School is in session all summer, and it’s hot out there. So my students and I are taking advantage of the sunny skies by dabbling with a variety of solar energy projects from the National Energy Education Development Project. This past week we have been making multi-color crayons using solar energy ovens. We were going to cook food in the ovens, but after much fretting and anxiety on my part, I decided melting crayons would be a safer, more appropriate challenge.
What are solar energy ovens? They are nifty little contraptions you can make out of materials around the house. They are containers covered in shiny foil so that the sun’s rays can be reflected onto what is being cooked, intensifying the amount of heat collected. I found instructions for making a solar oven at Instructables.
We used bathroom cups as a container for melting the crayons. Students unwrapped crayons, broke them into smaller pieces, and put them inside the cup. The cups were filled about half-way.
Next, we put the solar ovens outside and placed the cups inside the solar ovens. My students told me how they wanted to set up the ovens to catch the most rays.
One oven was tragically tossed around by the wind. Oops. Time for a do over.
I used a food thermometer to intermittently check on the temperature of the solar oven. This allowed students to track the increase in temperature and compare it with the regular outside temperatures.
When the crayons were all melty and looked like a strange witch’s brew, the solar ovens were brought inside. The melted crayons hardened as they cooled.
The kids were disappointed by the monochromatic appearance of their crayon mixtures, but then they peeled the cups away and found…
The project was a hit. I hope it is a memorable experience that will inspire my kids to keep looking for ways to harness the powers of solar energy.