towards the pots and the dark bottom, which is in contact with the pots. The box should have insulated sides. Thermal insulation for the solar box cooker must be able to withstand temperatures up to 150 °C (300 °F) without melting or out-gassing. Crumpled newspaper, wool, rags, dry grass, sheets of cardboard, etc. can be used to insulate the walls of the cooker. Metal pots and/or bottom trays can be darkened either with flat-black spray paint (one that is non-toxic when warmed), black tempera paint, or soot from a fire. The solar box cooker typically reaches a temperature of 150 °C (300 °F). This is not as hot as a standard oven, but still hot enough to cook food over a somewhat longer period of time. Panel solar cookers are inexpensive solar cookers that use reflective panels to direct sunlight to a cooking pot enclosed in a clear plastic bag. Solar Oven science experiments are regularly done as projects in high schools and colleges, such as the "Solar Oven Throwdown" at the University of Arizona. These projects prove that it is possible to both achieve high temperatures, as well as predict the high temperatures using mathematical models. Parabolic reflectors Parabolic solar cookers concentrate sunlight to a single point. When this point is focused on the bottom of a pot, it can heat the pot quickly to very high temperatures which can often be comparable with the temperatures achieved in gas and charcoal grills. These types of solar cookers are widely used in several regions of the world, most notably in China and India where hundreds of thousands of families currently use parabolic solar cookers for preparing food and heating water. Some parabolic solar cooker projects in China abate between 1–4 tons of carbon dioxide per year and receive carbon credits through the Clean Development Mechanism (CDM) and Gold Standard. Some parabolic solar cookers incorporate cutting-edge materials and designs which lead to solar energy efficiencies >90%. Others are large enough to feed thousands of people each day, such as the solar bowl at Auroville in India, which makes 2 meals per day for 1,000 people. If a reflector is axially symmetrical and shaped so its cross-section is a parabola, it has the property of bringing parallel rays of light (such as sunlight) to a point focus. If the axis of symmetry is aimed at the Sun, any object that is located