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Polish Pennies with a Pencil Experiment

Polish Pennies with a Pencil

Polish Pennies with a Pencil

Polish some dirty pennies with only a pencil.

A pencil eraser works by scratching and tugging at graphite particles until they loosen and eventually fall off a piece of paper. Instead of erasing graphite off a page, we can scratch the ugly patina—the covering caused by long-term exposure to oxygen and other elements—from a the surface of a penny.

Materials You'll Need:

Questions and Things to Notice

  • The patina on your coins is made up of several different chemical compounds, each with different appearances. Be sure to observe the different colors and textures of the pennies you've chosen.
  • We usually notice that older, more-circulated pennies are usually much less shiny than newer pennies. Why exactly do you think this is?


  1. Polish Pennies with a Pencil Step 1

    Step 1

    Out of your pennies, try to find the dirtiest, ugliest, greenest one. We had a few fitting this description in our piggy bank...

  2. Polish Pennies with a Pencil Step 2

    Step 2

    For your first attempt to shine up a penny, take a small piece of paper towel and dampen it slightly with water.

  3. Polish Pennies with a Pencil Step 3

    Step 3

    With as much effort as you can, try for a few seconds to polish the penny with the paper towel. You'll probably find that not much is happening. This is because the green coating on your pennies isn't just on the surface, but is actually part of the penny itself. To remove this layer, we're going to have to use something abrasive to scratch off this microscopic layer and polish the penny.

  4. Polish Pennies with a Pencil Step 4

    Step 4

    Now, take the pencil and, using some "elbow grease," try to use its eraser to scratch off the patina covering the penny. This time, if you put a bit of effort into it, you should see your penny slowly starting to become shinier.

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Materials Checklist