Copper doesn't actually "glow" green. Instead, it appears green due to a chemical reaction on its surface.
The Green Color: Copper Carbonate
The green color observed on copper surfaces is a result of the formation of copper carbonate. This compound is not inherent to copper itself but forms through a chemical process.
The Formation Process
Copper carbonate forms when copper interacts with specific environmental elements:
- Oxygen: Present in the air.
- Moisture: Humidity or water vapor in the air.
- Carbon Dioxide: Also a component of the air.
When these elements are present, they react with the copper surface, creating a layer of copper carbonate, which has a characteristic green color.
Example: Statue of Liberty
A famous example of this is the Statue of Liberty. Its outer layer is made of copper, which has, over time, reacted with the environment to form a layer of copper carbonate, giving it the iconic green appearance.
