Section: Stars Pages 32-38 Study Guide Chapter 2 Circle the letter of the best answer for each question. 1. What do scientists study to learn about stars? a. gravity c. space b. starlight d. colors COLOR OF STARS 2. How do scientists tell if a star is warm or cool? a. by its size c. by its color b. by its age d. by its shape 3. Which star is a cool star? a. a red star c. a blue star b. a white star d. a purple star 4. Which star is warmest? a. a red star c. a blue star b. a yellow star d. an orange star COMPOSITION OF STARS 5. What is a star made of? a. many kinds of gases c. both gases and solids b. many kinds of solids d. gases, solids, and liquids 6. What makes up a star s inner layers? a. cool gases c. red gases b. cool and dense gases d. hot and dense gases 7. What makes up a star s outer layers? a. cool gases c. hot gases b. dense gases d. hot and dense gases Holt Science and technology 14 Stars, Galaxies, and the Universe
The Colors of Light Read the words in the box. Read the sentences. Fill in each blank with the word or phrase that best completes the sentence. emission lines spectrograph continuous spectrum 8. The band of colors that make up white light is called a(n). 9. A spectrum that shows all the colors is called a(n) spectrum. 10. A tool that breaks a star s light into colors is called a(n). 11. Hot gases give off wavelengths of light that appear as. Trapping the Light Cosmic Detective Work 12. Why do lines appear in a star s spectrum? a. Its atmosphere absorbs some colors. b. Its atmosphere gives off colors. c. They show cool spots. d. They show hot spots. 13. What color are the lines that appear in a star s spectrum? a. green c. black b. yellow d. red Identifying Elements Using Dark Lines 14. What kind of spectrum does a star have? a. absorption spectrum b. continuous spectrum c. emission spectrum d. nuclear spectrum 15. What do the patterns of color in a star s spectrum show? a. how hot the star is b. how cool the star is c. some of its elements d. all of its elements Holt Science and technology 15 Stars, Galaxies, and the Universe
CLASSIFYING STARS 16. How did early scientists group stars? a. by their size c. by their temperature b. by their age d. by their elements Differences in Temperature 17. How do scientists now group stars? a. by their size c. by their temperature b. by their age d. by their elements 18. Which color star is the hottest? a. yellow c. orange b. blue d. red Differences in Brightness 19. What is a star s magnitude? a. its temperature c. its size b. its brightness d. its age 20. Which of these stars is the brightest? a. a first-magnitude star c. a second-magnitude star b. a third-magnitude star d. a sixth-magnitude star 21. What is the magnitude of Sirius, the brightest star in the night sky? a. 1.4 c. 9.8 b. 1.4 d. 9.8 Holt Science and technology 16 Stars, Galaxies, and the Universe
HOW BRIGHT IS THAT STAR? Apparent Magnitude Read the words in the box. Read the sentences. Fill in each blank with the word or phrase that best completes the sentence. absolute magnitude Apparent magnitude 22. How bright a star seems to be is called. 23. The actual brightness of a star is called. Holt Science and technology 17 Stars, Galaxies, and the Universe
Section: The Life Cycle of Stars Pages 40-45 THE BEGINNING AND END OF STARS Circle the letter of the best answer for each question. 24. What keeps a star from breaking apart? a. gravity b. energy c. mass d. density 25. During which stage of the life cycle is a star a ball of gas and dust? a. first stage b. second stage c. third stage d. last stage 26. What gas does hydrogen change into as a star becomes hotter? a. uranium b. helium c. gravity d. carbon DIFFERENT TYPES OF STARS 27. Which of the following is NOT a type of star? a. main-sequence stars b. supergiants c. white dwarf stars d. spectrum stars Main-Sequence Stars 28. What is the longest stage of a star s life cycle? a. first b. second, or main sequence c. third d. last Holt Science and technology 18 Stars, Galaxies, and the Universe
29. What type of star generates a lot of energy? a. main sequence b. red giant c. white dwarf d. supergiant Giants and Supergiants 30. What type of star becomes large and cool as it loses hydrogen? a. main sequence b. red giant c. white dwarf d. red dwarf White Dwarfs 31. What type of star is the leftover center of an old star? a. main sequence c. white dwarf b. red giant d. supergiant 32. Which of the following stars is the oldest? a. main sequence c. white dwarf b. red giant d. supergiant A TOOL FOR STUDYING STARS 33. What two things are graphed on the H-R diagram? a. a star s temperature and brightness b. a star s temperature and color c. a star s temperature and age d. a star s temperature and size Holt Science and technology 19 Stars, Galaxies, and the Universe
Reading the H-R Diagram 34. What is the name of the band where most stars are found? a. middle band b. absolute magnitude c. main sequence d. star path 35. Where are most stars found on the H-R diagram? a. top half b. bottom half c. far corners d. middle Read the description. Then, draw a line from the dot next to each description to the matching phrase. 36. top of modern H-R diagram 37. bottom of modern H-R diagram 38. right side of modern H-R diagram 39. left side of modern H-R diagram a. hot (blue) stars b. cool (red) stars c. dim stars d. bright stars WHEN STARS GET OLD Supernovas Read the words in the box. Read the sentences. Fill in each blank with the word or phrase that best completes the sentence. pulsar black hole supernova neutron star 40. A huge explosion in which a large star dies is called a. 41. A star made up of neutrons is called a. 42. A spinning neutron star that emits pulses of energy is called a. 43. An object so massive and dense that light cannot escape its gravity is called a. Holt Science and technology 20 Stars, Galaxies, and the Universe
Section: Galaxies Pages 46-49 Circle the letter of the best answer for each question. 44. Which of the following binds a galaxy together? a. dust c. stars b. gravity d. gas TYPES OF GALAXIES 45. How are galaxies classified? a. by size c. by color b. by age d. by shape Spiral Galaxies 46. Where are new stars found in a spiral galaxy? a. the supernova c. the spiral arms b. the center bulge d. the halo The Milky Way 47. What is the Milky Way thought to be? a. a spiral galaxy c. a quasar b. a round galaxy d. an odd-shaped galaxy Elliptical Galaxies 48. What is an elliptical galaxy made of? a. huge clouds of dust c. big blobs of stars b. huge clouds of gas d. large rings of star Irregular Galaxies 49. Where are irregular galaxies often found? a. near large spiral galaxies b. near dwarf elliptical galaxies c. near other irregular galaxies d. near giant elliptical galaxies Holt Science and technology 21 Stars, Galaxies, and the Universe
Read the description. Then, draw a line from the dot next to each description to the matching picture. 50. elliptical galaxy 51. irregular galaxy 52. spiral galaxy CONTENTS OF GALAXIES Gas Clouds 53. What is a nebula? a. large cloud of stars b. large cloud of dust and gas c. group of closely grouped stars d. tight group of stars ORIGIN OF GALAXIES 54. What do scientists study to learn about the early universe? a. nearby galaxies b. far galaxies c. spiral galaxies d. the sun Quasars 55. Which of the following statements is true about quasars? a. Quasars are close to Earth. b. Quasars are powerful energy sources. c. Quasars are very tiny. d. Quasars come from old stars. Holt Science and technology 22 Stars, Galaxies, and the Universe
Section: Formation of the Universe Pages 50-53 Circle the letter of the best answer for each question. 56. What does cosmology study? a. the solar system b. the universe s origin, structure, and future c. the makeup of stars d. space travel UNIVERSAL EXPANSION A Raisin-Bread Model 57. How is the size of the universe changing? a. It is expanding. c. It is not changing. b. It is shrinking. d. No one knows. 58. How do most galaxies move as the universe grows? a. They move closer. c. They do not move. b. They move apart. d. They move back and forth. THE BIG BANG THEORY A Tremendous Explosion 59. According to the big bang theory, how did the universe begin? a. as a cloud of gases c. with a small explosion b. as a sea of gases d. with a big explosion 60. According to the big bang theory, how long ago did the universe begin? a. 100 billion years ago c. 1 billion years ago b. 13.7 billion years ago d. 1 million years ago Cosmic Background Radiation 61. Which statement is true about cosmic background radiation? a. It fills all of space. c. It began in 1964. b. It is shrinking. d. It is getting weaker. Holt Science and technology 23 Stars, Galaxies, and the Universe
STRUCTURE OF THE UNIVERSE 62. How are objects placed in space? a. in a random pattern c. in a loose pattern b. in a rigid pattern d. in no pattern A Cosmic Repetition 63. What is every object in the universe a part of? a. a larger system c. a solar system b. a smaller system d. a planetary system 64. What is one system a galaxy belongs to? a. a planet c. a solar system b. a cluster of galaxies d. a planetary system HOW OLD IS THE UNIVERSE? 65. What do scientists measure to tell how old the universe is? a. distance to other planets c. distance to other galaxies b. distance to sun d. distance to moon A FOREVER EXPANDING UNIVERSE 66. What will the universe be like in the far-off future? a. hot and bright c. cold and bright b. hot and dark d. cold and dark Holt Science and technology 24 Stars, Galaxies, and the Universe