Building a volcano and making it go woosh

We got a little intro into the chemistry of making a volcano when studying the ph-value of different kitchen stuff earlier. However, building a volcano is a time honoured way of making science and it is quite fun, so we decided to build one. We used the magic dough we used also in making atoms.

For this experiment you need:

  • magic dough volcano
  • baking powder
  • red food colouring
  • vinegar (we used apple cider vinegar as we had that lying around)
  • When the volcano is ready, time needed for this experiment is about 5-10 minutes.

So first you need the volcano. The recipe for the magic dough is:

  • 3dl flour
  • 1,5dl salt
  • 1,5dl water
  • 1tablespoon of cooking oil

Mix everything up. If it is too wet, then add a bit of flour. If it is too dry, add a bit of water. Once it is easy to work with, then make the volcano. It is best to do this on top of a cooking tray one can put into the oven. This was a bit difficult to do for my 5 year old as she did not quite grasp how she could make the caldera of the volcano, so I helped. I used a spoon to make the caldera deep enough. We also made some small pebbles to put into it to test if they would flow out with the “magma”. Once the volcano was ready (top left image below), I placed it into the oven set at 125 Celsius degrees. I had it there for, I think, over two hours in two stages as it refused to dry out due to having a massive amount of magic dough. After two hours I took it out and left to dry over night on the table upside down. That worked and it was dry the next day.

volcano experiment preparation

The preparation stages for the volcano experiment.

So the next day I gathered all the necessary items with an impatient five year old waiting to do the actual experiment. I used two teaspoons of baking powder and 0,5dl of vinegar. I put the baking powder into the volcano and put the vinegar and food colouring in a small pouring cup I borrowed from daughter’s playthings. This way she could do the experiment herself.

volcano experiment

The bubbling of our volcano

I asked her to pour a little vinegar into the volcano. Straight away it started to bubble and overflow as the vinegar reacted with the baking powder. Daughter was overjoyed and jumped up and down (luckily not with the vinegar jug in hand). She added the vinegar a bit at a time, so we could follow the reaction for some time.

I found this really good explanation as to why this happens on UCSB science line – answer 5. I did not use it in full, so please go to that site to read the entire thing for more information. There are also 4 other answers to read through if needed:

Baking soda and vinegar react with one another because they both have a lot of energy that they don’t want and they can help each other get rid of it! You might think this explanation is too simple, but it’s true to what’s happening. (…)

Baking soda is a base, and vinegar is an acid. An acid is a chemical that wants to get rid of a proton, or a positively charged hydrogen atom. A base is a chemical that wants a proton. When you mix an acid with a base exciting things can happen because the acid is ready to give away its proton and the base is right there to receive it! (…)

When we mix baking soda and acetic acid in water together, acetic acid gives its proton to the broken-apart baking soda and together they form sodium acetate (CH3COONa), water (H2O), and carbon dioxide (CO2). These products are created quickly, and the carbon dioxide comes out as a gas, so the whole event is spectacular as you’ve seen!

By reacting with each other, the acidic acetic acid and the basic sodium bicarbonate give up a lot of their energy and create things that have a lower energy relative to each other. The universe favors things at their lowest energy, and so we see a lot of exciting reactions involving acids and bases.

If you have questions about these experiments or instructions, leave me a comment and I will answer and improve these instructions. Also, please remember like and share if you find this useful.

Copyright text and images: Satu Korhonen. You are free to try these experiments out, use them in your teaching. But instead of copying the text or images, link back to this page.

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