This hands-on construction project gets students cooking during a solar energy science unit. The class study begins by acting out the Earth's rotation around the sun to see how that causes shadows. Students conduct several investigations of the Earth's position and shadows with compass and thermometer measurements and observation. They research the dilemma of using fossil fuels and how solar energy might solve this problem. Students work as engineers, and their task is to build a solar cooker that can successfully cook an egg. If this works, it may be the basis for more exploration on using solar energy as an alternative to fossil fuels. Students display their learning in multimedia presentations or newsletters.
View how a variety of student-centered assessments are used in the Plugging In to the Sun Unit Plan. These assessments help students and teachers set goals; monitor student progress; provide feedback; assess thinking, processes, performances, and products; and reflect on learning throughout the learning cycle.
Prior to this unit:
Begin by asking the students the Essential Question, What causes people (scientists) to consider new alternatives to solve problems? Students can brainstorm in groups and reflect on what causes scientists to develop new inventions and find alternatives. Ask students, What would happen if we always did things the ways they have always been done? Students also reflect back on this question at the end of the project.
Begin with a project introduction slideshow, and follow the presentation with a class discussion framed around the following questions:
Develop the ideas of solar cooking further by posing the following questions:
As a class demonstration, cook an egg in a small custard cup in a standard preheated 350ºF toaster oven. Rest a meat thermometer in the egg and determine the internal temperature. While it's cooking, discuss whether radiant heat (heat transferring through space), conduction heat(heat transferring from direct contact with heat source), or convection heat (heat transferring though moving, heated air) is cooking the egg. When the egg is deemed cooked, read the thermometer. (Note: An egg is cooked when its internal temperature reaches 160ºF. Do not measure oven temperature.)
Introduce the following challenge: Students work as engineers, and their task is to build a solar cooker that can successfully cook an egg. If the cookers work, it may be the basis for more exploration on using solar energy as an alternative to fossil fuels. Tell students that they must develop a rationale for the use of solar energy based on research and address the question, Why should solar energy be considered as an alternative to fossil fuels?
Sessions 2 and 3
Have students meet in groups to determine the features they think their solar cooker will need to meet the challenge.
Reconvene and teach about reflection and absorption of the sun's rays. Discuss the reasons why an egg most likely cannot be cooked on a sidewalk, and have students further refine the necessary features of solar cookers. Discuss answers to the question, What effect does solar energy have on different materials, and how can we make use of these effects?
Next, using the students’ criteria and a set of print and electronic resources you provide, instruct students to begin evaluating a variety of solar cooker designs. Circulate around the room as groups work, taking anecdotal notes.
During the last 10 minutes, have students respond in their science journals to Questions 1 and 2 on the probing understanding sheet. Review the journals and provide further instruction as necessary.
Instruct groups to choose a preliminary solar cooker design from their Internet research. Tell them to be prepared to defend their choice.
Using Question 3 from the probing understanding sheet, have each group develops a short paper describing how the design of their oven relates to its function. This could be framed as a defense of the design they chose as compared to an oven design they rejected.
Have students read their papers to the class, and, informed by the discussion, make their final design selection.
Prior to constructing the designs, have students sketch their designs in journals, labeling each feature and describing its function.
Develop the concepts of heat transfer relating to radiant, convection, and conduction heat. Tell students to use this information when choosing the method of cooking they want to use (baking, broiling, boiling, or frying; in shell or out of shell).
Have each group assign tasks within their group and begin collecting materials. Pose Question 4 from the probing understanding sheet. Again, review the journals and modify instruction as necessary.
Sessions 7 through 9
Provide ample time for students to construct their cookers.
During these days, have students investigate the effects of the Earth’s rotation and the sun’s position on heat and temperature on Earth by completing the finding north activity, using the shadow plot procedures.
Have students respond to Question 5 from the probing understanding sheet.
Spend one period troubleshooting cookers and measuring interior temperatures. Students should create a chart or graph of temperatures and corresponding times. The temperatures can be compared to a temperature guide for foods found in their research.
Using Question 6 from the probing understanding sheet, ask students to interpret a solar cooker graph. Later, their data can be graphed using spreadsheet software. This activity, along with the shadow plot procedures, helps students fine-tune the function of their oven, and choose the time and position for cooking.
Conference with students to help answer any questions they have and to probe for understanding of the concepts they have encountered any difficulty with.
Session 11 (or the next sunny day)
Cook-Off! Students use their solar cookers to cook eggs.
Take lots of conventional, digital, and video images! Safety precaution: If eggs are eaten, make sure they have been cooked to at least 160ºF and are consumed immediately after cooking.
Sessions 12 through 14
Explain that students will now share their learning in a project.
In small groups or pairs, have students develop a slideshow presentation, brochure or newsletter.
Distribute the project checklist to help students keep track of their progress. Inform students that all projects should include:
Provide the solar rubric and review with students to help ensure they understand the assessment criteria before they start to work.
Conduct a class discussion on the Essential Question, What causes people (scientists) to consider new alternatives to solve problems? Students should be more enlightened on the factors that cause scientists to explore new solutions to problems.
Ask students to write responses to Questions 7 through 9 on the probing understanding sheet.
Much of this work can be done at a variety of academic levels. As needed, partner students for computer work with technically skilled students.
Special Needs Student
Marge Stembel of Garrett Park, Maryland participated in the Intel® Teach Program, which resulted in this idea for a classroom project. A team of teachers expanded the plan into the example you see here.
Grade Level: 6-8
Subject: Earth, Physical Science
Topics: Solar Energy, Heat Transfer, Fossil Fuels, Energy Conservation
Higher-Order Thinking Skills: Decision Making, Evaluation, Analysis
Key Learnings: Conduction, Convection, Radiation, Insulation, Reflection, Solar Cooking
Time Needed: 5-10 weeks, 2-hour lessons, 1 or 2 times per week
Background: From the Classroom in Washington DC, United States