Download Absorption Spectrum

Visible Light Spectra
Using a Spectroscope
Spectrum (Prisms)
– when light is passed through a prism
• The light is bent into the visible spectrum
Spectrum
• Visible Light
– Made of various colors, each with a different
wavelength.
– These are the colors seen in a rainbow,
Spectrum
• Visible Light
– Made of various colors, each with a different
wavelength.
• (Red, Orange, Yellow, Green, Blue, Violet)
– These are the colors seen in a rainbow,
Spectroscope
•Uses a prism to split the light gathered by a
telescope into a spectrum. (roygbv)
Parts of a Spectroscope
• Lens
• Prism
• Spectrum
Three types of Spectra
• Three different types
• Continuous Spectrum
• Emission Spectrum
also called a bright line spectrum
• Absorption Spectrum
also called a dark line spectrum
• Allow astronomers to figure out what
elements make up the atmospheres of
stars and planets.
Continuous Spectrum
• Unbroken band of colors
• Shows that the source is emitting all
visible wavelengths.
Emission Spectrum
• A series of unevenly spaced lines of
different colors and brightness.
• Called a bright line spectrum.
• The bright lines show that the source is
emitting light of certain wavelengths.
Emission Spectrum
• Produced by glowing gases.
• Every element has a unique emission
spectrum
– Allows scientists to determine the elements in
objects.
Absorption Spectrum
• A continuous spectrum crossed by dark
lines.
• Called a dark line spectrum.
• Lines form when light from a glowing
object passes through a cooler gas.
– The gas absorbs the wavelengths.
Absorption Spectrum
• The colors absorbed are the same that the
gas would emit.
– Absorption Spectrum for Hydrogen
– Emission Spectrum for Hydrogen
Chemical Composition
• Chemical elements in a star’s atmosphere
absorb light from the star.
• Each element absorbs a different
wavelength. Each absorbed wavelength is
shown as a dark line on a spectrum.
Chemical Composition
• It acts like a finger print each element has
a unique set of lines.
• By comparing the star’s spectrum to the
known spectrums of different elements,
astronomers can determine the elements
present.
Temperatures
• Most stars have a chemical composition
similar to the sun. 73% H, 25%He and 2%
other elements.
• Stars at different temps produce different
line spectrums.
• If the star is at about 10,000˚C it produces
a very strong spectral lines for H.
• If the hydrogen line is not strong, it means
the star is cooler than 10,000˚C
Absorption Spectrums
Absorption Spectrums
Absorption Spectrums