You can change a penny's color to silver and then gold using a chemical reaction involving zinc sulfate and zinc.
Here's a simplified process to turn a penny silver (and then briefly gold):
Changing a Penny to "Silver" and "Gold"
This process involves plating the penny with zinc, creating a silvery appearance. Heating the zinc-coated penny then causes the zinc and copper to alloy, creating a brass-like ("gold") appearance.
Materials You'll Need:
- A clean penny (pre-1982 pennies work best due to their high copper content)
- Zinc sulfate (approximately 30 grams)
- Water (100 mL)
- Mossy zinc (small pieces)
- A 250 mL beaker (or similar heat-safe container)
- Hot plate (or other heat source)
- Tongs or pliers
- Paper towels
Procedure:
- Prepare the Zinc Sulfate Solution: Dissolve 30 grams of zinc sulfate in 100 mL of water in the beaker. Using a hot plate to gently heat the solution can speed up the dissolving process.
- Add Mossy Zinc: Place the mossy zinc pieces into the beaker containing the zinc sulfate solution. Use enough zinc to almost cover the bottom of the beaker.
- Add the Penny: Place the clean penny into the beaker, ensuring it's in contact with the mossy zinc and submerged in the solution.
- Heat and Observe: Place the beaker on the hot plate and heat the solution. The penny will gradually become coated with a layer of zinc, giving it a silver-like appearance. This process may take several minutes.
- Rinse and Dry: Once the penny is thoroughly coated with zinc (appears silver), carefully remove it from the beaker using tongs. Rinse it thoroughly with water to remove any remaining zinc sulfate solution. Pat it dry with a paper towel.
- "Golden" Transformation (Optional): This step must be performed with caution and under supervision. Using tongs, carefully hold the "silver" penny over the hot plate (or a flame source). As the penny heats, the zinc and copper will begin to alloy, forming brass. You'll see the penny turn a gold-like color. Be careful not to overheat the penny, which can cause the zinc layer to bubble or flake off.
- Cool and Clean (If Heated): If you heated the penny, let it cool on a non-flammable surface.
Important Considerations:
- Safety: Use caution when working with heat and chemicals. Wear appropriate safety glasses and gloves. Conduct the experiment in a well-ventilated area.
- Penny Composition: Pennies minted after 1982 are primarily made of zinc with a thin copper coating. Pre-1982 pennies are almost entirely copper. While both types of pennies can be used, the results may vary.
- Zinc Plating: The "silver" color is due to a thin layer of zinc plating on the copper penny.
- Alloying: The "gold" color results from the formation of a brass alloy on the surface of the penny. This process diffuses the zinc and copper together.
