Copper Plated Coins

Use some household materials to plate your coins with copper! You can also try copper plating designs onto your coins!In this project, you’re going to do two things: put copper into a solution, and make that copper come out of the solution and stick to another piece of metal (the quarter). That first process is called “electrolysis” and the second is called “electroplating.” So how do you do those things? Well, their scientific-sounding names give you a clue: with electricity!

Electrolysis is a way to dissolve bits of metal into acidic liquids like vinegar. When you run electricity through vinegar, the vinegar helps to carry electricity from one side of the circuit to the other. Those bits of the vinegar react with the copper, making little bits of copper leave the positive side of the circuit and go into the liquid. You’ll see this happening when your solution turns blue.

Electroplating is a way to put those little bits of copper onto something else. The bits of copper are ionic, which means they have an electrical charge, like a balloon that you rubbed on your hair. And just like a charged-up balloon, ions love to stick to things! By giving them another electrified metal, they rush out of the solution and onto the metal’s surface. You’ll see this when your quarter starts to change colors. With just a little electricity, you can use electrolysis and electroplating to plate a quarter with copper. Does that make it look like a penny to you?

Introduce your young electrical engineer to even more techniques with a Light-It-Up Electronics Set from the KiwiCo Store -- perfect for engineering your very own light-up circuits!

  1. Ages: 9 - 16

  2. 2+ hours

  3. A little messy


Materials you'll need

Step-by-step tutorial

  • Step 1

    Gather your materials!

    Photo reference of how to complete step 1

  • Step 2

    Fill a cup up with vinegar so that it is about 2” high.

    Photo reference of how to complete step 2

  • Step 3

    Clip a copper strip to one end of both the red and black alligator clips.

    Photo reference of how to complete step 3

  • Step 4

    Mark a small piece of tape with “+” and another with “-”. Then, tape them to either side of the plastic cup.

    Photo reference of how to complete step 4

  • Step 5

    Submerge the copper strips into the vinegar, taping the alligator clips to the cup so that they stay in place and aren’t in the vinegar.

    Photo reference of how to complete step 5

  • Tip

    Use the + and - tape to keep track of which alligator clip is which. The black alligator clip is negative and the red alligator clip is positive.

  • Step 6

    Place the battery into the battery snap. Then, connect the black alligator clip to the black wire lead and the red alligator clip to the red wire lead.

    Photo reference of how to complete step 6

  • Step 7

    Wait about 3 hours or until the vinegar has turned a greenish-blue.

    Photo reference of how to complete step 7

  • Step 8

    Clean a quarter with rubbing alcohol. Try not to touch it after you’ve cleaned it.

    Photo reference of how to complete step 8

  • Step 9

    Take the positive alligator clip and the copper strip out of the vinegar. Replace the copper strip with a quarter and submerge it in the vinegar.

    Photo reference of how to complete step 9

  • Step 10

    Wait about 15 to 20 minutes. Then, take the quarter out of the vinegar and pat it dry with a paper towel.

    Photo reference of how to complete step 10

  • Step 11

    Now, you have a copper plated quarter! If you like copper plating, try it with a nickel or dime, or tape off sections of your coin to make cool designs!

    Photo reference of how to complete step 11

  • Learn moremagnifying icon graphic

    With this project, you electroplated a quarter to make it look kind of like a penny. Did you know that actual pennies are electroplated too? They aren’t solid copper — in fact, they’re only 2.5% copper by weight! The other 97.5% is another metal called zinc. The US Mint switched to electroplating their pennies in 1982 to help standardize how much they weigh. If you find a penny from before 1982, compare it to a modern penny and see what other differences you can spot!

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