Research Earth Science Agenda
November 1, Tuesday: A Day

Take out your CH#28 Preview and vocabulary diagrams/pictures (HW)
WARM-UPS:
1. ExC-ELL vocabulary: Electromagnetic Energy
OBJECTIVES: Stars, Galaxies, and the Universe
1. NOTES:
a. ELECTROMAGNETIC & VISIBLE-LIGHT SPECTRA (plural of spectrum)
b. Types of Visible Spectra
c. Doppler Effect (if time allows)
2. WRITE AROUND ExC-ELL strategy
a. Listen to directions – they are printed on the sheet at your group table
HOMEWORK
1. Be sure you have completed your CH#28 Preview
2. Be sure you have completed your CH#28 vocabulary words (10 diagrams – list on pg. 638)
a. Be sure your picture conveys the meaning of the word
b. CREATIVITY IS ENCOURAGED!!!
HAVE A GREAT DAY
Electromagnetic Spectrum
A. Electromagnetic Spectrum:
a. All forms of Radiant Energy
b. Emissions (energy) from Stars in the form of WAVES
c. Produced by Fusion (thermonuclear reaction: Hydrogen is fused to form Helium
in the core of stars)
d. Each Wavelength ( = lambda) is a different type of radiant Energy
e. WAVES:
λ
Radio Waves (longest )
Microwaves
Infra-Red
red
longest λ
orange
Visible Light
yellow
green
blue
Ultra Violet
violet shortest 
X-Rays
Gamma Rays (shortest )
A. Hot bodies (stars) emit mostly shorter wave radiations (UV, X-ray, Visible
light)
B. Cool bodies (planets) emit mostly long wave radiation (IR = ‘heat’ wave)
3 Types of visible Spectra
Visib
le
LIGH
T
Continuous Spectrum

All wavelengths of visible
light
“Rainbow” –
uninterrupted band of
colors
Continuum spectrum


EMISSION Spectrum





Synonym: Bright-Line spectrum
Unevenly spaced lines of different colors & brightness
Not all wavelengths represented
“fingerprint” of elements:
Every element
has its OWN
Continuous
Spectrum
(unique) emission spectrum
Example:
Produced by heated (hot) gases
ABSORPTION Spectrum


Emission Spectrum
Synonym:
Examples:
Synonym: Dark-line spectrum
Continuous spectrum withAbsorption
dark bands – represents
MISSING wavelengths
Spectrum
Visible
Lightwhen light from stars
 Produced
moves through a
Synonym:
cooler gas
o The dark lines appear
in the positions of the
Examples:
stars’ emission spectral lines
elements
in stars
Comparison of theIdentifying
ABSORPTION
Spectra from
stars to the
1.
Spectra
used:
EMISSION Spectra of the chemical elements indicates the
COMPOSTION of the Stars’ outer atmosphere
2. Description/Example:
Diagram an example of a Continuous, Emission, and Absorption
Spectrum at the top of each circle. Then complete the graphic
organizer.
Heated
Gas
Explain the differences in wavelength (size of wave) for each
color.
Why do you need a prism (or water) to see the colors?
Which wavelengths are shortest?
Which wavelengths are longest?
Where does visible light fall (short to long)?
Which waves are “dangerous”? WHY?
What type of visible spectra is each of these?
How do you know?
Are any of these the SAME (have the same bright-line pattern)?
WHY?
Why do the emission lines from the gas match the absorption spectral lines?
What must be true about the gas that produces the dark-line spectrum?
What is true about the gas producing the bright-line spectrum?
How can we “SEE” visible light spectra?
Hand-Held Spectroscope
1. Definition
2. Parts of the Spectroscope
3. Spectrograph
LAB: “What’s in a Color?”
Students use hand-held spectroscopes (like the example on the previous
page) to observe and draw (on a grid) the spectra they observe from:
Incandescent light bulb
Sunlight
Heated Gas tubes containing Helium, Hydrogen, Nitrogen
(observation only), and Neon (observation only)
REVIEW
http://spiff.rit.edu/classes/phys230/lectures/spectrographs/Fifteen.swf
The basic types of spectrum
When we pass light from a source through a spectrograph, we usually see one of three basic
types of spectrum, depending on the nature of the source. German astronomer Gustav Kirchoff,
working in the 1850s, figured out the reason for these different types of spectra. He explained the
three basic types of spectra as coming from three different situations:
1. Solids, liquids, and dense gases emit light of all wavelengths, without any gaps. We call
this a continuous spectrum.
2. HOT, thin gases emit light of only a few wavelengths. We call this an emission or bright
line spectrum.
3. If there is a source of light behind it, a thin gas will absorb light of the same wavelengths
it emits. We call this an absorption or dark line spectrum.
How can you tell what element/elements produced this spectrum?
From what you have learned about the 3 types of spectra and the SOURCE
of visible light, label and indicate the location of the absorption &
continuous spectra:
Interior of star
Atmosphere of star (2 locations)
Surface of star
Absorption spectrum produced
Continuous spectrum produced
Add to the diagram: What are the conditions needed for an emission
spectrum to form?
DOPPLER EFFECT
What happens to the sound when the siren APPROACHES the listener?
What happens to the sound when the siren moves AWAY FROM (recedes
from) the listener?
How does this apply to light?
What is occurring?
HOW does this apply to SOUND?
How does this apply to LIGHT?
WHAT does this mean?
Does this picture show RED shift or BLUE shift?
How do you know?
Is the object APPROACHING (coming toward) or RECEDING FROM (moving
away from) the viewer?
Is the source of THIS spectrum approaching or receding from the viewer?
How do you know?
What is the name of this shift?
The LARGER the shift, the FASTER the object is moving TOWARD or AWAY
FROM the viewer!