Using the principles of scientific investigation, students design a solar cooker using materials supplied by the teacher. Students then spend individual time designing a solar cooker on their own. Afterward, students are placed in groups to cooperatively design a cooker. The kids construct their cookers, and then try them out by sun-roasting apples. A report is written to summarize at least three science concepts utilized in their design. Through this engaging and inquiry-based activity, students learn the application of science by transforming insulation to heat energy.