In this instructable, we show you how to build a type of solar thermal cooker that actually works.

Step 1: Scope and Materials

First off, our goal was to successfully build a thermal cooker that could work at a high enough temperature that would cook food. Our maximum temperature reached was 325 degrees. People who would be interested in remaking this project are people who want to see if it works or anyone who needs an alternative to cook their food. People who don't have a way to cook their food, too.
MATERIALS:
1 piece of big foam board (2ft x 5ft)
1 roll of reflective tape
1 box of aluminum foil
1 box cutter
1 pair of scissors
1 roll of clear tape

Some materials you probably already have, like scissors and foil (standard price for foil is about $5). The foam board will be around $12 and the tape will be $8. The box cutter will probably be $14.
This project will take 2 days, with breaks, if you are a perfectionist. When handling the box cutters you will want to be careful, but other then that the rest of the materials aren't very dangerous. If you don't have any of the materials listed above, you can use cardboard, aluminum foil and standard scissors for the project. We found that the above materials work best, though.
When finished, the size of the cooker should be 26 x 12 x 24 (in inches).

Step 2: Physics Involved

Light enters the solar thermal cooker by being absorbed into the concentrated area. This makes the molecules vibrate and become 'excited', thus generating more heat. The light reflects one point on the box that the sunlight is directed to. All areas of our solar cooker are designed to absorb light except for the backing. These areas are covered in reflective material, making the light bounce off and onto all focused sections. Albedo determines how reflective the material is which then lays out how much heat we are able to generate.

Step 3: Pre Assembly

First, you want to grab your foam or cardboard.
Then you take some scissors or box cutters and cut the foam board into 6" x 7" squares.
You'll need six of these.
Lastly you want to cut out a bottom for the other six pieces to rest on.

Step 4: Assembly

Once you've cut out the pieces, you'll need some reflective tape and foil.
Choose what side you want to work with the foam board. Either side is okay as you'll be covering it.
Take the foil and begin to wrap the six pieces of foam board with it. the length of the foil should cover one side completely.
Then you want to take the reflective tape and cut strips.
Put those strips onto the bottom of what will be your structure, making sure there are no bumps.

Step 5: Assembly

After you've wrapped your pieces of foam, you want to start putting them together.
Here, you will want to work with the sunlight.
Put the bottom piece onto the floor.
Take the six pieces of foam board and make a stack of two, that is one square on top of the other.
The sunlight should hit one spot.

Step 6: Assembly

After you've checked the angles of reflection, you have a clear idea of where you want your pieces to go.
You'll notice that not all top pieces fit precisely together in angled form.
Here, you want to grab your box cutters/scissors again.
Check to see what parts on't fit, line them, then cut.

Step 7: Assembly

After all this, make sure your taping of the boards is precise.
There should be no gaps or any parts sticking out.
Additionally, you could paint the back of the boards if you'd like, or just leave them as is.

Step 8: Final Demo

Our solar thermal cooker worked very well. I think our physics teacher cooked a tortilla on there. We decided to cook a pizza bite on there to see if it really did work. Surprise to us, it did. The little pizza got very hot, golden almost. However, next time we could have tried to add any other materials that would have enabled the heat to stick more and to gather faster.

Step 9: Tips, Tricks, Hints (mostly Tips)

Before directly assembling, you'll really want to look up other solar cookers to get a general idea of what you want. Make sure you check for effectiveness and have a layout to begin with. My team attempted to start from nothing and that ended in confusion.

Step 10: Thank You's and Such

Well that is our project and we hope it works for you.
We are not liable if it doesn't, sorry.
But we can only thank the wonderful physics teacher that helped us out a bit and the team for working together.
The project was interesting overall.