|www . Science-Projects . com| |Flame Emission Spectroscopy| The
light emitted from glowing gases is characteristic of the
elements in that gas, and the brightness of each band of light
is directly proportional to the quantity of that element in the
glowing gas. While you are probably familiar with sodium vapor
lamps and with ordinary fluorescent tubes for lighting. While
the light from overhead fluorescent tubes seems white to our
eyes, that from the sodium vapor in many parking lots and along
highways is distinctly yellow-orange and objects within range
have a rather eerie cast about them. This lifeless color from
sodium lamps is due to the fact that they are essentially
monochromatic - only one wavelength of light is given off
(actually two very closely associate wavelengths; see below).
Just as sodium emits these two very close wavelengths of light,
all other elements can emit one to many distinctive wavelengths,
many of which are not visible to the human eye as they are in
the infra-red or ultraviolet. I