Optional Promo Message

Solar Oven S’mores!


A solar oven is a box that traps the heat from the Sun, making it hotter inside the box than outside of it. You can have fun building a solar oven to make a favorite snack: s’mores!   

Cardboard box solar oven

You will need: 

  • A small cardboard box with attached lid, at least 3 inches deep and big enough to set a pie tin inside 
  • Aluminum foil 
  • Clear plastic wrap 
  • Glue stick 
  • Tape (duct tape, masking tape, or whatever you have) 
  • Stick (about 1 foot long) to prop open reflector flap (a skewer, knitting needle, or ruler will work) 
  • Ruler 
  • Box cutter (To be used by ADULTS ONLY!) 
  • Graham crackers 
  • Large marshmallows 
  • Plain chocolate bars (thin will melt easier) 
  • Aluminum pie pan 
  • Napkins! 


Build the solar oven: 

  1. Using the ruler as a guide, have an adult cut a three-sided flap out of the top of the box, leaving at least a 1-inch border around the three sides.
  2. Cover the inside bottom of the flap with aluminum foil (shiny side facing out), gluing it down and making it as smooth as possible.
  3. Next, glue foil to the entire inside of the box, again making it as smooth as possible, so it acts like a mirror. 
  4. Tape two layers of plastic wrap across the opening you cut in the lid. This will keep the heat in while letting the light shine through.
  5. Use the stick to prop the lid up. You may have to use tape or figure another way to make the stick stay in place. 
  6. Set the oven in direct sunlight on a sunny day, when the outdoor temperature is at least 85 degrees F. Prop the flap open, so it reflects light into the box.  
  7. Preheat the oven for at least 30 minutes.


Make the s’mores: 

  1. Break graham crackers in half to make squares. Place four squares in the pie pan. Place a marshmallow on each then place in oven. Note: You will add the chocolate later.
  2. Quickly place the pan in the preheated solar oven, and close the lid of plastic wrap very tightly, to hold the heat in. Keep the flap propped-open to reflect the sunlight into the box. Depending on how hot it is, the marshmallows will take from 30-60 minutes to get soft.

  3. Once they are soft to the touch, add a square of chocolate on top and another graham cracker and gently squash down.  Close the lid again and allow the sun to heat it for a few more minutes to melt the chocolate.