The Build:
1. Cut a flap in the lid of the pizza box and fold it up.
Line the inside of that flap with foil to reflect sunlight.
2. Tape black paper to the bottom of the box (black absorbs heat).
Put your graham cracker, chocolate, and marshmallow inside and cover the opening with plastic wrap to trap the heat.
3. (Tips for Solar Success) -The Angle is Everything:
Propping the foil flap open at just the right angle is key. You want the sunlight to bounce off the foil and hit the marshmallow directly. You can use a ruler or a stick to hold the flap in place.
Pre-heat the Box: Just like a real oven, let the box sit in the sun for about 15 minutes before putting the food inside. This gets the black paper nice and hot.
The "Smush" Test: Marshmallows don't get "toasted" or brown in a solar oven like they do over a fire. Instead, they get very soft and gooey. Once the chocolate looks shiny and the marshmallow looks puffy, use your top cracker to "smush" it down—if it squishes easily, it’s ready!
