Download The Spectroscope

THE SPECTROSCOPE
What is it?
 A spectroscope is a tool used by astronomers
to separate light into its rainbow of colors in
the spectrum.
 This technique used to help scientists determine
the composition of objects made up of hot
incandescent gases (like stars) and cool gases (like
planetary atmospheres).
 Spectrometers are used to analyze the amounts
and types of spectral light that comes from
objects in space.
 Spectroscopes break down the light emitted or
absorbed by chemical elements into specific
lines of color.
 Every chemical element has a "fingerprint" of its
own that can be used to identify it.
 These fingerprints are generally produced when
electrons change orbital levels as they gain or
lose energy. That’s cool
 Different energies produce different colored
lines.
Star Fingerprints
 Every chemical element on the periodic table
has its own spectral fingerprint that identifies
it. (this is important)
 When looking at spectra from objects like
stars and planetary atmospheres, it is easy to
identify the chemical elements present by
matching the colored spectral lines with the
elements spectral fingerprint.
 See Spectra of gas discharge
Wavelengths
Look at the chart on the right –
notice the different areas of the
scale for each wavelength.
Where do you find:
Radio waves?
Microwaves?
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
What is the Electromagnetic
Spectrum?
Types of Spectra
 Continuous spectrum – unbroken rainbow of
color. What order do the colors go in?
Bright line spectrum
 Un evenly spaced lines of different colors
which are unique to each element.
Different types of spectrum
analysis
 Element discharge samples
 http://jersey.uoregon.edu/elements/Elements
.html
Spectroscope lab
 Let’s see how it works with some samples of
isolated gases
What is the doppler effect?
 A change in wavelength of light or sound
from moving objects ie: a train passing
 What happens as the train is moving closer?
 Moving away?
 Doppler effect animations
Doppler shift
 With stars in a spectrum there is also doppler
effect. We can see it through the
spectroscope signatures, and notice whether
there is a red or blue shift
Red Shift or Blue ?
 In red shift- stars are
moving away from
Earth, so the visible
spectrum shifts more
toward the red end,
 Blue Shift – stars are
moving closer toward
the earth