Solar Cookers

In December 2009, students had the opportunity to explore the quadratic equation and parabolas in an unusual way. After learning how to factor out and graph quadratic equations, they designed and built parabolic solar cookers. They identified what they felt to be the perfect equation for a parabola that would reflect the Sun’s rays, as they attempted to roast a marshmallow.

The solar cookers were built with recycled boxes, cardboard, aluminum foil, and a few other odds and ends. Students came up with a variety of designs, from a parabola that slides across an arch in the box, to a rotisserie style parabola for fast adjustment and alignment to wherever the Sun might be. The teams applied creativity, teamwork, and critical thinking skills as they attempted to build their curved parabolas while maintaining a smooth reflective surface (to avoid dispersed light).

It was a cold, windy day when the solar cookers were finally put to the test. The outside temperature was 61o degrees while the 2nd period students carefully adjusted their cookers to the low-lying sun. While no marshmallows ended up roasting, the winning solar cooker reached an internal temperature of 93o at the focus point. Mr. Coots’ 7th period class benefited from a 74o temperature outside, and several solar cookers passed 110o after 30 minutes in the Sun.