One of the many kits I had growing up was a grow your own Crystal garden it was lovely and the crystals were pretty and vibrant in colour - however I know that it used Borax which if you are in the EU you will know you can't get hold of easily. But I wanted to make some crystals with the kids and show them how they are made and I remembered a hanging crystal experiment from when I was a child that I just perfect for showing them crystal growth through evaporation and I had everything I needed in the kitchen cupboards.
Bicarbonate of Soda
2 jars or small glasses
Borax Free Crystal Growing
I set up a tray with everything we need - because it was a science experiment I wanted the kids to get into the habit of having the right equipment so from our lab set I put in the goggles as well.
After boiling the kettle I poured the boiling water into the two glasses and then T added 6 tea spoons of bicarbonate of soda and stirred in.
Once the mix was stirred she cut a piece of wool and placed either end in the glasses and a small plate underneath to collect any water.
We then put it aside for a week and we've been looking at the crystals grow.
The crystals grow on the wool as the water evaporates off. Sometimes the crystals will form up from the plate - this is the same process that happens within caves with the growth of stalagmites and stalactites but there it is calcium carbonate forming the structures and here bicarbonate of soda is sodium bicarbonate. Both of them are salts and form crystalline structures as a dissolved mix of the salt and water evaporates.