Today’s STEAM Activity is making s’mores in a solar oven! This is just in time for the Fourth of July, our favorite day to make and eat s’mores! 

The title of our Lil’ Smore magazine (that I shared last week), made me desperately want s’mores. It is my favorite summer treat. We often cook the marshmallows over the flame on our gas stove at home, but we decided to make our own solar oven to cook the s’mores today. 

My go-to marshmallow cooking method for s’mores at home

Every time I eat s’mores I’m reminded of The Sandlot, one of my favorite childhood movies. Ham and Smalls conversation always makes me laugh out loud:

Ham: Hey, Smalls, you wanna s’more?
Smalls: Some more of what?
Ham: No, do you wanna s’more?
Smalls: I haven’t had anything yet, so how can I have some more of nothing?
Ham: You’re killing me, Smalls! These are s’mores stuff! OK, pay attention. First you take the graham, you stick the chocolate on the graham. Then you roast the ‘mallow. When the mallow’s flaming… you stick it on the chocolate. Then cover with the other end. Then you scarf. Kind of messy, but good! Try some!

Ham Porter, Scotty Smalls – The Sandlot
Toasted marshmallow s’mores perfection


  • Graham crackers 
  • Chocolate bar
  • Large marshmallows
  • Small box with attached lid (like a subscription kit box or a pizza box)
  • Black construction paper
  • Foil
  • School glue
  • Clear food wrap (like Cling Wrap)
I recommend large, not jumbo marshmallows. These were too big (I didn’t know that was possible, but it is)


  1. Glue the black construction paper to the bottom of the box by covering the bottom of the box in glue, then placing the black paper on top. We used the box from one of our Tinkering Toddler Crates, and it worked perfectly. A KiwiCo crate box would also work well for this activity.

2. Glue the foil to the top of the box by covering the top of the box in glue, then placing the foil on top.

3. Build your s’mores in the bottom of the box: Break a graham cracker in half, place a few chocolate squares on one half of the graham cracker, place a marshmallow on top of the chocolate.

4. Cover the bottom half of the box with the clear food wrap. This traps the heat in the bottom of the box.

5. Place the solar oven outside facing the sun. Prop the lid up so the foil is reflecting the sun into the bottom of the box using a pencil or stick from your yard. 

Finding the right angle to reflect the sun

6. Watch the solar oven cook the s’mores. After a few minutes the chocolate will begin to melt and the marshmallow will soften. 

They cook faster if you watch them, right?

7. When the marshmallow is puffed up and soft, carefully remove the s’mores from the oven, and place the top half of the graham cracker on top of the marshmallow. 

melted s’mores perfection
adding the top for the finishing touch

8. Eat your s’mores! Don’t be afraid to get messy! 


  • Science: The solar oven uses solar energy to cook the s’mores. Solar energy is about using light and heat from the sun. The foil on the lid directs the sunlight into the bottom fo the box. The black construction paper absorbs heat making the bottom of the box hot and helping melt the chocolate and marshmallow. The clear food wrap creates a seal to trap the heat absorbed by the black paper in the bottom of the box. After a short time in the sun the box will get hot enough to melt the chocolate and soften the marshmallow. The temperature outside will affect how quickly the chocolate and marshmallows cook.
  • Math: It’s important to get the angle of the lid just right to direct the sunlight into the box. This is a great way to practice learning about angles with kids.  

You will notice the chocolate melts much faster than the marshmallow cooks. If you don’t want your chocolate completely melted into a sauce, you might want to add it later, after you notice the marshmallow begin to soften and puff up. 

This was a fun and tasty activity for us!  My kids liked being a part of the cooking process by making the oven themselves. They learned a lot and loved the solar cooked s’mores. I personally still prefer the fire toasted marshmallows, so I’ll stick to cooking them over my gas stove in the future.

This is toasted marshmallow perfection from our gas stove (you can see the jumbo marshmallow is way too big!)

I hope you get to enjoy eating delicious s’mores over the 4th of July weekend, whether you’re cooking the marshmallows over a campfire, your gas stove, or in a solar oven. Let me know your favorite way to make s’mores in the comments below! 


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