For Thursday Things this week, Mom and I made a solar oven in our back yard. I didn't have the stuff to make s'mores like the experiment where I got the idea so I up-cycled crayons. We used the power of the sun to make star shaped crayons, Solar Powered Stars. Get it?
I have re-made crayons in the oven and it takes just about the same amount of time, but you can't watch them cook and it isn't as much fun. I made the ones in the picture for Mother's Day. I think they make great art. I will make a post about the crayons next week.
To make the oven you need:
A box that opens like a pizza box or a shipping box
Black construction paper
2 Sheet protectors or plastic wrap
A bamboo skewer
tape and/or glue
something to cut with
First have a grown up cut a flap on three sides, in the top of box so that here is a window. Then glue a piece of foil to the bottom of the box and another on the flap. Next tape the construction paper to center of the bottom of the box. Then cut the sheet protector so that it is open and flat. Tape that to the inside of the window under the flap. We only needed one but if you need more plastic use more than one sheet and tape them together with clear tape. Finally tape the bamboo skewer so that it holds open the flap.
This was so much fun. I love how it works. The sunlight reflects off the flap into the plastic window. The light wave changes when it goes through the plastic, so it can't just leave again. It bounces around the inside of the box and the dark paper collects the heat and cooks the stuff. It took about 15-20 minutes to make our crayons, but I thought they were too melted. That is the same as the regular oven. Our thermometer on the table in full sunlight got to 105° and in the box at the end it showed at 120°. That is so great. Mom thinks that the thermometer might have been in direct sunlight inside the box so the temp isn't true and we need to test it again to be sure. We are going to make s'mores next time. I want to try nachos too, but I can't think of what else would be okay to cook and eat in my oven.
I am so happy this worked right the first time. A lot of our stuff takes a few tries to work. I think it is because the directions at the site where I got the idea were so good. You can see that experiment here http://www.stevespanglerscience.com/experiment/solar-oven . It is my favorite science site.