EcoLOGICAL Tip #6: Cookin' with the Sun

Trafton B.

July 16, 2010 - 5:10 PM

As my 9th Grade students are learning, solar power can be used in two different ways. Photovoltaics -- more commonly known as solar panels -- convert the sun's light directly into electricity by causing electrons to temporarily jump up to a high state of energy. Solar thermal energy, on the other hand, refers to harnessing the sun's heat energy and concentrating it on one specific area or object. Solar thermal energy can be used to heat water for homes or turn water into steam to generate electricity, but today in science class we decided to use solar thermal energy to do something a little bit more fun.

We roasted s'mores in our homemade solar cookers.

It's a fairly simple task. If nine soon-to-be high school students can properly make and use their solar ovens in a 45-minute period, I'm sure you all can figure it out.

First, your materials include a shoebox, aluminum foil, and tape. Any box will do the trick; just consider the size of the dish that you're preparing. We were cooking s'mores, which doesn't call for too large of an oven.

Next, the instructions. cut the sides of the box down so that you have one flat piece of cardboard. Cover the inside sections of the box with aluminum foil and make sure the foil is taped down properly. Then strategically build the sides of the box back up to create an oven. The main premise in designing your solar cooker is that you want the sides of your shoe box to be tilted outward so that they will be able to catch as much sunlight as possible and then reflect it towards one point in the center of the box; that's where we'll put the s'mores. Take a look at the picture of Ariel's solar cooker to see what I mean.

Last summer we made solar cookers and we spent an entire day making and designing them. They were very well done but we were missing one critical element, sunlight. I completely forgot that our class was during first period, which means that the morning cloud cover had yet to burn off by the time we were outside cooking. We still managed to eat s'mores (because I felt bad and put them in the microwave) but it was a bummer that we'd spent all that time for nothing.

Today went much more smoothly. The temperature in Redwood City was an easy 78° and not a cloud in sight. The marshmallows were a slightly stubborn, but the chocolate melted with about five minutes inside the cooker. We were able to discuss more about renewable energies and why one solar cooker design worked better than another while feasting on our fine s'mores. It was a perfect Friday activity. I think my favorite part of the day was seeing the students that are normally quiet inside the classroom get really engaged in making their boxes.

Learning is always more fun when you're working with your hands; drawing, painting, watering plants, feeding the fish, taping aluminum foil to an old shoebox. Maybe the chocolate treat at the end had something to do with it too.