Build a Volcano on the Beach


This activity adds a fun outdoor twist on the classic baking soda and vinegar volcano experiment! All you need is a sandbox or sandy beach and a few household materials.

About Our Materials

We sure love a good, messy experiment! And nothing beats the classic baking soda and vinegar volcano, especially since you can typically find those materials in your kitchen.

Have you ever wondered why those materials do the trick to create such a fun and foamy ‘explosion’? Here’s a bit about them to learn more.

What is Vinegar?

Vinegar is a common household item that can be used in both cooking and cleaning. Vinegar is made up of a chemical called acetic acid (CH₃COOH) diluted in water and it is classified as an acid. 

What is Baking Soda?

Baking soda is a common household item that can be used both in baking and cleaning. It’s chemical name is sodium bicarbonate (NaHCO₃) and it is classified as a base. 

What Happens When You Combine Vinegar and Baking Soda?

To explain a bit as to why a chemical change happens in this case, we need to talk about pH. pH, or “Potential of Hydrogen”, is a scale used to specify the acidity or basicity of an aqueous solution (phew – those are some big chemistry words!). The pH scale is from 0-14. A solution is considered acidic if it has a pH below 7, and a solution is considered basic if it has a pH above 7. Acids with a low pH sit around 1. These solutions can be very dangerous. This is also true for bases with a pH near 13. If a solution has a pH of 7, it’s neutral. An example of a neutral solution is distilled water. Can you name any other bases, acids, or neutral solutions?

To get back to our question about the chemical change we’ll observe in our activity – baking soda (or sodium bicarbonate) is classified as a base, and vinegar (or acetic acid) is classified as (you guessed it!) an acid. Acids and bases are very reactive substances when mixed together. When the sodium bicarbonate molecules interact with the acetic acid molecules, they produce carbon dioxide (a gas) and water molecules. When the gas in our experiment combines with the water, we see that as bubbles that look like foam. Pretty fun!

Did You Know:

The name vinegar comes to us from the French, “vin aigre,” literally meaning sour wine.

Did You Know:

Baking soda is used in fire extinguishers, because it produces a foam which comes in handy when dousing flames.

Did You Know:

pH is very important for the human body. The acid in your stomach helps digest food and kills bacteria, whereas your small intestine has a basic pH.

Let's Make a Volcano on the Beach (or in your Sandbox)!


  • Sand, either in a sandbox or on a beach
  • Bucket or large cup
  • Baking soda, 1-2 cups
  • Vinegar, 1-2 cups
  • Measuring cup
  • Food colouring (optional)


  1. Set up your bucket or large cup in the middle of a sand box or on the beach. Fill the bucket about half way with sand. This will allow for less materials to be used later on. Pack sand all around the bucket and shape it into a volcano. If you want to build a GIANT volcano, then build your sand mountain first, then dig a hole in the top large enough for your bucket or large cup, and place your bucket or large cup in the hole.

  2. Pour 1-2 cups of baking soda into the bucket. You may need more or less depending on the size of your volcano.

  3. If you choose to use food colouring, add it to the vinegar now. 

  4. Measure out the same amount of vinegar as you used in baking soda.

  5. Make a prediction! What do you think will happen when the baking soda and vinegar are mixed together? 

  6. Now – pour the vinegar into the bucket with the baking soda, and watch your explosion happen!

Try This!

Make a couple more volcanoes that range in size, or play around with the baking soda to vinegar ratio. Make observations of each eruption. Which ones were smaller? Which ones were bigger? Why do you think this is?


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