I bought 2 bags of marshmallows when I stocked up on groceries a few weeks ago, and we burned through both of them in one day! First, we made practiced STEM concepts while making Rice Krispies Treats (this was one of my most popular posts from a few years ago). Our second STEAM Activity for the day was building geometric shapes and structures.

Ok, I’ll admit my kids ate WAY too many marshmallows during this activity, but I’m ok with it because we don’t do this everyday and they learned a lot too. Here’s the details of what we did.


  • Toothpicks
  • Marshmallows and/or play dough


1. Use the point on the toothpick to pierce the marshmallow pushing it about halfway through. The marshmallows are the joints that hold the shapes and structures together.

2. Start by building 2D shapes like triangle, square, pentagon, hexagon, etc…


3. Try to turn the shape into a 3D structure by building up making a pyramid, cube, house, etc…


4. Play dough also works great rolled into small pieces the size of the marshmallows (we switched to this when my kids ate all the marshmallows 🤪)

Eating Marshmallows on a stick
Play dough on a stick is not as tasty
Cool play dough structure


  • Engineering: This is great 3D thinking development. Your kids will slowly learn how to visualize structures in 3D, which is an important engineering skill.
  • Math: We practiced math by making as many different shapes and structures as possible and then counting them.

We had a blast with this activity. It only requires 2 materials and is a no prep project. Just pull out the marshmallows or play dough and toothpicks and let your kids create.

I was so impressed with what my kids came up with and created on their own. I was also impressed with how many marshmallows they were able to eat in a short time period! We took a long walk after this activity to burn the excess energy!

I hope you give this a try and let me know what your kids create!


Some of the links below are affiliate links, which means that if you click on a product link I may receive compensation at no additional cost to you. I only link to products and pages I personally use and highly recommend. As an Amazon Associate I earn from qualifying purchases. Thank you for your support!

You have Successfully Subscribed!