October is the perfect month for having fun with pumpkins.
The bright orange fruits make cute decorations and are fun to use in a variety of pumpkin STEM activities.
If you’re carving pumpkins this year, use one to make a simple pumpkin volcano. It’s a fun fall twist to an old favorite science experiment.
If you have toddlers or preschoolers, you may want to let them explore whether or not your pumpkin sinks or floats before trying this activity.
Older kids might enjoy some of these other Halloween STEM activities.
Pumpkin Volcano Experiment
Materials Needed:
- Pumpkin
- Vinegar
- Baking soda
- Dish soap
- Sharp Knife
- Food coloring (optional)
To begin with, use the knife to remove the top portion of your pumpkin, much like you would when carving pumpkins. This portion of the activity should be done by an adult.
Then let your child remove the seeds and pulp from the pumpkin. They can use a spoon or their bare hands, adding a bit of sensory play into the activity.
Once the pumpkin is hollowed out, sprinkle a healthy dose of baking soda into the bottom of the pumpkin. How much you need will depend on the size of your pumpkin. We used 2 Tablespoons for our small pumpkin. You’ll want to use at least 1/4 cup for a larger pumpkin.
To increase the amount of bubbles produced, squirt a little bit of dish soap into the bottom as well.
If desired, you can add a drop or two of food coloring as well. We chose to leave ours plain.
When you are ready, slowly pour your vinegar into the pumpkin. We used 1/2 cup on our small pumpkin. Larger pumpkins may need a bit more.
You’ll have an instant volcano in a pumpkin.
For even more fun, try adding pumpkin seeds to the bottom of your pumpkin.
When the vinegar is added the foam will cause the pumpkin seeds to bubble up and spill out with the pumpkin volcano’s lava.
Does your child love being hands on? Grab a spoon and let them try stirring.
Mixing it helps more baking soda react with the vinegar and you get a second eruption.
This pumpkin STEM activity is so much fun!
Why Baking Soda & Vinegar Volcano Works
The vinegar is an acid. The baking soda is a base.
When these two materials mix, a chemical reaction happens.
One part of this reaction is that carbon dioxide forms. This gas causes the bubbling reaction that spills over the sides of the pumpkin.
For a more detailed explanation, check out this post on why vinegar and baking soda reacts.
I warn you, this simple Halloween science is addicting.
If your kids are anything like mine, the will ask to do it over and over again.
We used half a box of baking soda and quite a bit of vinegar before I had to call it quits.
This simple pumpkin volcano is so easy and so much fun to do in October.
Other fun fall activities to try:
- Pumpkin Activities — Discover 10 fun activities with real pumpkins.
- Apple Wrecking Ball STEM Activity — Challenge your child to make a wrecking ball with an apple.
- Vanishing Ghost Experiment — Kids of all ages will have fun with this STEM for Halloween.
- Apple-Scented Bubble Dough— Find out how to make amazing smelling play dough with just 2 ingredients.
Originally published 9/11/2015.
Hil says
What a creative way to incorporate the season in science!
OneMommy says
My son absolutely loves baking soda and vinegar…. With all the pumpkins popping up in our garden, it just seemed too perfect not to try it!
Deanna Hershberger says
It is amazing how simple ingredients like baking soda and vinegar and maybe food coloring can entertain a child so much! My daughter LOVES it! It is genius to put it all in a pumpkin! Very festive! And then you can turn it into a jack o lantern after. Love the idea!! Thanks for sharing at #made4kids. Hope you come back and share with us again this Sunday night!
OneMommy says
Yes — we had fun turning the volcano into a Jack-o-lantern when we were finished. Baking soda and vinegar ALWAYS gets my kids excited. 🙂
Donella Crigger says
We’re going to be doing that experiment soon, too. So fun! We’re featuring this post at the Get Your Shine On party tonight. We hope to see you link up again!
Ali Gilbert says
Oh my gosh! What fun! Gotta try this one with my toddler. Thanks for linking up on #ToddlerFunFriday!
OneMommy says
Definitely try it with your little one — it is sure to be a hit!
Elaine Livingstone says
with pumpkins at 50p each this looks like a great activity.