Here is a design for a solar box cooker that teachers and students can make to have a practical experience with an "appropriate technology" (AT). By doing this activity, students will be using a simple design to make a low-cost device, that is "environment friendly," and uses the unlimited power of the sun to cook chocolate chip cookies (or oatmeal cookies, or brownies etc.). The solar box cooker operates on the same principle as a car with the windows rolled up on a sunny day. The air inside is trapped and gets hotter and hotter (the solar box cooker you will build can measure 275 325 degrees on a very sunny day) and this trapped heat can be used to cook food. The solar box cooker actually works, and it is a real "crowd-pleaser" when you bring it inside, open it up, and the children can actually smell and taste the cookies that were baked using no eas or electricity; just the sun.
First, it is important to understand what appropriate technology (AT) is. Appropriate technology began to gather momentum after the publication of E. F. Schumacher's book, Small is Beautiful: Economics as if People Mattered (1973). Schumacher was a London economist who examined the inequalities between the developed and developing countries of the world. He was also concerned with the waste of natural resources and with inappropriate introduction of technology into developing countries. Using a technology that is "environment friendly," and is suitable for the local population became a guiding principle of appropriate technology. An appropriate technology philosophy can be introduced into an elementary classroom by discussing and using recycling, conserving, and re-using practices. The solar cooker gives teachers opportunities to involve students in a fun activity that teaches them how to be good "global citizens."
Here are the things you will need to make the solar cooker. The materials are inexpensive, and you probably already have the tools that you will need to construct it, i.e.: X-acto knife, circle and arc compass, white school glue, hot glue gun, yard stick, and a fine sharpie marker. These are the materials you will need: a sheet of rigid insulation (It usually comes in a 4' X 8' sheet, 1/2" thick, about $7.50. With a 4' X 8' piece you will be able to make many cookers. If you cannot find 1/2" rigid insulation, simply use what is available, 5/8" or 3/4", and adapt the dimensions to your material); a roll of duct tape; about 5' of thin dark yarn; a large freezer bag or some type of clear heat resistant plastic (glazing); some thick cardboard; and some shiny aluminum foil. After you have assembled all of the materials, you can begin making your solar oven by following these procedures:
1. Examine the plan for the solar cooker and use the yardstick and the marker to carefully mark out each numbered piece on the rigid insulation and the cardboard. Line up the pieces along a straight edge of the rigid insulation and, using the yardstick as a straight edge, cut them out. (Remember: be very careful with the X-acto knife. Be sure to cut on a working surface. Measure twice, cut once!)
2. Put all the pieces together without glue ("dry"), making sure that the smaller box will fit easily into the larger box with at least 1/8" of "play." (You might want to tape them together before you fasten them permanently to get an idea how they will look.)
3. Assemble the smaller box first by running a bead of hot glue along the edges of the sides and attaching them as shown in the "exploded view. …