Emerald Pennies

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Exploring the acidic reaction vinegar has on pennies in Emerald Pennies

Emerald Pennies

We have another easy and fun experiment with you! Exploring the acidic reaction vinegar has on pennies in Emerald Pennies.

Little Passports


Check it out in action!


Exploring the acidic reaction vinegar has on pennies in Emerald PenniesWhat You Will Need:

Paper towel

2 clean, shiny pennies

Vinegar (about 1/4 cup)

Small Bowl


Pens and crayons



Result Timing:



What to do:

    1. In your journal draw a picture of the pennies. What color crayons come closest to the color of the real coins?
    2. Write it down in your journal.
    3. Next fold the paper towel in half, and then in half again into a square.
    4. Put the folded paper towel in the bottom of the bowl.
    5. Slowly pour vinegar into the bowl until the paper towel is completely soaked. (There shouldn’t be a puddle of extra vinegar sitting on top of the paper towel.)
    6. Put the pennies on top of the wet paper towel and leave them there overnight.
    7. The next day, take the pennies out of the bowl. Write down in your journal how they changed, did they change on both sides or only one?
    8. Write down all of your observations and draw another picture in your journal of the pennies now.
    9. What color crayons do you need this time?

How it works

The main ingredient in pennies is a metal called copper. It’s copper that gives pennies their reddish-brown color. Vinegar contains a chemical called acetic acid. When acetic acid touches copper. something new is created-a green blue chemical called carbon acetate. In science, we call this kind to change a chemical reaction. The chemicals in the vinegar and in the copper react when they are combined, making carbon acetate on the pennies.

Did you Notice?

Did you notice that the tops of the pennies changed color, but not the bottoms? That is because this chemical reaction can only happen if something else is available- oxygen from the air around us! The tops of the pennies are exposed to the air and so oxygen is available to be part of the chemical reaction. The bottoms of the pennies don’t change because they don’t have enough oxygen next to them to make the reaction possible.


Did you try this experiment? How did you like it? Let us know in the comments section below. Share your videos and photos with us on FacebookTwitter and Instagram using the hashtag- #sciencesunday We would love to see you doing the experiments!


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