Friday, November 28, 2008

Make a Solar Oven

Pizza boxes can make a super oven. I tried it at home when it was 41 degrees Fahrenheit outside. The temperature inside my oven went up to 170 degrees Fahrenheit in a couple of hours. This is a great way to teach children how to rethink, refuse, reduce, reuse and recycle (refuse is not a character quality most children need to be taught...).

Here is what you need: Pizza box; black construction paper; aluminum foil; saran wrap; hot dogs; toothpicks; tape; glue

Doing it: Open up a clean pizza box. The box will have a top flap, and a bottom box. Line the bottom box with black construction paper and glue it down. Cover the top flap with aluminum foil and glue it on as flat as possible. Bumps or irregularities in the foil will reduce the ability of the top flap to collect sunlight. Poke two toothpicks into each end of a hot dog to make a little stand. Place the hot dogs in the box, and cover it with saran wrap. Make the saran wrap as smooth as possible too. Put the box in a sunny place, and adjust the top flap so that the sun is being reflected straight into the box. You may need to prop up the flap. I used two wooden skewers and two clothes pins to prop up the box.

Explanation: The sun is the ultimate source of almost all the energy on this planet. Black materials absorb light (which makes them black) and then have to get rid of all that energy they absorbed, which they do by heating up. The black construction paper heats up, and so heats the air all around it. The air can't escape the box because of the saran wrap, and so just gets hotter and hotter, cooking your food. A well built solar oven can reach far hotter temperatures, by making the solar reflector out of mirror instead of foil, by placing insulation around the box, and by using glass instead of saran warp.

Note: How does this help reduce using energy? Obviously, it eliminates the use of energy in an oven run by electricity or gas, but it also helps reduce energy usage in other parts of the home as well. Air conditioning on hot summer days is a massive energy drain, and those days are exactly when solar cooking could work, instead of heating your house with an oven only to cool it down again. Also, the oven is often placed right beside the fridge! The solar oven is an example of passive solar heating, which is using the energy of the sun to heat things up directly. Well designed houses can be heated by entirely passive solar, except during the darkest, coldest months of winter.

4 comments:

solarcooker-at-cantinawest said...

Greetings,
It is great to see that our children are learning valuable information, skills, and ideas to help them look outside of themselves and their own world, to better understand that there is much more to our lives than just the accepted and wrote status quot.

Solar Cooking is a great place to start on the path to greater and more beneficial changes that are so urgently needed in this world, not only within our physical and tangible natural world but also within our hearts, minds and souls as human beings.

I highly endorse solar cooking as; one alternative source of energy, among many available.
I also teach people how practical and feasible it can be, even to the ordinary person here in our highly advanced society.

Keep up the good work.

Sincerely
Nathan Parry
http://www.solarcooker-at-cantinawest.com

chaz steadman said...

We've always heard that children are the future of our world. That could not be more true than today, when the environmental issues that are facing us are potentially catastrophic.
My thanks to all teachers and parents for educating our children on the responsibility of taking care of our planet, even if it's one solar cooker at a time.
Thanks, Ellen!

Chaz Steadman
future site: http://www.solarcookerguide.com

Rachel said...

How cool! I'm going to have to try that at Christmas with Peter!

John Smith said...

Hi Ellen,

I'd like to use your image of a solar oven in a publication I am creating: a curriculum for grades 3-8 on energy and climate change.

I work with the Will Steger Foundation and we are going to use a lesson on making pizza box solar ovens in our curriculum as a renewable energy STEM project.

Please advise if you grant us permission to use the image - or if you know the original source of the image. Also, let me know if you have any specific way you would like the image credited.

Thank you!
John Smith
john@willstegerfoundation.org
Ed Program Assistant
Will Steger Foundation
Minneapolis, MN