Frozen Baking Soda Pumpkins

Today we’re adding a Halloween or fall pumpkin theme to one of our favorite ways to explore with baking soda and vinegar. Frozen baking soda pumpkins is a sensory science experience kids love. I get commissions for purchases made through the affiliate links in this post.

Supplies Needed for this Pumpkin Themed STEAM Activity

Silicone pumpkin mold (or just use an ice cube tray or a freezer safe bowl)
Small water safe treasures – we used Halloween themed erasers and gems )
Baking dish
Tray or container
Baking soda
Water
Vinegar
Squeeze bottles or droppers and a container
Washable liquid watercolors

How to Make Frozen Baking Soda Pumpkins

The process is the pretty much the same as our Frozen Baking Soda Dragon Eggs. My pumpkin mold is much smaller than the egg mold though, so I don’t use as much baking soda.

Mix baking soda with enough water so it starts to dissolve.

Add washable liquid watercolors, food coloring, or paint to color your baking soda. (Food coloring has the potential to stain, so I opt for a washable paint.)

Place the small treasures in the pumpkin mold.

Cover with the baking soda mixture and freeze until set.

frozen baking soda colored orange in pumpkin ice cube tray

Take the frozen pumpkins out of the mold and place in a container. I like to use a baking dish or plastic bin for this.

Add squeeze bottles of vinegar. Or use containers of vinegar with droppers. I picked up the squeeze bottles from the dollar store. (You can also used rinsed out soap or condiment bottles.) The droppers are the Jumbo Eyedroppers from Learning Resources. You could just spoon or pour on the vinegar. Squeezing the bottles and droppers adds some extra fine motor skills practice.

The Science Behind It

Baking soda (sodium bicarbonate) is a base and vinegar (acetic acid) is an acid. When combined, they react to form water, a salt (sodium acetate), and carbon dioxide gas. The bubbles produced by the reaction are the carbon dioxide gas escaping the water. Freezing the baking soda slows down the reaction a little.

More Pumpkin Themed Science Activities for Kids

Baking Soda Painted Pumpkins – Use baking soda and vinegar to create a fizzy painting experience.

Fall STEM Activity: Pumpkin Discovery Table

Pumpkin Oobleck Made with Real Pumpkin

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