Final answer:
A yellow flame indicates lower temperature and possible incomplete combustion, while a blue flame represents higher temperature and complete combustion. The perfect flame of a Bunsen burner has a double cone, is blue, and its height and air mix are adjustable. Flame color also reflects the quantum behavior of blackbodies and the unique line emission spectra of metals.
Step-by-step explanation:
The color of a flame provides valuable information about its temperature. A yellow flame, like that of a peach-scented candle, indicates that it is at a relatively lower temperature and may be incomplete in combustion, often because of a lack of oxygen or an excess of fuel. Conversely, a blue flame, such as that from a Bunsen burner, suggests a higher temperature and complete combustion of the fuel, which is usually methane in the case of a gas stove or laboratory burner.
A Bunsen burner perfect flame is often characterized by a non-flickering blue flame with a double cone structure - an inner and an outer cone. The perfect flame should not produce smoke, should not sputter flames from the barrel, and its height is usually adjusted with the bottom knob rather than the gas valve at the bench top. The blue color, indicating a higher temperature, can often be achieved by controlling the amount of air mixed with the gas, which is often done by twisting the barrel of the Bunsen burner.
In regards to energy characteristics, the color of a flame can also tell us about the quantum behavior of blackbodies. Hot embers that glow bright orange or whitish-yellow are an example of this, where the color indicates high energy thermal emission. The line emission spectra of metals, visible during a flame test, are directly tied to the electronic arrangements and excited states of the metal's atoms, which when returning to their ground state, release light at specific wavelengths that are characteristic of each element.