Glossary of Terms
- Absorb
- to take in or
soak up (the process is called absorption)
| - Light
- radiant energy; it travels in waves, moving
outward from its source at 300,000 kilometers per second (about 670
million mph). Light is produced in a continuous range of wavelengths;
each wavelength corresponding to a specific amount of
energy.
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- Absorption Line Spectrum
- a unique pattern of wavelengths of light that get absorbed
by a particular type of matter; the pattern appears as a series of dark
lines or of sharp dips on an intensity-vs-wavelength
graph.
| - Light Intensity
- the
amount of light energy from a given location (measured per unit
time).
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- Continuous
- without any gaps or
spaces.
| - Light-year
- the
distance light travels in a vacuum (space) during one year's time. A
light-year is equal to 9.5 trillion kilometers, or 5.9 trillion
miles.
|
- Diffraction
Grating
- a device- usually made of
glass, plastic or metal- with tiny parallel lines etched into its
surface. The parallel lines cause different wavelengths of light to be
separated by different angles of refraction or reflection, producing a
spectrum.
| - Nanometer (nm)
- a
distance equal to one-billionth of a meter (0.000000001 = 10
 m). This unit is used to measure the wavelengths of
visible light.
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- Discrete
- [in science or math the word means] individual
values as opposed to continuum
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- Photon
- the smallest quantity of
light.
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- Dispersion
- the separation of light according to
wavelength.
| - Prism
- a three-sided
glass object that separates light into its
spectrum
|
- Electromagnetic
Radiation
- the scientific term used to
describe light.
| - Spectrum
- a band or
range of light energy that has been spread out (dispersed) into its
component wavelengths (plural- spectra).
|
- Electromagnetic Line
Spectrum
- the complete range of
wavelengths of light, in order from smallest wavelengths to largest
wavelengths.
| - Spectroscopy
- the study of light spectra.
|
- Emission
Spectrum
- a unique pattern of
individual wavelengths of light that a type of matter gives off. The
pattern appears as single, discrete lines of color, or as a series of
sharp peaks on an intensity-vs-wavelength
graph.
| - Ultraviolet
- the
portion of the electromagnetic spectrum beyond the visible violet
region. Photons of ultraviolet light have more energy that photons of
visible violet light.
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- Emit
- to give off or send out (the process is called
emission)
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- Visible Light
- the part of the electromagnetic spectrum
(wavelengths between 400nm and 700 nm) that can be perceived by the
human eye.
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- Energy
- the ability to do work; light is a form of
energy.
| - Wavelength
- the
distance between two consecutive crests (or two consecutive troughs) on
a wave of the electromagnetic spectrum.
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