Fizzing Rocks – Baking Soda Activity

Modified: May 20, 2024 · Published: Aug 31, 2012 by Emma Vanstone · This post may contain affiliate links · 23 Comments

We love a good baking soda experiment. I spotted this brilliant and simple idea on Reading Confetti, who kindly said I could post it here. These are our fizzing rocks.

How to make fizzy rocks

You’ll need

Water

Bicarbonate of soda/baking soda

Vinegar

Food colouring

Instructions

Mix a little water with the bicarbonate of soda. I used a whole packet of bicarbonate of soda and added water slowly until I had a very thick paste type mixture.

Add a few drops of food colouring, mould the paste into rock shapes, and leave it to dry for a few hours.

Once the rocks have hardened, slowly add vinegar and watch as they fizz and dissolve.

vinegar being poured over rocks made from baking soda

The science behind baking soda rocks

Vinegar (an acid ) and bicarbonate of soda ( an alkali ) react to neutralise each other. This reaction releases carbon dioxide, a gas that causes the bubbles you see.

Other ideas

Add small objects to the rocks and drop them into a bowl of vinegar like Reading Confetti did.

Make one big rock and see how much vinegar is needed to dissolve it.

Try one of my other fantastic baking soda experiments.

Brilliant baking soda experiments including an erupting snow volcano, fizzy potions and baking soda rocks

Last Updated on May 20, 2024 by Emma Vanstone

More Early Years Science

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Comments

Lorie

August 31, 2012 at 1:13 pm

Thanks for the link. Love your idea of making one big rock. We might have to try that next!

Reply
- ScienceSparks
  
  August 31, 2012 at 1:23 pm
  
  I’m glad you spotted it! We had so much fun 🙂
  
  Reply
Ashley

September 01, 2012 at 12:30 am

I like that you made your own fizzing rocks! We may have to try that sometime.

Reply
- ScienceSparks
  
  September 05, 2012 at 8:15 pm
  
  you should it was great!
  
  Reply
Deborah

September 01, 2012 at 3:12 am

Oh – this idea really does rock!!

Reply
- ScienceSparks
  
  September 05, 2012 at 8:15 pm
  
  🙂 Ha ha
  
  Reply
maggy, red ted art

September 01, 2012 at 1:22 pm

Oooh this looks like great fun. Love the addition of colour.

Maggy

Reply
- ScienceSparks
  
  September 05, 2012 at 8:14 pm
  
  Thanks Maggy, it was very fun!
  
  Reply
  - maggy, red ted art
    
    September 06, 2012 at 5:17 pm
    
    PS Thanks for sharing on Kids Get Crafty!
    
    Reply
The fairy and the frog

September 01, 2012 at 5:53 pm

looks great fun

Reply
- ScienceSparks
  
  September 05, 2012 at 8:14 pm
  
  IT was great!
  
  Reply
JDaniel4's Mom

September 01, 2012 at 10:51 pm

This really looks like fun!

Reply
- ScienceSparks
  
  September 05, 2012 at 8:14 pm
  
  It really was!
  
  Reply
4th Grade Science Fun

September 04, 2012 at 4:17 am

Try this: make a batch, make small balls out of it in one color and let it dry. Then make a second batch, make it a different color, wrap it around the first balls and let dry. When you add the vinegar, the outside fizzes away in one color, then the inside ball fizzes a second color. Next we want to try putting something inside like you suggested.

Reply
- ScienceSparks
  
  September 05, 2012 at 8:14 pm
  
  oooh that sounds fantastic! Thanks for the idea.
  
  Reply
Beth

September 06, 2012 at 11:34 am

How fun! You guys always have the neatest experiments!!! Thanks for linking up to TGIF! Looking forward to seeing you linked up again tomorrow =-)
Beth

Reply
- ScienceSparks
  
  September 07, 2012 at 8:44 pm
  
  Thanks Beth!
  
  Reply
Sarah

October 14, 2016 at 11:41 pm

Great idea! I’m going to add this to my list of fun baking soda & vinegar activities with my kids. Thank you!!!

Reply