In this Instructable, I will show you how to make the BEST solar oven. I have looked at many designs on the internet, and I have designed what I believe to be the BEST solar oven. However, this cannot match any commercial solar ovens like GoSun, nor can it cook in anything but direct sun. It gets up to 200º F. I normally do electrical projects, so this one was not as easy as other Instructables I have written.
The best parts of this oven:
No paint (won't smell or contaminate your food)
Black paper to absorb heat on the inside instead of tin foil
Insulated by the shredded newspaper
Glass on top concentrates heat
Four foil reflectors (you only use three at a time though)
Step 1: What You Will Need
Here is a list of materials needed:
Two cardboard boxes, one bigger than the other but they should be the same height- this will make the main frame
Four big cardboard squares- these will serve as the reflectors
Tape- to keep it together
Tin foil- to reflect and magnify the light
Lots of black paper- to absorb the heat
Glass- to magnify the light and to keep the heat in
(Shredded) newspaper- to keep the heat in
Sunlight- to cook your food
Step 2: Prep the First Box
Take the smaller box and cut off the "flaps" around it. Then cover the inside completely in the black paper. That way all the sunlight will be absorbed. Tape the paper down, and set the box aside. You are using black paper instead of spray paint because the paint would not be that good to cook any food in.
Step 3: Finish the Frame
Now, with the second box, cut off the flaps on the outside. We will attach the reflectors later. Then, put the first box inside the second. Adjust it so that there is a proportional gap all the way around the first box. Then, in that gap, stuff all of the shredded newspapers. Stuff as much as will fit into there. Then more. Those newspapers will serve as the insulation for the oven. More will make it cook better.
Step 4: Make the Reflectors
With the cardboard squares that you have, cut them so that you can tape them on to where the flaps of the second box were. Then you can cover them with foil. Once you have done that, tape them on as flaps to the second box.
Step 5: Glass Time!
Now it is time to make the glass fit. You should cut the glass to the dimensions of the outside box. Set the glass aside. Then tape the edges of the glass in duct tape. That will make the glass safe to handle.
IMPORTANT: Remember, safety first! Get an adult to help with the cutting of the glass. Follow the instructions on the glass cutter package! Wear safety gloves and glasses at all times.
Step 6: Use Your Oven
You have finished making your solar oven! Now you can use it. To use, position it towards the sun. The flap closest to the sun will be folded down out of the way. Prop the three other flaps up on something. Adjust them so that the light concentrates directly on whatever you are making. Then, put the glass on top of the boxes. If you want, you can put in a thermometer to see how hot the oven can go. Enjoy your new solar oven!
Step 7: How Does It Work?
The solar oven uses the concentrated light to bake your food. The sun shines down on it. The light hits the glass, and the panels around it. The light is reflected off the panels onto the glass. All of the sun on the glass is magnified by going through it. Some of the magnified light hits the food, but most hits the black paper. The light is absorbed by the black paper. Why? Well, all the primary colors (red, green, blue) combined make white light. Our eyes perceive things as the color they are because when white light hits them, everything gets absorbed except for their color. It is reflected and gets bounced back into our cornea. So when light hits the black paper, since you cannot make true black light, it is all absorbed and nothing bounces back, so we see it as black. All the light is absorbed into the black paper. The insulation stops the heat from going out, so the heat stays in and heats up your food.
And that is how your new amazing solar oven works.