How to Create Silver Pennies

A common chemistry experiment yields silver pennies and even gold ones. The activity is relatively simple, but it comes with the standard hazards you must take into account when working with chemicals. The task is a great activity to illustrate chemical versus physical changes. The students in your classroom or kids at home are sure to enjoy the "magic" of this activity.

Instructions

Difficulty: Moderate

Things You’ll Need:

• Pre-1982 pennies
• 2 100 mL beakers
• Safety goggles
• Lab coat
• Protective gloves
• Ring stand
• Bunsen burner
• 2 g granular zinc
• 25 mL 1 M solution zinc chloride
• Water
• Watch glass
• Tongs

1. Obtain several pennies that date before 1982. Penny composition is slightly different before and after that year. Many have found this experiment works better with the older pennies. Clean up the pennies with some vinegar and rinse them well in warm water.
2. Wear safety goggles, a lab coat and gloves while conducting this experiment.
3. Use a ring stand to securely mount a 100 mL beaker over a Bunsen burner. Secure the beaker so it won't tip.
4. Add 2 g of granular zinc and 25 mL of 1 M solution zinc chloride to the beaker. Cover the beaker with a watch glass.
5. Fill a different beaker with water and set it nearby for later use.
6. Turn on the heat on the Bunsen burner and bring the mixture to a gentle boil. Turn down the heat so it continues to boil gently, not vigorously. Keep an eye on the solution and ensure it does not boil away.
7. Lift the watch glass carefully. Use tongs to place the pennies into the boiling liquid. Be careful not to drop the pennies in, or else the solution splashes. Replace the watch glass.
8. Observe as the pennies turn silver. When they appear to be completely coated in zinc, turn off the heat and use tongs to remove them from the solution. Place the pennies into the beaker of water and let the zinc chloride solution cool before disposal.
9. Rinse and dry your new zinc-coated silver pennies once they have cooled.

Tips & Warnings

• Hold one of the silver pennies in the outer cone of a Bunsen burner flame, and it will turn gold. The penny will stay the golden color even after it cools.
• Always follow safety instructions printed on chemical containers.
• Children younger than 14 should not participate in this activity.