How to Make a Pumpkin Volcano Experiment

Combine pumpkins and chemistry for a festive fall eruption. A hands-on science activity ideal for Halloween or seasonal STEM lessons.

Fall is the perfect season to turn pumpkins into more than just jack-o’-lanterns. With just a few ingredients, you can turn a regular pumpkin into a bubbling, fizzing volcano—and give kids a hands-on way to explore science while getting into the seasonal spirit.

Whether you're a teacher planning a Halloween STEM activity or a parent looking for something different to do with leftover pumpkins, this easy science experiment is a guaranteed hit.

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What You’ll Need

Here’s everything you need to create your own pumpkin volcano:

1 small pumpkin (scooped out)
Baking soda
Vinegar
Food coloring (red, orange, or green work great)
Dish soap (for extra foam)
Tray or shallow bin (to catch the eruption)
Spoon or scoop

Optional:

Glitter for extra sparkle
A carved jack-o’-lantern face for lava to spill out of

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Step-by-Step Instructions

1. Prepare your pumpkin.

Cut off the top and scoop out the inside, just like you would for carving.

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2. Set it on a tray or bin.

This keeps the mess contained (trust us on this one!).‍

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‍3. Add the eruption ingredients.

Drop 2–3 spoonfuls of baking soda into the pumpkin. Add a few drops of food coloring and a squirt of dish soap.

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4. Pour in the vinegar.

Slowly pour vinegar into the pumpkin and watch it erupt! You can repeat the eruption as many times as you like—just add more baking soda and vinegar.

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The Science Behind the Eruption

This experiment works through a chemical reaction between baking soda (a base) and vinegar (an acid). When they mix, they create carbon dioxide gas, which forms bubbles and foam that overflow from the pumpkin.

The dish soap traps the gas in bubbles, giving you a foamy, dramatic eruption that kids love—and that connects perfectly to lessons about real volcanic activity and pressure buildup.

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Tips for Teachers & Parents

Use mini pumpkins so each student can have their own experiment.
Perfect for Halloween science days or fall-themed STEM units.
Want less mess? Place pumpkins in large bins or do it outside.

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Customize Your Pumpkin

Try some of these fun variations:

Carve a face into the pumpkin so the "lava" erupts through the mouth
Add glitter or glow-in-the-dark paint for extra flair
Compare eruption styles with other versions like the lemon volcano or snow volcano

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