We love a good baking soda experiment. I spotted this brilliant and very simple idea on Reading Confetti, who kindly said I could post about it here. These are our fizzing rocks.
What you need:
Bicarbonate of soda/baking soda
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.
The Science bit
Vinegar (an acid ) and bicarbonate of soda ( an alkali ) react together to neutralise each other. This reaction releases carbon dioxide a gas which is the bubbles you see.
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 totally dissolve it.
We also have a Valentine version of this. Can you think of any other ideas?
Make sure you check out some of our other fun science for kids posts.