How to: Make a Gold Penny

These direction assume you have access to science materials. However, I think you could alter these directions based on what you have available. (ie. instead of a hot plate use your stove and instead of a Bunsen burner you could use an open flame of some sort.) Also please note I did not make up this experiment, I am just explaining an experiment I performed which demonstrates chemical reactions.

Introduction:
Pennies made after 1983 have a zinc core with a copper coating. Pennies made before 1983 are an alloy of 95% copper and 5% zinc. Modern pennies are lighter than older pennies, and are less expensive to make. This experiment will show what happens when a copper coin reacts with zinc and zinc chloride. Some of the zinc will “dissolve” in the copper of the penny. Then you’ll heat your penny. This will allow the copper atoms in the penny to move around, and will result in a mixture of copper and zinc on the surface of the penny. This is an alloy called “yellow brass.” Please after doing this process, don’t try to spend the pennies.
Materials needed
Hot Plate
Bunsen burner
25-mL graduates cylinder
2 250mL beakers
Long Tongs
Mossy Zinc
3 Molar NaOH solution
Two pennies- dated after 1982-

Directions:

1. Plug in the hotplate and set it for a medium high setting.
2. While the hotplate comes to temperature, weigh out .5g sample of zinc and obtain 15mL sample of sodium hydroxide solution and carefully pour both into beaker.
3. Put this solution onto the hotplate, when it comes to temperature, and wait until the solution starts to bubble.
4. Then adjust hotplate to keep the solution just bellow boiling.
5. Add your pennies to the hot solution carefully.
6. Move the pennies around until they have a uniform silver color. Then flip them to make sure both sides are silver.
7. Fill the other beaker with 25mL distilled water.
8. After the pennies are “silver”, using the tongs carefully remove them from hot solution and add them to other beaker filled with distilled water. Turn hotplate off.
9. Then, rinse and dry coins with paper towel.
10. Holding the coin edge to edge and vertically with tongs, heat them over the Bunsen burner’s outer cone. Heat until the coin looks entirely gold and then for an additional 3 seconds. Do not overheat.
11. Immediately immerse the coin the in the second beaker of water.
12. Repeat steps for the remaining coin(s).
13. Then Remove coins from water and dry them.

Remember to wash your hands to remove any acid.
What Happened
When you heated the coins, the zinc combined with copper forming a bronze coating. Because the bronze is high in zinc, your coin looks “gold.”


That’s it, you know have a “gold penny,” obviously it’s not real gold but it’s cool to whip out a gold looking penny for your buddies.

Your finished results should look similar to this (Compare to regular penny in middle):

Additional Experiment
Using a triangular file, cut four equally spaced notches around the outside of a post-1982 penny-deep enough to each the zinc core within-[note, make sure this is a new penny and not used in the steps above]
Now place the penny in a small beaker and add enough hydrochloric acid
Let stand for a couple of days in acid and then gently remove with forceps or tweezers.
Rinse Completely under running water.
You are now holding a paper thin copper shell previously encasing the zinc core.
Be careful, this Copper is fragile and will break under little force.