Apparatus: Copper wire, iron nail, beaker or big test tube, etc.
Chemicals: Aqueous solutions of ferrous sulphate and copper sulphate.
Procedure: i. Take a clean copper wire and a clean iron nail.
ii. Dip the copper wire in ferrous sulphate solution and the iron nail in copper sulphate solution.
iii . Keep on observing continually at a fixed interval of time.
How did you recognize that a reaction has taken place?

Explanation

The blue colour of the solution faded away gradually and turned into green. In addition this, copper coating is formed on the iron nail. These indicate that the reaction has taken place.