STEM Lab: Build a DIY Solar Oven for Delicious Sun-Baked S'mores

Eco-friendly, STEAM fun for kids on a hot summer day

By Courtney Jennings, publisher of Macaroni KID Acadia-St Landry, La. July 8, 2024

With the blazing hot days of summer upon us, building a campfire is out of the question. But my family found a cool and creative way to utilize these hot summer days for a tasty camp-style treat! 

Last year, while attending Girl Scout camp, my daughter learned how to create a solar oven for making hot dogs and s'mores. We thought this STEAM project would be fun to try at home to take advantage of the scorching hot temperatures.

Our solar oven worked well, and the kids loved this project, so we wanted to share how we did it so you can try it, too!

What You Need:

  • A sturdy cardboard box with a lid
  • Aluminum foil
  • Black construction paper
  • Clear plastic wrap
  • Tape or glue (optional)
  • Scissors
  • Pencil or marker
  • Ruler
  • A stick or skewer to hold up the lid
  • S'mores ingredients (graham crackers, chocolate, marshmallows)

Mom tip: We used mini marshmallows and chocolate discs because I thought they'd melt quicker and easier than the larger marshmallows and chocolate squares.

What You Do:

  1. With your clean cardboard box flat, use a marker and a ruler to outline a square on the top. Use scissors or a box cutter to cut out three sides of the square to create a "window," leaving about a half inch of an edge. 
  2. Now, you want to create a reflective surface. Cut a piece of aluminum foil slightly larger than the inside of the box lid. Wrap the inner part of the cardboard lid with tinfoil and line the inside of your box completely with the foil, ensuring it's smooth and shiny. Secure the edges with tape as needed. 
  3. Glue or tape a sheet of black construction paper inside the bottom of the box. This will be your cooking platform. Depending on the size of the box you chose, you may need to cut one of the sides of the construction paper to fit inside the bottom. The black sheet will absorb the sun's rays and convert them into heat.
  4. Assemble your s'mores! Place graham cracker squares on the black sheet of paper in your oven, add the pieces of chocolate bar, and finally, the marshmallows! We found it best to leave the top graham cracker off so the marshmallows were directly in the sun.
  5. Place plastic wrap on top to cover the window opening of the box and tape it in place. This will hold in the heat and help keep off flies and other pesky insects that might be attracted to your sweet treats while cooking. 
  6. Place your skewer or stick through the plastic wrap in the left bottom corner of the box and hot glue or tape the top of the skewer to the top left corner of the foil-wrapped cardboard 'lid' to prop it in place. 
  7. Carefully place your DIY solar oven in the sun, angled directly towards the sunlight, for about an hour or until the chocolate and marshmallows melt. 
  8. Once the s'mores are "cooked," you can remove the plastic wrap, top them with another graham cracker square, and then enjoy your sun-cooked treat!

Always have adult supervision when using sharp objects like scissors and box cutters, and be cautious when handling the solar oven, as it may get hot. 

Have fun and enjoy your eco-friendly cooking adventure!