What you'll need:
Cardboard pizza box (the kind delivered pizza comes in)
Box knife or scissors
Plastic wrap (a heavy-duty or freezer zip lock bag will also work)
Black construction paper
Ruler, or wooden spoon
1. Use a box knife or sharp scissors to cut a flap in the lid of the pizza box. Cut along three sides, leaving about an inch between the sides of the flap and the edges of the lid. Fold this flap out so that it stands up when the box lid is closed.
2. Cover the inner side of the flap with aluminum foil so that it will reflect rays from the sun. To do this, tightly wrap foil around the flap, then tape it to the back, or outer side of the flap.
3. Use clear plastic wrap to create an airtight window for sunlight to enter into the box. Do this by opening the box and taping a double layer of plastic wrap over the opening you made when you cut the flap in the lid. Leave about an inch of plastic overlap around the sides and tape each side down securely, sealing out air. If you use a plastic bag, cut out a square big enough to cover the opening, and tape one layer over the opening.
4. Line the bottom of the box with black construction paper - black absorbs heat. The black surface is where your food will be set to cook.
5. To insulate your oven so it holds in more heat, roll up sheets of newspaper and place them on the bottom of the box. Tape them down so that they form a border around the cooking area. The newspaper rolls should make it so that the lid can still close, but there is a seal inside of the box, so air cannot escape.
The best hours to set up your solar oven are when the sun is high overhead - from 11 am to 3 pm. Some recipes you may want to try making are toast, baked potatoes, chocolate fondue, nachos, s'mores, and roasted apples with cinnamon and sugar.