Solar Energy Oven

For my science experiment I’m making a Solar Energy Oven, and along with that we had to make 5 Questions, and one of them involved cooking food. The food I’m going to cook will be: Sausages, Pikelet, a medium sized potato, and an egg. The way the oven works is like this: When the sunlight hit the foil it bounces of it and enters through the plastic and, cannot escape and causing what ever’s in the oven to cook. And in the book it said not to be surprised if the oven reaches temperatures over 200'f. My Prediction is that it should cook in 20 minutes because no heat can escape no matter what.