Spectrometers are optical devices, and often are called prism spectrometers because they often
use a prism for light dispersion. As explained in the grating chapter, some devices use a diffraction
grating in place of a prism because the dispersion from a grating can be much greater than that of a
prism. Light dispersion occurs in a prism and in water particles in the atmosphere. Spectrometers
are commonly used to analyse the wavelengths emitted by a light source. These devices are very
useful to ﬁreﬁghters in identifying the ﬁre coming from a burning object. Once they identify the
type of the burning object, they easily can put out the ﬁre with an appropriate ﬁre extinguisher.