Crystals of copper sulphate are prepared by the method of crystallization. It is an example of physical change. 

The process is as follows:

• A cupful of water is taken in a beaker and a few drops of dilute sulphuric acid are added in it.
• The water is then heated and when it starts boiling, copper sulphate powder is added slowly with stirring.
• Copper sulphate powder is added continuously till no more powder can be dissolved.
• Then solution is filtered and allowed to cool down.
• Do not disturb the solution, when it is cooling.
• Crystals of copper sulphate slowly form at the bottom of the beaker.