Can you use the power of the sun without using solar cells? You bet! We’re going to focus the incoming light down into a heat-absorbing box that will actually cook your food for you.

Remember from Unit 9 how we learned about photons (packets of light)?  Sunlight at the Earth’s surface is mostly in the visible and near-infrared (IR) part of the spectrum, with a small part in the near-ultraviolet (UV). The UV light has more energy than the IR, although it’s the IR that you feel as heat.

We’re going to use both to bake cookies in our homemade solar oven. There are two different designs – one uses a pizza box and the other is more like a light funnel. Which one works best for you?

  • Two large sheets of poster board (black is best)
  • Aluminum foil
  • Plastic wrap
  • Black construction paper
  • Cardboard box
  • Pizza box (clean!)
  • Tape & scissors
  • Reusable plastic baggies
  • Cookie dough (your favorite)
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14 Responses to “Solar Cookies”

  1. Any color… for which part of the experiment?

  2. Laura Walters says:

    can you use any color

  3. Michelle Stevens says:

    do you think that I could use a Fresnel lens instead of plastic wrap?

  4. Science is the process of asking questions and getting back answers. I think you’ve asked a wonderful question and you have what you need to design an experiment to answer this question with this activity. Let me know what you find out – which one: white paper or foil (and which side of the foil?) works best to make cookies?

  5. Michelle Stevens says:

    Wouldn’t white paper be more reflective than the aluminum foil?

  6. I’ve never made a pizza in my solar oven before – you might want to try a small one at first and see how long it takes. It’s really going to depend on how well you keep it in the right position to collect as much solar energy as possible. Let me know how it goes.

  7. Lillian Jackson says:

    You can make other things besides cookies and s’mores right? I would like to make mini hummus and tomato pizzas with my friends ( the home-made kind that only need to be warmed) at play dates! Would something like that need to be in there for only about 1-2 hours? That would be great if it can, because the hummus does not even run so it could not stain the construction paper!

  8. Thanks – I’ll get that fixed right away!

  9. Barbara Campbell says:

    Don’t know if anyone mentioned this yet but there is a spelling error in 4th sentence under solar cookies. “remeber ” should be “remember.” Just thought you might want to know. 🙂

  10. Lydia Fancher says:

    made this it was easy!

  11. Heather Smith says:

    i saw this on tv

  12. Yes, you can get highly reflective mylar sheets – they are flexible, light weight, and don’t shatter the way mirrors do. Cover a lightweight box with this stuff and you should see a boost in your temperature. Also – don’t forget that the heat will also leak out the sides. If you can insulate your box to keep the leakage at a minimum, you’ll retain more heat (and reach higher temperatures). A cooler comes to mind…

  13. Anonymous says:

    We’ve already made the pizza box solar ovens that came close to 200 degrees and cooked some delicious s’mores.
    But now we’d like to take it a step further and make something that gets hotter and is better insulated. Can you recommend what to use for the reflectors besides foil? Is there something cheap I can get to have four flaps? Would any kind of shiny metal work? I know that mirrors would work but that’s not very practical or portable. We are going to build a wooden box and hopefully have a glass cover but would plexiglass be okay or would that give off a chemical reaction when heated like using plastic in a microwave? Thanks for the help.