Spectroscope

A spectroscope separates light into its component wavelengths so its spectrum can be inspected visually or qualitatively. It reveals spectral lines and bands associated with the light source or intervening material.

Diffraction grating: An optical element with regularly spaced grooves that diffracts light into wavelength-dependent directions. Many spectroscopes use its wavelength-dependent diffraction to spread light into a spectrum.
Spectroscopy: The study of interactions between matter and electromagnetic radiation, often through measured spectra. Spectroscopes provide visual observations used in qualitative spectroscopy.
Fraunhofer lines: Dark lines in the Sun's spectrum, systematically mapped by Joseph von Fraunhofer in the early nineteenth century. Their precise positions showed that a spectrum contains more than a continuous spread of colors.
Spectrometer: An instrument that measures properties of a spectrum, such as wavelength or intensity. Unlike a spectroscope's visual inspection, a spectrometer produces measurements.
Prism: A transparent optical element that refracts light, with different wavelengths bent by different amounts. A prism can disperse light into colors instead of a diffraction grating.
Emission spectrum: The wavelengths of light emitted by atoms, molecules, or other sources, often appearing as bright lines or bands. Bright features in a spectroscope can show which wavelengths a source emits.
Gustav Kirchhoff: A German physicist whose work with Robert Bunsen established principles of spectral analysis in the 1850s. Kirchhoff connected spectral lines to the elements emitting or absorbing light.
Spectrophotometer: An instrument that measures how much light a sample transmits or absorbs at selected wavelengths. It quantifies wavelength-dependent light absorption rather than merely displaying a spectrum.
Entrance slit: A narrow aperture that limits the width of a light beam entering an optical instrument. Its width helps determine how sharply neighboring spectral features appear.
Absorption spectrum: A spectrum with reduced intensity at wavelengths absorbed by matter along the light path. Dark features can reveal substances that absorbed light before it reached the instrument.

Linked from 9 pages