The kids might be back in school but there is still time to squeeze in some last minute science experiments. The girls and I made our own solar ovens! The best part about this end of summer experiment is that kids can set it up before school and see the results when they get home!

What you need:

• Shoe box or pizza box with lid (we used a kiwi crate box)
• Aluminum foil
• Black construction paper
• Cling wrap
• Graham crackers
• Marshmallows
• Chocolate (we used Hershey’s chocolate)
• A sunny location

How to assemble your oven:

1. Place black construction paper on the bottom of the box.
2. Place aluminum foil on the inside.
3. Assemble your s’mores and place it on top of the black construction paper.
4. Place cling wrap over the bottom of the box where the s’more is located.
5. Place your box outside in a sunny location and orient the foil lid show that the light is facing the black paper for a few hours.

What did we observe?

Our chocolate melted fairly quickly. Within about 30 minutes. We left the solar oven sit outside longer (about 2 hours) but the marshmallow only got a tad ‘squishy’. It is possible that the sun was not directed properly the entire time at the sunlight or it was not a hot enough day outside. We didn’t record the outside temperature so it’s hard to say what the problem might have been. 🙂 My photo above shows that the aluminum foil may not have been facing the sun the entire time. Oops! Generally though, chocolate has a lower melting temperature than the marshmallow, so it was not surprising that it melted first. We didn’t try closing part of the box to trap more of the heat inside. That might be an experiment for another day!

What’s happening?

1. The black construction paper is absorbing the heat! Have you ever worn black clothes on a hot summer day? I bet they got hot really quickly! As the color black absorbs the sunlight it converts it into energy – heat! Light and heat are both forms of energy and they convert from one form to the other. So when darker colors absorb light, it is then converted to heat.
2. The aluminum foil is acting like a mirror redirecting the light towards the black paper. I read separately that using the dull side may be better because it concentrates the light better across the s’mores, where as, the shiny side may cause concentrated hot spots. We used the shiny side for our experiment.

Other ways to perform this experiment:

I found the NASA has this experiment posted on their kids website. They set up with solar oven box a little differently so you might want to try that one out and let me know how it works :).

There are so many different ways to perform this experiment because of the number of variables involved and each day you will get different results because the weather is not always the same.

Sooooo, try out this experiment on home before we lose our last remaining HOT days of summer and let me know how it went!

-Kristen