Fire colors are determined by the temperature of the flames and the materials being burned. For example, cooler flames can appear yellow or orange, while hotter flames can be blue or white. The color changes occur due to the energy released by burning different elements, such as sodium producing a bright yellow and copper creating a green hue. In addition to temperature, the presence of certain chemicals can also influence fire colors. When metal salts are added to a fire, they can produce vibrant colors. For instance, lithium creates a red flame, while barium results in a green flame, showcasing the diverse palette of fire.