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!
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)
- Box cutter (To be used by ADULTS ONLY!)
- Graham crackers
- Large marshmallows
- Plain chocolate bars (thin will melt easier)
- Aluminum pie pan
Build the solar oven:
- 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.
- Cover the inside bottom of the flap with aluminum foil (shiny side facing out), gluing it down and making it as smooth as possible.
- Next, glue foil to the entire inside of the box, again making it as smooth as possible, so it acts like a mirror.
- 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.
- 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.
- 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.
- Preheat the oven for at least 30 minutes.
Make the s’mores:
- 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.
- 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.
- 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.