At the end of this lesson students should be able to:

To motivate students, the teacher might...

Using the materials listed above, students should be given the freedom to choose their own designs. The following considerations should be clearly explained prior to building the solar oven.

Design Considerations

A detailed explanation of how to construct an example solar oven can be found at http://www.backwoodshome.com/articles/radabaugh30.html

• Upon completion, students will test the effectiveness of their ovens on a sunny day by attaching and using a thermometer to measure the temperature every 10 minutes for 1 hour, then every 1 hour for the duration of the school day (at least 3-4 hours total). Alternatively, the teacher could take readings on the ovens during the school day if students are in other classes. They will also bake their cookies in the ovens to qualitatively determine how effective the ovens are.
• Students will use their data to plot temperature vs. time on a graph.
• Students will eat their baked goods.

• If the ovens are not reaching the desired temperatures, make sure that all seals are tightly closed and air is not leaking out. Make sure any cracks in the box are glued or taped and well insulated and make sure the lid forms a tight seal with the box and where the glass meets the box. Foam around the rim where the lid meets the box can help improve this seal.
• If all seals have been insulated and the box is still not reaching 185 degrees Fahrenheit, make sure that the box is facing toward the sun for at least 20 minutes every hour. This project should only be done during the spring or summer months. If the box still will not heat properly, add more insulation by placing the box inside an even larger container and adding insulation. Finally, perhaps the box is simply too large. Consider making the area that needs to be heated smaller by placing another box within the original space or allow more time for heating.
• Construct the solar oven as desired and then fit the Plexiglass to the box.
• To make the reflectors, simply cover the flaps of the box with tin foil.
• Get plenty of black duct tape, as it tends to run out.
• Foam insulation tends to work better than newspaper.
• The reflectors are hard to attach and sometimes cause the ovens to tip over. Encourage students to stabilize their ovens in case of mild wind.

General Methods of Assessment

Teachers can determine whether or not students grasped the key concepts from the solar oven activity by asking the following questions:

Have students compare their temperature versus time plots.

Scaling of this activity really depends on the amount of interaction between the students and the teacher during the design and building process.

• For advanced students, offer little to no advice and have students research different options so that they may develop their own design. Do not restrict their choice of materials or even offer examples of different devices. Have these students independently test their designs by designing an experiment and ask them to justify their design choices either through a presentation or paper. Students could even modify their designs to determine the importance of individual aspects, such as the color of the box or how different insulators affected the temperature.
• For students who need more help, interact with them through every stage of the planning and building process. Suggest the materials they should use or restrict them so they don't have to make as many choices. Offer a variety of examples or simply instruct all the students to construct their ovens based on an assigned design.