This project helps to understand how the greenhouse effect can be used to 'trap' the heat of the sun.
The sun's rays (short wavelengths of visible light) penetrate through the glass of the oven and heat the elements inside. When this heat is reissued as infra-red radiations (longer wavelengths) it can't pass through the glass again. This phenomenon called greenhouse effect increases the temperature inside the oven. The same principle is applied in solar thermal collectors to produce hot water.
The solar oven doesn't grill food but allows you to cook eggs, tomatoes and other vegetables.
On a sunny Summer day, the oven temperature reaches over 80°C degrees and an egg can be hard boiled in about an hour and a half.
The use of solar cookers could avoid deforestation in some third world countries.