How to make a "gold" bracelet
Making a unique “gold” bracelet at home
Perform this experiment only under adult supervision.
- copper wire;
- zinc granules;
- aluminum cup;
- zinc sulfate solution;
- thin-nose pliers.
Twist a copper wire into a spiral. Pour some zinc granules into an aluminum cup, place the copper spiral on top, and cover with a solution of zinc sulfate. Place the cup on a burner and heat for 35 minutes. With time, the entire wire will turn silver. Remove the wire from the solution, wash it with water, and dry it with a paper towel. Heat the spiral on the burner until it becomes uniformly golden. Cut the wire and twist it into rings to make a “gold” bracelet!
When the solution is heated, the zinc transfers some electrons to the copper wire, giving the wire a negative charge. Zinc ions Zn²⁺ are constantly switching moving between the solution and the wire. The negatively-charged wire attracts charged zinc particles – Zn²⁺ ions – which are reduced on the wire and then settle on the copper. At the same time, some metallic zinc from zinc pellets is oxidized and moves into solution in the form of Zn²⁺ ions. As a result, the copper coin is slowly covered with a layer of silvery metallic zinc. Wash it properly with water. If you further heat the wire over the burner, the zinc and copper atoms begin to mix, yielding a “golden” alloy – brass.
A similar experiment is included in the “Alchemy” kit from the MEL Chemistry subscription!