Why does fire turn green while burning copper?

Green fire is usually a result of the burning of copper sulfate. This occurs because when copper is heated, the electrons start to move very rapidly. This rapid movement causes the electon to move through different levels of energy. These different levels of energy cause different colors also known as the light spectrum. You can also cause fire to change colors by burning other chemicals such as lithium chloride (blue) and Calcium Chloride (intense orange).