEEP would like to acknowledge the land and water in what is now called Wisconsin. The University of Wisconsin - Stevens Point occupies the ancestral and contemporary lands of the Menominee and Ho-Chunk People. Please take a moment to acknowledge and honor this Menominee and Ho-Chunk land and the people who have worked to sustain it for many generations.

Acknowledge Indigenous Homeland we are on...

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Notes for teachers

  • Many thanks to Nate Mahr and Chris Mitchell , 2021 Energy Educator’s of the Year, for sharing this lesson with KEEP and encouraging KEEP to share it with you!
    • Learn more about Nate and Chris (from Oregon Middle School) and KEEP’s Energy Educator of the Year program on the KEEP website.
  • Recommended grade levels 5-12 (Elementary educators see alternate lesson)
  • Use this slideshow with the KEEP Solar Tilt Investigation Student Sheet
  • Make a copy of this slideshow to have a version you can edit to meet your needs.
  • Make copies of the Student Worksheets to edit to meet your needs.
  • Generate a sunpath diagram for your latitude at TheSolarPlanner.com
  • Remove this slide before using with students.
  • Slides with the logo on lower right of this slide are NOT part of this lesson, rather they are links to other KEEP lessons you may want to use to support this lesson or information for teachers. The links to original KEEP curriculum do NOT have supporting, editable google materials.

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STANDARDS supported by this lesson

Wisconsin Standards for Environmental Literacy and Sustainability

  • ELS.C1.B: Sense of Place
  • ELS.EN6.A: System Structure & Outcomes
  • ELS.EN6.C: Models of Sustainability
  • ELS.EN7.A: Inquiry & Investigation

Wisconsin Standards for Mathematics

  • Math Practice 4: Model with Mathematics

Wisconsin Standards for Social Studies

  • SS. Geog.5.a: Human Environment Interaction

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Wisconsin Standards for Science (based on NGSS)

  • SCI.PS3.A: Definitions of Energy
  • SCI.PS3.B: Conservation of Energy & Energy Transfer
  • Sci.PS3.C: Relationships between Energy & Forces
  • SCI.PS3.D: Energy in Chemical Processes
  • SCI.SEP1.A: Asking Questions
  • SCI.SEP4: Analyzing & Interpreting Data
  • SCI.SEP6.A: Constructing an Explanation
  • SCI.ESS3.A: Natural Resources
  • SCI.ESS3.D: Global Climate Change
  • SCI.ETS3.A: Science & Engineering are Human Endeavors
  • SCI.ETS.C: Science and Engineering Use Multiple Approaches to Create New Knowledge and Solve Problems

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LESSON OVERVIEW

Students will learn how solar panels generate electricity and use KEEP’s Solar Tilt Kit to determine the factors that impact the amount of electricity generated by a solar panel.

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OBJECTIVES

Students will…

  • Demonstrate how electrons move through a solar circuit to produce electricity
  • Understand the job of Solar Installers and Solar Design Engineers
  • Explore whether or not the angle at which sunlight shines on a solar panel significantly changes the amount of electricity generated by the solar panel.
  • Explain which angle of sun shining on the solar panel generates the most electricity.
  • Elaborate on how the Solar Tilt Investigation can be used to determine a general plan for installing residential solar panels in Wisconsin.
  • Evaluate…
    • Whether or not solar is accessible to all residents of Wisconsin
    • How we can make solar more accessible for all residents of Wisconsin
  • Extend learning to determine whether or not sunlight can be captured when reflected from surfaces.
  • Explain what types of surface reflect the most sunlight
  • Connect learning from the Solar Tilt Investigation to climate change

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INTRODUCTION - How Solar Cells Work

DISCUSS the following questions as a class:

  1. What do we use electricity for?
  2. How do we get electricity?
  3. What do the terms renewable and non-renewable mean?
  4. Why would someone want to use renewable energy?
  5. Why might someone be hesitant to use renewable energy?
  6. How do solar panels produce electricity?

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INTRODUCTION - How Solar Cells Work

I can demonstrate how electrons move through a solar circuit to produce electricity.

DEMONSTRATION:

You will explore one of the fastest growing renewable resources, solar energy from photovoltaic (PV) panels.

You will play the role of electrons in a solar panel connected to an electrical circuit.

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How Solar Cells Work

The sun turns on the flashlight and shines it through the negative layer (n-layer), p-n junction and positive layer (p-layer).

The electrons in the n-layer and p-layer start to move and wiggle.

When electrons bump into the sides of their layer, they change directions.

When electrons bump into the p-n junction one of two things happens:

  1. The p-n junction allows electrons from the p-layer to move into the n-layer.
  2. The p-n junction does not allow electrons from the n-layer to move into the p-layer.

Electrons in the n-layer move out (one by one) into the electrical circuit.

Electrons in the circuit start to move towards the p-layer.

The electrical device turns on.

Electrons in the circuit near the p-layer enter the p-layer from the circuit.

The process continues. When the sun turns off the flashlight, (or the flashlight is covered by a cloud), the electrical device turns off (or slows) and all electrons stop moving.

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INTRODUCTION - How Solar Cells Work

DISCUSS the following questions as a class:

  • Describe how electrons flow through a solar circuit to create electricity? (click for answer)
  • Why are solar panels a renewable source of electricity?
  • Will we ever run out of the sun?
  • Are there any waste products from solar energy?
  • What are some potential drawbacks of using solar panels to produce electricity/energy?

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The sun shines on solar cell going through the negative layer (n-layer), p-n junction and positive layer (p-layer).

The electrons in both n-layer and p-layer start moving and wiggling around.

When electrons bump into the sides of their layer, they change directions.

When electrons bump into the p-n junction one of two things happens:

  • Electrons that hit from the p-layer can move into the n-layer
  • Electrons that hit from the n-layer cannot move into the p-layer

Eventually, electrons in the n-layer move out into the electrical circuit. This causes the electrons in the circuit to start moving which turns the electrical device on.

Electrons in the circuit near the p-layer enter the p-layer from the circuit.

The process continues while the sun shines and stops when the sun is not shining.

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ENGAGE

TASK: Imagine that you are a Solar Installer or Solar Design Engineer who is responsible for the design and/or installation of rooftop panels for homes in your community…

  • Determine the best direction and angle to orient the solar panels
  • Draft a proposal to communicate your recommendation

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ENGAGE

Watch the video, Careers in Solar: Solar Installer (click on the video to play).

Read the career profile for a Solar PV Installer

View the International Renewable Energy Council (IREC) Solar Career Map

I can understand the job of a Solar Installer.

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ENGAGE

Watch the video, Days at Work: Solar Design Engineer (click on the video to play).

Read the career profile for a Residential PV System Designer

View the International Renewable Energy Council (IREC) Solar Career Map

I can understand the job of a Solar Design Engineer.

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ENGAGE

DISCUSS:

Describe the role of a Solar Installer.

Describe the role of a Solar Design Engineer.

What skills are needed to be a Solar Installer?

What skills are needed to be a Solar Design Engineer?

How are both installers and engineers helping to make a difference in the world?

​

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EXPLORE

EXPLORE:�Does the angle at which sunlight shines on a solar panel change the amount of electricity generated by the solar panel?

If so, which angle of the sun shining on the panel generates the most electricity?

MATERIALS:

  • Solar panel & stand
  • Protractor
  • Multi-meter
  • Alligator clips

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EXPLORE

SET-UP:

1. Gather all materials and return to your work space.

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2. Attach 1 leg to each peg on the side of the solar panel � (textured side facing out).

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3. Carefully insert tabs at the bottom of each leg into the � base at the same time (the legs do not need to be � inserted all the way,they just need to be even).

4. Attach the protractor over the peg on one side of the solar � panel stand with the curved edge of the protractor pointed � downward.

5. Use the alligator clips to attach the solar panel to the � multimeter. (red to red and black to black)

  • Turn the multimeter dial to 20 Volts.
  • Determine exactly where you want your solar panel.
  • Use a compass to determine the direction it is facing.

​

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EXPLORE

EXPLORE:�Does the angle at which sunlight shines on a solar panel change the amount of electricity generated by the solar panel?

If so, which angle of the sun shining on the panel generates the most electricity?

VARIABLES: What variables you are investigating in this exploration?

HELPFUL HINT

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Independent Variable: Variable in the experiment that the experimenter controls.

Dependent Variable: Variable in the experiment that changes in response to the Independent Variable

What is the Independent Variable?

Angle of the Sun shining on the solar panel

Electricity generated

What is the Dependent Variable?

Angle of

Electricity generated

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EXPLORE

HYPOTHESIS:

What do you think will happen to the Dependent Variable when the Independent Variable is changed?

Write a hypothesis on your student sheet.

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Does your hypothesis match one of these options?

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Changing the angle of the sun on the solar panel will not change the amount of electricity generated by the panel.

  • This is a null hypothesis. (there is no significant difference)

Changing the angle of the sun on the solar panel will change the amount of electricity generated by the panel.

  • This is an alternative hypothesis. (predicts there will be a significant difference)

If your hypothesis does not match one of these options, practice re-writing it to follow a similar structure.

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EXPLORE

EXPLORE:

  1. Adjust the solar panel so that it is horizontal to the surface it is setting on.
  2. Measure and record your first voltage.
  3. Tip the solar panel toward the sun 10 degrees (make sure the protractor is aligned correctly on the stand as you use it to determine the angles)and measure/record the voltage.
  4. Continue tipping the solar panel toward the sun and measuring/recording the voltage every 10 degrees until the panel is perpendicular to the surface (vertical).
  5. Return the solar panel to the horizontal position.
  6. Tip the solar panel away from the sun 10 degrees and measure /record the voltage.
  7. Continue tipping the solar panel away from the sun and measuring/recording the voltage every 10 degrees until the panel is perpendicular to the table (vertical).

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EXPLAIN

I can explain which angle of the sun shining on the solar panel generates the most electricity.

GRAPH both data tables in one graph:

Place independent variable data on the x-axis and dependent variable data on the y-axis.

Use positive numbers to represent the angle (degrees) when the panel was tilted towards the sun.

Use negative numbers to represent the angle when the panel was tilted away from the sun.

Set your graph up and WAIT to confirm you have done so correctly BEFORE adding your data points.

GRAPH YOUR DATA

Check to make sure your x and y axis are set up correctly.

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If they are, start adding your data points.

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EXPLAIN

USE YOUR DATA & GRAPH TO:

Explain if you should reject or accept the null hypothesis.

  • Changing the angle of the sun on the solar panel will not change the amount of electricity generated by the panel.

Explain if you should reject or or accept the alternative hypothesis.

  • Changing the angle of the sun on the solar panel will change the amount of electricity generated by the panel.

​

ANALYZE YOUR DATA

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EXPLAIN

USE YOUR DATA & GRAPH TO:

Find the angle on the protractor which generated the most electricity.

  • This angle determines the angle at which the solar panel is pointed towards the sun.

ANALYZE YOUR DATA

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EXPLAIN

USE THE SUN ANGLE DIAGRAM TO:

Determine the altitude (angle of sun above the horizon) when you collected your data.

*NOTE…

Geometry tells us the solar panel’s surface is perpendicular (90 °) to the sun’s direct rays when the angle on the protractor (your answer to #5) is the same as the sun angle (your answer to #6).

How close to perpendicular on the solar panel were the sun’s direct rays when the panel generated the most electricity in your exploration?

Hint…how different are your answers for #5 & #6?

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ELABORATE

TASK: Imagine that you are a Solar Installer or Solar Design Engineer who is responsible for the design and/or installation of rooftop panels for homes in your community…

  • Draft a proposal (paragraph) recommending the optimal direction and angle for solar panel installation in your community. Use evidence from the exploration to support your recommendation.
  • Include a sketch that demonstrates the solar panel / sun angle set-up that generates the most electricity
  • Suggest other factors homeowners in your �community might need to consider (in �addition to your recommended direction/�angle) when installing a solar panel.

I can elaborate on how the Solar Tilt Investigation can be used to determine a general plan for installing residential solar panels/arrays in Wisconsin.

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ELABORATE

DISCUSSION:

  • What was the optimal angle and direction for rooftop solar installation in our community?
  • What were other factors you thought homeowners would need to consider when installing a rooftop solar panel?

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EVALUATE

IS SOLAR ACCESSIBLE FOR ALL RESIDENTS OF WISCONSIN?

GROUP ACTIVITY

INITIAL DISCUSSION: Discuss the following questions with members of your group.

  • What were some of the factors you thought homeowners would need to consider when installing a rooftop solar panel?
  • Could any of these factors be a barrier that prevents some people from having access to solar energy? Explain.
  • Are there other barriers you can think of that make it challenging for some people to access solar energy? Explain
  • Do these barriers impact all people in the same way? Explain.

READ: Read the following text from Georgetown Climate Center with your group:

I can evaluate whether or not solar is accessible to all residents of Wisconsin and how we can make solar more accessible for all residents of Wisconsin.

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EVALUATE

IS SOLAR ACCESSIBLE FOR ALL RESIDENTS OF WISCONSIN?

POST READING DISCUSSION: AFTER reading the Enhancing Access to Solar Energy article, discuss these three questions with your group:

  • Are there other barriers you can think of �that make it challenging for some people �to access solar electricity? Explain
  • Do these barriers impact all people in the �same way? Explain.
  • Why is it important to consider ways for �all people to have access to solar electricity?

Did reading the article cause you to change/add on to your answers from your initial discussion? Explain.

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EVALUATE

Is solar accessible for ALL residents of Wisconsin? Explain.

How can we make solar more accessible for ALL Wisconsin residents?

CLASS DISCUSSION

Why is it important to consider ways for ALL people to have access to solar electricity?

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EVALUATE

SOLAR ACCESSIBILITY

If you are interested in the topic of expanding equity in solar and want to learn more check out work being done in these communities:

Or read additional articles on this topic:

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EXTEND

What we know…

  • The angle of a solar panel affects electricity generation
  • Some Wisconsin residents have little or no access to solar generated electricity

What we need to learn…

CAN WISCONSIN GO SOLAR?

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EXTEND

Sunlight reflects off various surfaces. Can sunlight from reflected surfaces be captured?

Use the Pyranometer to measure reflected light from various surfaces around your schoolyard.

What types of surface reflect the most sunlight?

How can this information be used?

PYRANOMETER

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EXTEND

TASK: Find the ideal place to install a solar panel/solar array using a pyranometer.

A pyranometer measures the solar irradiance or light energy from the entire sun that hits one single point on Earth. The higher the solar irradiance, the better a place is for solar panels.

What location combination is the best to install solar?

How can we use this information?

PYRANOMETER

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EXTEND

The Solar Pathfinder is used for shade analysis. Any trees, buildings or other objects that could cast shadows are reflected in the plastic dome showing shading patterns at that location.

You will explore how the Solar Pathfinder and online tools can help analyze the solar potential of a given location.

SOLAR PATHFINDER

& SHADE ANALYSIS

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EXTEND

PART 1: Define

Latitude

Longitude

Solar Azimuth

Solar Altitude / Elevation

Solar Noon

​

VOCABULARY

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EXTEND

PART 2

Use the sunpath diagram and this website to learn more about how the length of day/time of year affect solar potential.

  • Go to https://www.timeanddate.com/sun/
  • Type in WI and scroll to the city closest to your school
  • Access information Sunrise & Sunset tab to access

SUN GRAPH & DATA

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EXTEND

PART 3

  • Average daily sun path for each month is shown horizontally across the diagram
  • Percent of sunlight available for 30 minute increments for an average day for the month are shown between vertical 30 minute time segment lines.

SUNPATH Diagram

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CLIMATE CONNECTION

DISCUSSION QUESTIONS

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What percentage of CO2 emissions can be attributed to electricity production?

How can we reduce the amount of CO2 released into the atmosphere by production of electricity?

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CLIMATE CONNECTION

Electricity Production accounts for 25% of the CO2 entering our atmosphere.

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CLIMATE CONNECTION

Shifting Production of electricity from fossil fuels to Solar and other CLEAN energy sources is a way to reduce CO2 in our atmosphere!

Increasing access to solar also reduces CO2 in our atmosphere!

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CLIMATE CONNECTION

If you have the time, KEEP also recommends viewing, Climate Solutions 101, Unit 3: Reducing Sources. �Click here if the embedded video doesn’t play for you.

Curious about additional SOLUTIONS?

KEEP recommends exploring the Menu of Climate Solutions website by K12 Climate Action.

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Additional Solar Career - Solar Project Manager

A solar project manager coordinates the workers and materials involved in a solar installation project.

Learn more about solar project managers:

View a Solar Career Map:

Watch a solar energy careers video:

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Additional Solar Career - Solar Energy Technician

A solar energy technician is responsible for the construction, repair, maintenance and general operation of solar energy systems.

Learn more about solar energy technicians:

View a Solar Careers Map:

Watch a Solar Energy Careers video:

Photo by Walt Ratterman

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Additional Solar Career - Solar Site Assessor

A solar site assessor evaluates sites for solar potential. They can evaluate sites in-person or remotely.

Learn more about solar site assessors:

View a Solar Careers Map:

Watch a Solar Energy Careers video:

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KEEP Solar Lessons / Resources

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KEEP values your feedback. Please use the QR code �to fill out a brief evaluation about this resource.

Thank you for using this resource.

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KEEP: Wisconsin K-12 Energy Education Program - www.uwsp.edu/keep

Wisconsin K-12 Energy Education Program (KEEP)

What does KEEP do?

  • KEEP leverages teacher education to improve and increase energy literacy in Wisconsin's K-12 schools as a means of contributing to statewide energy savings.

​

What is KEEP?

  • Partnership between Wisconsin utilities and the WCEE within the CNR at UWSP

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KEEP: Wisconsin K-12 Energy Education Program - www.uwsp.edu/keep

Lessons, Activities & Teaching Tools

Educator Engagement

Youth & Community Engagement

Networking & Communications

Consultation

& Support

What We Do & How We Do It

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KEEP: Wisconsin K-12 Energy Education Program - www.uwsp.edu/keep

KEEP’s Partners

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KEEP: Wisconsin K-12 Energy Education Program - www.uwsp.edu/keep

Clean Energy Career Video Series

Link to all videos

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KEEP: Wisconsin K-12 Energy Education Program - www.uwsp.edu/keep

KEEP Curriculum & Lessons

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WISCONSIN CENTER FOR ENVIRONMENTAL EDUCATION - www.uwsp.edu/wcee

Trunks and Kits

  • 30+ Kits and Trunks Available
  • KEEP, LEAF, WCEE Themed
  • Ready to go
  • Most can ship (share shipping costs)

Energy Audit Tool Kit

Sun Oven

Pedal Power

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WISCONSIN CENTER FOR ENVIRONMENTAL EDUCATION - www.uwsp.edu/wcee

Wisconsin Center for Environmental Education

Created in 1990, the WCEE envisions an actively engaged, educated population who create and maintain sustainable human and natural communities.

​

Mission: Provide leadership and resources to advance education for sustainable human and natural communities.

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KEEP: Wisconsin K-12 Energy Education Program - www.uwsp.edu/keep

STAY CONNECTED

www.KEEPprogram.org

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https://www.facebook.com/wiskeep

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KEEP@uwsp.edu

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715-346-4770

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Subscribe to our newsletter

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KEEP: Wisconsin K-12 Energy Education Program - www.uwsp.edu/keep

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https://bit.ly/solartilt

This slideshow can also be accessed

...at this short link

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...at this QR code

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