E.T. A LOCAL WAY OF LEARNING
Title: SOLAR COOKING
Author: Ted Seymour
Eulalie R. Rivera Elementary School
Grade Level: 4-12
1. The Sun 1. Social Studies
6. Natural Resources 2. Science
8. Values and Attitudes 3. Language Arts
Students shall construct a solar oven according to the attached specifications
(cardboard instead of sheet metal), and cook and eat food. Student shall make
oral or written presentation of the reason for creating the oven, why it works
as it does, and the possible emergency uses.
The earth has a finite supply of natural resources which are rapidly being
depleted. -As this occurs, the cost of energy producing fuels escalates.
Utilization of Solar Energy will offset the necessity of cooking with fossil
The Virgin Islands are fortunate in having mostly sunny days and being located
in the sub-tropics, having hot sun for the project. Flat black paint is used
on-the oven's inside surface because black absorbs all light (and heat).
At lower grades substitute packing boxes for sheet metal. Linoleum knife to cut
Insulating materials, i.e., Styrofoam pellets or fiberglass
One sheet of Plexiglas or glass
Flat black paint
Using the attached specification sheet, students can work in groups, under
supervision, to assemble the materials listed, measure and cut the cardboard to
the desired sizes, assemble, and stuff with insulation. The door in the back of
the oven must be insulated also and fit tightly enough to prevent escape of
Inside the oven, make temperature tests with a thermometer, setting the oven
in various positions with respect to the sun. Experiment with reflectors to
test for impact upon oven temperature.
Bake as you would in a conventional oven, using covered dishes, or foil wrapped
food in a pan. Attention must be given to the movement of the sun to reposition
the oven for maximum exposure. When the food is cooked, enjoy.
The Virgin Islands Energy Office will send a representative to the classroom
to discuss alternate sources of energy. Solar oven plans may be obtained from
the Energy Office.
HOW TO BUILD A SOLAR OVEN
If you want to cook with free fuel, try a solar oven. It is simple, easily
made, and inexpensive. The oven consists of a box for the food, a glass to
admit and trap heat, and reflectors to direct the sunlight into the oven.
Besides the sheet metal* parts, you will need a piece of window glass, sealing
strips for the glass, and three handles. You will insulate the box with
fiberglass insulation two inches thick for greater heat retention.
26 Gauge Sheet Metal*
Double strength window glass
Flat black paint
16 sq. feet
12 sq. feet
22 x 24"
22 x 24" (3 pieces)
1 x 1" (2 pieces)
Here are the dimensions to which the sheet metal should be cut. Unless you are
familiar with metal work, it is a good idea to let a sheet metal shop do the
cutting and bending.
I" ~ L~I~E~FI
*Intermediate grades (4-6) substitute corrugated cardboard for sheet metal and
make other adaptations as necessary to make a simple oven sufficient to
demonstrate cooking an egg.
Now, with the metal parts formed either in a sheet metal shop or at home, you
are ready to assemble the oven. The simplest way is with 1/8 inch rivets. With
the bottom of the oven on a flat surface, hold the side panel against it and in
its proper place. Use a 1/8" drill bit, placing holes in the side panel and on
into the flange of the bottom. It is a good idea to pop a rivet as each is
drilled in insure alignment and prevent shifting of the parts. With both side
panels attached to the bottom, the back of the box may now be put in place and
holes drilled. Be careful to keep the parts lined up as you progress.
The spun glass insulation, is now cut to fit the bottom, sides, and top
metal pieces. Glue them in place, tape the seams, and spray all the inside
area with flat black paint. When the paint has dried, place the oven floor (22
x 16 inch piece) on the insulation and paint this piece.
Now it is time to fit the glass in place. First, cut strips of the foam sealing
tape and attach them to the edges of the glass on both sides (8 pieces). Place
the glass in position so that the bottom ed-e of glass is under the bend of the
bottom sheet metal. Lightly press one 22 inch angle against the glass and rivet
it in place. Do the same for the other side. Do not force the glass so that it
flattens the sealing strip, because the strip acts as a cushion to prevent
breakage of the glass, in addition to its sealing function.
With the glass installed, the top may be put on and riveted to the back and
sides. Fit the door into the back opening and rivet hinges in place. The oven
is now complete except for the carrying handles on each side and a similar
handle on the door. These are attached with screws.
In tests, the box itself will reach an inner temperature of 250 degrees. If
we could increase the amount of heat- going into the box, the oven would get
hotter. For this reason we add the light aluminum reflectors. Rivet two hinges
to each reflector, then the sides. Swing the top reflector up and down while
watching the inside of the oven, and you will be able to tell when you have it
at the proper angle by the reflection of the sun's rays on the insulation.
Bend the end of a piece of wire to act as a stop; insert the wire in a hole
in the top reflector and wrap the other end around a loosened screw on the
top of a box. Swing the side reflectors into position. Using two wires, attach
then to the reflector.
This oven reached a temperature of 350 degrees in 15 minutes. The first time it
was used it baked a loaf of bread in just over an hour, and then cooked a three
pound roast in three and a half hours! A whole meal can be cooked in the solar
oven. The menu is limited only by your imagination.