How to Make a Coca-Cola Volcano Experiment (With Mentos or Baking Soda)

Watch soda explode with Mentos or baking soda in this high-energy volcano experiment. A fun STEM activity kids love.

If you’re looking for a high-energy twist on the classic volcano experiment, the Coca-Cola version brings the fizz, and fast! This variation swaps vinegar for soda and can be done two different ways: with Mentos for a dramatic reaction, or baking soda for a more classic-style eruption.

It’s perfect for outdoor fun, group demos, or just blowing your kids’ minds in the driveway.

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What You’ll Need

There are two ways to make a Coca-Cola volcano. Choose your favorite—or try both!

Option 1: Mentos + Coke

1 bottle of Diet Coke (works best!)
3–5 Mentos
Optional: A funnel or rolled paper to drop the Mentos in quickly

Option 2: Baking Soda + Coke

1 bottle of Coke (any kind)
Baking soda
Optional: a funnel for easy pouring
Optional: food coloring

📌 Do this one outside—it gets messy fast!

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Step-by-Step Instructions

Option 1: Mentos + Diet Coke

1. Open the bottle of Diet Coke and place it on a flat surface.

Coca-cola volcano experiment with mentos step 1

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2. Quickly drop 3–5 Mentos into the bottle.

Coca-cola volcano experiment with mentos step 2

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3. Step back and watch the geyser shoot into the air!

Coca-cola volcano experiment with mentos step 3

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Option 2: Baking Soda + Coca-Cola

1. Open the bottle and add a few spoonfuls of baking soda (a funnel helps here).

Coca-cola volcano experiment with baking soda step 1

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2. Stand back—the foamy eruption will bubble up quickly.

Coca-cola volcano experiment with baking soda step 21

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3. Add food coloring if you want to change the look of the “lava.”

Coca-cola volcano experiment with baking soda step 3

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The Science Behind the Reaction

Mentos + Diet Coke:

This is a physical reaction, not a chemical one. The Mentos cause carbon dioxide in the soda to rapidly release, forming tons of bubbles that shoot out like a geyser.

Baking Soda + Coke:

This one is a chemical reaction—baking soda (a base) reacts with the phosphoric acid in the Coke to release carbon dioxide gas, causing foaming and fizz.

Both versions show how gases under pressure can create explosive results—just like in real volcanoes.

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Tips for Parents & Teachers

Do this outside! It sprays high and fast.
Use Diet Coke for less stickiness and the best eruption.
Use a paper tube or funnel for safer, quicker Mentos drops.
Turn it into a mini science project: Which soda reacts the most?

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Customize Your Coke Eruption

Try different sodas and compare results (Coke, Sprite, root beer)
Add food coloring to baking soda for colored foam
Have students guess which brand of soda erupts highest
Use larger bottles or different-sized Mentos drops for variations

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Bring Hands-On Science to Your School

At All Things Science, we bring STEM to life with exciting hands-on experiments like this one. Students explore everything from chemistry and robotics to rocketry and 3D printing—all in our after school STEM clubs.

Want to bring our programs to your child’s school?

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