Halloween Fizzing Pumpkin Treasure Rocks

My kiddo struggles with playing alone.  Boring, she says…  But my girl loves her some science potions.  It’s pretty much the only thing that will keep her occupied solo for more than half an hour.  One of the other things she loves is surprises. So for Halloween this year, I combined the two into some fun Fizzing Pumpkin Treasure Rocks.  And they rock, pun intended.  The chemical reaction between baking soda and vinegar reveals fun, Halloween trinkets hiding inside.  And they’re super easy to make, too, so get ready for some crazy foaming pumpkins!  This post contains affiliate links.These fizzing pumpkin treasure rocks are great Halloween STEM / STEAM fun for kids. They're perfect party favors for your Halloween bash, too.

Check out the Fizzing Pumpkins in Action

Second best to playing with these pumpkins is definitely watching how they fizz :)

Halloween Fizzy Pumpkin Treasure Rocks Supplies Needed

Makes 4 treasure rocks.

  1. Make your baking soda mixture by adding 1 T yellow liquid watercolor and 1/2 T red liquid watercolor to two cups of baking soda. (Or use orange color if you’ve got it on hand.) Mix well with a whisk until the color is fairly well distributed.  Then add water a bit at a time until the mixture can be molded.  Don’t worry if you don’t add all of the water.

Mixing Pumpkin Ingredients Left Brain Craft Brain

  1. Grab one of your trinkets and about half a cup of the baking soda mixture.  Hide the trinket inside the mixture and form into a pumpkin like ball.  Place on a cookie sheet covered in parchment or aluminum foil and set aside.  Repeat with remaining trinkets.

Forming Fizzy Pumpking Left Brain Craft Brain

  1. Cut your pipe cleaner into 4 pieces and twist each into a vine like curl.  Insert one end into the top of the treasure rock.
  2. The pumpkins will be dry in about 24 hours, but good luck getting the kids to wait that long :)

Three Fizzy Pumpkins Left Brain Craft Brain

Halloween Fizzing Science Play

All you need to have some amazing science fun this Halloween is one of these pumpkins, a little vinegar and dish soap.  I squirted some soap in the bottom of the tray and then placed the pumpkins in it.  Squeeze bottles and pitchers work great for the vinegar.  As for the fun, I think the pictures speak for themselves :)

Peeking Pumpkins Left Brain Craft Brain

Finding a Spider Left Brain Craft Brain

Overflowing Fizzy Pumpkins Left Brain Craft Brain

Halloween Party Favors

These make great Halloween party favors, too.  I had some clear treat bags {affiliate} and pumpkin ribbon and tied them up into a pretty package.  Your guests can add their own vinegar, or you can give them a little bottle too.

Fizzing Pumpkins Party Favor Left Brain Craft Brain

Halloween STEAM Challenges

Like to integrate other topics into your engineering? Try these 31 Days of Halloween STEAM Challenges! Download the cards HERE.

Or, you can get more fun hands-on Halloween projects here in my STEAM Kids Halloween ebook!

Pumpkins, ghosts, & spiders, oh my! Make your fall educational & fun with these Halloween Engineering Projects for Kids. STEM activities get fun & festive!

Halloween Projects to Wow the Kids



Science, technology, engineering, art, and math projects you -and- the kids will love.

Posted by Left Brain Craft Brain – STEM & STEAM Activities for Kids on Monday, October 2, 2017

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