Awesome Light III: Teacher Packet

Home , Albireo, Henrietta Swan Leavitt

Compiled by: Morehead State University Star Theatre with help from Bethany DeMoss

Table of Contents

Table of Contents 1

Corresponding Standards 2

Vocabulary 4

Starry Night Activity Pack (Primary) 6

The Milky Way (Middle Grades) 17

The Universe: Big Bang Balloon (High School) 21

References 24

1 Corresponding Standards: Awesome Light III

Next Generation Science Standards

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 5-ESS1-1. include other factors that affect apparent brightness (such as stellar masses, age,

stage).] 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 06-ESS1-2. 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.] 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 06-ESS1-3. 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.] Develop a model based on evidence to illustrate the life span of the sun and the role of nuclear fusion in the sun’s core to release energy that eventually reaches Earth in the form of radiation. [Clarification Statement: Emphasis is on the energy transfer mechanisms that allow energy from nuclear fusion in the sun’s core to reach Earth.

Examples of evidence for the model include observations of the masses and HS-ESS1-1. lifetimes of other stars, as well as the ways that the sun’s radiation varies due to

sudden solar flares (“space weather”), the 11-year sunspot cycle, and non-cyclic variations over centuries.] [Assessment Boundary: Assessment does not include details of the atomic and sub-atomic processes involved with the sun’s nuclear fusion.] 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 HS-ESS1-2. 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),

2 which matches that predicted by the Big Bang theory (3/4 hydrogen and 1/4 helium).] Communicate scientific ideas about the way stars, over their life cycle, produce elements. [Clarification Statement: Emphasis is on the way nucleosynthesis, and HS-ESS1-3. therefore the different elements created, varies as a function 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 assessed.] Use mathematical or computational representations to predict the motion of orbiting objects in the solar system. [Clarification Statement: Emphasis is on Newtonian HS-ESS1-4. gravitational laws governing orbital motions, which apply to human-made satellites as well as planets and moons.] [Assessment Boundary: Mathematical representations for the gravitational attraction of bodies and Kepler’s Laws of orbital motions should not deal with more than two bodies, nor involve calculus.]

KY Department of Education Social Studies Standards

Students interact effectively and work S.S 2.17 (5th) cooperatively with the many ethnic and cultural groups of our nation and world. Students interact effectively and work S.S 2.17 (6th) cooperatively with the many diverse ethnic and cultural groups of our nation and world.

3 Awesome Light III Vocabulary

Older

Vocabulary Words Definition Satellite 1. object put into orbit around Earth or another planet in order to relay communications signals or transmit scientific data Galactic Plane Plane passing through a galactic center Telescopes instrument used for viewing distant astronomical objects Star a self-luminous gaseous spherical celestial body of great mass which produces energy by means of nuclear fusion reactions Mars 1. third smallest planet in the solar system and the fourth planet from the Sun. Jupiter Fifth planet from the sun and largest planet in our solar system Comet A group of small objects orbiting the sun that are composed of ice and dust, when a comet approaches close enough to the sun it can produce a long luminous tail Gas Giants 1. a class of a large, low-density planets composed primarily of hydrogen, helium, methane, and ammonia in either gaseous or liquid state (Jupiter) Universe all of space and everything in it including the galaxies, stars, planets, gases, and dust etc. 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 Binary System two stars that orbit a common center of mass, appearing as a single star when visible to the unaided eye

Awesome Light III Vocabulary

Younger

Vocabulary Words Definition Satellite 2. object put into orbit around Earth or another planet in order to communicate with Earth Telescopes Tool used for viewing distant objects in the sky Star point of light in the sky Mars 1. third smallest planet in the solar system and the fourth planet from the Sun. Jupiter Largest planet in the solar system Comet object in the sky that is identified by its long luminous tail Gas Giants 2. a large, low-density planet (Jupiter) Supernova explosive end to a star’s life Binary System two stars that are close together and appear as one star Constellations group of stars that form a pattern in the sky

Starry Night Activity Packet From: Starry Night Education

6 Lesson Plan G2 Activity Part Two • Student worksheets The Stars • Pens or pencils Activity Part Three • 1 small flashlight Introduction • 1 large and bright flashlight • A room that can be darkened We see the stars as tiny points of light in the sky. They may all look the same but they are not. They range in size, color, temperature, power, and Time Required life spans. Hands-on Activity Part One: 10 minutes In these hands-on and Starry Night computer Hands-on Activity Part Two: 30 minutes exercises, your students will explore the nature Hands-on Activity Part Three: 10 minutes of stars. They will see how different from one Starry Night Computer Exercise: 35-45 minutes another individual stars can be. They will observe a glowing body as it changes temperature and color. Your students will plot some Conceptual Background properties of stars and learn how these different properties of stars are related to one another All stars form from cold clouds of hydrogen gas and to the mass of the star. They will learn that that collapse under their own gravity. The center the apparent visual brightness of a star is not a of the cloud heats up from the resulting increase good indicator of its distance. In Starry Night in pressure and friction. Eventually the heat and they will examine several different stars and pressure are great enough to force hydrogen they will see how some stars end their lives. nuclei to fuse together and form helium nuclei. This nuclear fusion process releases energy and the star shines with its own light. Key Concepts Stars are made of mostly hydrogen, which is Stars are born, evolve and die. the most abundant element in the universe. Stars Stars have a life cycle that depends on the use hydrogen as a building block to make heavier initial mass of the star. elements. As a star ages it fuses hydrogen into The composition and structure of stars helium, and later the helium will be fused into changes at different stages in their life cycle. a series of increasingly heavier elements. As Stars in the Milky Way can be different from the stars age and continue the fusion process, the Sun in size, temperature, age and brightness. percentage of hydrogen in the stars decreases The Sun is a main sequence star. and the percentage of other heavier elements Stars can be described as having apparent increases. The heaviest elements are fused in magnitude, absolute magnitude and luminosity. the most massive stars. This planet and all that it Other planets orbit around other stars. contains, plus other planets in the solar system Elements heavier than lithium are created in and around other stars, comes from the star-for- the cores of stars. mation process.

Most of the characteristics of a star are gov- Materials Required erned by how much mass the star contains when it first forms. Low mass stars survive for Activity Part One billions of years. They burn their fuel slowly • Small lamp with a clear (not frosted) bulb and at low temperatures. They die a quiet death • Electrical socket with a dimmer switch and leave behind a small white dwarf star that (rheostat) slowly cools into a black dwarf.

7 www.starrynight.com G2.1 Starry Night High School High mass stars only survive for a few million years. They burn their fuel at extremely high temperatures and rates. Big stars die in spectacular supernova explosions. The supernova can leave behind either a neutron star or a black hole. Electrical Outlet Even in a telescope, stars are so far away that Lamp with they look like tiny points of light. But stars come unfrosted bulb. in a range of sizes, colors, temperatures, energy outputs, and life spans. Most stars are small, dim, red, and cool. They are so small and dim that we can’t see them. When we look into the night sky we see mostly the big, hot, and bright stars.

We think of the Sun as an average star. But if we look at all the stars in the Milky Way galaxy, Rheostat we find that 90 per cent of them are smaller, (Dimmer switch) dimmer and cooler than the Sun. So, although the Sun fits in the middle of the range of stellar properties, it is bigger, brighter and more powerful than most of the stars in our galaxy.

Activity Part One Figure G2.1 Set up to demonstrate the relationship between color and temperature. Stars are hot, glowing objects. This activity is a simple demonstration that shows the relationship between the temperature and color of another hot, glowing object. Our Earth-based experiences often give us the idea that blue is cool or cold, Activity Part One and red is hot, as in “red hot.” With stars, the Discussion Questions opposite is true. It’s all a matter of scale. A. When the lamp is turned down very low, 1. Set up the lamp with the clear, unfrosted what color is the filament in the bulb? bulb so all the students can easily see it. B. When the lamp is turned on full power, is 2. Plug the lamp into a rheostat or an electrical the filament hotter or cooler than when it outlet that is connected to a dimmer is turned down low? switch. C. What color is the filament when the lamp 3. Darken the room. is turned on at full power?

4. Turn on the lamp and dim it until it is just D. What progression of colors did you observe barely on. as the lamp was turned from minimum power up through full power? 5. Ask the students to observe and note the color of the glowing filament in the bulb. E. At what power level did the lamp glow most brightly? Why? 6. Slowly turn up the bulb so it gets brighter and brighter (hotter and hotter). Many students think of something very hot as 7. Have the students observe and note the being “red hot.” They seldom think of blue as changing color of the glowing lamp filament. being a “hot” color. With the lamp turned down to a minimum, the filament glows a dim red

8 Starry Night High School G2.2 www.starrynight.com color. The filament glows because it is hot, but it Activity Part Two can get much hotter and glow much more brightly. This is a graphing activity that shows the rela- As the lamp is turned up the filament receives tionship between color, temperature and mass more power. It gets hotter and glows brighter. in stars. Table G2a Star Comparison Chart Its color progresses from dim red to orange to gives data for 12 stars. yellow to white. As it gets hotter it glows brighter. There is a relationship between the Your students will use this data to make a temperature and the color of the glowing fila- Hertzsprung-Russell (H-R) diagram that plots ment. If the filament could be made to glow star color versus temperature. A clear relation- even hotter, it would progress from white to ship will emerge. Astronomers call this curve blue in color. At even higher temperatures it on the graph the main sequence. The main would glow with invisible ultraviolet light. sequence is where stars spend most of their lifetimes. Main sequence stars are powered by Most students have seen this color progression hydrogen fusion. from red through yellow to blue in the flame of a propane torch or a propane camp stove. The As you examine the data in Table G2a, you will cool flame is red or orange and the hottest notice a pattern that follows through, more or flame is blue. The same color progression holds less, in descending order, for color, temperature, true for the stars. The coolest stars at 3,000 mass and power. degrees Celsius glow red. The hottest stars have surface temperatures in the tens of thousands of The students’ plots should look similar to the degrees and they glow with a fierce blue light. one shown in figure G2.2. Such stars are extremely bright, powerful, and easy to see from great distances. Much of their radiation is in the form of energetic ultraviolet, X-ray and gamma radiation.

Table G2a Star Comparison Chart

Star Color Temperature in Mass in terms Power in Radius in terms Distance in degrees Celsius of solar mass Suns of Solar Radii Light Years

Sun Yellow 5,700 1 1 1 8 light min. Proxima Centauri Red 2,300 0.1 Unknown Unknown 4 Barnard’s Star Red 3,000 0.1 0.01 0.2 6 Epsilon Eridani Orange 4,600 0.1 0.4 0.8 11 Alpha Centauri Yellow 6,000 1 2 1.4 4 Altair White 8,000 3 12 2 17 Vega White 9,900 3 61 3.3 25 Sirius White 10,000 3 27 2 8.6 Rigel White 10,000 3 52,000 92 777 Regulus White 11,000 8 221 4.3 78 Hadar Blue 25,500 20 79,000 24 526 Alnilam Blue 27,000 20 112,000 44 1,360

9 www.starrynight.com G2.3 Starry Night High School 1. Give each student a Hertzsprung-Russell D. Look carefully at the data in table G2a. Can diagram worksheet. you see a relationship between power, color and temperature? 2. Use the data from Table G2a to plot each of the 12 stars on the H-R diagram. Star E. Where does the Sun fit into the pattern? color is on the horizontal axis and star temperature is on the vertical axis. Stars come in different sizes and they produce 3. Label each star’s data point with the name different amounts of energy. The energy a star of the star. produces is related to its temperature and color. White and blue stars burn their fuel at the highest 4. Draw a curve as best you can that joins the temperatures. They produce the most energy, data points smoothly. and are the most powerful and most luminous stars. These stars are also the most massive stars. 5. On the outer vertical axis labeled “Mass in Solar Masses” mark the value of each Mass is everything to a star. More mass means star’s mass in terms of solar mass. more self-gravity so the star presses in on itself more strongly. This means it gets hotter in the core than a smaller star, so it burns faster and at a much higher temperature. Because it burns Activity Part Two hotter it also gives off more energy than a Discussion Questions smaller, cooler star.

A. Is there a relationship between the color and The Sun fits in the middle of the range of stellar temperature of a star? properties. It is a yellow star. Compared to other stars, it is neither very hot nor very cool. It is B. What is the relationship between color and neither very massive nor very powerful. Because temperature? of this we think of the Sun as an average star.

C. Generally speaking, are the most massive stars also the hottest?

20 30,000

Alnilam

Hadar 24,000

18,000

12,000 Regulus 8 Rigel Sirius 3 Vega Altair 1 Alpha Centauri 6,000 Sun 0.1 Epsilon Eridani

Mass in Solar Masses in Degrees Celsius Temperature Barnard’s Star 0 Proxima Centauri 0 Blue White Yellow Orange Red

Figure G2.2 Your students’ star plots should look similar to this illustration.

10 Starry Night High School G2.4 www.starrynight.com Activity Part Three Activity Part Three Discussion Questions The thing we notice first about stars is that some are brighter or dimmer. It looks as though A. If you didn’t know which flashlight was the brighter ones are closer to us and the dimmer which, would you be able to tell which one ones are further away from us. We have just produced the most light? learned that stars vary a lot in the energy, and therefore the amount of light, they produce. B. From this exercise, and the data in table G2a, what conclusion can you draw about This is a simple demonstration activity to prove the stars Rigel and Sirius? that the apparent brightness of a star cannot be used to judge its distance. This is one of the most fundamental questions 1. Place the small flashlight on a desk or table about the stars. Is it bright because it is close, near the front of the room. or is it bright because it is intrinsically bright? This is why astronomers must know the dis- 2. Place the large flashlight on a desk or table tance to a star. Without knowing the distance, near the back of the room. it’s hard to get meaningful information about the other properties of the star. Some stars look 3. Have the students gather at the front of the bright because they are very near the Sun. Others room so they can all see both flashlights look equally bright but are many times further easily. away from the Sun. These more distant stars are extraordinarily bright. Without knowing the 4. Turn on both flashlights. distance it’s impossible to distinguish between the two. 5. Darken the room. The two flashlights can be compared to the stars 6. Observe and compare the apparent Sirius and Rigel. Sirius is about twice as bright brightness of the two flashlights. as Rigel, but Rigel is almost 100 times further away than Sirius. Sirius is about 27 times as 7. Move the two flashlights back and forth powerful as the Sun, but Rigel has the power of until they both appear to have the same many thousands of Suns. Sirius looks very bright brightness. because it is close. If Rigel were as close as Sirius it would be blindingly bright.

Large Flashlight Small Flashlight Observer Far from observer the large Close to observer small flashlight looks dimmer flashlight looks brighter than small flashlight than the large flashlight.

Figure G2.3 Two flashlights of different power placed at different distances can be used to demonstrate that apparent brightness is not a good indicator of distance.

11 www.starrynight.com G2.5 Starry Night High School Starry Night Computer Exercise Lesson G2: The Stars

Even a cursory examination of the night sky shows Stellar evolution is a complex subject but students that not all stars are the same -- some are brighter, should be able to understand that in general, hot some are fainter. A more careful inspection will show bluish stars are young, yellowish stars are middle-aged that star colors are not the same. But the difference is and large reddish stars are near the end of their life. subtle. Astronomers can deduce a lot of information about stars from their properties. This exercise examines some Students might be interested in using the interactive of these. H-R diagram on other stars. The status pane can be used whenever catalogued stars are visible in the main Teaching Strategies window. (Some stars do not have sufficient data to be plotted on the H-R diagram) Students should be aware that all values entered in the database are approximate and subject to errors. If a small telescope is available, it is strongly suggested Indeed, different sources will give different values for that observations of some colorful stars like Albireo be most of the parameters. attempted.

Colors are difficult to detect and have been exaggerated Students can be expected to complete this exercise in in Starry Night. If a more realistic appearance is desired, 35 to 45 minutes. see Using Starry Night in the Appendix of this binder on how to change color saturation.

Conclusion Lesson Specific Resources

Stars are not simple points of light. After SkyGuide completing these activities and exercises, Guided Tours>Our Solar System, the Stars and students should know that stars have a range Galaxies> The Stars of properties. They should understand that the Guided Tours>Our Solar System, the Stars and color, temperature and mass of a star are inter- Galaxies> Nebulae related. Students should know that the mass of a star governs everything about the star. Students Guided Tours>Our Solar System, the Stars and should know the apparent brightness of a star Galaxies> Novas and Supernovas cannot be used to judge its distance.

12 Starry Night High School G2.6 www.starrynight.com Lesson Plan G2 The Stars Student Worksheet: Hertzsprung-Russell Diagram

Table G2a Star Comparison Chart Use the information in this table to help build your own H-R diagram.

Star Color Temperature in Mass in terms Power in Radius in terms Distance in degrees Celsius of solar mass Suns of Solar Radii Light Years

20 30,000

24,000

18,000

8 12,000 3

1 6,000 0.1 Mass in Solar Masses in Degrees Celsius Temperature 0 0 Blue White Yellow Orange Red

13 www.starrynight.com G2.7 Starry Night High School Starry Night Computer Exercises Name: Lesson G2: The Stars Class:

Instructions for the Student

Click on the SkyGuide pane, choose Student Exercises > G – Stars > G2: The Stars and follow the instructions given. Record your answers to the questions in the spaces provided. Leave the last column blank for now.

Right click on each star and choose “Show Info” from the menu. Under the headings “Position in Space” and “Other Data” you will find all the information you need to complete the chart.

Star Database

Star Color Distance Radius Apparent Temperature Luminosity from Sun in compared magnitude in Kelvins light years to Sun

Sirius

Aldebaran

Pollux

Capella

Procyon

Orange

Return to SkyGuide to complete the rest of the exercise.

Question 1: Colorful stars

a) Do all stars have approximately the same temperature? Explain.

b) What seems to be the color of stars that have a temperature in the 3000’s degrees?

Continued next page

14 Starry Night High School G2.8 www.starrynight.com Lesson G2: The Stars c) Pick any other orange star in the main window and enter its name and temperature in the table. Was your prediction in b) correct?

d) Are all stars about the same size?

e) Do stars always appear brighter when they’re closer to us? Explain.

f) Do bigger stars always appear brighter to us? Explain.

Question 2: In the beginning

Why are stars born in a nebula?

Question 3: Going out gently

Why is the central star of the nebula difficult to see?

Question 4: Going out with a bang

The Crab Nebula requires a telescope to see. Telescopes were not invented until the 1600’s. How could the supernova have been seen in 1054?

Continued next page

15 www.starrynight.com G2.9 Starry Night High School Lesson G2: The Stars

Question 5: The H-R Diagram

All the stars shown in the main window are plotted on the H-R diagram. Point to any star in the main window and a red dot will show its position on the H-R diagram. Go ahead, try it!

a) Now let’s fill in the last column on your Star Database. Record to what group each star in your database belongs. (i.e. red giant, main sequence etc)

b) To what group do you think the star Rigel belongs? (Hint: read the introduction carefully)

Return to SkyGuide to complete the Extra Credit for this exercise.

Extra Credit

a) What appear to be the colors of Albireo and its companion?

b) What do the colors of these two stars tell us about their surface temperatures?

c) How would you find Albireo in the summer sky?

16 Starry Night High School G2.10 www.starrynight.com

The Milky Way From: The University of Texas at Austin (McDonald Observatory)

17 The Milky Way

Stretching across the dark night sky, not easily visible when the Moon GE OF THE ILKY AY is in the sky, is a faint irregular glowing strip of light. For thousands of A M W years peoples of various cultures tried to explain what they saw, some- The Milky Way arches high overhead times using stories. Here are some examples: this evening.This subtle band of light is the combined glow of Chinese millions of stars, which outline The seventh Princess of Heaven fell in love with a poor herdsman and the flat disk of our Milky Way Galaxy. ran away to marry him. When her mother sent soldiers to bring her Everything about the Milky Way is home, the herdsman chased them away. Seeing her daughter’s husband gigantic. Its disk spans 100,000 light- running, the mother dropped a silver pin to make a silver stream to sepa- years, and contains hundreds of bil- rate the lovers forever. Eventually, her father allowed her to have an lions of stars. And according to a team annual reunion led by University of Texas astronomer with her husband Globular Clusters Chris Sneden, it’s about 14 billion — black birds Edge-on Milky Way years old, give or take a few billion. escorted her Sun Astronomers arrived at this age by across the stream. measuring the age of a single star.The The Milky Way is galaxy can’t be any YOUNGER than its that silver stream. oldest stars, so this technique yields a The young lovers MINIMUM age for the Milky Way. are the stars Vega and Altair on 27,000 light-years Astronomers determined the star’s either side of it. 100,000 light-years

age by measuring its chemistry. They TIM JONES found that it contains only minute Navajo traces of anything heavier than hydro- When the world was created, the people gathered around Black God to gen and helium, the two lightest ele- place stars in the sky. Coyote was frustrated by how long it was taking. ments.That alone shows that the star He threw the bag of stars over his head, forming the Milky Way. must have formed early in the history of the Milky Way, since heavier ele- Egyptian ments were forged inside stars, then The goddess Isis spread large quantities of wheat across the sky. We see expelled into space, where they could this bounty as the Milky Way. be incorporated into NEW stars. One of the most important tracers African Bushmen of the star’s age is a radioactive ele- The Milky Way is made of the ashes of campfires. ment called thorium.The star contains only about half as much thorium as Polynesian expected.Thorium has a half-life of 14 The Milky Way is a long, blue, cloud-eating shark. billion years. In other words, in 14 billion years, half the star’s thorium Greek should have turned into other ele- The Milky Way is along the circular path where the Sun once moved ments. Since half of the thorium has across the sky. It looks different than the rest of the sky because the Sun disappeared, astronomers deduce that scorched it. the star is about 14 billion years old — and so is the Milky Way. ACTIVITY 1 Show students a picture of the Milky Way. Read several of the selections above. Tell them to work in groups to make up a story and picture that explains how someone living thousands of years ago in their location might have explained it. When the pictures are done, have each group present its report. For a link to Social Studies, have them choose a civi- lization to research to discover what important elements of their culture are reflected in these stories.

18 24 S TARD ATE/UNIVERSO T EACHER G UIDE NATIONAL SCIENCE EDUCATION STANDARDS BACKGROUND Galileo, the first person to look at the sky with a telescope, discovered • Content Standard in 9-12 Science as that the Milky Way is actually made up of countless faint stars. Other Inquiry (Abilities necessary to do sci- astronomers discovered it also had many star clusters and nebulae entific inquiry) (clouds of gas and dust). In the 20th century, astronomers put together • Content Standard in 9-12 History clues from many types of observations to deduce that we live at the edge and Nature of Science (Science as of a spiral arm in the Milky Way galaxy. Because we are in the arm, we a human endeavor, Historical per- look at the rest of the galaxy edge-on and don’t easily see its structure. If spectives) we could take a picture of the Milky Way from a vast distance, we would see it as a majestic cosmic pinwheel. The Sun is just one of hundreds of billions of stars in the Milky Way galaxy. The stars in the arms are young, and many of them are hot and blue. The stars in the core and between the spiral arms are mostly older and redder.

ACTIVITY 2 Examine color pictures of spiral galaxies. Using them as examples, take yellow and red fluorescent poster paint to make a nucleus-shape in the center of a piece of black paper. Add blue spiral arms swirling out from the center. Within the arms, glue small pieces of cotton balls to indicate the gaseous nebulae. Add a flag attached to a toothpick saying “You are here” to indicate the Sun’s position about two-thirds of the way from the center, on the edge of a spiral arm. 2MASS/IPAC

Seen from a distance, our Milky Way galaxy would look something like the two majestic spirals at left. From our earthly vantage point, infrared telescopes can I (2)

C peer through the intervening dust into the heart of the Milky Way (above, in red),

STS 27,000 light-years away. 19 S TARD ATE/UNIVERSO T EACHER G UIDE 25 The Milky Way

Texas Essential Knowledge and Skills

Science, grade 8: §112.20.(b)-8(A) describe components of the universe, including stars, nebulae, and galaxies, and use models such as the Herztsprung- Russell diagram for classification. §112.20.(b)-8(B) recognize that the Sun is a medium-sized star near the edge of a disc-shaped galaxy of stars and that the Sun is many thousands of times closer to Earth than any other star.

Astronomy, grades 9-12:

§112.33.(c)-4(A) research and describe the use of astronomy in ancient civilizations such as the Egyptians, Mayans, Aztecs, Europeans, and the native Americans. §112.33.(c)-4(B) research and describe the contributions of scientists to our changing understanding of astronomy, including Ptolemy, Copernicus, Tycho Brahe, Kepler, Galileo, Newton, Einstein, and Hubble, and the contribution of women astronomers, including Maria Mitchell and Henrietta Swan Leavitt. §112.33.(c)-6(C) examine the scale, size, and distance of the stars, Milky Way, and other galaxies through the use of data and modeling. §112.33.(c)-12(B) recognize the type, structure, and components of our Milky Way galaxy and location of our solar system within it.

The Universe: Big Bang Balloon From: Discovery Channel School’s Curriculum Center

21 hands-on activities The Universe

Big Bang Balloon

Background Information In the 1920s astronomer Edwin Hubble used the red shift of the spectra of stars to determine that the universe was expanding. By carefully observing the light from galaxies at different distances from Earth, he determined that the farther something was from Earth, the faster it seemed to be moving away. This relationship has become known as Hubbleís Law, and itís just one piece of a bigger puzzle known as the Big Bang theory.

Developed over many years and by many people, the theory states that about 15 billion years ago the universe was compressed into an infinitely small space, known as the primordial atom. It exploded in a sudden burst of energy and created a small, superdense, extremely hot universe that began to expand in all directions. Over time things cooled, and tiny bits of matter clumped together to form stars and galaxies. As a result of this explosion, all of these objects are still moving away from each other. In this experiment, you'll create a simple model to learn how the universe expands over time.

What You Need ï 12-inch (30-cm) round latex balloon ï a permanent felt-tip marking pen ï 24-inch (60-cm) piece of string ï metric ruler

What to Do 1. Inflate your balloon until it is about 4 inches (10 cm) in diameter, but do not tie the end. 2. Using the felt-tip marker, make six dots on the balloon in widely scattered locations. Label one dot "home" and the others A-E. The home dot represents the Milky Way galaxy, and the others represent galaxies formed in the early universe. 3. Without letting air out of the balloon, use the string and ruler to measure the distance from home to each dot. Record the distances in the worksheet table under the heading "Time 1." 4. Inflate the balloon so that its diameter is about 2 inches (5 cm) bigger. Again measure the distances to each of the dots, and record the distances under "Time 2" on the worksheet. 5. Inflate the balloon in 2-inch (5-cm) increments three more times. After each inflation, measure and record the distances on the worksheet. 6. Answer the follow-up questions on the worksheet.

http://www.discoveryschool.com/curriculumcenter/universe

22 hands-on activities The Universe Big Bang Balloon Worksheet

Name:

Record your measurements below.

Distance Time 1 Time 2 Time 3 Time 4 Time 5 from home

Dot A

Dot B

Dot C

Dot D

Dot E

How did the distance from the home dot to each of the other galaxies change each time you inflated the balloon?

Did the galaxies near home or those farther away appear to move the greatest distance?

How could you use this model to simulate the ìBig Crunch,î a time when all the galaxies might collapse in on themselves?

http://www.discoveryschool.com/curriculumcenter/universe

23 References for Activities

Starry Night Activity Pack

"Starry Night." Starry Night. Starry Night, n.d. Web. 14 July 2014.

The Milky Way

"Classroom Activities and Resources." McDonald Observatory. The University of Texas at Austin, McDonald Observatory, Apr. 2011. Web. 14 July 2014. .

The Universe: Big Bang Balloon

The Universe. Boston: Pearson Prentice Hall, 2006. Dsicovery Channel Schools. Discovery Channel School's Curriculum Center. Web. 14 July 2014. .