Does the type of reflective lining in a box solar cooker matter?

by Josh

My name is Josh. For our 6th grade science fair project, we are investigating, "The effect of type of lining on maximum temperature reached." To make our introduction for our project, we have to answer, "Have others tried to answer this question in the past? If so, what research have they found to answer the question?" So I was wondering, has anybody ever investigated this kind of thing before?


Thank you for your question Josh,
I hope it is not too late to help with your answer.

Dark or shiny solar oven interior?

Yes, many people ask this same question.

And, we and many others have found that it can work both ways when it comes to the interior lining of a solar box cooker.
You can get good results using a dark solar oven interior only, and also by using a shiny reflective interior.
The greatest factor in both would be to make sure that your cookware (pots/pans) are dark in color.
This way your pot/pan is sure to absorb the heat (energy) so that you food will cook.

If your interior is dark also then it will absorb heat as well and transfer (conduct) heat to the pot that is sitting on the floor of your cooker interior and if your solar oven interior is shiny it will help to reflect (direct) the suns rays onto your dark cooking pot which will then absorb the heat (energy) from the sun, allowing you to cook.

That is the explanation in a nutshell ;)

Here is some more information given by a colleague of mine:

"This is probably one of the most asked questions from beginners.

There are people who believe that heat is generated inside a box cooker when
solar radiation strikes the walls of the cooker. This is very likely the best
way to get the best AIR temperatures.

However, its very likely that the best way to heat the FOOD is to make the walls
a continuation of the external reflector panels, so that as much radiation as
possible gets focused on the container holding the food. To understand this
principle, consider the CooKit and other panel cookers, which have NO box and
yet manage to cook food.

One of the reasons that the issue will never be resolved is because people use a
variety of cooking vessels. If you're using a cooking pan that covers most of
the interior of the box, it hardly matters what color the inside of the box is.
So the SPORT, which accepts a 3 qt graniteware vessel perfectly, is painted
black. But an almost identical unit made in South Africa is left shiny on the

Over the years I've come to realize that the AIR temperature inside a box cooker
is mostly irrelevant. The thermometers are always stationed at the top of the
box, but it might be 50 degrees cooler at the bottom! Still the food cooks,
because light is being reflected down onto it from the external reflectors.

My take is that; the best overall way to make a cooker is with reflective sides
and a black bottom. The bottom is black so that light doesn't get bounced
straight back out the window ... and into your eyes. The sides are reflective to
help focus the light onto the food. It probably helps to put a slight slant on
the inner box sides."

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Jan 21, 2013
Noodletools citation
by: danakx

Hi Josh,
I've never used Noodletools, but it does look like a great source. They sure do have a large selection of options for citations. Scrolling through the list, it seems that web forum is the category most closely related to this site. Here's the direct link to their web forum page:

I think you should be able to fill in most of the information on that cite, and it should lay it out correctly for you.

Jan 21, 2013
by: Josh

We are using the format Noodletools, my teacher recently announced this. However, I'm not sure it offers a format for forum discussions. You see, in Noodletools you click the type of article you are citing, and it gives you a form to fill. It shows all the necessary information. Should I cite it as a website?

Jan 04, 2013
by: danakx

First of all, well done on taking care with citations! It definitely can get tricky with online information. I'd double check with your teacher, but would probably go with something like Citation Machine has for online discussions. Here's the link for that form (assuming you are using MLA formatting; if not I believe you can change the format type):

It defaults to settings for citing an email, but if you click the help buttons on the side, it gives suggestions for how to use the information for citing an online forum discussion.

I've also used for help on figuring out how to format some sources, but I think Citation Machine will be more helpful with this particular type of forum webpage.

Best wishes on your project!

Jan 03, 2013
Ok, this should help.
by: Josh

Thanks a lot, this will help with my research. However, I am stuck on how I should cite this- as a website (webpage) or something else. Thank you for your comments, I can still take a few more as I have some time left. My science teacher also saw this page by the way. Thanks again!

Jan 01, 2013
Shiny vs black
by: Jim La Joie

Good comments all...
In side by side testing, exact same cookers, one painted black, the other covered with shiny aluminum foil tape, matching black cooking vessels and exact same amount of water. Really the only variable was the type of surface of the cooking area - black vs shiny.
The water in the shiny cooker heated twice as fast as the water in the black painted cooker.
I do not put any black inside my cookers - just the cook pot - because that is what I want to get hot.
And any light that misses the pot and strikes the floor will then reflect back onto the pot or onto one of the sides and then onto the pot.
You want hot food, not a hot cooker. I recommend shiny throughout.
I appreciate the opportunity to comment
Jim La Joie

Jan 01, 2013
My experience
by: danakx

I agree with Nathan's colleague--we had the best success with making the bottom of the cooker black, so as to minimize how much light energy we were reflecting back out, and the sides of the box reflective.

Sounds like a great science project. Best wishes on your research.

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