Some Terms You Should Know: the Spectrum
These are some terms you will come across in your lab class dealing with
the visible spectrum.
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Spectrum
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The order of colors produced when light is dispersed. A rainbow is
a spectrum.
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Continuous Spectrum
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A spectrum that contains an entire range of colors and not just separate
wavelengths.
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Absorption Spectrum
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A spectrum that is continuous except for dark lines that appear due to
material that absorbs specific wavelengths of light.
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Emission Spectrum
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A spectrum that is made up of separate wavelengths on a dark bakground
due to material that emits specific wavelengths of light.
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Diffraction Grating
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A grid with small openings that can be used to separate light into its
component wavelengths.
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Doppler Shift
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The observed change in a wavelength that occurs when a wave source is moving
toward you or away from you.
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Hubble Constant
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The ratio of a galaxy's recessional velocity (how fast it is moving away
from Earth) to its distance from Earth. This constant can be used
to estimate the age of the universe.
Back to the definitions page
This page was last updated on 8 March 1998
and is © 1998 by Jim McDonald.