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How to Do the Classic Baking Soda Volcano Science Experiment

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For our creative STEM activities for kids series, I wanted to do science experiments for kids that were easy, but also impressive at the same time. This made a volcano science experiment a must.

We’ve made a volcano science experiment before, but this time, we decided to make it look a little more impressive by adding a play dough mountain around our bottle and making the inside of the volcano a deeper red.

Although everyone has does the volcano science experiment at least once (at least everyone should!), it still remains a classic science fair project. If your student(s) haven’t tried this project yet, add this activity to your list of elementary school science fair projects.

Every kid needs to try the classic volcano science experiment at least once! This version uses a baking soda and ketchup reaction.

The Classic Volcano Science Experiment for Kids

Every child should get to make a volcano as a science project at least once! Follow along with these instructions if you’re making a ketchup and baking soda volcano!

How to Turn the Volcano Science Experiment into a Science Fair Project

A science fair project requires variables. Good variables for this project is to test if different acids create bigger or smaller eruptions. Kids may also want to try different bases or what happens when they add other materials to the volcano to see how the reaction changes with each variation.

What Makes the Baking Soda and Ketchup Reaction?

What causes the volcano to explode in the volcano science experiment is the reaction between the baking soda and vinegar.

Baking soda is a base and vinegar is an acid. When a base and an acid are mixed, it creates a byproduct of carbon dioxide, which causes the mixture to overflow just like a shaken soda bottle.

When dish soap is added to the mix, it makes things even more foamy and bubbly.

Supplies for the Volcano Science Experiment

Here is what you will need to complete the volcano experiment as an addition to classic science fair projects.

  • Ketchup or tomato paste
  • Vinegar
  • Dish soap
  • Baking soda
  • Play dough
  • Small bottle
  • Funnel

What You Need for a Science Fair

You’ll want to have these supplies on hand before doing your science fair project. Shop the included Amazon storefronts to make things easier and don’t forget to download the free science fair planning checklist before getting started!

Science Fair Project Planning

When you’re planning your project, you want to keep everything organized. Click the image below to get my free science fair project checklist so you can start organizing your project from the start.

You may also want to check out this list of science fair project research supplies.

Supplies for a Science Fair Project

There are so many supplies for science fair projects that are individual to each project, but if you want a general list of possible supplies and inspiration for your project, check out my selection of science fair experiment supplies on Amazon.

Supplies for a Science Fair Presentation

Your science fair presentation is important! It should look presentable and eye-catching. Check out this list of my favorite science fair presentation supplies.

science fair display board example

How to Make a Baking Soda Volcano

Place about 2 tablespoons of baking soda into a bowl. Add about 10 drops of dish soap on top of the baking soda and about ¼ of a cup of ketchup or tomato paste.

Mix together gently with a spoon so you don’t make too many suds at once.

Girl pouring vinegar into baking soda and vinegar volcano

Cover the bottle with play dough and place it on a tray. We put ours in a garden box. Carefully pour the baking soda mixture into the bottle using a funnel.

Add vinegar to the bottle slowly, a little at a time. We ended up adding too much vinegar to ours (as you can see in the video), which made our eruption a little less impressive.

Monkey loved seeing the science demonstration and had a lot of fun setting up the volcano and watching the reaction.

Girl makes playdough volcano erupt

If you want to go further with this experiment, you can experiment with various additives to the vinegar and baking soda mixture to see if you can make the eruption more impressive or change the speed at which it leaves the bottle.

science fair display board example

More Volcano Experiments for Kids

Colorful Snow Volcano Experiment Using Real Snow

Pumpkin Volcano Experiment for Kids

Easy DIY Volcano Slime Recipe that Really Erupts!

Apple Volcano Experiment

Save this idea for later so you don't forget to use it!