Science for Kids: Make a Penny Turn Green (with free printable)

make a penny green science experiment for kids

Welcome to another Science Invitation Saturday! Last Science Saturday we had fun with Exploring Fingerprints! This time we’re going to make pennies turn green.

Chemical reactions are such a great way to pique a child’s curiosity. This experiment involving a chemical reaction is quite simple and always amazes kids!





  1. Fold a paper towel so that it fits inside your dish.
  2. Place the pennies on top of the paper towel.
The pennies placed on the paper towel

The pennies placed on the paper towel


3. Pour vinegar over the pennies so that the paper towel is fully saturated.


Pennies with vinegar ready to be observed

Pennies with vinegar ready to be observed

4. Observe the pennies over the next few hours and days. You can record your observations using the free printable.

Screen Shot 2013-06-28 at 1.04.19 PM




– We left this experiment out for a few days, adding more vinegar as the paper towel began to dry out and flipping the pennies over occasionally. The longer we waited, the more green they became!


Question to Spark Curiosity & Critical Thinking:

What happened to the pennies over time? What is your theory as to why this happened? 

Can you think of any other chemical reactions you’ve seen in everyday life?


 What’s Going On:

A chemical reaction has occurred! (A chemical reaction is the combination of two reactants to form something entirely new.) A penny is made of copper. The vinegar on the paper towel helps the copper in the penny easily react with the oxygen in the air to form a blue-green colored compound called malachite.

This is similar to why  the Statue of Liberty (which is covered with a layer of copper) has turned greenish-blue.  The statue would naturally turn greenish-blue due to exposure to the oxygen in the air. However, because some rain has acid from pollution in it, the rain speeds up the reaction (just as the vinegar caused the reaction with the penny).


green pennies



Want to go even further?

Even more activities to inspire creativity and critical thinking for various ages.

  • Try a similar experiment: Fill a cup with 1/4 cup vinegar and 1 teaspoon salt. Stir. Add some pennies and let them sit for 5 minutes. Take them out and rinse them. What happened?
  • Make a volcano using baking soda and vinegar.
  • Make a torch and crown just like the Statue of Liberty!




Don’t forget to follow along with Buggy and Buddy on FacebookTwitter,  and Pinterest!





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  1. What a great science activity! We’ll have to do this one this week. Thanks!
    Jessica @ Play Trains! recently posted…Sand Tracks: Train Beach Activity Inspired by Peter’s RailwayMy Profile

  2. Seriously? I cannot believe I didn’t know you could do this with vinegar! I have a copper tea pot and a milk can that I have let nature take care of, and it’s taking YEARS for them to turn green! Guess what I’ll be giving them a shot of?!
    jackie recently posted…Fairy SoupMy Profile

  3. What a great experiment!! We will have to try it after our post using the Statue of Liberty as our symbol of NYC. Thank you for sharing at Sharing Saturday!!
    Carrie recently posted…Fairy Tales in Different Cultures: Cinder-EllyMy Profile

  4. Oh, I am curious to try it out. I would expect the vinegar to actually clean the coins, but I can see that letting them dry out in vinegar would accelerate oxidation.
    Natalie recently posted…China Activities for Elementary–Bucket List StyleMy Profile

  5. I’ve seen a lot of experiments for turning them back to copper colored, this is the first one I’ve seen to turn them green.

    Thanks for linking up to Science Sunday!
    Ticia recently posted…Duct Tape WarfareMy Profile

  6. What a great science activity! I think this would be a great, meaningful activity when talking about the Statue of Liberty (as you mentioned). Thanks for sharing at Stress-Free Sunday — I’m featuring you this weekend!
    Mary Catherine recently posted…35 Fun, Simple Kids’ Activities {Stress-Free Sunday #16}My Profile

  7. Great activity!! I’m featuring this tomorrow at the After School Linky Party. Stop by to check it out and share more of your great ideas while you’re there! Thanks!
    Deceptively Educational recently posted…July 4th Painted Flag ShirtMy Profile

  8. Love the activity. Featuring you on iGameMom. Thanks for sharing at Mom’s library.
    iGameMom recently posted…FREE App: Classical Kids – Beethoven Lives UpstairsMy Profile

  9. HI,
    I can’t wait to try this with my kindergartners, however I can’t seem to access the printable. When I click on it I’m taken to a google doc page that is denying access. Help!


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