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Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide Grade Level: 5-9 Curriculum Focus: Science Lesson Duration: 5 class periods Program Description Measuring the Universe: The Light-Year (5 min.)—Explains what a light-year is and its use in measuring distances in outer space. Galaxies (2 min.)—Describes different types of galaxies including our own galaxy, the Milky Way. The Life Cycle of Stars (7 min.)—Provides an overview of stars’ life cycles, and explains nuclear fusion’s role in their evolution. Star Color (2 min.)—Explains how scientists determine stars’ approximate temperatures. Dark Matter (1 min.)—Introduces the unexplained matter that comprises 90 percent of the universe. The Big Bang (5 min.)—Explains the Big Bang theory and the expansion of the universe. Discussion Questions • What is a light-year? • What are the three types of galaxies? • How are stars formed? • When did the “Big Bang” occur? Lesson Plan Student Objectives • Explain how galaxies are created • Research and be able to accurately describe the life cycle of stars • Analyze and share their understandings about the Big Bang theory • Research and write a two-page report about a heavenly body or system in the universe • Create a presentation for the class based on the subject matter of the two-page report Materials • Exploring Space—The Universe: The Vast Reaches of Space video • Computer with Internet access • Print and Web resources about scientific exploration of the universe Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide • 2 Poster boards (one per student), tape, and markers for class presentations Procedures 1. Before viewing the video, ask students what interests them most about the universe. Is it the enormous distances? The idea of planets and galaxies far different than our own? Do they believe that there is life in other parts of the universe? Do they believe that our country and other nations should continue to explore outer space? Inform the students that they will be viewing a program about the various entities that make up the universe. 2. After viewing the program, discuss how distances are measured in outer space. What is a lightyear? Explain that a light-year is the distance light travels in one Earth year. What is the closest star to our planet besides the sun? (Proxima Centauri.) How far away is Proxima Centauri from our planet? (Proxima Centauri is 4.3 light-years, or 26 trillion miles, away from Earth.) 3. Discuss with students the location of the solar system within the Milky Way galaxy. What are the three types of galaxies? Discuss answers from the video. (The universe contains spiral, elliptical, and irregular galaxies.) What type of galaxy is the Milky Way (A spiral galaxy.) Do they think there are types of galaxies that have not yet been discovered? How are galaxies created? Explain that spiral galaxies form from the collapse of a protogalactic cloud, whereas elliptical galaxies are formed as a result of a merger between two disk galaxies. 4. Review with students the life cycle of a star. How are stars formed? (A star is born when gravity pulls hydrogen gas from a nebula into a spinning cloud. The resulting nuclear reaction and nuclear fusion keep the star evolving.) How old is the sun? (Approximately 5 billion years old.) What happens when stars get older? What is a supernova? What do students think will happen to the Earth billions of years from now when the sun expands into a red giant and eventually becomes a dead star? 5. Discuss the Big Bang theory with the class. According to scientists, when did the “Big Bang” occur? (12 to 13 billion years ago.) How has the Hubble telescope been able to prove this theory? Explain how the Hubble telescope has been able to detect that galaxies are gradually moving away from each other. What does it mean when scientists say they have detected a redshift in the color of the galaxies? Discuss answers from the video. (As wavelengths of light spread out, their color appears on the red end of the visible spectrum.) Does this mean that the universe is getting bigger? 6. Assign each student a topic related to one aspect of the universe (for example, a white dwarf star, a supernova, or a black hole). Students will write a two-page report on their assigned topic, citing at least three relevant facts about their topic. The following Web sites contain relevant data: • Universe (Wikipedia) http://en.wikipedia.org/wiki/universe • BBC Science and Nature (Space) www.bbc.co.uk/science/space/solarsystem Published by Discovery Education. © 2006. All rights reserved. Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide • 3 Kidsastronomy.com www.kidsastronomy.com/universe.htm • Curious About Astronomy? Ask an Astronomer (Cornell University) http://curious.astro.cornell.edu/index.php • Exploring the Universe (NASA) www.nasa.gov/vision/universe/features • Imagine the Universe (NASA) http://imagine.gsfc.nasa.gov • Universe Forum Learning Resources (Harvard University) http://cfa-www.harvard.edu/seuforum/learningresources.htm 7. Based on the content of their reports, each student will create a “What Am I?” presentation and deliver it to the entire class. The students will reveal several facts about their subject matter and ask their classmates to guess what they are describing. Distribute the poster board to students and ask them to fold their boards in half. They are to write their clues on the front of their folded poster board and write the answer (with an appropriate illustration or graphic) on the “inside” of the folded board. Assessment Use the following three-point rubric to evaluate students' work during this lesson. • 3 points: Students produced a complete report and individual project, included all of the requested information in the report and the in-class presentation; accurately cited three interesting, relevant points in their report and during their presentation. • 2 points: Students produced an adequate report and individual project, included most of the requested information in the report and the in-class presentation; satisfactorily cited two relevant points in their report and during their presentation. • 1 point: Students created an incomplete report and individual project, included little or none of the requested information in the report and the in-class presentation; did not cite any relevant points in their report or during their presentation. Vocabulary black hole Definition: An invisible region believed to exist in space having a strong gravitational field; thought to be caused by the collapse of a star Context: The gravity of a black hole is so strong that nothing nearby can escape being pulled into it. Published by Discovery Education. © 2006. All rights reserved. Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide 4 comet Definition: A bright heavenly body that develops a cloudy tail as it moves closer to the sun in its orbit Context: Comets are also called shooting stars because of the streak of light created as the comet burns n the Earth’s atmosphere. galaxy Definition: One of the very large groups of stars and other matter that are found throughout the universe Context: The Milky Way is a spiral-shaped galaxy. light-year Definition: A unit of measurement in astronomy equal to the distance that light travels in one year Context: A light-year is equivalent to 5,880,000,000,000 miles. nebula Definition: Any of many huge clouds of gas or dust in deep space Context: The Helix Nebula—the closest planetary nebula to Earth—is 450 light-years away. planet Definition: A heavenly body other than a comet, asteroid, or satellite that travels in orbit around the sun Context: There are nine planets in our solar system. pulsar Definition: A neutron star that emits rapid and periodic pulses of radiation Context: A pulsar gives off radio waves due to the lack of synchronization between its rotation axis and its magnetic axis. star Definition: A massive, ball-shaped gaseous celestial body that shines by its own light Context: Compared to other stars in the universe, the sun is relatively young. supernova Definition: The explosion of a very large star in which the star temporarily gives off up to one billion times more energy than the sun Context: The Hubble Space Telescope has obtained the clearest images of a supernova. Published by Discovery Education. © 2006. All rights reserved. Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide 5 spectrum Definition: The grouping of colors including red, orange, yellow, green, blue, indigo, and violet arranged in the order of their wavelengths and seen when white light passes through a prism Context: Each element creates its own distinct spectrum. Academic Standards Mid-continent Research for Education and Learning (McREL) McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K–12 Education addresses 14 content areas. To view the standards and benchmarks, visit http://www.mcrel.org/compendium/browse.asp This program addresses the following national standards: • Science—Nature of Science: Understands the nature of scientific knowledge; Understands the nature of scientific inquiry; Understands the scientific enterprise • Science—Earth and Space Science: Understands the composition and structure of the universe and the Earth’s place in it National Academy of Sciences The National Academy of Sciences provides guidelines for teaching science in grades K–12 to promote scientific literacy. To view the standards, visit this Web site: http://books.nap.edu/html/nses/html/overview.html#content This lesson plan addresses the following national standards: • Science as inquiry: Abilities necessary to do scientific inquiry; Understandings about scientific inquiry • Earth and space science: Structure of the Earth system; Earth’s history; Earth in the solar system • Science and technology: Abilities of technological design; Understandings about science and technology • History and nature of science: Science as a human endeavor; Nature of science; History of science Published by Discovery Education. © 2006. All rights reserved. Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide 6 Support Materials Develop custom worksheets, educational puzzles, online quizzes, and more with the free teaching tools offered on the DiscoverySchool.com Web site. Create and print support materials, or save them to a Custom Classroom account for future use. To learn more, visit • http://school.discovery.com/teachingtools/teachingtools.html DVD Content This program is available in an interactive DVD format. The following information and activities are specific to the DVD version. How to Use the DVD The DVD starting screen has the following options: Play Video—This plays the video from start to finish. There are no programmed stops, except by using a remote control. With a computer, depending on the particular software player, a pause button is included with the other video controls. Video Index—Here the video is divided into sections indicated by video thumbnail icons; brief descriptions are noted for each one. Watching all parts in sequence is similar to watching the video from start to finish. To play a particular segment, press Enter on the remote for TV playback; on a computer, click once to highlight a thumbnail and read the accompanying text description and click again to start the video. Curriculum Units—These are specially edited video segments pulled from different sections of the video (see below). These nonlinear segments align with key ideas in the unit of instruction. They include onscreen pre- and post-viewing questions, reproduced below in this Teacher’s Guide. Total running times for these segments are noted. To play a particular segment, press Enter on the TV remote or click once on the Curriculum Unit title on a computer. Standards Link—Selecting this option displays a single screen that lists the national academic standards the video addresses. Teacher Resources—This screen gives the technical support number and Web site address. Video Index I. Measuring the Universe: The Light-Year (5 min.) When we see stars in the sky we are looking at light that was emitted years ago. Discover what a lightyear is and how it is used as a measurement in space. Published by Discovery Education. © 2006. All rights reserved. Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide 7 II. Galaxies (2 min.) Scientists have identified three kinds of galaxies. Find out more about elliptical and irregular galaxies, as well as spiral galaxies such as our own Milky Way. III. The Life Cycle of Stars (7 min.) Stars are created when gravity pulls hydrogen gas from the nebula into a spinning cloud. Learn more about how stars evolve and die out, or explode into a supernova. IV. Star Color (2 min.) In outer space, the hottest stars are blue, while the coolest stars are red. Learn how scientists use a spectroscope to gather information about stars. V. Dark Matter (1 min.) Scientists believe that dark matter makes up about 90 percent of the universe. Discover the important role that dark matter plays in holding galaxies together. VI. The Big Bang (5 min.) The most popular scientific theory about the origin of the universe is called the Big Bang. Learn how the Doppler effect provides evidence that the universe is still expanding. Curriculum Units 1. The Light-Year as a Unit of Measurement Pre-viewing question Q: How do scientists measure distances in space? A: Answers will vary. Post-viewing question Q: What is the speed of light? A: The speed of light is 186,000 miles (or 300,000 kilometers) per second. Published by Discovery Education. © 2006. All rights reserved. Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide 8 2. Galaxies Pre-viewing question Q: What is the name of the galaxy where our solar system is located? A: The Milky Way. Post-viewing question Q: What are the three types of galaxies? A: The three types of galaxies are spiral (like the Milky Way), elliptical, and irregular 3. The Birth and Death of Smaller Stars Pre-viewing question Q: What do you know about the sun? A: Answers will vary. Post-viewing question Q: What will happen to the sun after its supply of hydrogen is nearly used up? A: Over the course of billions of years, the helium core of the sun will begin to shrink, and the helium atoms will fuse to form carbon atoms. The sun’s hydrogen outer shell will expand until the sun becomes a red giant, before collapsing into a white dwarf and, eventually, a dead star. 4. Supernovas Pre-viewing question Q: What do you know about supernovas? A: Answers will vary. Post-viewing question Q: What is a pulsar? A: A pulsar is a neutron star that emits “pulses” or beams of high-energy radiation. Published by Discovery Education. © 2006. All rights reserved. Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide 5. The Light Spectrum Pre-viewing question Q: What is a spectrum? A: Answers may include the colors of a rainbow. Post-viewing question Q: From hottest to coolest, what are the color classifications of stars? A: Blue stars are hottest, followed by white, orange, yellow, and red, red being the coolest. 6. Detecting Dark Matter Pre-viewing question Q: What lies between the stars and planets in a galaxy? A: Answers will vary. Post-viewing question Q: Based on current scientific knowledge, what purpose does dark matter serve? A: Dark matter provides the gravity needed to keep a galaxy together. 7. The Big Bang Theory Pre-viewing question Q: What do you know about the Big Bang theory? A: Answers will vary. Post-viewing question Q: According to the Big Bang theory, how old is the universe? A: The universe is estimated to be 12 to 13 billion years old. 8. Gathering Information About the Universe Pre-viewing question Q: How do scientists gather information about the universe? A: Answers may include shuttle missions, the space station, telescopes, and space probes. Published by Discovery Education. © 2006. All rights reserved. 9 Exploring Space The Universe: The Vast Reaches of Space Teacher’s Guide Post-viewing question Q: What is the difference in wavelengths between high-pitched sounds and low-pitched sounds? A: High-pitched sounds have wavelengths that are close together, while low-pitched sounds have wavelengths that are more spread out. Credit Robyn Kurth, freelance writer Published by Discovery Education. © 2006. All rights reserved. 10 EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 1 Pre-Test Name ______________ Directions: Answer the following questions in the space provided. 1. What is a light-year? 2. Define these terms: a. nebula b. Supernova c. Galaxy d. Milky Way 3. When we look into the night sky we are actually looking into the past. How do you explain that? 4. What is the nuclear fusion reaction that takes place in the core of the sun? 5. What is the solar wind? 6. What is the Big Bang theory? 7. What is a black hole? 8. Why is a telescope orbiting the Earth a better location for observations than a landbased telescope on top of a mountain? All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 2 Program Quiz Name ______________ 1. What is the Big Bang theory? 2. Why do stars look so small to us? 3. What is dark matter? 4. Stars go through a life cycle. What is the expected outcome for our star, the sun, in five billion years? 5. How do scientists use a spectroscope to gather information about a star? All rights to print materials cleared for classroom duplication and distribution. Name ______________ EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 3 Vocabulary Directions: Pick the definition in column II that best matches the word in column I. Write the letter of the definition on the blank line. I 1. light-year _______ 2. sunspots _______ 3. solar system _______ 4. galaxy _______ 5. supernova _______ 6. nebula ______ 7. nuclear fusion _______ 8. spectroscope _______ 9. black hole _______ 10. solar wind _________ II a. A cloud of gas that is known as the birthplace of stars b. Hydrogen atoms combine to make helium atoms c. Areas of strong magnetic activity on the sun d. A huge group of stars e. The remains of an enormous star that has erupted in a supernova explosion and then collapsed in on itself f. The explosion of a star g. A measure of distance used by astronomers h. Made up of a star or two and other bodies that orbit the star or stars. i. Electronically charged particles that spray out from the sun causing problems with radio transmissions and power failures on Earth j. An instrument used to break light into parts for analysis All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 4 The Hubble Telescope Name ______________ The Hubble telescope was designed to help astronomers see deep into the universe and possibly far enough back in time to collect information about the beginning of the universe. 1. How is it possible that a telescope can see back into time? 2. Why is having a telescope in Earth orbit better than a ground-based telescope? All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 5 Scientific Notation—Page 1 Name ______________ The numbers used to describe distances in space are huge. To make things easier to work with, astronomers use scientific notation to represent these large numbers. It is like a numeric shorthand or abbreviation. The system is based on multiples of ten and can be used to represent large or small numbers. Here are some examples of scientific notation: 100 could be written as 10 x 10, or in scientific notation as 102. The 2 is called an exponent of 10. It could be read as ten to the second power or ten to the second. 10,000 could be written as 10 x 10 x 10 x10, or in scientific notation as 104, (ten to the fourth power or ten to the fourth). 50,000 could be written as 5 x 104. 234,035 could be written as 2.34035 x 105. To change large numbers into scientific notation, simply count from the decimal point to the first digit. There are five digits between where the decimal point in 234,035 is located and the first digit, which is the digit 2. Therefore, the scientific notation would be 2.34035 x 105. Write these numbers in scientific notation: a. 100,000 = b. 3,000 = d. 244,000 = e. 2,345,000 = Change these numbers from scientific notation: b. 3 x 104 = a. 106 = d. 1.002 x 105 = e. 5 x 109 = c. 60,000 = f. 45,000 = c. 2.34 x 104 = f. 3.4 x 104 = Small numbers can also be represented in scientific notation. To change a number less than zero to scientific notation, count the number of zeros after the decimal point to the first nonzero digit and then add one. Here is an example: 0.00045 is written 4.5 x 10-4. (The – symbol in front of the four tells us that this is a negative or less than one number). The number is read as four point five times ten to the minus four. Change these numbers to scientific notation: a. 0.00003 = b. 0.058 = c. 0.003056 = All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 6 Scientific Notation—Page 2 Name ______________ Multiplication and division with scientific notation is easy to do because you only need to work with the exponents and you use addition and subtraction instead of multiplication and division. Here is how it works: To multiply 30,000 times 2,000 follow these steps: Step 1: Change the numbers to scientific notation. 30,000 = 3 x 104 2,000 = 2 x 103 Step 2: multiply the 3 and 2 to get 6 Step 3: add the exponents 4 and 3 to get 7 So the answer is 6 x 107 To divide 40,000,000 by 0.002 follow these steps: Step 1: change the numbers to scientific notation. 40,000,000 = 4 x 107 0.002 = 2 x 10-3 Step 2: divide the 4 by 2 to get 2 Step 3: subtract the exponents 7-(-3) = 10 So the answer is 2 x 1010 Solve these problems using the scientific notation method: 1. 500,000 x 5,000 2. 500,000 / 5,000 3. 70,000 x 20,000 4. 6,000,000,000/2,000 5. 6,000,000,000 x 200,000 Change these numbers from scientific notation: 1. average Earth-sun distance 1.5 x 1011m 2. average Earth-moon distance 3.84 x 108m 3. diameter of the sun 1.39 x 106km 4. mass of the sun 1.99 x 1027 tons 5. mass of the Earth 5.976 x 1021 tons 6. mass of a neutron 1.6749 x 10-27 kg All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 7 A Light-Year Name ______________ Distances are so great in space that a special unit of measurement is used. It is called a light-year. This sounds like a measurement of time, but it is a unit used to measure distance. By definition a light-year is the distance that light travels in one year. To calculate the distance of one light-year, you determine the number of seconds in a year and then multiply that number times the speed of light. Light is the fastest thing we know of, as it travels at an incredible 186,000 miles (300,000 kilometers) per second. Your job is to calculate the value of one light-year. Calculate the number of seconds in one year. Calculate the number of miles, or kilometers, in a light-year by multiplying the number of seconds in a year by 186,000 miles, or 300,000 km. Now that you know how many miles or kilometers are in a light-year, determine the distance of these objects (round light-year to nearest trillion): 1. The closest star to Earth other than the sun is 4.3 light-years away. 2. The Andromeda galaxy is 2.2 million light-years away from Earth. 3. The diameter of the Milky Way galaxy is 100,000 light-years. All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 8 Emission Spectra Name ______________ Everything in the universe is made of elements called the building blocks of matter. There are just over one hundred natural or man-made elements. Each element has its own special spectral lines. This makes it possible to identify what elements are present when looking at the spectral lines given off by the light from stars. For example here are the spectral lines for some elements: hydrogen helium strontium calcium Here is an emission spectrum containing two of the above elements. Which two elements are represented? All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 9 Fill in the Blanks Name ______________ Directions: Use the words from the box to fill in the blanks in the following paragraphs. Some words from the box will not be used. The Doppler Effect Scientists know that ________ are moving away from each other because of a ____ shift in their color. This is called the _______ ______. We can demonstrate this effect using sound. Light and sound travel in ____________ of varying size. _____ sounds have wavelengths that are close together. ____ sounds have wavelengths that are more spread out. When an ambulance or police car is coming toward you the wavelengths are pushed ______ together and the sound is _____ pitched. But as the vehicle passes and moves away from you, the wavelengths _______ ____ and the pitch is lower. Light will do the same thing. As the light moves away from us it becomes elongated and shifts to the _______ wavelengths or the ___ end of the visible _________. Scientists have seen the ____ shift with all the _______ observed so far. Therefore, everything is moving away or expanding outward. No one knows if the expansion will continue, or whether it will slow down and stabilize, or whether it will ________ itself. Police reverse high (2) longer wavelengths blue low large science red (3) shift pitch far galaxies (2) spread out visible loud theory spectrum longer sound close shorter green Doppler Effect All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 10 Life Cycle of Stars Name ______________ Directions: Use the diagram to help you describe the stages in the life cycle of a star. Write your explanation on a separate sheet of paper. Main Sequence Red Giant Formation Lower Mass Star Massive Star White Dwarf High Mass Neutron Star Black Hole Very High Mass All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 11 Fusion Name ______________ The unbelievable energy and power produced by stars, such as the sun, comes from nuclear fusion. Fusion occurs when atoms of lightweight elements unite, or combine, to form larger atoms. During this process a tremendous amount of energy is released. The basic fusion reaction that takes place in stars is fueled by hydrogen atoms that fuse to make helium atoms. Elements are the building blocks of all matter. Elements are made of only one kind of substance. Each element has its own makeup of protons, neutrons, and electrons. A hydrogen atom has one proton and one electron. A helium atom has two protons, two neutrons, and two electrons. A lithium atom has three protons, three neutrons, and three electrons. This continues throughout all the known elements, different numbers of protons, neutrons, and electrons identify each unique element. There are just over one hundred elements. Elements have the same number of protons and electrons so that their electrical charges are balanced. Protons have a positive (+) charge and electrons have a negative (-) charge. Neutrons have no charge. Within a star gravity exerts tremendous pressure the star’s core produces extremely high temperatures. Temperatures in our sun’s core reach 15,000,000 degrees Kelvin. Under these conditions hydrogen atoms fuse, or join, to make helium. Fantastic quantities of energy are released during this process. + + hydrogen + hydrogen equals helium + ENERGY On Earth we can’t duplicate the gravity or temperatures found inside the sun. Scientists are working on a different approach to generating energy from fusion. Directions: Find out more about nuclear fusion by investigating one of the following questions: ¾ How are scientists attempting to use nuclear fusion to generate energy? ¾ How is nuclear fusion different from nuclear fission? ¾ Why would nuclear fusion be an important breakthrough for the future? ¾ What is a tokamak? All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 12 Post-Test Name ______________ Directions: Answer the following questions in the space provided. 1. What is a light-year? 2. When you look into the night sky you are looking into the past. Explain this statement. 3. How does the sun produce the tremendous amount of energy it releases every second? 4. What is the solar wind? 5. Explain why a land-based telescope is not always an effective observation tool. 6. What is a black hole? 7. What is the Big Bang theory? 8. Define the following terms: a. nebulae b. supernova c. galaxy d. solar system e. Milky Way Galaxy All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Masters Answer Key Blackline Master 1—Answer Key Pre-Test 1. What is a light-year? A light-year is the distance that light travels in one year. Light travels 300,000 km, or 186,000 mi, per second. A light-year is a measurement used to measure distances in space. 2. Define these terms: a. nebula A nebula is the gaseous birthplace of stars. b. supernova A supernova is the explosion of a star. c. galaxy A galaxy is a collection of billions of stars held together by gravity. d. Milky Way The Milky Way is the galaxy in which our solar system is found. 3. When we look into the night sky we are actually looking into the past. How do you explain that? Distances in space are so huge that it takes the light from stars a long time to travel to Earth. The closest star to Earth other than the sun is 4.3 light-years away. It takes the light 4.3 years to travel from that star to the Earth. So the light we see from that star left there 4.3 years ago. 4. What is the nuclear fusion reaction that takes place in the core of the sun? Nuclear fusion is what powers the stars. The tremendous heat and pressure in the cores of stars causes hydrogen atoms to combine to make helium atoms. In the process a great deal of energy is released. 5. What is the solar wind? The solar wind is made up of light particles released in all directions from the sun. These radioactive particles travel to the outer planets. 6. What is the Big Bang theory? All rights to print materials cleared for classroom duplication and distribution. The Big Bang Theory describes the beginning of the universe. It says that all the matter of the universe once occupied a space no larger than an atom. Then it burst forth and expanded outward, providing the building blocks for everything in the universe. 7. What is a black hole? A black hole is the remains of a supergiant star that has collapsed upon itself with such force that not even light can escape its gravitational pull. 8. Why is a telescope orbiting the Earth a better location for observations than a land-based telescope on top of a mountain? The images from telescopes on Earth are filtered through the particles in our atmosphere. Clouds can make it impossible to view the stars. Dirt and dust in the atmosphere can make viewing difficult. In space a telescope provides a clearer picture because the image isn’t viewed through an atmosphere of gases. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 2—Answer Key Program Quiz 1. What is the Big Bang theory? The Big Bang Theory describes the beginning of the universe. It says that all the matter of the universe once occupied a space no larger than an atom. Then it burst forth and expanded outward, providing the building blocks for everything in the universe. 2. Why do stars look so small to us? Stars look small because they are so far away. Most stars are much larger than our own star, the sun. The sun is so big it could hold a million planets the size of Earth. All rights to print materials cleared for classroom duplication and distribution. 3. What is dark matter? Observations of the way galaxies move and spin suggest that they are made up of a lot more matter than we can detect. Black, or dark, matter is that matter that we can’t see or detect. 4. Stars go through a life cycle. What is the expected outcome for our star, the sun, in five billion years? The sun will eventually increase in size as a red giant. It will expand to the orbit of Earth and then shrink to a planet-sized white dwarf. 5. How do scientists use a spectroscope to gather information about a star? Elements are the building blocks of all matter. Each element has its own signature spectrum. White light is broken into a rainbow of colors when it bends through a prism. A spectroscope can be used to analyze the light given off by a star. It breaks the light into spectral lines that can be compared with the known spectral lines of elements. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 3—Answer Key Vocabulary 1. light-year _g_____ 2. sunspots _c_____ 3. solar system _h_____ 4. galaxy _d_____ 5. supernova _f_____ 6. nebula _a____ 7. nuclear fusion _b_____ All rights to print materials cleared for classroom duplication and distribution. 8. spectroscope _j_____ 9. black hole _e_____ 10. solar wind __i______ EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 4—Answer Key The Hubble Telescope 1. How is it possible that a telescope can see back into time? The universe is so huge that the light from distant stars and galaxies take hundreds, thousands, millions, and billions of light-years to reach Earth. The unit of measurement in the universe is the light-year. It is the distance light travels in one year. Light travels at the incredible speed of 186,000 miles, or 300,000 kilometers, per second. So the distance light travels in a year is equal to almost 6 trillion miles. The closest star to Earth other than the sun is 4.3 light-years away. So if that star explodes tonight we won’t see the explosion for another 4.3 years. 2. Why is having a telescope in Earth orbit better than a ground-based telescope? A telescope in Earth orbit doesn’t face the problems that a ground-based telescope has to deal with on a regular basis. The telescope in orbit is above the atmosphere so clouds and dust don’t get in the way. Light going through our atmosphere can be scattered, which makes obtaining clear pictures difficult. All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 5—Answer Key Scientific Notation—Page 1 Write these numbers in scientific notation: b. 3 x 103 c. 6 x 104 a. 105 d. 2.44 x 105 e. 2.345 x 106 f. 4.5 x 104 Change these numbers from scientific notation: a. 1,000,000 b. 30,000 c. 23,400 d. 100,200 e. 5,000,000,000 f. 34,000 Change these numbers to scientific notation: a. 3 x 10-5 b. 5.8 x 10-2 c. 3.056 x 10-3 EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 6—Answer Key Scientific Notation—Page 2 Solve these problems using the scientific notation method: 1. 5 x 105 2. 5 x 105 3. 7 x 104 4. 6 x 109 5. 6 x 109 x 5 x 103 / 5 x 103 x 2 x 104 / 2 x 103 x 2 x 105 25 x 108 1 x 102 14 x 108 3 x 106 12 x 1014 2,500,000,000 100 1,400,000,000 3,000,000 1,200,000,000,000,000 Change these numbers from scientific notation: 1. 150,000,000,000 m 2. 384,000,000 m 3. 1,390,000 km All rights to print materials cleared for classroom duplication and distribution. 4. 1,990,000,000,000,000,000,000,000,000 tons 5. 5,976,000,000,000,000,000,000 tons 6. 0.0000000000000000000000000016749 kg EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 7—Answer Key A Light-Year Calculate the number of seconds in one year. Seconds in an hour: 60 x 60 = 3600 Seconds in a day: 24 x 3600 = 86,400 Seconds in a year: 365 x 86,400 = 31,536,000 Calculate the number of miles, or kilometers, in a light-year by multiplying the number of seconds in a year by 186,000 miles, or 300,000 km. Miles in a light-year: 186,000 x 31,536,000 = 5,865,696,000,000 Scientists round it off to 6 trillion. In kilometers: 300,000 x 31,536,000 = 9,460,800,000,000 kilometers Scientists round it to 9 trillion km. Determine the distance of these objects (round light-year to nearest trillion): 1. The closest star to Earth other than the sun is 4.3 light-years away. 25.8 trillion miles 38.7 trillion km 2. The Andromeda galaxy is 2.2 million light-years away from Earth. 13.2 quintillion miles 19.8 quintillion km 3. The diameter of the Milky Way galaxy is 100,000 light-years. 600,000 trillion miles 900,000 trillion km All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 8—Answer Key Emission Spectra Here is an emission spectrum containing two of the above elements. Which two elements are represented? Hydrogen and helium EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 9—Answer Key The Doppler Effect Scientists know that galaxies are moving away from each other because of a red shift in their color. This is called the Doppler Effect. We can demonstrate this effect using sound. Light and sound travel in wavelengths of varying size. High sounds have wavelengths that are close together. Low sounds have wavelengths that are more spread out. When an ambulance or police car is coming toward you the wavelengths are pushed close together and the sound is high pitched. But as the vehicle passes and moves away from you, the wavelengths spread out and the pitch is lower. Light will do the same thing. As the light moves away from us it becomes elongated and shifts to the longer wavelengths or the red end of the visible spectrum. Scientists have seen the red shift with all the galaxies observed so far. Therefore, everything is moving away or expanding outward. No one knows if the expansion will continue, or whether it will slow down and stabilize, or whether it will reverse itself. All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 10—Answer Key Life Cycle of Stars Stars form in gas clouds called nebulae. Gravity pulls more and more of this gas together and the temperature increases. When it reaches 20 million degrees, a nuclear reaction begins. Hydrogen atoms combine, or fuse, to form helium atoms—releasing huge amounts of energy in the form of light and heat in all directions. The star is born. How long a star takes to evolve is determined by its mass. The more massive the star, the shorter its life. A star about the size of our sun will live for around ten billion years. Eventually the supply of hydrogen is almost used up. The core, which is mainly helium, shrinks and, as a result, heats up causing helium atoms to fuse and form carbon atoms. The hydrogen outer shell expands to an enormous size. At this point the star is considered a red giant. Then the star will blow away its outer atmosphere and collapse to what is called a white dwarf. The star shrinks to planet size and gives off white, cool light. A more massive star goes through a different death. When a star that is many times larger than our sun turns into a red giant or a supergiant it doesn’t evolve into a white dwarf. Instead, because of its terrific gravity, it fuses the carbon atoms made from fused helium atoms into heavier elements. In other words, the star continues to carry on fusion and produces heavier and heavier elements. By the time the core of the star is mainly made up of iron atoms, it stops the fusion process. Then the star explodes in a violent explosion called a supernova. The elements, gases, and dust of the star explode into space to form a new nebula. This nebula could become the birthplace for a whole new group of stars. The core of a star that has exploded in a supernova ends up as either a neutron star or a black hole depending on its original mass. Stars that are 6 to 30 times more massive than our sun turn into a neutron star. Neutron stars are very massive. If the star was originally 30 or more times larger than our sun the fate of the core is very strange. After the supernova explosion the core is so heavy and the gravity so strong that the star is pulled in on itself to form what is called a black hole. A black hole has such strong gravity that everything that comes near is swallowed into it. Not even light can escape a black hole. All rights to print materials cleared for classroom duplication and distribution. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 11—Answer Key Fusion Students are encouraged to use the Internet to discover the answers to these questions. Students’ answers will vary. EXPLORING SPACE The Universe: The Vast Reaches of Space Blackline Master 12—Answer Key Post-Test 1. What is a light-year? A light-year is the distance light travels in one year. It is a measurement of distance. 2. When you look into the night sky you are looking into the past. Explain this statement. Distances are so huge in space that it takes years for the light from stars to reach our eyes. The closest star to Earth other than the sun is 4.3 lightyears away. That means it takes 4.3 years for the light from that star to reach Earth. 3. How does the sun produce the tremendous amount of energy it releases every second? The sun, like other stars, is constantly fusing, or combining, hydrogen atoms to make helium atoms. This is called nuclear fusion. During this process a great deal of energy is released. All rights to print materials cleared for classroom duplication and distribution. 4. What is the solar wind? The sun constantly releases charged particles in all directions. This is called the solar wind. 5. Explain why a land-based telescope is not always an effective observation tool. A telescope on Earth must look through our atmosphere to view the stars. The atmosphere is thick with gases and dust, which makes viewing difficult. Cloud coverage can make viewing impossible. 6. What is a black hole? Stars that are more than 30 times the mass of the sun can evolve into what is called a black hole. The star explodes in a supernova explosion and then falls in on itself. Its gravity is so strong that nothing can escape it. Everything that comes close is pulled into the black hole. The gravity is so intense that even light can’t escape. 7. What is the Big Bang theory? The Big Bang Theory says that about twelve to thirteen billion years ago all the matter of the universe was contained within an area the size of an atom. Then this matter began to expand outward. 8. Define the following terms: a. Nebulae Nebulae are the gaseous birthplaces of stars. b. supernova A supernova is an enormous explosion of elements, gases, and dust given off by a dying star. c. galaxy A galaxy is a collection of stars that are relatively close to one another. d. solar system A solar system is made up of one or more stars with planets, asteroids, and comets all circling around a central region. e. Milky Way Galaxy The Milky Way Galaxy is the galaxy where our sun and solar system are found. Our solar system is in one of the outer arms of this spiral galaxy. All rights to print materials cleared for classroom duplication and distribution.