What do you think these rocks are made from? They are just bicarbonate of soda ( Baking Soda ), water and food colouring.
 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:
Water
Bicarbonate of soda/baking soda
Vinegar
Food colouring
Instructions
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.
Last Updated on March 23, 2014 by Emma Vanstone
Thanks for the link! We’re going to have to make some heart shaped rocks soon – my daughter would love it!
I was going to do this, failed abysmally!
Such a good idea…it reminds me of a bath bomb (although I would never use vinegar and it probably wouldn’t fizz the same!)
really cool idea
That is very clever!
Another great science experience! *Lovely* to have something for Valentine’s!
Thanks for sharing on Kids Get Crafty.
Maggy
way cool – love it…
I really should do more of your experiemnets and not just look and think oh great idea!
What a great ideas – I can think of at least half a dozen kids that would try this.
Let me know if you do 🙂
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?
I think it is the type of food colouring, was yours bake stable?
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!
Brilliant, I’m glad you liked it.
We recently filled a volcano with cola and bicarbonate with incredibly messy consequences!
Can I use baking soda for this experiment?