Fizzing Rocks Valentine Style

What do you think these rocks are made from? They are just bicarbonate of soda ( Baking Soda ), water and food colouring.

bicarbonate of soda

  We’ve made fizzing rocks before, they are very simple, but great fun to watch. I used a heart cookie cutter to get the shape.

What you need:


Bicarbonate of soda/baking soda


Food colouring


Mix some water with the bicarbonate of soda, I used a whole packet of bicarbonate of soda and just added water slowly until i had a very thick paste type mixture. Add a few drops of food colouring, mould into rock shapes and leave to dry for a few hours. Once the rocks have hardened, add vinegar very slowly and watch as they fizz and dissolve.

Once again, thanks to Reading Confetti for the idea.

There are 17 comments

      1. Preschool teacher

        My attempt at making these had some kind of reaction that looked like mold after a couple of days. Does baking soda mold after its mixed with food coloring and water?

          1. Preschool teacher

            My food cooling was McCormick black I don’t see anywhere on it saying bake ready so maybe that is why I still am going to try this in the classroom because my 5 year old sat for a long time making the rocks fizz! Thanks for sharing!

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