In a jar we mixed 6-8 tablespoons of salt and filled the jar half-way with water. We mixed it up to dissolve as much of the salt as possible. Some of us added food colouring to make coloured crystals.
We tied a piece of string around an ice-block stick and hung it so that the string just touched the mixture. Then we sat the jars up on the bench to wait for them to grow.
As the mixture moves around the jar the salt particles collide and join together. Salt is special as its crystals form in perfect looking square shapes! See the photos below for some of the crystals we made!