What is the best way to make a Solar Oven?

Question

I need to make a project in science and i can use anything but magnifying glasses, batteries, solar pannels, or any other heating devices. Some ideas are tin foil, cooking bags... oh and also, it has to fit in a backpack.

Answer 1

Paint the inside/outside of box black.  Use foil to redirect the sun, keep the opening small, so that the heat stays in. You can google it too, there are some cool ideas out there!