Cosmic Journey: Teacher Packet

Cosmic Journey: Teacher Packet

Compiled by:

Morehead State University Star Theatre

with help from Bethany DeMoss

Table of Contents

Table of Contents 1

Corresponding Standards 2

Vocabulary 4

Sizing up the Stars (Primary) 5

Spectroscopic Observations (Middle Grades) 11

The Life Cycles of Stars: These Stars are Classified (High School) 22

References 27

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Corresponding Standards: Cosmic Journey

Next Generation Science Standards

5-ESS1-1

Support an argument that differences in the apparent brightness of the sun

compared to other stars is due to their relative distances from Earth. [Assessment

Boundary: Assessment is limited to relative distances, not sizes, of stars.

Assessment does not include other factors that affect apparent brightness (such as

stellar masses, age, stage).]

6-ESS1-1

Develop and use a model of the Earth-sun-moon system to describe the cyclic

patterns of lunar phases, eclipses of the sun and moon, and seasons. [Clarification

Statement: Examples of models can be physical, graphical, or conceptual.]

6-ESS1-2

Develop and use a model to describe the role of gravity in the motions within

galaxies and the solar system. [Clarification Statement: Emphasis for the model is

on gravity as the force that holds together the solar system and Milky Way galaxy

and controls orbital motions within them. Examples of models can be physical

(such as the analogy of distance along a football field or computer visualizations of

elliptical orbits) or conceptual (such as mathematical proportions relative to the

size of familiar objects such as their school or state).] [Assessment Boundary:

Assessment does not include Kepler’s Laws of orbital motion or the apparent

retrograde motion of the planets as viewed from Earth.]

6-ESS1-3

Analyze and interpret data to determine scale properties of objects in the solar

system. [Clarification Statement: Emphasis is on the analysis of data from Earth-

based instruments, space-based telescopes, and spacecraft to determine similarities

and differences among solar system objects. Examples of scale properties include

the sizes of an object’s layers (such as crust and atmosphere), surface features

(such as volcanoes), and orbital radius. Examples of data include statistical

information, drawings and photographs, and models.] [Assessment Boundary:

Assessment does not include recalling facts about properties of the planets and

other solar system bodies.

HS-ESS1-2

HS-ESS1-2. Construct an explanation of the Big Bang theory based on

astronomical evidence of light spectra, motion of distant galaxies, and composition

of matter in the universe. [Clarification Statement: Emphasis is on the

astronomical evidence of the red shift of light from galaxies as an indication that

the universe is currently expanding, the cosmic microwave background as the

remnant radiation from the Big Bang, and the observed composition of ordinary

matter of the universe, primarily found in stars and interstellar gases (from the

spectra of electromagnetic radiation from stars), which matches that predicted by

the Big Bang theory (3/4 hydrogen and 1/4 helium).]

HS-ESS1-3

HS-ESS1-3. Communicate scientific ideas about the way stars, over their life

cycle, produce elements. [Clarification Statement: Emphasis is on the way

nucleosynthesis, and therefore the different elements created, varies as a function

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of the mass of a star and the stage of its lifetime.] [Assessment Boundary: Details

of the many different nucleosynthesis pathways for stars of differing masses are

not asses

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Cosmic Journey Vocabulary

Vocabulary Word Definition

Cosmic Microwave Background Radiation a form of electromagnetic radiation filling the universe created during the Big Bang

Star self-luminous gaseous spherical celestial body of great mass which produces energy by means of nuclear fusion reactions

Gravity

A natural force that cause two particles to move towards each other. The gravitational force is proportional to the mass of the two objects and inversely proportional to the distance between them.

Galaxy A group of stars, gas, and dust can be spiral, elliptical or irregular shaped held together by gravity

Nebula a cloud of dust and gas in interstellar space

Binary System two stars that orbit a common center of mass, appearing as a single star when visible to the unaided eye

Globular/Open Cluster a dense grouping of old stars

Planetary Nebulae A shell of gas ejected by a low mass star late in its evolutionary lifetime

Supernova

explosive end to a star’s life that occurs when the star is no longer in equilibrium, caused when gravitational forces in the star are overcome by interior pressure pushing outward

Milky Way our home galaxy, referred to as the barred galaxy due to shape of the central bulge and the shape of the galaxies arms

Light Years unit of length in astronomy equal to the distance that light travels in one Earth year (1

light year is 5,878,000,000,000 miles)

Sun yellow star located at the center of our Solar System, surface temperature is 10,000F and the core is 27 million Fahrenheit

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Sizing Up the Stars From: Stanford Solar Center

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Spectroscopic Observations From: Stanford Solar Center

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Teacher Overview

Materials List (continued)

••••• Spectroscopic ObservationsSpectroscopic ObservationsSpectroscopic ObservationsSpectroscopic ObservationsSpectroscopic Observations• Spectroscope

• Spectroscope poster (with scope template and directions)• To order this invaluable poster check the Web site:

http://solar-center.stanford.edu/poster• 11” x 17” spectroscope template sheet• 11” x 17” black card stock• Diffraction Grating

• Edmund Scientific 609-573-6250• Catalog # F39502 $23.60 for a package of 25• Catalog #F50183 $58.00 for package of 80

• Scissors• Straight edge (used to bend the cardboard)• Clear tape• Glue stick

• Gas tubes or Web site’s spectra for spectral analysis

• Student Guidesheet: Spectroscopic Observations #1, #2 & #3

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Science Exploration Guidesheet

Science Explorations (continued)

••••• Spectroscopic ObservationsSpectroscopic ObservationsSpectroscopic ObservationsSpectroscopic ObservationsSpectroscopic Observations

For these activities students will construct their own spectroscope, observe common lightsources, record their spectra and compare their findings with fellow classroom scientists.

For directions to build a spectroscope, see the Spectroscope Poster (purchase informationfound in the Materials List. Allow approximately 3 class sessions to construct and calibratethe spectroscopes before having students perform these science explorations.

Unlike a prism, which disperses white light into the rainbow colors through refraction, thediffraction grating used in this homemade spectroscope disperses white light through aprocess called interference The grating used for this spectroscope consists of a transpar-ent piece of plastic with many thousands of microscopic parallel grooves. Light passingbetween these grooves is dispersed into its component wavelengths and appears as paral-lel bands of color on the retina of the observer’s eyes.

••••• Spectroscopic Observation #1: Observing SpectraSpectroscopic Observation #1: Observing SpectraSpectroscopic Observation #1: Observing SpectraSpectroscopic Observation #1: Observing SpectraSpectroscopic Observation #1: Observing SpectraStudents observe common light sources, record their spectra and compare their findingswith fellow classroom scientists.

••••• Spectroscopic Observation #2: Mystery Gas TubesSpectroscopic Observation #2: Mystery Gas TubesSpectroscopic Observation #2: Mystery Gas TubesSpectroscopic Observation #2: Mystery Gas TubesSpectroscopic Observation #2: Mystery Gas TubesTeacher purchases in advance 3 - 5 gas tubes (recommended helium, hydrogen, mercury,neon and water). Do not tell the students what gas is found in each gas tube. Have stu-dents observe each tube using their spectroscopes and record their findings. Then, havethe students compare each spectrum with the Spectra Reference Chart (located on theWeb site or available to be printed on a color printer from this PDF file). Students can nextdetermine which gas is contained in each tube by comparing the spectra they observe andrecord to the reference chart.

••••• Spectroscopic Observation #3: Solar SpectrumSpectroscopic Observation #3: Solar SpectrumSpectroscopic Observation #3: Solar SpectrumSpectroscopic Observation #3: Solar SpectrumSpectroscopic Observation #3: Solar SpectrumHave students observe sunlight through their spectroscopes by using a white wall to reflectthe sun’s light. Do NOT have students view the sun directly through their spectroscopes.Do NOT have students view the sun directly through their spectroscopes.Do NOT have students view the sun directly through their spectroscopes.Do NOT have students view the sun directly through their spectroscopes.Do NOT have students view the sun directly through their spectroscopes.Students record the solar spectrum. Next, have students compare their solar spectrum withan actual solar spectrum from the Spectra Reference Chart. These will be different simplybecause of the difference in quality between the homemade device and the more precisescientific instrument. Then, review with the students the directions on how to identify ele-ments in the solar spectrum from the Student Guideheet: Solar Spectrum. Finally, have thestudents follow the same procedure and attempt to determine the other elements found inthe sun.

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Student Reading

Spectroscopy: Starlight, Star Bright

Spectroscopes are important tools for astronomy. They enable astronomers to analyzestarlight (and sunlight) by providing a measure of the relative amounts of red and bluelight a star gives off. Knowing this, astronomers can determine a star’s temperature.They can also deduce its chemical composition simply by observing and analyzing itslight.

Starlight is made up of photons. These photons originate from the inside of a star.There, pressures are enormous and nuclear fusion is triggered. Intense radiation isproduced as atoms, consisting of a nucleus surrounded by one or more electrons,collide with each other millions of times each second. The number of collisions de-pends on the temperature of the gas inside the star. The higher the temperature, thegreater the rate of collisions.

Because of these collisions, many electrons are boosted to higher energy levels, aprocess called excitation. The electrons spontaneously drop back to their originalenergy level. In doing so, they release energy as photons. This is what happens to thefilament of an electric light bulb or to an iron bar when it is heated in a furnace. Asthe temperature of the filament rises, it begins to radiate reddish light. When thefilament becomes even hotter, it radiates a bluish light. Thus, the color it radiates is anindicator of the filament’s temperature. Stars that radiate a great amount of red lightare much cooler than stars that radiate a great amount of blue light. Stellar spectratherefore can be used as a star thermometer.

One of the important applications of spectroscopes is their use for identifying chemicalelements. Each chemical element radiates light in specific wavelength combinationsthat are as distinctive as fingerprints. Knowing the “spectral fingerprint” of eachelement enables astronomers to identify the elements present in distant stars by ana-lyzing their spectra.

There are 3 kinds of spectra: continuous, absorption and emission.

When observed through a spectroscope, the continuous spectrum appears as a continuous bandof color ranging from red to violet.

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Student Reading

Spectroscopy: Starlight, Star Bright (continued)

An absorption spectrum happens when the light from a star passes through a cloud of gas beforereaching the spectroscope. For example, let’s say that light from a star passes through a cloud ofhydrogen gas before reaching the spectroscope. Some of the wavelengths of light will be ab-sorbed by the hydrogen atoms. This absorption will produce a spectrum that has a broad band ofcolor interrupted by dark lines. These dark lines represent the certain wavelengths of light thatwere absorbed by the hydrogen cloud.

An emission spectrum is observed when energy is absorbed by the gas atoms in a nebula and isreradiated by those atoms at specific wavelengths. This spectrum consists of bright lines against ablack background. The light from fluorescent tubes and neon lights produce emission spectra.

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Student Reading

Spectroscopy: Starlight, Star Bright (continued)

Stellar spectra allow astronomers to determine a star’s temperature and its chemical composition.This enables astronomers to classify stars into spectral categories, estimate their age andpostulate their life cycle. When available, astronomers prefer stellar spectra collected by orbitingspacecraft over spectra collected by Earth-based telescopes. The Earth’s atmosphere acts as afilter and can give inaccurate readings. Orbiting spacecraft are not affected by the Earth’satmosphere because they orbit above the atmosphere. These orbiting spectroscopes can alsocollect infrared, ultraviolet, x-ray and gamma ray bands that simply do not reach spectroscopeson the ground.

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Spectroscopic Observation #1: Observing Spectra

DirectionsDirectionsDirectionsDirectionsDirections: Use your spectroscope to observe and record the spectrum for 3 light sources givenbelow. Then choose 2 light sources of your own (for example: streetlight, neon signlight, Television light, computer monitor screen light) and record your spectroscopicobservations. Do NOT choose the sun for this activity. When you’re finished com-pare your results with your classroom scientists.

1.1.1.1.1. Light Source: fluorescent lights in the classroomLight Source: fluorescent lights in the classroomLight Source: fluorescent lights in the classroomLight Source: fluorescent lights in the classroomLight Source: fluorescent lights in the classroom

2.2.2.2.2. Light Source: soft-white lightbulbLight Source: soft-white lightbulbLight Source: soft-white lightbulbLight Source: soft-white lightbulbLight Source: soft-white lightbulb

3.3.3.3.3. Light Source: ____________________________Light Source: ____________________________Light Source: ____________________________Light Source: ____________________________Light Source: ____________________________

44444..... Light Source: ____________________________Light Source: ____________________________Light Source: ____________________________Light Source: ____________________________Light Source: ____________________________

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Spectroscopic Observation #2: Mystery Gas Tubes

DirectionsDirectionsDirectionsDirectionsDirections: Observe and record using your spectroscope the spectrum for each mystery gastube. Then use the Spectra Reference Chart to identify what element is in each tube.

1.1.1.1.1. Mystery Gas Tube #1: ____________________________Mystery Gas Tube #1: ____________________________Mystery Gas Tube #1: ____________________________Mystery Gas Tube #1: ____________________________Mystery Gas Tube #1: ____________________________





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Spectra Reference Chart

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Spectroscopic Observation #3: Solar Spectrum

To figure out what elements a star is burning for fuel, scientists compare a star’s absorptionspectrum to the emission spectrum of an element found on earth. Let’s look at the Sun’s Spectrum.

Notice where the dark lines occur. Note the number and color where the dark lines are located.

Next, look at the emission spectrum for hydrogen. Look closely at the red and blue lines.

Is the red line located in the same place on the hydrogen spectrum as a dark line in the red areaof the solar spectrum?

Is the thick, blue line in the same place on the hydrogen spectrum as a thick, dark line in the bluearea of the solar spectrum?

Is the thin, blue line in the same place on the hydrogen spectrum as a thin, dark line in the bluearea of the solar spectrum?

You should have answered “yes” to all three questions.

So, if the colored lines from the helium spectrum match exactly to the location of the black lines inthe same colored areas on the solar spectrum, then that means that the sun is burning hydrogen.

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Spectroscopic Observation #3: Solar Spectrum (continued)

Follow this same procedure to compare the other elements found on the Spectra Reference Chartto the Solar Spectrum and list below the elements that the sun is burning. Then, draw the emissionspectrum for each element given.

1.1.1.1.1. hydrogenhydrogenhydrogenhydrogenhydrogen

2.2.2.2.2. ___________________ ___________________ ___________________ ___________________ ___________________

3.3.3.3.3. ___________________ ___________________ ___________________ ___________________ ___________________

4.4.4.4.4. ___________________ ___________________ ___________________ ___________________ ___________________

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The Life Cycles of Stars: These Stars are Classified From: Stanford Solar Center

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Reference for Activities

Sizing up the Stars

Ashby, S., Mortfield, P., Hoeksema, T., Chaussee, A. “All About the Sun, Suns and Stars.”

Stanford Solar Center and NASA. (n.d) 9, 14-15, 36-37. Web. 1 July 2014.

Spectroscopic Observations

Ashby, S., Mortfield, P., Hoeksema, T., Chaussee, A. “All About the Sun, Suns and Stars.”

Stanford Solar Center and NASA. (n.d) 11, 21, 33-35,41-45. Web. 1 July 2014.

The Life Cycle of Stars: These Stars are Classified

Whitlock, L., Granger, K. “The Life Cycles of Stars.” Imagine the Universe. (n.d.) 7-10). Web. 1

July 2014. <http://imagine.gsfc.nasa.gov>

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Cosmic Journey: Teacher Packet

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