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DIYs » Stem Activities » Chemistry » Age 9 - 12 » Erupting Pumpkin

Erupting Pumpkin

Stem Activities

Ages: 9-12

Less than 30 minutes

Grownup needed

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Concoct a spine-chilling mixture that makes vomiting fun! With just a few simple kitchen ingredients, you can make your pumpkin "vomit" sticky, colorful foam, adding a touch of spooky fun to science!

Materials Needed

Pumpkin
Vinegar (120ml)
Baking soda (1 tablespoon)
Dish soap (20ml)
Food coloring
Carving knife
Tray
safety goggles

A whole pumpkin, a bowl of water, a small bottle of green liquid, safety goggles, a knife, a measuring spoon with white powder, and a small beaker of clear liquid are arranged on a clear tray placed on a dark gray surface. A sheet of green paper, a roll of tape, scissors, a pencil, a ruler, some gold string, and a pile of small, colourful pom-poms are arranged on a light wooden surface.

Step-by-step tutorial

Step 1

First, we need to carve the pumpkin. Cut a 8-10 cm hole in the top of the pumpkin, then carve out the eyes and mouth (this step may require adult assistance).

A carved pumpkin with a spooky face sits on a clear plastic tray next to a clear glass bowl of pumpkin pulp and seeds, against a two-toned yellow and dark blue background.

Step 2

Put on your safety goggles, it's experiment time! Add 20ml of dish soap and food coloring to 120ml of vinegar, and mix well.

A small, clear glass container with a wooden handle, containing a bright green liquid and a black spoon, sits on a clear plastic tray against a two-toned yellow and dark blue background.

Step 3

Pour one tablespoon of baking soda into the pumpkin.

A carved pumpkin, illuminated from within, sits on a clear plastic tray against a two-toned yellow and dark blue background.

Step 4

Quickly and carefully pour the mixture from step 2 into the pumpkin. Then, watch the pumpkin start to bubble! Keep experimenting! Try doubling the recipe or continue the experiment using jack-o'-lanterns with smaller or larger holes.

The Science Behind It:

This involves an acid-base chemical reaction. When baking soda (an alkaline compound) mixes with vinegar (an acidic compound), a chemical reaction occurs, producing a large amount of carbon dioxide - the bubbles we see. Adding dish soap makes the foam even richer. The gas produced by citric acid and baking soda forms a porous structure in the dish soap (liquid), increasing the number of bubbles and causing them to seep out, producing more and longer-lasting foam. The amount of different ingredients used in the experiment can change how your pumpkin produces foam. Try using more or less baking soda and vinegar, or more or less dish soap, and see how these changes affect the pumpkin's foam!

Who Are We?

We’re a passionate team of scientists, engineers, and educators dedicated to delivering hands-on fun. Our mission is to inspire creativity and confidence in the next generation of young innovators.