The pizza box solar oven is a great project for kids because it shows two passive solar principles working together to accomplish a goal the kids can really relate to: making something yummy!
The principles demonstrated are:
- Solar Gain – arranging for sunlight to enter a device as a source of energy. In this case, the gain is accomplished both by reflection and direct gain. This principle also includes using dark colored surfaces to absorb the solar energy that enters a device.
- Insulation – containing heat by trapping air inside and around a device to contain heat, and reflecting thermal radiation back into a device. The simplest pizza box solar oven design, as given below, can get up to two hundred degrees fahrenheit on a warm sunny day.
Things you need:
- pizza box
- box cutter
- aluminum foil
- plastic wrap or heavy plastic laminate
- electrical tape (can withstand heat)
- black construction paper
- dowel or stick.
- scissors (teachers or older students may also want to have an exacto knife on hand, to better be able to cut cardboard with)
- The first step in making a pizza box solar oven is to prepare the top. Draw a square on the top that leaves a border of about 4cm. It will look like a picture frame. Cut the top of the box along three sides of the drawn square leaving one side attached. Fold the cut out square flap back along the remaining line.
- Line the flap with aluminum foil on the inside so that the foil will face the interior of the solar oven when it is closed. Bring the foil to the outside and secure with electrical tape. You do not want tape inside of the box. Electrical tape is recommended because it will stand up to heat.
- Next you will line the interior of the solar oven with aluminum foil. Secure the foil with electrical tape. Do not put the tape inside of the box, wrap the foil over the edges of the box and secure on the outside. You are trying to keep the interior of your solar oven reflective.
- Cut a piece of plastic wrap or heavy plastic laminate larger than the hole in the top. Plastic wrap will suffice if you are only using the oven once or twice. Tape the plastic to the inside of the top of the box making sure it is sealed to prevent the heat from escaping.
- Close the solar oven. Place plastic wrap over the hole in the top and secure with electrical tape.
- Line the bottom of the box with black construction paper. The interior of solar ovens are usually black because it absorbs heat.
- You can form additional aluminum foil into a holder for the food to be cooked or use aluminum pie plates or shallow dark containers.
- To cook in the pizza box solar oven place the food in the box, close the box and place in direct sunlight. Lift the flap and prop it open with a dowel or stick. Adjust the flap to capture the most sunlight and reflect it into your pizza box solar oven. The reflected sunlight will provide the heat and cook the food. You will need to move the oven as the sun’s position changes.
Tips & Warnings
- To maximize the heat solar ovens from a pizza box, cook in a shallow dark colored pan.
- Your solar oven can reach over 100oC when it is sunny.
- Items cooked in solar ovens will be hot. Use oven mitts to remove food.
- Do not let children cook with the pizza box solar oven unsupervised.