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Weird Science with Chocolate and Marshmallows

Today’s post is all about our latest and most fun STEM challenge ever!
And I know I say that about all of them!
But I mean it this time. This one is topped only by building boats and roller coasters. It’s about building little ovens and testing them and then cooking something in them!

What kind of box do we use?

First, of all I needed boxes. A local restaurant offered to give me some pizza boxes and I had a gazillion shoe boxes, but in the end, I ordered a supply from Cause you can buy anything from Amazon and you get it the next day. So, I got this very heavy box with 100 pizza boxes in it.

Will this really work?

STEM Challenge: Can you really use the sun's heat to toast a treat? Yes, you can! It works surprisingly well!
Can this actually work? After the huge box of pizza boxes came I sure hoped this challenge would work. Otherwise, I would have a large supply of unused, sad pizza boxes.
Then I had another thought. It’s only going to take about four and a half minutes to build this and then ten or so to cook the stuff and my class lasts for an HOUR.
So, of course, I had to add some science to the whole process. We ended up doing some experimenting first with different kinds of materials to reflect or absorb heat. Kids kept data charts of the changes in temperature. We had to use a thermometer inside the box and check the beginning and ending temperatures.


Third graders do not know how to read a thermometer.
So, that added some more to our class time because I had to get each group to tell me the reading on their thermometer and then I checked to see what it really was. Because 220 degrees inside the classroom did seem a wee bit over the actual temp.
Yeah, it was really 76 degrees.
STEM Challenge: Experiment with different heat reflecting or heat absorbing materials to see just how to make the solar oven work best!
So, after that, we took our ovens outside to test them.


Kids don’t really care if their experiment is laying on DIRT.
Dirt, people. They put their stuff down right on the dirt. Never mind, that there was grass available.
STEM Challenge: Just how long does the solar oven need to soak up the sun? Can we play on the playground while they are baking?
But, anyway, we soaked up some sun and then checked the temps and they did go up! One even went up to 98 degrees. Pretty impressive for a pizza box.So we tested some more materials and talked about what made the temps go up and then we tried it all again.

Finally, finally, finally we ready to cook something!

STEM Challenge: This task involves some experimentation with finding the right materials to use for the solar oven. Then you cook!

We layered up some s’mores goodies and trooped back outside to see if it would turn into a gooey delicious mess.

STEM Challenge: Finally, we have experimented and the ovens have done their work! Time to enjoy our desserts!
And of course, we ate the stuff when we came back inside. So, did this work? Does it really matter?

We ate chocolate and crackers and marshmallows and did some science! And it lasted for the whole one hour class!

Sounds good to me!
Also, here is a link to the pizza boxes I ordered. It’s an Amazon Affiliate link (which means a few pennies come my way when you order).


  1. Carol Davis says

    Hi! Thanks for your interest! Both projects are available in my TpT store. Here's the link:

    Thanks again!

  2. JennVT says

    I live in Vermont. What is the minimum outdoor temperature needed to make the solar ovens actually work?

  3. Carol Davis says

    Great question! We tested this in the spring and it was probably 70-75 degrees outside. We had direct sunlight and it was around lunchtime, the hottest part of the day. Ideally, you would want it to be warmer than that!