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GSCO STEM Club Activity: Volcano—Acid Base Reaction

Today, we’re going to learn how to make a volcano at home using an acid (vinegar) and a base (baking soda). If you would like more activities like this one, join us every other week on Thursdays after school for one of GSCO’s STEM Clubs. Click here for Daisy STEM Club. Click here for Brownie and Junior STEM Club.

Materials Needed:

  1. Vinegar

  2. Baking Soda

  3. Cookie sheet or tray

  4. Two styrofoam, paper, or plastic cups of any size

  5. Scissors

  6. Paper, markers, or crayons- If you would like to decorate your volcano

  7. Piece of plain paper and something to write with

What is an acid and a base?

Acid– When we hear the word acid, we often think of things that are dangerous. They can be, but they can also be common things we find every day. Acids have a sour taste to them. Maybe you had an acid with breakfast?

Base- A base is a more bitter taste and has a kind of soapy feel if you rub it between your fingers. A base can also be a common item.  Maybe you baked cookies and added something base to help them rise.

Examples of Acids and Bases:


  1. Orange

  2. Lemon

  3. Vinegar

  4. Many dangerous chemicals


  1. Baking Soda

  2. Sugar

  3. Laundry detergent

  4. Soup and cleaning products

  5. Heavy solvents and grease

Now that we have talked about what acids and bases are, let’s do an experiment to see how they work together.

Acids and bases do not like each other and they fight when they are mixed together. This is because they are trying to neutralize each other. When they are mixed, lots of bubbles are created. This is a reaction.

Making a Volcano to Test Mixing an Acid with a Base

First, we will create our volcano body.  You can use any type of cups for this.

Step One: Have an adult help you cut a medium size hole in the bottom of one of your cups.

Step Two: You will also need to ask for help to cut the other cup in half.

Let’s begin:

Creating the Outside of the Volcano

If you would like to decorate the outside of your volcano, you can do it several ways:

  1. If your cup is paper or styrofoam, you can use sharpies and color right on the cup.

  2. If your cup is plastic, you can decorate a piece of plain paper the same height as your cup. When you are done, wrap the paper around the cup and tape it to fit.

Creating the Acid Base Reaction

  1. Step One: Take the small cup and put about one tablespoon of baking soda in it.

  2. Step Two: Set that cup on a cookie sheet or tray of some kind.

  3. Step Three: Place the “volcano” you made on top of the small container making sure not to spill the baking soda.

  4. Step Four: Measure 1/4 cup of vinegar into a measuring cup or glass.

  5. Step Five: Ready for magic! Slowly pour the vinegar into the mouth of the volcano and watch the fight! You may not need all of the vinegar.

We want to hear how your girl is using her Girl Scout skills by taking initiative, caring for the community, and Girl Scouting at home. She can send in her story here.

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