Crystals of copper sulphate are prepared by the method of crystallisation.
The process is as follows:
A cup full of water is taken in a beaker. The water is then heated and when it starts boiling, copper sulphate powder is added with stirring. Copper sulphate powder should be added till no more powder can be dissolved. It is then filtered into a china dish and allowed to cool. The solution should be kept undisturbed. After some time, you will see the crystals of copper sulphate.

A blacksmith grinds the edges of iron axe against a spinning wheel to sharpen it. Sparks of fire and heat are generated due to the friction between the objects. So,we can say that it is a physical change as only the shape of the axe changes. 

The process of coating a layer of zinc over iron articles is known as galvanization.In this process, a layer of metal such as chromium, or zinc is deposited on iron which helps to prevent the iron objects from rusting. The iron pipes we use in our homes to carry water are galvanised to prevent rusting.