Read descriptions, see photos, and borrrow recipes from participants in the most recent Solar Oven Challenge.
St. Peter's Secondary School, Grade 11, Barrie, ON
Honours with Distinction
The Solar Oven Challenge was a great opportunity for the students in my Environmental Science class to apply what they have learned about renewable energy sources and energy saving devices in a fun and practical way. There are 27 students in my class. We split into teams of 2 or 3 and built a series of solar ovens, each uniquely designed and fully functional. Our goal was to create a meal for each other using solar ovens built from recycled materials.
The ovens were all constructed using recycled cardboard for the main frame. One oven was constructed with plywood. The ovens were painted black on the inner bottom surface in order to maximize absorption of solar radiation. They all made use of reflective materials, such as aluminum foil, recycled CDs, and old locker mirrors to direct the sun's light onto the cooking surface. Silver duct tape, recycled coat hangers, elastic bands and glue were used to bind the pieces of the ovens together. Most ovens were covered with reused plastic food wrap and clear tape to trap the heat and allow the ovens to reach a higher internal temperature. Finally, the ovens were insulated with recycled newspaper and styrofoam packing. We placed a thermometer inside each oven to record the temperature.
The class met at 8:00 am, right after homeroom, to set up the ovens. We chose to set up the ovens on black pavement in the far corner of the parking lot, in full sunlight. The day was very hot (about 30 degrees Celcius), and there was no breeze. Once the ovens were set up and all the food items were prepared, the students went to their classes.
We met at 9:20 am, during our class time, to monitor the progress of the cooking, make adjustments to the position of the ovens, and take pictures. We made our final observations and had our class meal at 10:40. The students had a great time and enjoyed the treats! They shared hot dogs on warmed buns, cookies (which were a little doughy, but tasty), garlic bread, s'mores, bruschetta, brownies (mostly dough), and toast. One group tried to make scrambled eggs, but the internal temperature of that oven did not get hot enough.
The internal temperature of one of the ovens reached 100 degrees Celsius! This was hot enough to bake the cookies so they held their shape and were edible. The ovens that cooked the hot dogs reached about 75 degrees Celsius. Most of the other ovens reached an internal temperature of about 55 degrees Celsius. My students brainstormed ways to improve on their designs to increase the internal temperature. They decided that having more reflective materials directing sunlight onto the food would have allowed the ovens to get hotter. Most ovens could have been sealed better to prevent heat escaping to the environment. Having the ovens out later in the day, closer to noon, as well as having them outside for a longer period of time would have made a difference as well. Finally, using more insulating materials on the sides and bottom of the ovens may have prevented heat lost to the environment.
The students truly enjoyed doing this project. They gained practical knowledge on solar energy and how it can be used effectively to heat and cook food. They also had the opportunity to share ideas, design, build and test their structure in a fun and open learning environment. Students got to know each other and made new connections within our class. They worked hard, and the reward was in their finished products, food party and new friendships.
Jasper Place High School, Grade 10, Edmonton,
Honours with Distinction
We built the solar oven. Our class modified last year's basic plan. We painted the outside of our oven black hoping to help attract the sun's rays. Secondly, we decided to place our oven in two truck tires. We insulated the truck tires with hay from our permaculture project. The reason for this was to attract more of the sun's rays to our project. We built a barrier between the tires and our solar oven to also help keep the heat in. Also we placed our oven on a sloped hillside to improve the angle to the sun.
We discovered the importance of the angle of the oven to the sun. We believe our black tires and insulation also helped create more heat for our oven. This year's project increased the cooking temperature by 20 degrees C.
We enjoyed taking last year's project and making modifications to it. Also we enjoyed the opportunity to share some ideas with our permaculture club in the construction of our project.
Centre Peel Public School, Grade 7/8, Drayton, ON
Honours with Distinction
The two grade 7/8 classes at Centre Peel were challenged to create solar ovens in small groups. All students were given the template created by re-energy.ca. After discussion, some groups decided to follow the plan, others used pieces of the plan, and still others chose to do their own thing. The final ovens were made from cardboard, wood, tin, glass, and/or foil.
The students were excited to get started. Some were confident that the plan provided would be the best and the hunt for cardboard began. Meanwhile, others wanted to think about which materials would attract the sun the best, and tin was their choice. Finally, a few groups talked about holding the heat and decided to use wood for their ovens. Using mostly school time, the students got busy. Those who followed the template provided were quick to get started. The others worked hard to draw up plans of what they needed and the lengths of the materials required.
Sadly, the hottest weather in May passed as we were putting our finishing touches together. Nevertheless, students were able to put their projects outside to test. The groups who finished on time cooked a frozen pizza which was crispy and melted, but it took about 2 hours to bake. There were a lot of nacho and cheese snacks. One teacher described his snack as "tastey, but a bit dry." We decided that was because of the long time we had to wait for the cheese to melt. One team tried to fry an egg, but they decided this would need to be attempted again.
What did the students say?
- "I learned that it's actually kind of fun. We thought it would be hard and not fun, but now it's the opposite."
- "We learned that all sides have to be turned outwards. It needs to be built out of wood not cardboard. Wood is a better insulator. A challenge is to get it to 300 degrees - keep an eye on your food!"
- "Tips: use steel for a box instead of aluminum, test on a sunny day, use silicone instead of duct tape. Some challenges were testing on a rainy cloudy day, forgetting to put butter in the pan, and a side panel that didn't fit quite right."
- "Something fun and exciting was to see how long it actually took to bake nachos and cheese."
- "It was fun to cook and taste the food."
Royal Canadian Montessori School, Grades 4 to 6, Whitby, ON
Our school decided to compete in the solar oven challenge, and at the beginning of May there was a heavy competition starting to heat up (no pun intended). There was a challenge made within the classroom: boys against girls.
The Boys' Team
The boys decided to make a Sun Box to try to absorb as much sun as possible and focus it down onto the tray. They propped the lid up with paper towel rolls and used pizza boxes to make a cube. They used saran wrap to try to trap the heat in the box.
The boys said they wished that they had thought about the shadow that was cast by the front side of the cube. They believe that was why part of their cake was a "little doughy".
The boys loved strategizing and tried half a dozen different ideas (and an equal number of pizza boxes) until they came up with this approach. They said everything went great, but next time they don't want it to be so healthy. They'd prefer to lose the blueberries and coat their cake with chocolate icing.
The Girls' Team
The girls wanted to think outside of the oven box. They took a large thin rectangular box and connected and bent it to make a large satelite-looking structure. Then, as if it were perfectly moulded, they "borrowed" one of the girl's younger brother's chaotic box and used it as the cooking chamber. It has a see-through cover and is heavy cardboard. The girls went a little crazy with the tinfoil, and even the inside of the chaotic box was covered. They tried it a couple of times during the month of May. But May 31 was the perfect day. Before they even put the tin into the chamber, the inside of the chamber was starting to heat up well.
The girls realized that they should have considered the size of the cooking tin when building the model. The tin had to be scrunched up and resulted in a "less than perfect" shaped cake. But they didn't mind one little bit once they could have a taste. The cake didn't look pretty but it smelled delicious.
After only 5 minutes the girls started to notice the cake rising. They quickly compared their results to the boys and they relished the fact that their design was working well. The only other exciting happening was when the student's younger brother realized where his chaotic box had went and we all had to try to convince him to let the experiment finish first. He was promised the biggest piece of cake for his donation.
Blueberry Upside Down Cake
2 cups flour
baking powder a tsp
2 eggs (but we used egg whites)
1/2 cup vegetable oil
1 cup water
1 pint of blueberries
Add all the wet ingredients together firs. Sift together the dry ingredients and add one third of the dry ingredients to the wet ingredients. Mix well, and it should be the same consistency as paste.
Pour into the container and cook in a solar oven for 2 hours. Place a layer of blueberries on top and then flip. Voila!
Ecole St Gerard School, Grades 2/3 and 4, Calgary, AB
The grade 2/3 and 4 classes built solar ovens using a pizza box, black paper, aluminum foil and plastic. We used black paper in the oven and all around it because black will absorb the heat. The aluminum foil will reflect the heat. We did this project because our classes have been learning about resources, especially energy resources and solar power is a renewable energy resource. We can\'t wait for a sunny day when we are going to try them out and prepare our appetizers, main course and dessert!
We learned that there are a lot of ways to make energy. To modify our solar oven we are going to put more tin foil inside the oven to make the heat move around the oven and then go back into the black paper. Another group is going to use a bigger box and more black paper.
The fun part of the project was actually building the solar oven because you get to say your ideas to your friends, and cooking and eating the food after!