Grade 5. Practice Test. Telescopes: An Introduction Powerful Telescopes

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1 Name Date Grade 5 Telescopes: An Introduction Powerful Telescopes

Their observations were limited to what could be seen with the unaided eye.

2 Today you will read two passages. Read these sources carefully to gather information to answer questions and write an essay. Excerpt from Telescopes: Eyes on Space by David Dreier and Brian Roberts Introduction 1 For many thousands of years, curious people have gazed into the sky and wondered about the things they saw. Their observations were limited to what could be seen with the unaided eye. It wasn t until about 400 years ago, with the invention of the telescope, that our knowledge of space took a huge leap forward. Since that time, telescopes have evolved into powerful tools for viewing stars, planets, and other objects in space. History 2 The invention of the telescope was first made possible through the development of the glass lens. A lens is a curved piece of glass that bends and focuses light. Early eyeglass lenses for reading were developed by Italian glassmakers. But it was the Dutch lens maker, Hans Lippershey, whom most historians say was the first to discover how to combine lenses to look at distant objects. He put two lenses in line so that the first lens magnified the light from the second lens. That made distant objects appear much nearer. In 1608, Lippershey built his first crude telescope. He named it The Looker. Other people were also experimenting with lens combinations, but Lippershey was the first to apply for a patent. His invention became an important military tool. The telescope provided a big advantage in warfare. It allowed Dutch armies to watch enemy troop movements from afar. 3 A year after Lippershey invented his telescope, a man in Italy, Galileo Galilei, was hard at work building a telescope for observing objects in space. He greatly improved on the work of Lippershey and other Dutch lens makers. He created telescopes that magnified objects five times and, eventually, thirty times. Galileo used his telescope to observe distant objects in space. Because of this early work, he became known as the Father of Astronomy. 1 of 10

3 Galileo s Observations Below is a list of the important observations Galileo made with his telescopes. Craters and mountains on the Moon s surface Four of Jupiter s moons Phases of Venus proving that it orbits the Sun Sunspots on the Sun s surface The Milky Way s composition as a galaxy of stars rather than a cloud of cosmic dust as previously thought Neptune though he failed to realize that it was a planet 4 As a professor of astronomy, Galileo was required to teach a model of the solar system. This model placed Earth at the center and had the Sun and all planets revolving around it. But his observations of space convinced him that a different theory might be more accurate. This theory placed the Sun at the center of the solar system, with the planets revolving around it. His teaching of this theory upset the Roman Catholic Church. The Church believed that God had designed the universe to revolve around Earth. Galileo s theory displaced humanity from the center of the universe. It made Earth just one of a number of planets revolving around one of many stars. The Church banned Galileo s Sun-centered theory and sentenced him to life in prison. But because Galileo was already old, he was allowed to serve his sentence at home, under house arrest, for the rest of his life. REFRACTING TELESCOPE objective lens eyepiece lens Refracting Telescope Galileo s telescope was a refracting telescope. In a refracting telescope, light first travels through a piece of curved glass called a lens. The curve of the lens causes the light to bend, or refract. Light rays pass through a tube, come together, and pass through a second lens. The second lens refracts the light again before it passes into the eye. The eye sees a large image of the object. light 2 of 10

4 1. Part A Read the following sentences from paragraph 4: Galileo s theory displaced humanity from the center of the universe. It made Earth just one of a number of planets revolving around one of many stars. What does the word displaced mean in the passage? A caused B explained C moved D saw What does the word humanity mean in the sentence? A Lippershey B Italy C people D the Sun 2. Part A What are two main ideas of the passage? A Telescopes were developed after eyeglasses. B Telescopes helped the Dutch win wars in the 1600s. C Telescopes make it possible to see faraway things. D Telescopes helped change the theory of the solar system by placing the Sun, not Earth, at the center. Which two details from the text support one of the correct main ideas in Part A? A For many thousands of years, curious people have gazed into the sky and wondered about the things they saw. B Lippershey s telescope helped Dutch armies watch enemy troop movements from afar. C Galileo used his telescope to observe distant objects in space. D Galileo was a professor of astronomy. E Galileo was allowed to serve his sentence at home. 3 of 10

5 3. Which sentence from paragraph 2 states a fact and expresses an opinion? A The invention of the telescope was first made possible through the development of the glass lens. B A lens is a curved piece of glass that bends and focuses light. C In 1608, Lippershey built his first crude telescope, which he named The Looker. D The telescope provided a big advantage in warfare, allowing Dutch armies to watch enemy troop movements from afar. 4. Part A Based on information in paragraph 4, what power did church leaders have in Italy in the early 1600s? A They could build telescopes. B They could teach astronomy. C They could put people in prison. D They could observe objects in space. How did church leaders use this power? A to invent better telescopes B to learn more about our solar system C to stop people from spreading new ideas D to prove the Earth revolved around the Sun 4 of 10

6 Excerpt from Telescopes: Eyes on Space by David Dreier and Brian Roberts Powerful Telescopes 1 Are there planets outside our solar system? What are stars made of? Is there a black hole at the center of the Milky Way galaxy? How big is the universe? Astronomers rely on a very important type of tool to help answer these questions: the telescope. 2 There are many different types of telescopes. Some use mirrors to collect light, while others use glass lenses. Some collect visible light, while others detect light that we can t see. Some make observations from Earth, while others are out in space. Reflecting Telescopes Early refracting telescopes, like those used by Galileo, had some problems. It was hard to grind the glass lenses perfectly, so the images were often fuzzy and the colors were not quite right. In 1668, Isaac Newton invented the reflecting telescope. These telescopes use mirrors instead REFLECTING TELESCOPE secondary mirror eyepiece lens light primary mirror of lenses to gather light. In a reflecting telescope, light from the object travels through the telescope and reflects, or bounces off, a curved mirror. The curved mirror focuses light to a small point, where there is another, smaller mirror. The light then bounces off that mirror and travels to the eye. Most large modern telescopes are reflecting telescopes. 3 Increasing the size of a telescope s mirror usually leads to a more powerful telescope. Bigger reflectors gather more light. They allow us to see objects that are much smaller, fainter, or farther away than smaller telescopes do. 4 However, it is very hard to make large mirrors that are perfectly shaped. Also, their weight causes them to bend. Then the light does not bounce off the surfaces in the right direction. The images become distorted. 5 of 10

7 5 To avoid this problem, engineers often make mirrors that are actually many smaller mirrors put together. The large mirror of the South African Large Telescope (SALT) is made of 91 mirrors, each of which is 1.2 meters (4 ft.) across. Together, they make a mirror that is 11 meters (36 ft.) by 9.8 meters (32 ft.). It can help us see objects that are one billion times fainter than what you can see when you look at the sky. 6 Another way to avoid extra large mirrors that can bend is to build several identical telescopes close to each other and combine the light from them. This is called a telescope array. The Very Large Telescope (VLT) in Chile is an array of four telescopes. Each telescope has a mirror that is 8.2 meters (28 ft.) across. In addition, it has four movable telescopes. Each of these has a mirror that is 1.8 meters (6 ft.) across. When the telescopes work together, astronomers can see details 25 times finer than when using just one of the telescopes. 7 Astronomers answer many questions about the universe using large telescopes and telescope arrays on the ground. But even the best groundbased telescopes have challenges. 8 As light travels from space to Earth s surface, the gases in Earth s atmosphere reflect and absorb it. As a result, not all the light from space reaches telescopes on the ground. 9 For example, almost all gamma rays are absorbed by Earth s atmosphere. There is no way to study gamma rays in space by using telescopes on Earth s surface. To solve this problem, engineers have designed space telescopes. These telescopes are launched into orbit around Earth or the Sun. From there, they can make observations far above our atmosphere. They use radio signals to send data to scientists on Earth. Like ground-based telescopes, space telescopes are designed to make different kinds of observations. The Hubble Space Telescope (HST), for example, was able to gather light from galaxies more than 13.2 billion light-years away! These galaxies formed shortly after the universe itself formed. 6 of 10

8 5. Part A What does detect mean in paragraph 2? A bend B block C magnify D sense Which phrase from paragraph 2 is a clue to the meaning of the word detect? A different types B glass lenses C out in space D we can t see 6. According to the passage, what can a telescope in space do that one on Earth cannot? A show gamma rays B identify light from space C tell what stars are made of D magnify the Milky Way galaxy 7. Part A According to the passage, which problem is associated with reflecting telescopes? A keeping the mirrors from bending B launching them into space C making observations from Earth D getting the colors right Select two ways in which the passage explains how this problem can be solved. A by grinding the lenses B by moving the telescopes C by putting many small mirrors together D by using two or more telescopes together E by using refracting and reflecting telescopes together 7 of 10

9 8. Part A Which topics are included in the first passage? Choose all that apply. A reflecting telescopes B refracting telescopes C Galileo D Roman Catholic Church E telescopes used in space F telescope arrays Which topics are included in the second passage? Choose all that apply. A reflecting telescopes B refracting telescopes C Galileo D Roman Catholic Church E telescopes used in space F telescope arrays 9. Part A Which of the following details describe refracting telescopes? Choose all that apply. A has an eyepiece lens B uses mirrors C uses curved glass lenses D commonly used today E used by Galileo Which of the following details describe a reflecting telescope? Choose all that apply. A has an eyepiece lens B uses mirrors C uses curved glass lenses D commonly used today E used by Galileo 8 of 10

10 10. You have read two texts about telescopes. Summarize the features and capabilities of the type of telescope Galileo used in the 1600s and modern space telescopes. Include at least one way the two kinds of telescopes are similar and one way they are different. Be sure to include supporting evidence from both passages in your response. 9 of 10

11 : Answer Sheet 1. Part A 2. Part A E Part A 5. Part A Part A E 8. Part A E F E F 9. Part A E E 10. Constructed Response 10 of 10

TELESCOPES POWERFUL. Beyond the Book. FOCUS Book

TELESCOPES POWERFUL. Beyond the Book. FOCUS Book FOCUS Book POWERFUL TELESCOPES Why do we need telescopes in order to observe stars that are very far away? Why do stars look bright in the sky while most galaxies, which have billions of stars, are too