Transcript Chemical Composition of Stars II

Chemical Composition of Stars
• What is the purpose of fingerprints?
• How are fingerprints useful?
• Where do you see fingerprints being used?
Activity
• Students are to press their thumb gently
onto the ink pad and then press their thumb
onto the notes
• Students should wipe the ink off their
thumb with the wipe provided
• Students should compare/contrast their
fingerprint with their neighbor.
Types of Fingerprints
Review-Electromagnetic Spectrum
Spectrometer
• Students will put on the glasses provided and take
note of the spectral lines that appear on the right
(3:00 position)
• Students should write notes as to what colors are
being observed and in which order the colors
appear
• Students will reproduce what they observed using
colored pencils on the spectrometer worksheet
provided for two gases
Class Discussion
• How did the fingerprint activity relate to the
spectrograph activity?
• Each person has a unique set of fingerprints and
each element of a star has a unique line spectrum
• By comparing a star’s spectrum with the spectrum
of known elements, astronomers can infer how
much of each element is found in the star
Examples of Line Spectrums of Elements
Chemical Composition Of Stars In Clusters Can Tell
History Of Our Galaxy and Others
Doppler effect
• If the spectral lines are shifted toward the blue end of the
spectrum for the star, then the star is moving towards us.
• If the dark lines are shifted toward the red end of the
spectrum for the star, it is moving away from us.
Animation
• http://www.classzone.com/books/earth_science/terc/conten
t/visualizations/es2802/es2802page01.cfm