- Age:4+
- Time:30 min
- Difficulty:Easy
- Mess level:High
- Supervision:Yes
How do Volcanoes even form?
The Earth’s crust is made of tectonic plates, huge chunks of rock that constantly shift. Volcanoes mostly occur in areas where those plates connect. As those plates continue to shift, that friction melts Earth’s core and magma forms.
Molten magma creates pressure and, with time, it finds a way to the Earth’s surface through the volcano. That is called eruption and magma becomes lava.
That eruption can be simulated by chemical reaction and we will show you how you can do it.
An erupting volcano: the show we will recreate with a simple chemical reaction.
With eruption of Volcano, Magma becomes Lava
What types of volcanoes exist?
When we talk about volcanoes, we usually think about those big mountains sprawling big cloud of smoke and lava. But scientists differentiate 3 types of volcanoes:
Cinder Cone Volcanoes
Cinder Cone Volcanoes are the simplest type of volcano. They grow from a single vent in the Earth’s crust and are rarely taller than 300 meters. Lava that is gas charged is blown violently out of the volcano and the pieces that fall down around the vent eventually build circular cone, with a bowl-shaped crater at the top.
Shield Volcanoes
Shield volcanoes are large, broad volcanoes that look like shields from the air – that is how they got their name. The lava that pours out is thin, so it can travel for great distances down the shallow slopes of the volcano. They build up slowly over time, with hundreds of eruptions which creates many layers.
Time after time, lava pours out of the vent, slides down the slopes of the volcano, and builds up the size. They rarely explode catastrophically. The best-known shield volcanoes are the ones that make up the Hawaiian Islands, especially Mauna Loa and Mauna Kea that have been created from thousands of lava flows.
Shield Volcanoes typically grow 5-10 km across and about 500 meters high. The largest shield volcano in the Solar System is Olympus Mons on Mars and measures 27 km above the surface of Mars and spreads for 550 km in length.
Composite Volcanoes
Composite volcanoes are formed over hundreds of thousands of years through multiple eruptions. They are also called stratovolcanoes and they make up some of the world’s most famous (and most dangerous) mountains: Mount Fuji, Mount Rainier, and Mount Cotopaxi are just some of the examples.
Composite volcanoes are connected by a conduit system which taps into a reservoir of magma deep within the Earth. That magma can erupt from several vents across the composite volcano, or from a large central crater at the summit of the volcano.
They can grow thousands of meters tall and they were the cause of some of the most devastating eruptions in history like Mount St. Helens that left hundreds of people homeless.
The three main volcano types: cinder cone, shield and composite.
Scientists differentiate 3 types of Volcano: Cinder Cone, Shield and Composite Volcanoes
What makes the homemade volcano erupt and foam over?
Make your prediction, then tap an answer to check!
The Science Behind the Eruption
Our model volcano doesn't use heat like a real one - it uses a chemical reaction. When you pour vinegar (an acid) onto baking soda (a base), the two react and produce carbon dioxide gas. The gas needs somewhere to go, so it rushes up and out of the bottle, and the dishwashing liquid traps it into thousands of bubbles - that's the foamy "lava" spilling down the sides.
It's the very same harmless gas that makes fizzy drinks bubble. Real volcanoes are driven by heat and immense pressure deep underground, but the way trapped gas forces its way up to the surface is a neat parallel to what's happening inside your bottle.
Materials needed for building a volcano
If you want to see a video on how to make a homemade Volcano, there is one at the beginning of the article. Or continue reading and see the instructions below.
Everything you need for a homemade volcano, from flour and salt to vinegar and baking soda.
All we need for Homemade Volcano are Dirt or Playdough, Little plastic bottle, Baking soda, Vinegar and Dishwashing liquid
We recommend that you do this activity outside. You can use dirt or sand for making a great volcano and avoid making a mess at home. You can easily make it indoors if you choose so, but make it on some easily cleanable surface.
- Dirt or Playdough
- Little plastic bottle
- Baking soda
- Vinegar
- Dishwashing liquid
- Bonus: Food coloring
Instructions for building a homemade volcano
👨👧 Adult supervision needed
An adult should cut the plastic bottle with scissors or a knife. Vinegar can sting eyes, so keep faces back when it erupts, and set up outside or on a wipe-clean surface - this one is meant to overflow!
- Cut the bottle with scissors or knife and take just the bottom part which we will use in the rest of the experiment.
- Shape playdough or dirt around that bottle so it resembles a volcano. Here you can find out how to make a homemade playdough.
- Put a few spoons of baking soda into the bottle/volcano.
- Put a few drops of dishwashing liquid.
- If you want, you can put a few drops of food coloring.
- Finally, pour quickly some vinegar and enjoy the eruption!
What will you develop and learn?
- What is a volcano and how does it work
- Chemical reactions
- Fine and gross motor skills
- Creativity
- That science is fun!
Key takeaways
- Real volcanoes form where tectonic plates meet and magma is forced up to erupt as lava.
- Scientists group them into three main types: cinder cone, shield, and composite (stratovolcano).
- The model eruption is not heat - it's an acid–base reaction between vinegar and baking soda.
- That reaction makes carbon dioxide gas, and dishwashing liquid traps it into foamy "lava".
- It's a safe reaction using the same gas that fizzes in fizzy drinks.
Frequently Asked Questions
How do you make a homemade volcano erupt?
Build a volcano shape from dirt or playdough around the bottom of a plastic bottle. Put a few spoons of baking soda inside, add a squirt of dishwashing liquid and some food colouring, then quickly pour in vinegar. The reaction foams up and "erupts" out of the top.
What is the chemical reaction in a baking soda and vinegar volcano?
It's an acid–base reaction. The acetic acid in vinegar reacts with the sodium bicarbonate (baking soda) to produce carbon dioxide gas, water, and sodium acetate. The rapidly escaping carbon dioxide is what drives the eruption.
Why does the volcano foam and bubble so much?
The reaction makes carbon dioxide gas, and the dishwashing liquid you add traps that gas into lots of tiny bubbles instead of letting it escape quietly. That turns a simple fizz into a thick, foamy "lava" that flows down the sides.
Is the homemade volcano eruption hot like real lava?
No. Despite looking like lava, the eruption is not hot at all - it's just gas bubbles from a chemical reaction at room temperature. That's what makes it a safe experiment to do with children.
How do real volcanoes form?
Earth's crust is broken into shifting tectonic plates. Where they meet, friction and heat melt rock into magma. Pressure pushes that magma up through cracks until it bursts out at the surface as an eruption, where the magma becomes lava.
What are the three types of volcanoes?
Cinder cone volcanoes are small and built from a single vent; shield volcanoes are broad and gently sloped, built from thin, runny lava; and composite volcanoes (stratovolcanoes) are the tall, layered, and often dangerous mountains like Mount Fuji.
Is the baking soda volcano safe for kids?
Yes, with light supervision. The vinegar and baking soda are harmless, though vinegar can sting eyes, so keep faces back during the eruption. An adult should do any bottle-cutting, and it's best done outside or on a wipe-clean surface.
If you’re looking for more fun science experiments we recommend you check out How to make a Lava Lamp for another amazing effect, and How to make Homemade Rocket so you can use those vinegar and baking soda leftovers from making the volcano.
