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Grade Level:
5-8 |
Subjects:
Astronomy
Energy |
Topics:
Heat Transfer
Solar energy
Solar system |
Key Learnings:
Conduction
Convention
Insulation
Solar cooking |
Time Needed:
5-10 weeks, 1 or 2 2hr/sessions/weekly |
Background:
From the Classroom |
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Unit Summary
This hands-on construction project gets fifth graders 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 design and build solar cookers that will cook an egg. They display their learning in multimedia and Web presentations.
Curriculum Framing Questions
- Essential Questions
How does the sun heat the earth through millions of miles of cold space?
What would we be without the sun?
- Unit Questions
How can we use the sun to cook food?
How is solar energy reflected or absorbed, and how can we make use of this in our cooking?
How is energy transferred from one material to another?
How can solar energy be used as an alternative for fossil fuels?
Instructional Procedures
Prior to this unit:
- Terms and general concepts are defined for the teacher in Background Information.
- Students learn the solar energy concepts detailed in �Prerequisite Skills�, below.
- Enlist volunteer help for sessions 7-9 (below).
Session 1
Begin with a project introduction slideshow, and follow with a class discussion framed around the following question: How does a conventional oven cook food? (Probe for and develop two ideas: oven cooking requires a heat source, and an insulated box that holds heat. A temperature gauge is a helpful additional feature.) Develop the ideas of solar cooking further by posing this question: Some say an egg can be fried on a sidewalk on a hot day. Is this true? Has anyone tried it? How hot would it have to be to cook an egg? Cook an egg in a small custard cup in standard pre-heated 350oF toaster oven. Rest a meat thermometer in the egg and determine the internal temperature. While it�s cooking, discuss whether radiant heat (broiling by the heating element) or convection heat (moving, heated air) is cooking the egg. When the egg is deemed �cooked�, read the thermometer. (An egg is cooked when internal temperature reaches 160oF. Do not measure oven temperature). Introduce the challenge: Students are to build a solar cooker that can successfully cook an egg.
Sessions 2 and 3
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. Next, using their criteria and a set of print and electronic resources you provide (below), students begin evaluating a variety of solar cooking designs. In the last ten minutes, have kids respond to question 1 of Probing Understanding in their science journals.
Session 4
Groups choose a preliminary design and defend their choice. Using Question 2 of Probing Understanding, 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 another oven design they rejected.
Session 5
Students read their papers to the class, and, informed by the discussion, make their final design selection. If time remains, they can sketch their designs in journals, labeling each feature and describing its function.
Session 6
Develop the concepts of heat transfer relating to radiant and convection heat, and conduction. Students use this information to choose the method of cooking they want to use (baking, broiling, boiling or frying; in shell, out of shell). Students assign tasks within their group and begin collecting materials. Pose question 3 of Probing Understanding.
Sessions 7, 8, 9
Students construct their cookers. During these days, carry out the Finding North activity, using Shadow Plot Procedures.
Session 10 Spend one period trouble-shooting cookers and measuring interior temperatures for a temperature chart using Measuring Cooker Temperature as a guide. Using Question 4 of Probing Understanding, ask students to interpret a solar cooker graph. Later their data can be graphed using Microsoft Excel* or other spreadsheet software. This activity, along with shadow plot work (above) helps students fine-tune the function of their oven, and helps them choose the time and position for cooking.
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 10-14
Preparing and presenting. Students work in small groups or pairs on a slideshow presentation, a brochure or newsletter, or a Web page. Tool selection depends on access to programs and preferred information delivery methods. All projects should include:
- A rationale for design choice
- One or more digital photos of the cooker, preferably in stages of development
- Graph showing oven temperature over time, plus a caption interpreting the graph
- Discussion of the process and results (introduction, process, trouble-shooting, challenge results, final thoughts)
- Citation for cooker design and other information
Prerequisite Skills
This unit plan follows prior study of solar energy. Using the FOSS kit �Solar Energy�, or similar lessons, students learned to:
- Become aware of the potential of solar energy as an alternative energy source to fossil fuels
- Observe differences in size and position of shadows as a result of the relative positions of the earth and sun
- Gain experience using a compass to orient objects on earth
- Become proficient in using a thermometer to monitor temperature change in a variety of materials
- Observe solar energy transfer in a variety of situations
- Design solar water heaters and passive solar space heaters
- Apply mathematics in the context of science
- Acquire the vocabulary associated with solar energy and energy transfer
Additionally, students should come to these lessons with basic keyboarding and computer navigation skills (opening, saving documents, launching programs).
Differentiated Instruction
- Resource Student
Team students with better readers; allow students to dictate journal entries or test answers; narrow assignments to most important features; allow student to make selection rather than production responses on tests; ask support personnel for assistance; provide a daily outline of tasks to aid organization and work completion.
- Gifted Student
Provide opportunities for extended activities such as constructing a more complex parabolic cooker, studying radiation, convection and conduction, studying atomic fusion as it relates the sun�s energy, or studying how microwaves agitate molecules to heat food.
- English Language Learner (ELL)
Provide visual models when possible; ask for translation help from more proficient bilingual students; ask ESOL support personnel to develop a two-language glossary of terms to aid vocabulary development; allow students to write in their native language for later translation.
Assessment
Assessment is ongoing throughout the course of study. Assessment is based on journal responses to Probing Understanding questions and the final media project, using the solar rubric. For students with writing or language difficulties, allow for dictated responses or writing in the native language.
Credits
Marge Stembel of Garrett Park, Maryland participated in the Intel� Teach to the Future program, which resulted in this idea for a classroom project. A team of teachers expanded the plan into the example you see here.
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