Look out, she’s gonna blow! The classic baking soda and vinegar volcano experiment (and a couple of interesting variations).

The infamous baking soda volcano experiment

In this experiment, we will build a real working volcano. After mixing just the right amount of ingredients together, we’ll add the final item to make our volcano ‘blow its top,’ spewing red lava down the sides.  Yes, this is the famous “Baking Soda Volcano” experiment – found exclusively at Geek Slop (and on the websites of the millions of Geek Slop’s minion slaves).

1. First, we need to create the ‘salt dough.’ Mix 6 cups flour, 2 cups salt, 4 tablespoons cooking oil, and 2 cups of water in a large bowl. Work the ingredients with your hands until smooth and firm. Add more water to the mixture if needed.
2. Stand the soda bottle in the baking pan. Mold the salt dough around the bottle making sure you don’t cover up the bottle mouth or drop any dough into the bottle. Take your time on this step and build your volcano with as much detail as you like. You can even paint the dough for added effect.
3. Fill the bottle most of the way with warm water mixed with a little of the red food coloring.
4. Put 6 drops of the liquid detergent into the bottle.
5. Add 2 tablespoons of baking soda.
6. Slowly pour vinegar into the bottle and jump back quickly!

The vinegar (acetic acid) and baking soda reaction explained

Notice the red ‘lava’ that flows out of your volcano. This happens because of the baking soda (sodium hydrogen carbonate) and vinegar mixture. Mixing baking soda and vinegar produces a decomposing chemical reaction in which carbon dioxide gas is created – the same gas that bubbles in a real volcano (and the same gas used to make carbonation in sodas). The gas bubbles build in the bottle, forcing the liquid ‘lava’ mixture of the bottle and down the sides of your volcano.

Scientifically speaking, when baking soda (the base) and vinegar (an acid) are combined, the bicarbonate ion of the baking soda reacts to form carbonic acid, which decomposes into carbon dioxide, water, and sodium carbonate completing the carbon cycle. The dish soap is added to create foamy bubbles.

Tweak up the baking soda volcano experiment a bit

Discover the answer to these questions:

1. Does the amount of vinegar change the reaction?
2. Does the amount of water affect the eruption?
3. Does the amount of baking soda impact the reaction?

A cool variation of the baking soda and vinegar volcano experiment – an ice volcano!

Here’s an interesting variation of the baking soda and vinegar volcano experiment – make your volcano with ice!

1. To build an ice volcano, place a heavy ball at the bottom of a bowl. Line the bowl with plastic wrap.
2. Add a mixture of baking soda, water, and food coloring to the bowl so that it completely covers the ball underneath. Don’t add the vinegar yet or the volcano will explode!
3. Place the bowl in the freezer until the water is completely frozen.
4. Once it’s frozen, pry out your ‘volcano’ from the bowl.
5. You’re now ready to ignite your ice volcano. Add a few drops of vinegar into it and stand back!

Another cool variation of the baking soda and vinegar volcano experiment – mini volcanoes using an egg carton!

Here’s an interesting variation that uses an egg carton to create a dozen little mini volcanoes.

1. Place a piece of cardboard on the counter.
2. Cut out the bottom of each egg holder in your egg carton and flip it over. You’ll notice that each slot now looks like a mini volcano.
3. Pour some baking soda into each slot.
4. Add some colored vinegar solution (vinegar + food coloring) into the slot and run for your life!

Experiment supplies required for the baking soda and vinegar volcano experiment

Supplies: Plastic bottle, Food dye, Baking soda, Salt, Vegetable oil, Liquid detergent

Image Credits

In-Article Image Credits

Giant erupting volcano prop via MCSDino with usage type - Product photo (Fair Use). Prop for sale by MCSDino, maker of animatronics and entertainment robots, walking costumes, puppets.
Baking soda and vinegar via Flickr by Jessica Mullen with usage type - Creative Commons License. March 14, 2010
Vinegar, baking soda, food coloring, and a volcano made of dough via Flickr by Andrew Gatt with usage type - Creative Commons License. January 28, 2008
Smoking volcano on the Island of Stromboli via Wikimedia Commons by Steven W. Dengler with usage type - GNU Free. September 28, 2004

Featured Image Credit

Vinegar, baking soda, food coloring, and a volcano made of dough via Flickr by Andrew Gatt with usage type - Creative Commons License. January 28, 2008