If the green color of copper coating that covers statue liberty is different from a typical penny what caused to turn green?

The green color of the Statue of Liberty is due to a process called patination. Patination is the process of metal reacting with oxygen and other elements in the environment to form a layer of corrosion on the surface. The patina on the Statue of Liberty is composed of copper carbonate, which is a green compound.

The Statue of Liberty was originally a copper-brown color when it was first dedicated in 1886. However, over time, the copper reacted with the oxygen and water in the air to form a layer of patina. The patina has gradually darkened over time, giving the statue its current green color.

The patina on the Statue of Liberty is not just a cosmetic effect. It actually helps to protect the statue from corrosion. The patina acts as a barrier between the copper and the environment, preventing the copper from corroding further. This is why the Statue of Liberty has remained in good condition for over 100 years.

In contrast to the Statue of Liberty, a typical penny is made of copper-plated zinc. The zinc coating on a penny prevents the copper from reacting with the environment and forming a patina. This is why pennies retain their original copper color for a long period of time.

However, if a penny is exposed to oxygen and water, the zinc coating will eventually corrode and the copper underneath will begin to form a patina. This is why old pennies often have a greenish color.