Posted by on Mar 13, 2014 in Rainbow Activities, Science Activities, St. Patrick's Day | 0 comments

The spectacular chemical reaction of baking soda and vinegar never gets old in our house! There’s just something exhilarating and oddly satisfying about causing something to fizz, bubble and erupt. With this in mind, it only makes sense that causing ordinary sculpted creations to ooze and explode into a flurry of rainbow colours would be exponentially cooler….right?!


rainbow eruptions

shaving cream
a box of baking soda
food colouring
a baking pan or a shallow bin
eye droppers, syringes, spoons, etc

Rainbow Erupting Sculptures

We started by making ‘snow’ sculptures, a fabulous idea I got from Growing A Jeweled Rose. Basically, you just add enough shaving cream to a box of baking soda until you create a fluffy, moldable substance.

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The boys had a great time exploring the texture of the ‘snow’ and creating sculptures by patting, squeezing, stacking, and shaping it.

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When they had finished creating their sculptures, we gathered all of the fake snow into a big mountain/ volcano. Then came the really fun part… making our volcano erupt in a bubbly, rainbow explosion! The boys used eye droppers, syringes, and spoons to transfer the coloured vinegar onto the volcano; my bugs liked using the syringe best!

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So many swirling, colourful eruptions!

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At the end, the boys just dumped the rest of the coloured vinegar into the bin to create a foaming rainbow brew.

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The Science Behind the Experiment

When the coloured vinegar (an acid) comes into contact with the baking soda ‘snow’ mixture (a base),  a chemical reaction occurs which produces flowing carbon dioxide gas bubbles.

Click on the links for more rainbow activities science experiments, and St. Patrick’s Day fun!