Here Comes the Sun

This lesson explores the concept of how solar energy is gathered by solar panels and adapted to provide power to a variety of machines, from calculators to spacecraft. Students disassemble a solar powered calculator and explore the component parts. Students work in teams to suggest design enhancements to the calculator to improve performance.

Learn about solar power and solar panel design and operation.
Learn about how calculators work and how the product is comprised of many different component parts.
Learn about teamwork and the engineering problem solving/design process.

Age Levels: 8-18

Lesson Plan Presentation

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Materials & Preparation

Build Materials (For each team)

Required Materials

One old or new calculator (many are less than $5) — look for ones with screws on the back for easy disassembly
Eyeglass Repair Kit or mini screwdriver (must be very small gauge)

Engineering Design Challenge

Design Challenge

You are a team of engineers given the challenge of disassembling a solar powered calculator and exploring the component parts. You’ll then study the solar panel and see how it is connected to the other parts of the calculator. As a team, suggest design enhancements to the calculator to improve performance.

Criteria

Remove all the small screws that hold the top and bottom together
Unscrew the circuit board from the front panel
Be careful touching the solar panel and the LCD (liquid crystal display) as the glass edges may be sharp.

Constraints

Use only the materials provided.

Activity Instructions & Procedures

Break class into teams of 3-4.
Hand out the Here Comes the Sun worksheet, as well as some sheets of paper for sketching designs.
Discuss the topics in the Background Concepts Section.
Review the Engineering Design Process, Design Challenge, Criteria, Constraints and Materials. Explain to students that they should be sure that they remove all the small screws that hold the top and bottom of the calculator together, some are often hidden under pads or rubber strips. They will need to unscrew the circuit board from the front panel of the calculator too — there are many screws. They should also be very careful touching the solar panel and the LCD (liquid crystal display) as the glass edges may be sharp.
Instruct students to start brainstorming and sketching their designs.
Provide each team with their materials.
Explain that students must complete 4 steps:
- Step One: As a team, observe whether the calculator operates when you completely block the solar power panel. What happens if you partially block the solar panel? Write your observations, and explanations of what you found below.
- Step Two: Suggest five other products you can think of that are either completely or partially powered by solar panels.
- Step Three: As a team, disassemble either a new (inexpensive) or old unusable solar powered calculator, using the materials provided to you.
- Step Four: As a team, observe the solar panel and see how it is connected to the other parts of the calculator. Examine all the other parts of the calculator, and discuss what you find. Then make suggestions on how the calculator can be improved.
Announce the amount of time they have to disassemble and study the calculator.
Use a timer or an on-line stopwatch (count down feature) to ensure you keep on time. (www.online-stopwatch.com/full-screen-stopwatch). Give students regular “time checks” so they stay on task. If they are struggling, ask questions that will lead them to a solution quicker.
Teams disassemble and study their calculator.
Teams should document how the solar panel is connected to the other parts of the calculator. As a team, they should discuss and document suggestions on how the performance may be improved.
As a class, discuss the student reflection questions.
For more content on the topic, see the “Digging Deeper” section.

Student Reflection (engineering notebook)

How many individual parts did you find? Describe them.
What surprised you the most about the interior parts of the calculator?
How was the solar panel connected to the circuit board?
If there was a battery back up for this calculator, how was it connected to the circuit board?
Some calculators will still operate in the disassembled state, as long as the wires from the solar panel and battery are still connected to the circuit board. Does your calculator still operate? If you reconnect the wires with scotch tape, does it still work?
Why do you think there was a rubber or plastic sheet separating the circuit board from the buttons you press?
What type of material do you think is embedded under the plastic or rubber sheet and the circuit board? Why do you think engineers included this sheet in their design?
Assuming you could repower your calculator, if you reconstructed your calculator with all the buttons in different positions, would it still work properly? Why, why not?
Is there anything you would recommend, as part of an engineering team, to improve the functionality of the calculator you disassembled? Attach a drawing or sketch of your proposed component part or improvement, and answer the questions below:

What new materials will you need (if any)
What materials or parts will you eliminate (if any)
How will this new product improve the functionality of a calculator?

How do you think your new design will impact the cost of this calculator? Why?

Time Modification

The lesson can be done in as little as 1 class period for older students. However, to help students from feeling rushed and to ensure student success (especially for younger students), split the lesson into two periods giving students more time to brainstorm, test ideas and finalize their design. Conduct the testing and debrief in the next class period.

Engineering Design Process

Background Concepts

How Solar Panels Work

Solar Panels are Used Everywhere!

Solar panels work by converting the energy of the sun into electricity. This is used to power many products on earth and support power on spacecraft too. In this lesson we are working with solar powered calculators, which have been a simple but effective application for many years. If you look carefully, you will find many applications in your town or school including stoplights and road signs. You may even have decorative solar powered lights in your yard to help guide you safely at night. As solar technology advances and becomes more efficient, the applications for solar power continue to expand. Solar phone chargers, like the one to the right, help hikers keep in touch which can be lifesaving in an emergency.

Flexibility

Solar panel can now be flexible which helps with building design and opens all sorts of applications not available ten years ago. The illustration below depicts a flexible solar panel powered bus stop which would allow those waiting to charge their phones, have lighting after dark, and potentially communicate bus arrival schedules or delays.

What is a Simple Circuit?

A simple circuit consists of three minimum elements that are required to complete a functioning electric circuit: a source of electricity (battery),a path or conductor on which electricity flows (wire) and an electrical resistor (lamp) which is any device that requires electricity to operate. The illustration below shows a simple circuit containing, one battery, two wires, a switch, and a bulb. The flow of electricity is from the high potential (+) terminal of the battery through the bulb (lighting it up), and back to the negative (-) terminal, in a continual flow when the switch is in the on position so current can flow.

Schematic Diagram of a Simple Circuit

The following is a schematic diagram of the simple circuit showing the electronic symbols for the battery, switch, and bulb.

Vocabulary

Constraints: Limitations with material, time, size of team, etc.
Criteria: Conditions that the design must satisfy like its overall size, etc.
Engineers: Inventors and problem-solvers of the world. Twenty-five major specialties are recognized in engineering (see infographic).
Engineering Design Process: Process engineers use to solve problems.
Engineering Habits of Mind (EHM): Six unique ways that engineers think.
Iteration: Test & redesign is one iteration. Repeat (multiple iterations).
Prototype: A working model of the solution to be tested.
Solar: Produced or made to work by the action of the sun’s light or heat solar energy.
Solar cells: Make electricity directly from sunlight.
Solar energy: Energy generated directly from sunlight
Solar panel: Made of solar cells, which is the part that turns the solar energy in sunlight into electricity.

Dig Deeper

Internet Connections

Recommended Reading

Solar Electricity Handbook, 2010 Edition: A Simple Practical Guide to Solar Energy – Designing and Installing Photovoltaic Solar Electric Systems by Michael Boxwell (ISBN: 978-1907670008)
Power from the Sun: A Practical Guide to Solar Electricity by Dan Chiras (ISBN: 978-0865716216)

Writing Activity

Write an essay or a paragraph describing how solar panels have been engineered into a product you find in your home or school. Explain why solar energy is a good choice for powering this product.

Curriculum Alignment

Alignment to Curriculum Frameworks

Note: Lesson plans in this series are aligned to one or more of the following sets of standards:

U.S. Science Education Standards (http://www.nap.edu/catalog.php?record_id=4962)
U.S. Next Generation Science Standards (http://www.nextgenscience.org/)
International Technology Education Association’s Standards for Technological Literacy (http://www.iteea.org/TAA/PDFs/xstnd.pdf)
U.S. National Council of Teachers of Mathematics’ Principles and Standards for School Mathematics (http://www.nctm.org/standards/content.aspx?id=16909)
U.S. Common Core State Standards for Mathematics (http://www.corestandards.org/Math)
Computer Science Teachers Association K-12 Computer Science Standards (http://csta.acm.org/Curriculum/sub/K12Standards.html)

National Science Education Standards Grades K-4 (ages 4-9)

CONTENT STANDARD A: Science as Inquiry

As a result of activities, all students should develop

Understanding about scientific inquiry

CONTENT STANDARD B: Physical Science

As a result of the activities, all students should develop an understanding of

Properties of objects and materials
Light, heat, electricity, and magnetism

CONTENT STANDARD E: Science and Technology

As a result of activities, all students should develop

Abilities of technological design
Understanding about science and technology

National Science Education Standards Grades 5-8 (ages 10-14)

CONTENT STANDARD A: Science as Inquiry

As a result of activities, all students should develop

Understandings about scientific inquiry

CONTENT STANDARD B: Physical Science

As a result of their activities, all students should develop an understanding of

Transfer of energy

CONTENT STANDARD E: Science and Technology

As a result of activities in grades 5-8, all students should develop

Abilities of technological design
Understandings about science and technology

National Science Education Standards Grades 9-12 (ages 14-18)

CONTENT STANDARD A: Science as Inquiry

As a result of activities, all students should develop

Understandings about scientific inquiry

CONTENT STANDARD B: Physical Science

As a result of their activities, all students should develop understanding of

Interactions of energy and matter

CONTENT STANDARD E: Science and Technology

As a result of activities, all students should develop

Abilities of technological design
Understandings about science and technology

Next Generation Science Standards – Grades 3-5 (Ages 8-11)

Energy

Students who demonstrate understanding can:

4-PS3-4. Apply scientific ideas to design, test, and refine a device that converts energy from one form to another.

Engineering Design

Students who demonstrate understanding can:

3-5-ETS1-1.Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.
3-5-ETS1-2.Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

Next Generation Science Standards – Grades 6-8 (Ages 11-14)

Engineering Design

Students who demonstrate understanding can:

MS-ETS1-2 Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

Standards for Technological Literacy – All Ages

The Nature of Technology

Standard 1: Students will develop an understanding of the characteristics and scope of technology.
Standard 3: Students will develop an understanding of the relationships among technologies and the connections between technology and other fields of study.

Technology and Society

Standard 4: Students will develop an understanding of the cultural, social, economic, and political effects of technology.
Standard 5: Students will develop an understanding of the effects of technology on the environment.
Standard 6: Students will develop an understanding of the role of society in the development and use of technology.

Standards for Technological Literacy – All Ages

Design

Standard 8: Students will develop an understanding of the attributes of design.
Standard 9: Students will develop an understanding of engineering design.
Standard 10: Students will develop an understanding of the role of troubleshooting, research and development, invention and innovation, and experimentation in problem solving.

Abilities for a Technological World

Standard 13: Students will develop abilities to assess the impact of products and systems.

The Designed World

Standard 16: Students will develop an understanding of and be able to select and use energy and power technologies.

Student Worksheet

Dissect a Solar Powered Calculator

Step One: As a team, observe whether the calculator operates when you completely block the solar power panel. What happens if you partially block the solar panel? Write you observations, and explanations of what you found below.

Step Two: Suggest five other products you can think of that are either completely or partially powered by solar panels.

Step Three: As a team, disassemble either a new (inexpensive) or old unusable solar powered calculator, using the materials provided to you. Be sure that you remove all the small screws that hold the top and bottom together, some are often hidden under pads or rubber strips. You will need to use a very small screwdriver, such as the type commonly found in eyeglass repair kits. And, you will need to unscrew the circuit board from the front panel of the calculator too — there are many screws.

Safety Note: Be careful touching the solar panel and the LCD (liquid crystal display) as the glass edges may be sharp.

Step Four: As a team, observe the solar panel and see how it is connected to the other parts of the calculator. Examine all the other parts of the calculator, and discuss what you find. Then answer questions below.

Questions:

1. How many individual parts did you find? Describe them.

2. What surprised you the most about the interior parts of the calculator?

3. How was the solar panel connected to the circuit board?

4. If there was a battery back up for this calculator, how was it connected to the circuit board?

5. Some calculators will still operate in the disassembled state, as long as the wires from the solar panel and battery are still connected to the circuit board. Does your calculator still operate? If you reconnect the wires with scotch tape, does it still work?

6. Why do you think there was a rubber or plastic sheet separating the circuit board from the buttons you press?

7. What type of material do you think is embedded under the plastic or rubber sheet and the circuit board? Why do you think engineers included this sheet in their design?

8. Assuming you could repower your calculator, if you reconstructed your calculator with all the buttons in different positions, would it still work properly? Why, why not?

9. Is there anything you would recommend, as part of an engineering team, to improve the functionality of the calculator you disassembled? Attach a drawing or sketch of your proposed component part or improvement, and answer the questions below:

What new materials will you need (if any)

What materials or parts will you eliminate (if any)

How will this new product improve the functionality of a calculator?

How do you think your new design will impact the cost of this calculator? Why?

5. Present your ideas to class.