Baking Soda and Vinegar Chemical Volcano

Students and their teacher watch a volcano school science project

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The baking soda and vinegar volcano is a fun chemistry project you can do to simulate a real volcanic eruption or as an example of an acid-base reaction. The chemical reaction between baking soda (sodium bicarbonate) and vinegar (acetic acid) produces carbon dioxide gas, which forms bubbles in dishwashing detergent. The chemicals are non-toxic (though not tasty), making this project a good choice for scientists of all ages.

01
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Baking Soda and Vinegar Volcano Materials

baking soda and bottle of the vinegar

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  • 3 cups flour
  • 1 cup salt
  • 1 cup water
  • 2 tablespoons cooking oil
  • Empty 20-ounce drink bottle
  • Deep plate or a pan
  • Gel food coloring
  • Dishwashing detergent
  • Baking soda (sodium bicarbonate)
  • Vinegar (dilute acetic acid)
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Make the Volcano Dough

Father and daughter making homemade playdough

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You can cause an eruption without making a "volcano," but it's easy to model a cinder cone. Start by making the dough:

  1. Mix together 3 cups flour, 1 cup salt, 1 cup water, and 2 tablespoons of cooking oil.
  2. Either work the dough with your hands or stir it with a spoon until the mixture is smooth.
  3. If you like, you can add a few drops of food coloring to the dough to make it volcano-colored.
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Model a Volcano Cinder Cone

A model volcano

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Next, you want to shape the dough into a volcano:

  1. Fill the empty drink bottle most of the way full with hot tap water.
  2. Add a squirt of dishwashing detergent and some baking soda (~2 tablespoons). If desired, you can add a few drops of food coloring.
  3. Set the drink bottle in the center of a pan or deep dish.
  4. Press the dough around the bottle and shape it to look like a volcano.
  5. Be careful not to plug the opening of the bottle.
  6. You may wish to dribble some food coloring down the sides of your volcano. When the volcano erupts, the "lava" will flow down the sides and will pick up the coloring.
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Cause a Volcanic Eruption

Students working on a science volcano project

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You can make your volcano erupt over and over again.

  1. When you are ready for the eruption, pour some vinegar into the bottle (which contains hot water, dishwashing detergent, and baking soda).
  2. Make the volcano erupt again by adding more baking soda. Pour in more vinegar to trigger the reaction.
  3. By now, you probably see why it is important to use a deep dish or a pan. You may need to pour some of the "lava" into the sink between eruptions.
  4. You can clean up any spills with warm soapy water. If you used food coloring, you could stain clothes, skin, or countertops, but the chemicals used and produced are generally non-toxic.
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How a Baking Soda and Vinegar Volcano Works

An erupting volcano science project

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The baking soda and vinegar volcano erupts because of an acid-base reaction:

baking soda (sodium bicarbonate) + vinegar (acetic acid) → carbon dioxide + water + sodium ion + acetate ion

NaHCO3(s) + CH3COOH(l) → CO2(g) + H2O(l) + Na+(aq) + CH3COO-(aq)

where s = solid, l = liquid, g = gas, aq = aqueous or in solution

Breaking it down:

NaHCO3 → Na+(aq) + HCO3-(aq)
CH3COOH → H+(aq) + CH3COO-(aq)

H+ + HCO3- → H2CO3 (carbonic acid)
H2CO3 → H2O + CO2

Acetic acid (a weak acid) reacts with and neutralizes sodium bicarbonate (a base). The carbon dioxide that is given off is a gas. Carbon dioxide is responsible for the fizzing and bubbling during the "eruption."