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1. How to Use This Presentation • To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” • To advance through the presentation, click the right-arrow key or the space bar. • From the resources slide, click on any resource to see a presentation for that resource. • From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. • You may exit the slide show at any time by pressing the Esc key.

2. Resources Bellringers Chapter Presentation Transparencies Standardized Test Prep Image and Math Focus Bank CNN Videos Visual Concepts

3. Chapter 18 Studying Space Table of Contents Section 1Astronomy: The Original Science Section 2Telescopes Section 3Mapping the Stars

4. Chapter 18 Section 1The Nine Planets Bellringer Choose a planet to research. Create a poster that features the planet and includes a cross section of the planet’s interior. Provide factual information and mythology about the planet on your poster.

5. Chapter 18 Section 1The Nine Planets Objectives • List the planets in the order in which they orbit the sun. • Explain how scientists measure distances in space. • Describe how the planets in our solar system were discovered. • Describe three ways in which the inner planets and outer planets differ.

6. Section 1Astronomy: The Original Science Chapter 18 Astronomy • People in ancient cultures used the seasonal cycles to determine when they should plant and harvest crops. They built observatories to study the night sky. • Over time, the science of astronomy developed. Astronomy is the study of the universe.

7. Section 1Astronomy: The Original Science Chapter 18 Our Modern Calendar • What Is Our Calendar Based On?The years, months, and days of our modern calendar are based on the observation of bodies in our solar system.

8. Section 1Astronomy: The Original Science Chapter 18 Who’s Who of Early Astronomy • Ptolemy: An Earth-Centered UniversePtolemy thought that the Earth was at the center of the universe and that the other planets and the sun revolved around the Earth.

9. Section 1Astronomy: The Original Science Chapter 18 Who’s Who of Early Astronomy • Copernicus: A Sun-Centered UniverseCopernicus thought the sun is at the center of the universe, and all of the planets—including the Earth—orbit the sun.

10. Section 1Astronomy: The Original Science Chapter 18 Who’s Who of Early Astronomy, continued • Tycho Brahe: A Wealth of DataIn the late-1500s, Danish astronomer Tycho Brahe made the most detailed astronomical observations that had ever been recorded. • Johannes Kepler: Laws of Planetary MotionJohannes Kepler stated three laws of planetary motion. These laws are still used today.

11. Section 1Astronomy: The Original Science Chapter 18 Modern Astronomy • Milestones in Modern AstronomyThe invention of the telescope and the discovery of gravity were two milestones in the development of modern astronomy. • Edwin Hubble: Beyond the Edge of the Milky WayIn 1924, Edwin Hubble proved that other galaxies existed beyond the edge of the Milky Way.

12. Chapter 18 Section 2Telescopes Bellringer Have you ever bent or slowed down light? Explain how. Record your answer in your science journal.

13. Chapter 18 Section 2Telescopes Objectives • Compare refracting telescopes with reflecting telescopes. • Explain how the atmosphere limits astronomical observations, and explain how astronomers overcome these limitations. • Listthe types of electromagnetic radiation that astronomers use to study objects in space.

14. Chapter 18 Section 2Telescopes Telescopes • A Telescope is an instrument that gathers electromagnetic radiation from objects in space and concentrates it for better observation. • There are many different types of telescopes.

15. Chapter 18 Section 2Telescopes Optical Telescopes • Refracting Telescopes Telescopes that use lenses to gather and focus light are called refracting telescopes. A refracting telescope is shown on the next slide. • Reflecting TelescopeA telescope that uses a curved mirror to gather and focus light is called a reflecting telescope. A reflecting telescope is shown on the next slide.

16. Chapter 18 Section 2Telescopes Optical Telescopes • Refracting Telescopes Telescopes that use lenses to gather and focus light are called refracting telescopes. A refracting telescope is shown on the next slide. • Reflecting TelescopeA telescope that uses a curved mirror to gather and focus light is called a reflecting telescope. A reflecting telescope is shown on the next slide.

17. Chapter 18 Section 2Telescopes Refracting and Reflecting Telescopes

18. Chapter 18 Section 2Telescopes Optical Telescopes, continued • Very Large Reflecting TelescopesIn some very large reflecting telescopes, several mirrors work together to collect light and focus it in the same area.

19. Chapter 18 Section 2Telescopes Optical Telescopes, continued • Optical Telescopes and the Atmosphere The light gathered by telescopes on the Earth is affected by the atmosphere. • Optical Telescopes in SpaceTo avoid interference by the atmosphere, scientists have put telescopes in space

20. Chapter 18 Section 2Telescopes The Electromagnetic Spectrum • What Is the Electromagnetic Spectrum? The electromagnetic spectrum is made up of all of the wavelengths of electromagnetic radiation. • Detecting Electromagnetic RadiationVisible light is only a small band of the electromagnetic spectrum. Radio waves, microwaves, infrared light, ultraviolet light, X rays, and gamma rays— are invisible to the human eye.

21. Chapter 18 Section 2Telescopes The Electromagnetic Spectrum

22. Chapter 18 Section 2Telescopes Nonoptical Telescopes • Radio Telescopes Radio telescopes detect radio waves. Because radio wavelengths are much larger than optical wavelengths, radio telescopes much be very large. • Linking Radio TelescopesAstronomers can get more detailed images of the universe by linking radio telescopes together. Working together, the telescopes function as a single giant telescope.

23. Chapter 18 Section 2Telescopes Nonoptical Telescopes, continued • Nonoptical Telescopes in SpaceBecause most electromagnetic waves are blocked by the Earth’s atmosphere, scientists have placed ultraviolet telescopes, infrared telescopes, gamma-ray telescopes, and X-ray telescopes in space.

24. Chapter 18 Section 3Mapping the Stars Bellringer Is it possible to determine the direction of the North Pole just by looking at the stars? Explain your answer. Write your answer in your science journal. .

25. Chapter 18 Section 3Mapping the Stars Objectives • Explain how constellations are used to organize the night sky. • Describe how the altitude of a star is measured. • Explain how the celestial sphere is used to describe the location of objects in the sky. • Compare size and scale in the universe, and explain how red shift indicates that the universe is expanding.

26. Chapter 18 Section 3Mapping the Stars Patterns in the Sky • Constellations Help Organize the Sky A constellation is a region of the sky. Each constellation shares a border with neighboring constellations. A constellation map is shown on the next slide. • Seasonal Changes As Earth revolves around the sun, the apparent locations of the constellations change from season to season.

27. Chapter 18 Section 4Moons Spring Constellations in the Northern Hemisphere

28. Chapter 18 Section 3Mapping the Stars Finding Stars in the Night Sky • You can describe the location of a star or planet by using an instrument called an astrolabe and the following points of reference: • Thezenithis the point in the sky directly above on observer on Earth. • Thealtitudeis the angle between an object in the sky and the horizon. • Thehorizonis the line where the sky and the Earth appear to meet.

29. Chapter 18 Section 4Moons Zenith, Altitude, and Horizon

30. Chapter 18 Section 3Mapping the Stars Finding Stars in the Night Sky, continued • Using an astrolabe allows you to describe where a star or planet is relative to you. Scientists need a different method that describes location independently of the observer’s location. • Astronomers describe the location of a star or planet in terms of the celestial sphere.

31. Chapter 18 Section 4Moons The Celestial Sphere

32. Chapter 18 Section 3Mapping the Stars Describing a Star’s Position Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

33. Chapter 18 Section 3Mapping the Stars The Size and Scale of the Universe • In the 1600s, Nicolaus Copernicus noticed that the planets appeared to move relative to each other but that the stars did not. Thus, he thought that the stars must be much farther away than the planets. • Measuring Distance in SpaceA light-year is a unit of length equal to the distance that light travels in 1 year.

34. Chapter 18 Section 3Mapping the Stars The Size and Scale of the Universe, continued • It is important to consider scale when thinking about the universe. Although stars looks tiny in the night sky, remember that they are actually a lot larger than Earth.

35. Chapter 18 Section 3Mapping the Stars The Doppler Effect • What Is the Doppler Effect?Have you ever noticed that when a driver in an approaching car blows the horn, the horn sounds higher pitched as the car approaches and lower pitched after the car passes? This effect is called the Doppler effect. • An Expanding UniverseThe Doppler effect has been used to discover that galaxies are rapidly moving apart from each other.

36. Chapter 18 Section 3Mapping the Stars Red Shift Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

37. Chapter 18 Studying Space Concept Map Use the terms below to complete the concept map on the next slide.

38. Chapter 18 Studying Space

39. Chapter 18 Studying Space

40. End of Chapter 18 Show

41. Standardized Test Preparation Chapter 18 Reading Read each of the passages. Then, answer the questions that follow each passage.

42. Standardized Test Preparation Chapter 18 Passage 1In the early Roman calendar, a year had exactly 365 days. The calendar worked well until people realized that the seasons were beginning and ending later each year. To fix this problem, Julius Caesar developed the Julian calendar based on a 365.25-day calendar year. He added 90 days to the year 46 BCE and added an extra day every 4 years. A year in which an extra day is added to the calendar is called a leap year. Continued on next slide

43. Standardized Test Preparation Chapter 18 Passage 1, continued In the mid-1500s, astronomers determined that there are actually 365.2422 days in a year, so Pope Gregory XIII developed the Gregorian calendar. He dropped 10 days from the year 1582 and restricted leap years to years that are divisible by 4 but not by 100 (except for years that are divisible by 400). Today, most countries use the Gregorian calendar.

44. Standardized Test Preparation Chapter 18 1. According to the passage, which of the following years is a leap year? A 46 BCE B 1582 C 1600 D 1800

45. Standardized Test Preparation Chapter 18 1. According to the passage, which of the following years is a leap year? A 46 BCE B 1582 C 1600 D 1800

46. Standardized Test Preparation Chapter 18 2. How long is a year? F 365 days G 365.224 days H 365.2422 days I 365.25 days

47. Standardized Test Preparation Chapter 18 2. How long is a year? F 365 days G 365.224 days H 365.2422 days I 365.25 days

48. Standardized Test Preparation Chapter 18 3. Why did Julius Caesar change the early Roman calendar? A to deal with the fact that the seasons were beginning and ending later each year B to compete with the Gregorian calendar C to add an extra day every year D to shorten the length of a year

49. Standardized Test Preparation Chapter 18 3. Why did Julius Caesar change the early Roman calendar? A to deal with the fact that the seasons were beginning and ending later each year B to compete with the Gregorian calendar C to add an extra day every year D to shorten the length of a year

50. Standardized Test Preparation Chapter 18 Passage 2The earliest known evidence of astronomical observations is a group of stones near Nabta in southern Egypt that is between 6,000 and 7,000 years old. According to archeoastronomers, some of the stones are positioned such that they would have lined up with the sun during the summer solstice 6,000 years ago. The summer solstice occurs on the longest day of the year. At the Nabta site, the noonday sun is at its zenith (directly overhead) for about three weeks before and after the summer solstice. Continued on next slide