This fun pumpkin science activity is always a hit with students. They love watching the pumpkin volcano explode and erupt! I usually add it as an activity on the day we are carving/exploring pumpkins, but it can be done anytime during the fall season.
pumpkin (can use a small baking pumpkin or a large pumpkin)
cookie sheet or pan
food coloring (optional)
small container that will fit inside pumpkin (optional)
Cut a hole in the top of the pumpkin & clean out pulp and seeds.
Cut a hole in the top of the pumpkin. This is the hole where the “lava” will come out so size it accordingly. Since I used a large pumpkin, I placed a small container inside so I cut my hole to fit the container. Clean out the pulp and seeds.
Add baking soda.
Add enough backing soda to cover the bottom of the pumpkin or the bottom of the container.
Add dish soap.
Add enough dish soap to cover the baking soda.
Pour in the vinegar.
Place the pumpkin on a deep cookie sheet or pan to catch the overflow. Add food coloring to the vinegar if desired. Pour vinegar over the baking soda and dish soap until the “lava” comes up over the pumpkin.
Watch the pumpkin volcano in action!
The Science Behind It:
The vinegar (acid) reacts with the baking soda (base) causing carbon dioxide bubbles. As the carbon dioxide bubbles rise up they bring some of the mixture with them causing it to “explode” or “erupt”. The dish soap makes the mixture more “bubbly” and slows the reaction a bit so it lasts a little longer.