How color emitted when atoms are heated?

When atoms are heated, they gain energy, which excites their electrons to higher energy levels. As these excited electrons return to their original states, they release energy in the form of light, a process known as photon emission. The color of the emitted light depends on the specific energy transitions of the electrons, which correspond to particular wavelengths of light, resulting in different colors. This phenomenon is the basis for the emission spectra of elements, which can be observed in flame tests and other applications.