The Statue of Liberty and Green Coin Experiment...
Did you ever wonder why the Statue of Liberty is green? The statue was originally dull and brown in color that reflected its natural copper layer. This layer that covers this monument is only about two pennies thick. Over a period of 30 years The Statue of Liberty's color changed to green and people were worried that this treasure was breaking down. This natural weathering process is actually called oxidation and actually protects the copper from further decay. You can experiment with oxidation at home with this Green Coin Experiment and get an up close look at what happened to the Statue of Liberty on a much smaller scale. The amount of copper that covers Lady Liberty would actually be enough to make 50 million pennies, so imagine that when you are viewing the results of one or two of the pennies that you are using.
How to Do It
The copper penny has gone through a process called oxidation. The copper in the coin reacts to the oxygen in the air to form a coating called green copper oxide.