GO IN DEPTH

Mitigating Climate Change through Passive Solar Design

What You Need

Materials

  • Small empty boxes (tissue boxes work very well)
  • Small plastic bottles and clear plastic containers with lids that fit inside the boxes
  • Plastic wrap
  • Thermometers
  • Heat lamps
  • Butter or margarine
  • Rocks
  • Black and white construction paper
  • Stop watch or clock
  • Tape
  • Water in a bottle
  • Wood
 
Mitigating Climate Change through Passive Solar Design By Fred Bauder [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0), via Wikimedia Commons

Purpose

To understand our impact on climate change by researching passive solar design and technologies in the context of the environmental impact of the burning of fossil fuels and global warming.


Context

This lesson is part of the Inventing Green Project, a collection of invention education resources that can be used to engage students in grades 6–12 in problem-solving, creativity, design, and social awareness. Invention education encompasses the idea that learning is powered by hands-on experiences that allow students to turn ideas into inventions with impact. You can learn more about invention education by reading the first part of the Invention Education Educator Toolkit.

This lesson is the first in a series of three lessons that focus on the environmental impact of burning fossil fuels and how passive solar design and technologies can help mitigate that impact. In this lesson, students will be introduced to the concepts of a thermal mass and latent heat. A thorough understanding of those concepts is not the goal of the lesson. Students should come to understand that some materials will “trap” heat that will keep the environment of their simulated house warmer longer. That concept can then be used as a basis for discussion of passive solar energy using a thermal mass.

This first lesson relies on the students having some prior knowledge of climate change. As a prerequisite, we recommend using the lesson How We Know What We Know about Our Changing Climate to familiarize students with the topic.

In the second lesson in the series, Designing a Building Using Passive Solar Energy, students will design a building using passive solar energy techniques. They will first study the local geography around their school to determine a building site. Then they will use software to design a passive solar building.

In the third lesson, Modeling Solar Homes, students will build a prototype of the home that uses passive solar to help decrease the amount of energy used for heating and cooling. They will be encouraged to try something new and innovative.

This lesson will focus on the concept of a thermal mass through a simple experiment. In doing so, it will help to set up the other lessons in this series and it will help students understand the ideas set forth in the benchmarks for this lesson: namely that by doing the thermal mass activity, they will be able to see for themselves how energy is transformed in a system and how thermal energy is associated with the temperature of an object. It will also help them understand how scientific knowledge can be used to solve practical problems.

Ideas in this lesson are related to concepts found in the following Next Generation Science Standards:

Energy

  • MS-PS3-4.
    Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.

Engineering, Technology and Applications of Science

  • MS-ETS1-1.
    Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
  • MS-ETS1-2.
    Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

Ecosystems: Interactions, Energy, and Dynamics

  • MS-LS2-5.
    Evaluate competing design solutions for maintaining biodiversity and ecosystem services.

Planning Ahead

This lesson will take 2–3 class periods to complete. It includes a lab activity and it requires some preparation. You will need enough materials for each group. You will also need to organize the class into lab partners. We suggest you read through the lesson and activities to determine the best schedule for your class.

Before you start this lesson with your students, we encourage you to read the Invention Education Educator Toolkit. We also suggest that you provide your students with the Invention Education Toolkit student sheet so they can get background information on invention education.

For background information on passive solar energy, you can read the Passive Solar teacher sheet and/or go to Passive Solar Design.


Motivation

Global warming, if you’ll pardon the pun, is a hot topic. Most scientists will agree that global temperatures are rising, and many are convinced that human-made carbon dioxide emissions are one of many factors causing that climate change. But, there are dissenting views.

Begin by reviewing with students what they already know about climate change. Ask these questions:

  • What is meant by global warming or climate change?
    • (Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earth's climate system and its related effects.)
  • What evidence is there that the climate is changing?
    • (There are changes in migration of animals. Some plants are expanding their ranges. Glaciers are melting.)
  • What are some greenhouse gasses that contribute to climate change?
    • (Greenhouse gasses that contribute to climate change are carbon dioxide and methane.)
  • What is the cause of climate change?
    • (Answers may vary, and there is not a simple answer to this question.)

After discussing these questions, students should use their Climate Change and Passive Solar Energy student esheet to watch Consensus Sense, from the American Association for the Advancement of Science. This video shares what climate experts have concluded from the evidence about climate change.

After students have watched the video, hold a class discussion and ask them these questions:

  • What percentage of the world's climate scientists have concluded that human-caused climate change is happening?
    • (97% of the world's climate scientists have reached that conclusion.)
  • What are some of the risks of climate change?
    • (One of the risks is that our future will get worse than we expect. It could be possible for gradual climate change to experience abrupt jumps that hurt economies and ecosystems.)
  • What do you think about Katherine Hayhoe's idea about buying "insurance" for the risks of climate change? How do you think that would work?
    • (Answers may vary. Encourage your students to explain their answers.)
  • What are the benefits of being more efficient with energy and investing in things like passive solar design?
    • (The benefits include saving money and reducing our impact on climate change at the same time.)
  • After listening to some of the examples the scientists provide for the assessment of risk and the importance of taking action, do you have some ideas about what could be done to reduce the risks of climate change?
    • (Answers may vary. Encourage your students to explain their answers.)

Development

Now that students have had a chance to review their understanding of climate change, they should do some more research on it.

They can begin by using their esheet to go to Climate Change: How Do We Know? Students should answer the questions on their Climate Change and Passive Solar Energy student sheet and be prepared to discuss them in class.

  • Looking at the graph of CO2 levels, it is clear that CO2 varies over time. However, the graph climbs rapidly in the recent past. What could have caused that increase? Does it seem logical that it could be a natural occurrence?
    • (Answers may vary. Encourage your students to explain their answers.)
  • Read the brief descriptions for the evidence for climate change. Which evidence seems most compelling to you?
    • (Answers may vary. Encourage your students to explain their answers.)
  • Some gases in the atmosphere are said to be forcing climate change, while others are seen as feedbacks. Explain the difference between the two, and list the gases that fit in each category.
    • (The gases that force climate change are the ones that remain semi-permanently in the atmosphere and do not respond physically or chemically to changes in temperature. They include carbon dioxide and methane. The gases that act as feedbacks respond physically or chemically to changes in temperature. They include water vapor.)
  • What is the probability that human activity has contributed to the global climate change that has been observed?
    • (The Intergovernmental Panel on Climate Change, a group of 1,300 independent scientific experts from countries all over the world under the auspices of the United Nations, concluded there's a more than a 90 percent probability that human activities over the past 50 years have warmed our planet.)
  • Is it likely that the sun is responsible for the observed changes? Explain.
    • (Answers may vary but according to the article, it is reasonable to assume that the sun is responsible for some of the climate change.)

After students have learned more about climate change, they should focus on some possible solutions. They should use their student esheet to go to Be Part of the Solution. As students go through this resource, they should answer the questions on that same student sheet. Once they are done, you should discuss their answers as a class. During the discussion, focus students on passive solar energy and thermal mass.

  • Wind Energy: What is a wind farm and where might you find one?
    • (A wind farm is a group of wind turbines together. They are often placed on top of windy hills, open plains, and shorelines.)
  • Geothermal Energy: What are the two types of geothermal energy and how do they work?
    • (Two types of geothermal energy are geothermal power plants and geothermal heat pumps. The power plants use heat from deep inside the Earth to generate steam to make electricity while the heat pumps tap into heat close to the Earth's surface to heat water or provide heat for buildings.)
  • Which type of geothermal energy would work best where you live?
    • (Answers may vary. Encourage students to explain their answers.)
  • Energy Efficient Buildings: What are some ways we can save energy in our homes and other buildings?
    • (Answers could include using technologies like efficient heating, lighting, and air conditioning.)
  • Solar Energy: List and describe the three types of solar energy discussed in the article.
    • (Three types of solar energy are: photovoltaic cells, solar thermal energy, and passive solar heating. Photovoltaic cells convert sunlight directly into electricity, solar thermal power plants use heat from the sun to create steam that can be used to make electricity, and passive solar heating uses heat from the sun to warm buildings.)

Thermal mass is a key component of passive solar energy design. Students should use their student esheet to go to Thermal Mass. Be sure to discuss the pictures the author provides about how he had to remove snow from his deck, but not the sidewalks when it snowed at his house. Ask students:

  • Why does the author have to shovel the deck and not the walk?
    • (He doesn't have to shovel the walk because the heat energy was stored in the rocks in the sidewalk, as well as in the larger cement-type paverstones in the walkway because these dense types of materials have thermal mass. The thermal mass had heat energy stored within them from the sun shining on them the previous day. The radiant heat was released through the evening and night and had melted the snow. Since the deck is made of wood, however, it does not have [relatively large amounts of] thermal mass. Although the winter sun shines on it in the afternoon, it does not have thermal mass and does not retain heat.)
  • Have you ever experienced something like this? What are some other examples?
    • (Answers may vary. Encourage your students to explain their answers.)
  • Why does the temperature of a swimming pool stay relatively constant during the summer and the air temperature fluctuates by as much as 30 degrees F? How is that similar to the snow on the deck and walks?
    • (Answers may vary but could include the idea that the water has more thermal mass than the air.)

Once students have learned more about passive solar energy and thermal mass, they should complete the thermal mass activity. Students can use their Thermal Mass Lab student sheet to do this activity. You can use the Thermal Mass Lab teacher sheet to help you set up the lab and guide students.

In this activity, students should work in groups of two or three students. Each group should test one material that could be used as a thermal mass in a passive solar home. The material should be placed in a box (tissue box or shoe box works well) to simulate the house. Students should measure the air temperature in the box for a 10-minute period of heating and a 10-minute period of cooling. Each solar mass material will affect how quickly the temperature will rise and fall as it absorbs and releases energy. An effective thermal mass should moderate the temperature range.

Once students have finished testing their material, they should enter their results in the Thermal Mass Lab Class Data Spreadsheet. This Excel file contains both the spreadsheet and a graph that will be automatically generated once students enter their results.

It is important to monitor the students as they complete the lab. Make sure that they set up the box and lamp/sun in such a way as to be able to read the thermometer with as little movement as possible and without removing the thermometer from the box. It may be necessary to review with the students how to read the thermometer prior to starting data collection. If you have access to digital thermometers or a temperature probe that can collect data directly to the computer, modifying the lab to allow for that may be helpful.


Assessment

The questions on both the student sheet and the lab will be the primary form of assessment.

Results may vary, but there are several trends to the data that should become apparent. Look for patterns in the data that show:

  • Darker materials absorb more heat than lighter colored ones. As a result, the temperatures should not drop as quickly during the cooling period for darker materials.
  • More dense materials should be better thermal masses than less dense ones. Although the lab did not specifically deal with density, students may infer this since the masses are the same, but not all the samples are the same volume.
  • The empty box (air as the only mass) should show the largest temperature range since there is nothing to absorb heat energy.
  • The phase change of the oil should trap a lot of heat energy (latent heat of fusion) and this should help keep the temperature of the air around it warmer for a longer time during the cooling phase. However, this may or may not be apparent in this time frame. It is possible that the oil will not refreeze in 10 minutes. If that is the case, you may suggest that the group continue data collection for a few more minutes. The important thing here is that they understand the idea that melting absorbs heat and freezing releases it. So, in a thermal mass, a material that can melt during the day and refreeze at night will effectively convert solar energy into thermal energy during the day to help heat that home at night by releasing energy as the material freezes.
  • The best thermal mass is going to be the one for which the temperature rises and falls slowly. The results may vary due to errors that are possible in the lab, but look at the data the class collected and consider which material kept the temperature most constant. That’s the one they should conclude is the best thermal mass.

In addition to the lab and questions, have each student write a paragraph or two on this question:

If you were to design a home to take advantage of passive solar energy, which thermal mass would you choose for your home? Take into account the effectiveness, practicality, aesthetics, and any other factors that you think are important to that decision.


Extensions

You should follow this lesson with the next two lessons in this series:


Solar Heating and You provides students with more information about the various ways people use heat from the sun to warm their homes.


If your students are interested, they can learn how to Build a Solar Cooker. This site provides links to plans for different kinds of solar cookers.


Funder Info
The Lemelson Foundation
Based in Portland, The Lemelson Foundation uses the power of invention to improve lives. Inspired by the belief that invention can solve many of the biggest economic and social challenges of our time, the Foundation helps the next generation of inventors and invention-based businesses to flourish. The Lemelson Foundation was established in the early 1990s by prolific inventor Jerome Lemelson and his wife Dorothy. To date the Foundation has made grants totaling over $200 million in support of its mission. For more information, visit http://lemelson.org.

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Lesson Details

Grades Themes Type Project 2061 Benchmarks National Science Standards

Other Lessons in This Series

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