We just finished a fun unit on American Symbols. One of the symbols we learned about was the Statue of Liberty. We learned Lady Liberty was a gift from France AND when we received her, she was copper! Why, then, is she green now? We experimented to find out.
First, we made predictions! How great are these?
Then, we found some copper pennies. (They have to be made of copper, minted before 1980.) We soaked them in salt and vinegar for 48 hours. (They don't really have to soak that long. It just makes it more fun to watch the vinegar.) We observed the vinegar slowly turn blue.
Here are the pennies right after they were put in the salt and vinegar mixture.
Vinegar slowly turning blue...
We took the pennies out of the mixture and let them air-dry on a paper towel. As the pennies dried, they changed color. Once they were dry, we transferred them to a paper plate.
The kids thought the turquoise pennies were pretty cool! They WERE pretty cool...
Close up shot of the pennies.
We found out the mixture of salty water and oxygen in the air caused the pennies AND the Statue of Liberty to change colors. This is called Oxidation!
Next up for Science is Weather!