Question

directions: create a model to help you explain the phenomenon shown below. all models must include an explanation.

phenomenon: new york city is full of statues. the statues commemorate famous new yorkers, figures in global history, moments in popular culture, and other figures that hold importance for the artists and their communities. one of nyc’s most famous statues, the statue of liberty, looks very different now than it did when it was assembled in 1886. the statue of liberty’s outside is made of copper. when the statue was first built, it wasn’t green. however, over the next 30 years, the statue’s color changed. what happened?

the table below lists the materials of three different statues in new york city: the statue of liberty, the charging bull, and a piece from daniel arsham’s relics of kanto through time.

statue	year constructed	year pictured	artist	picture	materials (coating)	materials (statue body)

steel (mixture: fe + cu) |

statue of liberty

1886

1886

frédéric auguste bartholdi

color only image, brown

copper (cu)

cast iron (fe)

steel (mixture: fe + cu) |

the statue of liberty is made of copper

if it is made of copper is having more of a reaction with oxygen therefore the reason why it turns green since its not made of bronze

Explanation:

Step1: Identify the core question

The question asks why the Statue of Liberty changed color from its original (non-green) to green over ~50 years, with its exterior being copper.

Step2: Recall copper's reaction with elements

Copper (Cu) reacts with oxygen (O₂), water (H₂O), and carbon dioxide (CO₂) in the air over time.

Step3: Write the chemical reaction

The reaction forms copper(II) carbonate hydroxide, a green compound:

$$2\text{Cu} + \text{O}_2 + \text{H}_2\text{O} + \text{CO}_2 ightarrow \text{Cu}_2(\text{OH})_2\text{CO}_3$$

Step4: Name the process

This gradual color change due to environmental reaction is called patina formation.

Answer:

The Statue of Liberty turned green because its copper exterior underwent patina formation: a chemical reaction with oxygen, water, and carbon dioxide in the air, producing green copper(II) carbonate hydroxide ($\text{Cu}_2(\text{OH})_2\text{CO}_3$) over ~50 years.