An interesting demonstration to show plating and alloys.
A ‘copper’ coin is dipped into a solution of sodium zincate in contact with zinc. The coin is plated with zinc and appears silver in colour. The plated coin is held in a Bunsen flame for a few seconds and the zinc and copper form an alloy of brass. The coin now appears gold.
Turning Copper Coins into Silver and Gold
Turning Copper Coins into Silver and Gold – Risk Assessment