Valentine’s Day STEM Project

Looking for a new and creative activity with your kids this Valentine’s? Then try this Valentine’s Day STEM Project made off of marshmallows and paper straws.  Since this day is usually filled with sweet treats, you might just have some marshmallows in your house! A perfect activity before or after treating your kids with some chocolates or candies.

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Valentine’s Day STEM Project

Supplies List:

  • 16 heart-shaped or large plain marshmallows
  • 8 paper straws, cut in half
  • 3 additional straws, cut in thirds (You will need 8 pieces)
  • Scissors, for cutting the straws in half
  • For the optional challenge:
  • Additional straws and marshmallows

Valentine’s Day Marshmallow STEM Project

STEM projects are a good way to enhance a kid’s problem-solving skills. It’s also fun and they will surely enjoy taking a bite of the marshmallows while doing the project.


Instruct the children to build a 3-dimensional heart using the marshmallows and straws.

Valentine’s Day STEM Project

If the children struggle to construct the heart, mention that it is easier to build one heart first by connecting the longer (half-cut) straws into the marshmallows, using the marshmallows as a joint between straws. The straws may need to be twisted while pushing into the marshmallows to make them stick.

Valentine’s Day STEM Project

Then, push the shorter straws (third-cut) vertically into each marshmallow. This creates the supports for the second layer.

Valentine’s Day STEM Project

Children should continue building the second layer by pushing marshmallows onto each vertical straw and then connecting the marshmallows with horizontal straws.

Valentine’s Day STEM Project

Optional: Once the hearts are built, challenge the children to make the structures more stable without instructions. If multiple children are each constructing their own heart, test to see who has the strongest heart by picking them up or by placing paper on top one sheet at a time.

Optional: Challenge the children to create a smaller or larger heart using the same methods.

Did you like this STEM project? How about some sensory play for your next activity? Here are some you might like 20 Ocean Activities for Kids20 Sorting Activities for Kids (this is also a perfect activity if you want to teach your kids about money/finance) or 20 Sensory Bin Activities for Kids.

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