STEM Challenges for elementary students! Students will experiment with heat-resistant materials and then use their test results to design the best oven possible. This is so exciting as they troop outside to test the materials, record the temperatures of the ovens, & choose the materials to design the best oven. Finally, they put together a chocolate treat and use the sun to help cook the item. This STEM resource includes detailed teacher directions, photos, lab sheets, and rubrics.