Key Question: How does the motion of celestial objects affect life on Earth?

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Chapter 9 Our Place in Space

Key Question: How does the motion of celestial objects affect life

on Earth?

Key Concepts Vocabulary

The Solar System consists of all the objects orbiting the Sun.

The motion of Earth causes day, night, and the seasons.

Earth’s motion affects our view of the night sky. Celestial objects can be used to predict annual events and to navigate.

The positions of the Sun, Earth, and the Moon result in the lunar cycle and eclipses. Scientists have strong evidence that the Universe began around 14 billion years ago.

geocentric model heliocentric model astronomical unit (AU) meteoroid meteor comet revolve rotates axis time zone solstice equinoxes constellation asterism circumpolar azimuth altitude gravitational force lunar cycle phases of the Moon waxing waning solar eclipse lunar eclipse red shift cosmologists Big Bang theory

TEACHING NOTES

• Have students look at the chapter opener photo on page 326 of the Student Book.

– Ask, When would you guess the photograph was taken, and by whom? (Students will likely guess that the photo was taken by NASA astronauts during a Moon mission. This image was taken by the crew of Apollo 8, the first crewed mission to orbit the Moon.)

– Ask, If an observer were standing with this view from the Moon, how might Earth’s appearance change over time? (Sample answer: As the Moon orbits Earth, different parts of Earth would become visible. Different amounts of Earth’s lit side would also be visible.)

Engage the Learner Chapter Introduction

• To preview the major ideas that will be explored in the chapter, review the Key Concepts. Have a student volunteer read each Key Concept aloud before it is discussed. Then ask prompting questions to assess students’ prior knowledge and to engage students in the topics. Examples are given: 1. What are some of the celestial objects that make up the Solar System? (Sample answer: Earth, the Moon, comets)

2. How do you think days would be different if Earth rotated faster on its axis? (Sample answer: I think days would be shorter.)

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3. Why does Polaris not seem to move during a night? (It is located above Earth’s axis of rotation.)

4. What are some events related to the Solar System that occur repeatedly? (Sample answer: The Moon’s appearance changes in a regular pattern. The length of daylight changes during the course of a year.)

5. Do we always know when the Moon is going to be full? (Yes, because the Moon always takes the same amount of time to orbit Earth and its phases are therefore predictable.)

6. Why is studying a distant galaxy like looking back in time? (The Universe is so vast and the objects in it, such as galaxies, are so far apart that it takes even the light from these objects millions or billions of years to travel from them to reach us on Earth.)

Engage in Science

• The purpose of this reading is to introduce some of the factors that make Earth livable. Remind students that nearly all the energy in Earth’s ecosystems comes from the Sun, and that all known living things require liquid water to survive. Explain that one of the main reasons that life could not survive on Earth if Earth were significantly closer to or farther from the Sun is that liquid water could not exist on its surface at those locations. Point out that scientists have confirmed that water exists on Mars, but it is all frozen because Mars is too cold for it to exist as a liquid. Explain that one of the reasons Mars is too cold to have liquid water is because of its distance from the Sun.

What Do You Think?

• Together with students, consider each photo and statement in the anticipation guide on page 328 of the Student Book. Below are some sample questions you can use to elicit students’ previous knowledge and experience. Encourage students to express their opinions, acknowledging that their opinions may change as they read through the chapter.

1. What is a solar eclipse?

2. Why does the Sun appear to rise and set?

3. Do most things in nature stay the same all the time?

4. Do you see the same celestial objects if you look at the night sky from different directions?

5. In what ways does the appearance of the Moon change? 6. What causes the seasons?

• After students have discussed each statement, poll the class on whether they agree or disagree with each one. Revisit the poll results at the end of the chapter in the What Do You Think Now? section.

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Focus on Reading

• Use the excerpted passage presented in this feature to describe how to summarize a text. Draw students’ attention to the tables, which describe and give examples of the steps in writing a summary. Remind students how to find the main idea of a paragraph and how to identify details. Review with students the words that indicate supporting facts, such as for example and one type of.

• Distribute BLM 0.0-11 Reading Strategies Checklist to help students improve their reading skills.

Reading Tip

Direct students’ attention to the Reading Tip in the margin of page 329 of the Student Book. Tell them that they will see Reading Tips as they read the chapter. Students should apply the tips to help them understand the text. [margin]

DIFFERENTIATED INSTRUCTION

• To help auditory and other learners understand the Engage in Science feature, read each paragraph aloud. Then ask students to identify the main idea in the paragraph. Encourage them to question each other and justify their choices.

• You may want to have students who are interested in computers set up a class blog, wiki, or website for posting reports, lab results, presentations, images, videos, links, and other forms of information.

LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Start a word wall for students to use as they work through the chapter.

Remind students to add new words to the wall as they encounter them in the chapter.

Related Resources

Earth, Sun, and Moon: Our Moving Earth. Science Object, 2007. Science Connections 9 ExamView® Test Bank

Science Connections 9 Teacher eSource SUITE Upgrade

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9.1 Motion in the Solar System

OVERALL EXPECTATIONS: A1, D2, D3 SPECIFIC EXPECTATIONS

Scientific Investigation Skills: A1.11, A1.12, A1.13

Developing Skills of Investigation and Communication: D2.1, D2.3 Understanding Basic Concepts: D3.1, D3.2

The full Overall and Specific Expectations are listed on pages xx–xx. KEY CONCEPTS

• The Solar System consists of all the objects orbiting the Sun. • The motion of Earth causes day, night, and the seasons. • Earth’s motion affects our view of the night sky. EVIDENCE OF LEARNING

Look for evidence that students can

• identify and describe the objects in the Solar System

• describe the motions of the planets and other objects in the Solar System • describe the relationship between Earth’s motions, the length of a day, and

time zones

SCIENCE BACKGROUND The Heliocentric Model

• Aristarchus of Samos was the first to propose the heliocentric model in the 3rd century B.C.E. In addition to proposing that Earth moved around the Sun, he proposed that the Sun was 6–7 times wider than Earth, or hundreds of times larger in volume.

Sources of Meteoroids

• Most meteoroids originate as pieces of asteroids. Some come from planets, the result of impact events between the planet and an asteroid or comet. By comparing the chemical compositions of meteoroids with the composition of rock from Mars, scientists have confirmed that at least 30 known meteorites that have landed on Earth came from Mars. Among these Mars meteorites is a famous one known as

ALH84001, which contains microscopic features that some scientists think are fossils of ancient Martian organisms. Planetary Motions

• To make one orbit around the Sun, Mercury takes just under 88 Earth days. For every two of these orbits, Mercury spins only three times on its axis (taking 58.65 Earth days to spin once), so that the apparent movement of the Sun from sunrise to sunrise on the planet takes 176 Earth days, or two Mercurian years. Venus also spins very slowly. A Venusian day (243 Earth days) is a little longer than a Venusian year (225 Earth days). Planets close to a star tend to spin more slowly than planets farther out because they are gravitationally locked to the star.

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POSSIBLE MISCONCEPTIONS

– Identify: Students may think that Earth orbits the Sun once a day. – Clarify: Earth makes two kinds of movements in relation to the Sun: it

rotates on its axis and at the same time revolves around the Sun. A day is the amount of time required for Earth to rotate once on its axis. A year is the amount of time required for Earth to orbit, or revolve around, the Sun once.

– Ask What They Think Now: At the end of the lesson ask, How long does it take Earth to orbit the Sun once? (Earth takes 1 year to orbit the Sun.)

TEACHING NOTES Engage

• Have each student write down everything he or she knows about the motions of objects in the Solar System. Then pair students and have them discuss their lists. Tell students to pay particular attention to ideas that they disagree about. Ask each pair to identify two ideas that they disagree on. Record those ideas on the board. As students work through the section, remind them to consider those ideas and apply their new knowledge to determining whether each idea is correct.

Explore and Explain

• Have students study Figures 1 and 2 on page 330 of the Student Book. Ask, In Figure 1, what object is at the centre? (Earth) In Figure 2, what object is at the centre? (the Sun) Point out that both the geocentric model and

Copernicus’s heliocentric model placed the Solar System at the centre of the Universe. Ask, Is our Solar System at the centre of our galaxy? (no) How is the modern model of the Solar System different from the heliocentric model Copernicus proposed? (In the modern model, the Solar System is not at the centre of the Universe.)

• Have students complete Try This: Distances in the Solar System. TRY THIS: DISTANCES IN THE SOLAR SYSTEM

Skills: Observing, Communicating

Purpose

• To create a scale model of the Solar System

Equipment and Materials (per student): calculator; metre stick; tape (or paperweight); ruler; coloured pencils; roll of art paper

Notes

• The scaled distances for the planets are: Mars, 30 cm; Jupiter, 104 cm; Saturn, 190 cm; Uranus, 384 cm; Neptune, 600 cm. • Just a little more than 6 m of paper is necessary, rather than 8 m, since the distance of Neptune from the Sun comes out to

6 m on this scale. Use your judgement in balancing the need not to tip off students as to scaling of the outermost planet with the need not to waste paper.

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Suggested Answers

A. Increasing the scale by 10, which means multiplying every distance by 10, would result in 1 AU, the distance from the Sun to Earth, becoming 2 m. Neptune would have to be moved out to 60 m from the Sun.

B. Sample answer: Planetary diameters are much, much smaller than 1 AU. If I used the same scale for planetary diameters and distances, either the planets would be so small that they would be invisible or the distances between the planets would be too large to be practical.

• Draw a three-column table on the board. Label the columns asteroids, meteoroids, and comets. Ask students to read the information on page 332 of the Student Book and identify the main characteristics of each type of object. Record the features in the table. When students agree that all the important information has been recorded in the table, tell them to copy the table into their notebooks to refer to later.

• Have students examine Figure 5 on page 333 of the Student Book. Ask, Which planet revolves the most quickly? How do you know? (Mercury revolves the most quickly, because it is closest to the Sun. Planets close to the Sun revolve more quickly than planets that are farther from the Sun.)

• Set an axis-mounted globe on a desk. Spin the globe from left to right slowly and point out the axis of rotation to students. With the classroom lights turned off, have a student shine a bright flashlight on the globe, and ask the class to note how that one side of the planet receives sunlight. Place a coloured sticker on the globe to represent Toronto. Spin the globe slowly, stopping periodically. Each time you stop, ask, Is it day or night in Toronto? (If the sticker is lit, it is day; if it is not lit, it is night.)

• To help students understand why time zones exist, return to the globe and flashlight simulation. Place additional coloured stickers on the globe to represent locations in British Columbia, eastern Russia, Germany, and the United Kingdom. Slowly rotate the globe. As each coloured sticker rotates into the light, say, When a location starts to be lit, the Sun is rising in that location. Suppose you wanted to define 7:00 a.m. as the time the Sun rises. Continue to spin the globe so that students can see that the Sun does not rise in every location at the same time. Ask, Would 7:00 a.m. occur at the same time everywhere in the world? Why or why not? (No. When the Sun is rising at some locations on Earth, it is setting at others.) Explain that people have created time zones so that a given time (such as 7:00 a.m. or noon) refers to the same time of day in every location.

Extend and Assess

• Have students complete BLM 9.1-X Optional Try This: Another Solar System Model for additional practice in making scale models and exploring distances in the Solar System. In this activity, students create their own scale model of the Solar System. Provide students with, or with access to, a map of Canada to complete the activity.

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• Direct students to make a table that lists down the first column: their city or town; a city or town in another time zone of Canada; and a city in the Eastern Hemisphere in the first column. In the second column, beside each of the locations named, tell students to describe approximately where the Sun should appear in the sky (or where it should be if it is night) for each location when it is noon in that place.

•

Have students complete the Check Your Learning questions on page 335 of the Student Book.

CHECK YOUR LEARNING—SUGGESTED ANSWERS

1. Sample answer: A day on Mercury and a day on Earth would be closer in length compared with the length of a day on the larger planets of Jupiter or Saturn. A day on Mercury is probably much hotter than a day on Earth day.

2. An asteroid is a small celestial object made mostly of rock and metal. A comet is made up mostly of dust, gases, and ice. 3. (a) From our perspective on Earth, the Sun and stars seem to move across the sky every day. That apparent movement led

early people to think that if all objects in the Universe moved around Earth, then Earth must be at the centre of the Universe. (b) A major clue that Earth was not at the centre was that some planets periodically seemed to change direction in their

course through the sky.

4. Earth rotates approximately 365 times on its axis in 1 year.

5. The length of a day on Earth is determined by the time it takes for Earth to rotate on its axis.

6. There are different time zones on Earth because, as Earth rotates on its axis, the Sun is always rising (day is starting) and setting (night is starting) at different times over different regions of Earth. Thus, when it is midday on one side of the planet, it is midnight on the opposite side. The system of time zones was developed to make times within a region standard, because relying completely on solar time means that there are small time differences between locations that are very close together.

• To engage multiple learning styles, ask students to prepare summaries of the section in a format of their choosing. Examples of formats include a written summary, a concept map, and an oral presentation.

LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Review the meanings of the word roots geo- and helio- with students. Ask

them to explain how these roots related to the geocentric and heliocentric models of the Universe.

Time 45–60 min Vocabulary • geocentric model • heliocentric model • astronomical unit (AU) • meteoroid • meteor • comet • revolve • rotates • axis • time zone

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Skills Observing Communicating Lesson Materials per student • calculator • metre stick • tape or paperweight • ruler • coloured pencils • roll of art paper Assessment Resources

Assessment Rubric 1: Knowledge and Understanding Assessment Rubric 2: Thinking and Investigation Assessment Rubric 3: Communication

Assessment Summary 1: Knowledge and Understanding Assessment Summary 2: Thinking and Investigation Assessment Summary 3: Communication

Other Program Resources

BLM 9.1-X Optional Try This: Another Solar System Model Skills Handbook 3: Scientific Inquiry Skills

Science Connections 9 website www.nelson.com/scienceconnections/9

Gizmo: Solar System; Solar System Explorer Science Connections 9 ExamView® Test Bank

Science Connections 9 Teacher eSource SUITE Upgrade Science Connections 9 Student Success Toolkit

Science Connections 9 website www.nelson.com/scienceconnections/9

Reading Tip

Restate the Idea

Model restating the main idea for students. Read a paragraph aloud, and explain how you use text clues (e.g., headings, bold words) to identify the main idea. Write the main idea as it is stated in the Student Book on the board. Think aloud for students while you rephrase the main idea.

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Awesome Science: Chicxulub Crater

TEACHING NOTES Before Reading

• Before students read the passage, help them with the correct pronunciation of Chicxulub: “SHEEK-sue-loob.”

• Distribute copies of BLM 0.0-4 Two-Column Table. Ask students to list in the first column any facts they know about Chicxulub Crater, craters in general, what killed the dinosaurs, and meteorites. Ask students to write one fact in each row of the table.

During Reading

• Read the first three sentences aloud to students. Say, The passage does not specifically define meteor or meteorite, but we can use context clues to figure out what the words mean. Ask students to give possible definitions for each term and to explain their reasoning. Write students’ ideas on the board. Organize students to work together to figure out the correct definition of each term. When the class has agreed on the definitions, write these on the board and erase students’ other ideas.

• Have students read through the entire passage with their lists of facts on BLM 0.0-4 Two-Column Table at hand. Tell students that in the second column of the table they will be indicating whether each fact they listed is supported, contradicted, or not addressed by the passage. In the second column beside each fact, students are to put: a check mark if the passage supports the fact; an X if the passage contradicts the fact; and a question mark if the passage does not address the fact at all.

After Reading

• Ask students to look back at their list of facts and focus on the ones that the passage contradicted. Tell students to discuss with a partner where they had learned the information they thought was factual.

• Organize students to work in groups to write a summary of the passage. Remind them of the key parts of a summary: statement of the main idea, identification of supporting details, and omission of irrelevant details. Remind students to write the summary in their own words.

• Conclude by having students complete BLM 9.AS Awesome Science: Chicxulub Crater as OSSLT practice.

• All learners will benefit from exploring the content of the passage in different ways. Ask students to create diagrams, poems, or other products to convey the information in the passage.

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LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Lower-proficiency English language learners will benefit from a review of

the different forms of the past tense. Review with students how different forms of the past tense can indicate sequence and continuity, and point out examples in the passage. For example, read the first sentence of the third paragraph to students. Explain that the phrase since…have suspected indicates that scientists began suspecting a meteorite collision in the 1980s, and still suspect it today—that is, the action is ongoing. In contrast, the phrase may have led indicates an action that is completed.

Time 30 min

Literacy Resources

BLM 9.AS Awesome Science: Chicxulub Crater Other Program Resources

BLM 0.0-4 Two-Column Table

Science Connections 9 ExamView® Test Bank

Science Connections 9 Teacher eSource SUITE Upgrade Science Connections 9 website

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9.2 Seasons

OVERALL EXPECTATIONS: D2, D3 SPECIFIC EXPECTATIONS

Developing Skills of Investigation and Communication: D2.1 Understanding Basic Concepts: D3.2

• The motion of Earth causes day, night, and the seasons. • Earth’s motion affects our view of the night sky. EVIDENCE OF LEARNING

• describe the effects of Earth’s rotation, revolution, and tilt

• describe the relationship between a planet being tilted on its axis and whether or not it has seasons

SCIENCE BACKGROUND NCE BACKGROUND

• At 25°, the tilt of the axis of rotation of Mars is very similar to that of Earth. For this reason, Martian hemispheres experience four seasons. The seasons are nearly twice as long as those on Earth, however, since a year on Mars is nearly twice as long as an Earth year. The effect of seasons on Mars is very striking in the appearance of the Martian poles. These poles are covered with ice- caps, each of which is biggest when it is winter in its hemisphere, shrinks as its hemisphere moves through spring and into summer, and then begins to grow again in autumn.

• The Martian seasons also may have an influence on decisions related to timing and landing sites of future human mission to Mars. Landing on a part of Mars where it is mid-spring and where astronauts would remain through summer means that the atmosphere of that region would be slightly warmer and thus expanding to higher altitudes compared with the atmosphere in winter regions. This, in turn, would reduce the amount of radiation reaching the surface of the planet where astronauts would be exploring, thus reducing the overall radiation dose the astronauts would receive.

– Identify: Students may think that Earth’s axis tilts toward or away from the Sun at different times of year—that is, that the axis itself changes angle relative to the Sun.

– Clarify: Earth’s axis is always tilted in the same direction. As Earth orbits the Sun, the axis stays fixed.

– Ask What They Think Now: At the end of the lesson ask, Does the angle of Earth’s axis change during a year? (No. The angle stays the same. Only Earth’s position changes.)

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• Distribute copies of BLM 0.0-1 K-W-L Chart to students. Have them work individually to describe what they Know and Wonder about seasons. Make a class list of facts that all students agree on and a list of questions that all students are curious about. At the end of the section, return to the chart. Explore and Explain

• Use a globe with a tilted axis and a lamp with a bare light bulb to illustrate the concepts in this section. Place the lamp in the centre of the room. – To show the effects of Earth’s tilt and orbital location on the seasons, hold

the globe a short distance away from the lit bulb. Spin the globe and ask students to describe which parts of it receive the most light as the globe spins. Next, carry the globe to the direct opposite side of the lamp, maintaining the correct axis of tilt. Again rotate the globe and ask students to describe the lit portions.

– To show that the length of day changes as Earth orbits the Sun, place a coloured sticker near Toronto and another one near Buenos Aires in

Argentina. Give two students stopwatches. Rotate the globe very slowly and ask the students to use the stopwatches to determine how long each sticker is lit and how long it is dark. Then carry the globe 90° farther around in its orbit and repeat the process. Repeat this step three more times, until you have moved the globe in a complete orbit around the lamp. Record the times on the board and ask students to compare them. Students should be able to see that the amount of daylight each location receives varies during the course of the year.

• Have students complete BLM 9.2-X Optional Try This: Model the Seasons for further exploration of the causes of the seasons. In this activity, student groups use a large foam ball and a flashlight to explore the intensity of solar radiation at different points during different times of year. The balls students use should be as large as possible—the size of a soccer ball is ideal.

• Have students return to their K-W-L charts and record what they learned in this section. As a class, review the statements in the Know column and identify and correct any errors. Review the Wonder column and ask students to give the answers to any questions they learned the answers to in this section. Ask students for ideas of resources they could use to find the answers to any unanswered questions.

•

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1. Seasons result from Earth’s axis being tilted, which results in one hemisphere receiving more light each day while the other hemisphere receives less light.

2. A sample diagram is shown below.

3. Because Earth spins on a tilted axis, during summer in the southern hemisphere, the South Pole faces the Sun for 24 hours per day and the North Pole faces away from the Sun.

4. A solstice occurs when Earth’s axis is most inclined toward or away from the Sun. Equinoxes happen halfway between the solstices and occur when day and night are of equal length.

5. If a planet were not tilted on its axis, then you would know that it experiences no seasons.

• All learners, and especially kinesthetic learners, will benefit from exploring three-dimensional models of Earth’s motions. Allow students to experiment with balls, lights, and other objects to model the motions of Earth. To address other learning styles, ask students to describe what they observe either in written form or by discussing it with a partner.

LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Have English language learners and struggling readers draw a three-column

table in their notebooks. As they read, tell them to record in the first column any words or phrases they do not understand, and, in the second column, what they think the words or phrases mean based on the context clues. Then have students work with partners to determine the correct meaning for each word or phrase, recording the correct meaning in the third column of the table. Time 45–60 min Vocabulary • solstice • equinoxes Assessment Resources

Assessment Rubric 1: Knowledge and Understanding Assessment Summary 1: Knowledge and Understanding Other Program Resources

BLM 0.0-1 K-W-L Chart

BLM 9.2-X Optional Try This: Model the Seasons

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Gizmo: Seasons Around the World; Seasons: Why do we have them?

Donna Governor, Ayla Cetin-Dindar, Pat Doney, Jessica Harper, Lynda Jenkins, Clintia Ortiz-Blanco, and Deborah Tippins. Solar Paths: An International and Integrated Look at the Sun and Seasons. Science Scope, 2009.

www.nelson.com/scienceconnections/9

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9.3 Star Patterns

OVERALL EXPECTATIONS: A1, D2 SPECIFIC EXPECTATIONS

Scientific Investigation Skills: A1.3, A1.10, A1.11

Developing Skills of Investigation and Communication: D2.1, D2.2

• Earth’s motion affects our view of the night sky.

• Celestial objects can be used to predict annual events and to navigate. EVIDENCE OF LEARNING

• define and differentiate between constellations and asterisms • explain why stars seem to move across the sky

SCIENCE BACKGROUND

• After the Sun, the next brightest star in Earth’s skies is Sirius, in the constellation Canis Major. Polaris is the 49th brightest star in the sky. Though Polaris is above the North Pole at the current time, its status as” North Star” will eventually change, as a result of a wobble in the Earth’s axis. Approximately 12 000 years from now, the North Star will be Vega, in the constellation Lyre.

• The stars and constellations shown in Figure 4 (page 341 of the Student Book) for the Northern Hemisphere are

circumpolar if viewed by someone located on Earth above a certain northern latitude. As one moves south, toward and beyond the equator, parts of these constellations farther out from Polaris rise and set until finally Polaris no longer is visible. • The pole star for the south is Sigma

Octantis in the constellation Octans. Since it is more than 1° away from the point above the pole and extremely dim, Sigma Octantis is not as useful for finding the south celestial pole as Polaris is for finding the north celestial pole.

– Identify: Students may think that all the stars they can see in a constellation or asterism lie at the same distance from Earth.

– Clarify: The stars in a constellation or asterism are at varying distances from Earth. They are in a three-dimensional arrangement, not

two-dimensional. Because of their relative size and brightness, they only appear to lie as though they were on a flat background at exactly the same distance away.

– Ask What They Think Now: At the end of the lesson ask, If you could travel anywhere in space, why would it be impossible to travel to a constellation or asterism? (The stars within a constellation or asterism are not actually located together in space. They just appear that way from Earth because we cannot tell how far apart they are from one another, and they appear to be part of the same two-dimensional image.)

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• Lead a class discussion about constellations. Ask students to describe what they know about constellations and stars in general. Write students’ ideas on the board. As students work through the section, ask them to identify any ideas they had that are incorrect.

• Distribute copies of BLM 0.0-2 Venn Diagram. Have students work in pairs to complete the Venn diagram to compare constellations and asterisms. • To help students understand why Polaris does not appear to move but the

other constellations do, model the motion of Earth relative to the constellations. Have a student sit in a desk chair that can rotate. Hold an illustration of the circumpolar constellations above the student’s head, with Polaris in the centre. Instruct the student to tilt his or her head back while you slowly rotate the chair to simulate Earth’s rotation. Ask the student to

describe what happens to the stars as the chair rotates.

• Have students complete Try This: Mapping Constellations on page 342 of the Student Book.

TRY THIS: MAPPING CONSTELLATIONS

Skills: Observing, Analyzing, Communicating

Purpose

• To model the changes in constellation patterns over the course of a year

Equipment and Materials (per student): paper

Notes

• The same constellations are visible at points along the same latitude. Therefore, if students have difficulty finding a star map for their specific area, they can substitute one for an area at similar latitude.

A. Sample answer: The time that the constellation rises and sets would change throughout the 2-week period.

B. As Earth orbits the Sun, different constellations are in Earth’s line of sight at different times of day. We can see only the ones that are in the line of sight at night.

• After students complete Try This: Mapping Constellations, ask them to predict how the results might be different if they chose a location near the North Pole. Once students have made their predictions, ask them to investigate the constellations visible at the North Pole during different seasons.

•

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1. An asterism is a pattern of stars. A constellation is a large region of stars in the night sky.

2. Most constellations appear to move from east to west across the sky each night because Earth rotates on its axis toward the east.

3. We see different constellations in the night sky during different seasons because both Earth’s orbit around the Sun and Earth’s tilted axis mean that our direction of view out towards the stars is constantly changing throughout the year. 4. A circumpolar constellation is a constellation that always is visible in the sky.

• Have students create media products to describe the constellations visible in your area. Explain to students that their products should be directed at younger students. Allow students to choose the format of their products. LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Review the meaning of the word root aster- with students. Ask them for

additional examples of words with this root that they think they will encounter in this unit (such as asteroid, astronomy, and astronomical). Time 45–60 min Vocabulary • constellation • asterism • circumpolar Skills Observing Analyzing Communicating Lesson Materials per student • paper Assessment Resources

Assessment Rubric 1: Knowledge and Understanding Assessment Rubric 2: Thinking and Investigation Assessment Summary 1: Knowledge and Understanding Assessment Summary 2: Thinking and Investigation Other Program Resources

BLM 0.0-2 Venn Diagram

Skills Handbook 3. Scientific Inquiry Skills Skills Handbook 4. Research Skills

José Rios. Stargazing in Your Classroom. Science Scope, 2003. Science Connections 9 ExamView® Test Bank

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History Connection

Many of the constellations are named after characters in ancient myths. Have students research the historical bases of one or more constellations and present their findings to the class in a creative way, such as a documentary or ballad-style poem.

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9.4 How People Use the Stars

OVERALL EXPECTATIONS: D2, D3 SPECIFIC EXPECTATIONS

• Celestial objects can be used to predict annual events and to navigate. EVIDENCE OF LEARNING

Look for evidence that students can • describe ways that people use stars

• define, differentiate between, and describe the use of azimuth and altitude

• One of the most obvious examples of celestial navigation (navigation making use of star positions) is the use of Polaris to know which way is north. The ancient Phoenicians first recognized that Polaris’ position is fixed in the sky. Before this discovery, ships travelling on the Mediterranean Sea tended to stay within view of the coastline to avoid getting lost, even if this made the route to their destination extremely indirect.

• Once navigators realized that they could maintain an accurate course by keeping

Polaris directly in front or in back of their ship at night, ships began crossing the Mediterranean along direct north-south routes. Now possible were fast trips between Africa and points across the sea such as Cyprus, Anatolia, Greece, Crete, and Italy. This, in turn, is thought to have helped to bring about a renaissance of culture and international trade that corresponded with the spread of the Canaanite alphabet, the end of the Greek Dark Age, and the beginning of the phase of civilization known as the Iron Age.

– Identify: Students may confuse astronomy and astrology.

– Clarify: Astronomy is a scientific discipline: the study of space and the objects in it. Astrology is a non-scientific belief that the positions of the stars and planets relative to Earth can affect human behaviour or the events that occur.

– Ask What They Think Now: At the end of the lesson ask, Which is more similar to biology, astronomy or astrology? (Astronomy is more similar to biology because both are scientific disciplines.)

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• Engage students’ interest by showing images of various ancient structures that were inspired by the heavens and discussing their origins and

significance. Examples of such structures include Stonehenge, the Great Pyramid at Giza, and the Maya Palace of the Governor at Uxmal.

• Remind students of what they already know about Earth’s motions and the effect of those motions. Say, You know that Earth orbits the Sun, and that the seasons follow a pattern as Earth moves in its orbit. You just learned that Earth’s orbit also affects the patterns of stars that are visible in the sky. Ask students to summarize how Earth’s orbit affects the visible stars. Then, ask, Do you think the same star patterns appear in the sky at the same times each year? Why? (Sample answer: Yes, I think they appear at the same time each year, because Earth moves through its orbit at the same speed each year.)

• Explain to students that it is not only the stars that have different positions during different seasons. The Sun also follows a different path through the sky during different seasons. During the winter in the northern hemisphere, the Sun does not rise as high in the sky during the day as it does during the summer. Ask, What have you noticed about the size of your shadow at different times of day? (When the Sun is low in the sky, my shadow is longer.) Explain that just as a person’s shadow changes size over the course of a day, the shadow of an object at a certain time of day changes over the course of the year as the Sun moves to different positions overhead. These changes in the shadows allowed ancient peoples to use shadow length to predict the seasons.

• Demonstrate for students how to measure altitude and azimuth using a

finger, a fist, and an outstretched hand (shown in Figures 5–7 on page

345 of the Student Book). Measure the altitude and azimuth of various

objects in the classroom.

• Have students complete BLM 9.4-X Optional Try This: Determining Azimuth and Altitude for practice using their hands to calculate altitude and azimuth. If possible, students should complete this activity outside, in an area where the horizon is visible. Students will need to use a compass to determine which direction is north. If compasses are unavailable, tell students which direction is north.

•

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1. Many ancient civilizations used the appearance of certain stars to determine when planting seasons began and ended. 2. Large structures such as Stonehenge were built as a means of helping early people keep track of changing seasons, predict

annual events such as flooding, and honour their religious beliefs.

3. Before the invention of navigational devices, sailors used the positions of stars and constellations to determine their location and course direction.

4. Students should explain to their partners how to use a finger, fist, and outstretched hand to estimate the azimuth of an object in degrees from north (0°).

• Have students make how-to instructions for measuring azimuth and altitude. Tell them that their instructions should be clear enough for a member of the general public to understand. Allow students to present their instructions in a method of their choosing, such as written instructions, a video, or a series of diagrams.

LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • The terms azimuth and celestial may present pronunciation difficulties for

English language learners. Enunciate these terms clearly for students, and give them opportunities to practise pronouncing the terms.

Time 45–60 min Vocabulary • azimuth • altitude Assessment Resources

Assessment Rubric 1: Knowledge and Understanding Assessment Rubric 2: Thinking and Investigation Assessment Rubric 3: Communication

Assessment Summary 1: Knowledge and Understanding Assessment Summary 2: Thinking and Investigation Assessment Summary 3: Communication

Other Program Resources

BLM 9.4-X Optional Try This: Determining Azimuth and Altitude Science Connections 9 website www.nelson.com/scienceconnections/9

Bob Riddle. Scope on the Skies: Celestial Grid System. Science Scope, 2003. Science Connections 9 ExamView® Test Bank

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9.5 Conduct an Investigation: What Can You See Tonight?

OVERALL EXPECTATIONS: A1, D2

SPECIFIC EXPECTATIONS

Scientific Investigation Skills: A1.5, A1.10, A1.11, A1.12, A1.13 Developing Skills of Investigation and Communication: D2.2

• Celestial objects can be used to predict annual events and to navigate. EVIDENCE OF LEARNING

• make diagrams showing the altitude and azimuth of objects in the night sky

• Planets moving in relation to

constellations are very difficult to detect in the course of a few hours in a single evening. From night to night, the movement of a planet can be very obvious, particularly for an inner planet. Planets, as well of the Moon, appear in the sky in a band of constellations known as the Zodiac. Because the inclination of the Moon’s orbit around Earth is only 5.5°

with respect to Earth’s equator, and because Earth and other planets orbit inclined within a few degrees of one another, and inclined within several degrees of the Sun’s equator, the Zodiac is a band running several degrees on either side of the ecliptic, the path that the Sun appears to take through the sky. Thus, from Canada, the Zodiac constellations and the planets and Moon appear to the south.

TEACHING NOTES

• Have students work individually on this investigation. Testable Question

• Remind students that “move across the night sky” refers to apparent movement, not actual movement.

Prediction

• Sample prediction: I think celestial objects will appear to move from east to west across the sky.

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Experimental Design

• Clarify for students that they will make observations each hour for 3 hours. Equipment and Materials

• If students do not have a hand-held compass, they may find south by locating circumpolar constellations that they recognize in the north, using those to find Polaris, and then turning around and facing exactly the opposite direction to face the south.

• Students can use a flashlight with red cellophane over the bulb to light their papers as they draw. They should not use an unfiltered light, as it will cause their pupils to constrict and make it more difficult for them to observe the stars.

Procedure

• Review with students how to note the azimuth and altitude of an object. Azimuth is given first with the symbol A, and altitude is given second with the symbol Z. For example, an object with an azimuth of 60° and an altitude of 30° would be indicated with the text A = 60°, Z = 30°.

• Remind students that they do not have to record the azimuth and altitude of every star; they only need to record the positions of the brightest objects in the sky.

• Explain that some objects close to Earth, such as planes and satellites, are visible at night. These objects will move noticeably over the course of a few minutes. Tell students not to record the positions of objects that move that quickly.

Analyze and Evaluate

(a) Celestial objects appear to move from east to west.

(b) Sample answer: My observations agreed with my prediction. I thought the stars would move from east to west across the sky, and they did.

(c) Sample answer: Objects that were directly overhead at the first

measurement moved approximately 45° westward in altitude over a period of 3 hours.

(d) Sample answer: Objects moved noticeably in the sky throughout the evening. Objects rose and set at different times, or appeared at noticeably different locations when observed at the same times on different evenings. I think if I repeated the investigation in a few more days, the positions of the stars would be different again.

Apply and Extend

(e) Check that students’ sketches outline each constellation and identify it by name. The exact constellations visible will depend on the time of year, the student’s latitude, and how much light pollution is present in the student’s area.

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• Group students with different learning styles and ask them to discuss the procedure, clarifying anything that is unclear. Encourage students to explain the investigation procedure in ways that address different learning styles. LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Lower-proficiency English language learners will benefit from a review of

directional terms (north, east, south, west) and time-related terms (hour, day). Time 45–60 min Skills Predicting Controlling Variables Performing Observing Analyzing Evaluating Communicating

Equipment and Materials per student

• compass • paper • pencil

Assessment Resources

Assessment Rubric 5: Conduct an Investigation Assessment Summary 5: Conduct an Investigation Self-Assessment Checklist 1: Conduct an Investigation Other Program Resources

Skills Handbook 3: Scientific Inquiry Skills Skills Handbook 4: Research Skills

Bob Riddle. “Scope on the Skies: Tracking Planets Around the Sun.” Science Scope, 2008.

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9.6 Phases of the Moon

Scientific Investigation Skills: A1.5, A1.8, A1.10, A1.11

Developing Skills of Investigation and Communication: D2.1, D2.2, D2.3 Understanding Basic Concepts: D3.2, D3.5

• Earth’s motion affects our view of the night sky.

• The positions of the Sun, Earth, and the Moon result in the lunar cycle and eclipses.

EVIDENCE OF LEARNING Look for evidence that students can

• explain that gravity is what keeps the Moon in orbit around Earth

• explain why the Moon changes in appearance over the course of a

month

• Not all of the light that reflects from the Moon comes directly from the Sun. There is a phenomenon known as Earthshine, in which light reflected from Earth reaches the part of the night side of the Moon that is facing Earth and lights it slightly. In such cases, the “unlit” part of the Moon is visible as a darker area that completes the circle that is lit only partly by the Sun.

Observing the Moon with Earthshine, one can see easily the entire disc of the Moon, even though only a section of it is brightly illuminated by the Sun. • When the shape of the Moon is larger

than a half moon and smaller than a full circle, the Moon is referred to as gibbous. Thus, the Moon goes through the following eight phases: new moon, waxing crescent, waxing half moon, waxing gibbous, full moon, waning gibbous, waning half moon, and waning crescent (and then back to new moon again).

– Identify: Students may think that people on different parts of Earth see different phases of the Moon at any given time.

– Clarify: When the Moon appears full in the sky, it is full everywhere that it can be seen from Earth. When it appears as a crescent, everybody on Earth who can see it is seeing it as a crescent.

– Ask What They Think Now: At the end of the lesson ask, If you see a full moon tonight, what phase of the moon will someone in Australia see? (a full moon)

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• Have students do a Think/Pair/Share activity to summarize what they know about the phases of the Moon. Tell students to discuss what causes the phases, what the phases are, and what order they occur in. Record students’ ideas on chart paper and post them in the classroom. Tell students to modify the ideas on the paper as they work through the section. Explore and Explain

• Have students examine Figure 1 on page 348 of the Student Book. Point out that the gravitational force between Earth and the Sun keeps Earth in orbit around the Sun. Ask, How would the diagram in Figure 1 be different if it showed the motion of the Moon around Earth? (The Moon would be where Earth is and Earth would be where the Sun is in the diagram.)

• To help students understand why we always see the same face of the Moon, have two student volunteers model the motion of the Moon around Earth. Have one student stand in the middle of the room, representing Earth. Have the other student (the Moon) stand at least 1 m away, facing the first student. Then, have the Moon walk slowly around Earth, keeping his or her body facing Earth. (Earth should not move.) Ask , What is happening to the Moon’s body? (It is rotating.) When the Moon returns to his or her initial spot, point out that he or she made one complete rotation and one complete revolution in the same amount of time. Explain that the only way for the visible part of the Moon to be the same at all times is for the rotational period and the orbital period to be the same.

• Ask, Why can we see the Moon? (It reflects light.) Why do you think we cannot see the Moon when it lies in the same direction from Earth as the Sun? (If the Moon lies between the Sun and Earth, all light reaching the Moon is reflected away from Earth.)

• To help students understand how the phases of the Moon relate to the positions of Earth, the Moon, and the Sun, draw a diagram on the board similar to the one shown below.

[Image to come]

Point out to students that one-half of the Moon is always lit, but that the lit half does not always face Earth. Ask students to relate the photographs in Figure 2 on page 349 of the Student Book to the positions of the Moon in the drawing.

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TRY THIS: MODELLING THE LUNAR PHASES

Skills: Observing, Communicating, Analyzing

Purpose

• To describe the phases of the Moon

Equipment and Materials (per student): a lamp with a 40- to 60 W incandescent light bulb (lampshade removed); polystyrene ball; pencil

Student Safety: As with any electrical device, students should be careful not to touch any un-insulated parts of wires. They should avoid touching the bulb, as it can get hot enough to cause burns.

Notes

• In order for the phases of the simulated Moon to show, the classroom has to be made very dark.

A. When the Moon lies in the same direction from Earth as the Sun, the entire unlit side faces Earth and it is called a new moon. One-quarter of the way around the simulated orbit, half of the illuminated part of the ball faces Earth and the other half of the illuminated part of the ball faces away from Earth. This is a first-quarter moon. Half-way around the circle, when the Moon and Sun are in opposite directions from Earth, the entire illuminated side is visible from Earth. This is called a full moon. Three-quarters of the way around, half of the illuminated part of the ball is again visible from Earth. This is a last-quarter moon. After another last-quarter revolution around Earth, it is a new moon again.

B. Sample answer: Using a more powerful light with a focussed beam and a larger ball would make the phases of the moon appear more distinct.

• Ask students to guide you in making a flow chart, concept map, or mind map of the section. Tell students to first identify the main ideas of the section and to record their ideas on the board. Then ask students to explain how each of the main ideas is connected to the other ideas.

•

1. Gravity holds the Moon in orbit around Earth.

2. The same side of the Moon always faces Earth because the Moon takes the same amount of time to rotate once on its axis as it takes to revolve once around Earth.

>

4. The waxing phases occur when the Moon is getting bigger, during the first half of the month. The waning phases are when the Moon is shrinking.

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• To help visual, kinesthetic, and other learners complete the Try This activity, demonstrate the steps for them as they follow along in the Student Book. This will help students understand the instructions.

LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Students may confuse waxing with the noun wax, referring to the substance

used in candles. Explain that wax can also be a verb meaning to increase. Explain that the two different forms of wax have different roots and became part of the English language in different ways.

Time 45–60 min Vocabulary

• gravitational force • lunar cycle

• phases of the Moon • waxing • waning Skills Observing Communicating Analyzing Lesson Materials per group

• lamp with a 40- to 60 W incandescent light bulb (lampshade removed) • polystyrene ball

• pencil

Assessment Resources

Assessment Rubric 1: Knowledge and Understanding Assessment Rubric 2: Thinking and Investigation Assessment Summary 1: Knowledge and Understanding Assessment Summary 2: Thinking and Investigation Other Program Resources

Skills Handbook 3: Scientific Inquiry Skills

Gizmo: Phases of the Moon

Page Keeley, Francis Eberle, and Lynn Farrin. “Gazing at the Moon.” Chapter in Uncovering Student Ideas in Science: 25 Formative Assessment Probes. NSTA, Vol. 1, 2005.

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Reading Tip

Organization of Text

Point out the organization of this section: first, gravitational force is defined and described. Next, the causes of the phases of the Moon are explained. Finally, the order in which the phases occur is described. Explain to students that a summary of this section should follow the same organization.

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9.7 Eclipses

Scientific investigation Skills: A1.4

Developing Skills of investigation and Communication: D2.1 Understanding Basic Concepts: D3.5

• The positions of the Sun, Earth, and the Moon result in the lunar cycle and eclipses.

• describe the causes of solar and lunar eclipses

• The shadow of the Moon that falls on Earth during an eclipse has two parts, the umbra and the penumbra. The umbra is the darkest portion of the Moon’s shadow. Locations on Earth that lie within the umbra experience a total solar eclipse.

• The penumbra is the outer portion of the Moon’s shadow. In this area, only some of the Sun’s light is blocked. Locations on Earth that lie within the penumbra experience a partial solar eclipse. The umbra is much smaller than the penumbra, which is why each total solar eclipse is visible only from a small area of Earth’s surface.

• Our ability to see a total solar eclipse is the result of the positions and sizes of the Sun and Moon. Although the Moon is much smaller than the Sun, it is much closer to Earth. As a result, the Sun and

the Moon appear to us to be the same size in the sky. If the Moon were farther from Earth, we would never see a total solar eclipse.

• Solar and lunar eclipses occur only during specific moon phases. A solar eclipse can occur only during a new moon, when the Moon lies between Earth and the Sun. A lunar eclipse can occur only during a full moon, when Earth lies between the Moon and the Sun.

• The plane of the Moon’s orbit around Earth is tilted relative to the plane of Earth’s orbit around the Sun. As a result, Earth, the Moon, and the Sun lie directly in line only occasionally. If the Moon’s orbital plane and Earth’s orbital plane were the same, we would see a solar eclipse and a lunar eclipse each month.

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– Identify: Students may think that the Moon moves around Earth from east to west, since it rises in the east and sets in the west.

– Clarify: The Moon orbits Earth from west to east, the same direction that Earth spins on its axis. Since Earth makes one eastward rotation faster than the Moon makes one eastward orbit (one day vs. one month), the Moon seems to be moving from east to west across Earth’s skies.

– Ask What They Think Now: At the end of the lesson ask, In which direction does the Moon orbit Earth? (The Moon orbits from west to east.)

• Ask if anyone in the class has ever seen a solar eclipse or lunar eclipse. If students have, invite them to share their experience with the class. Have students brainstorm things they have heard about eclipses (e.g., why eclipses happen, how often they occur, what ancient people thought they were).

• Using the same setup from Try This: Modelling the Lunar Phases in Section 9.6 (on page 350 of the Student Book), demonstrate for students the arrangement of the Sun, Earth, and the Moon that can produce a solar eclipse. Direct a student representing Earth to stand 1–2 m from the lit lamp. Hold the ball representing the Moon between Earth and the bulb. Point out the shadow that the ball casts on Earth.

• Distribute copies of BLM 0.0-3 Compare and Contrast Chart. Have students work in pairs to complete the chart to compare solar eclipses and lunar eclipses.

• As an extension activity, organize students into pairs and have them conduct Internet research to learn when the next solar and lunar eclipses will occur. Ask students to create informational posters to inform their classmates about the causes of eclipses and about when the next eclipses will be visible from their area.

•

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1. An eclipse is a good time for scientists to observe the outer atmosphere of the Sun because the outer atmosphere is normally not bright enough to be seen through the light of the rest of the Sun.

>

3. A sample diagram is shown below. >

4. If you were standing on the daytime side of the Moon during a total lunar eclipse, you would see Earth move in front of the Sun, causing it to get dark as if it were night.

• Allow students to answer the Check Your Learning questions in a format of their choice. For example, instead of drawing a diagram to show how a solar eclipse occurs, kinesthetic learners could act it out and verbal learners could write a paragraph.

LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Review the meanings of the adjectives solar and lunar with students. Ask

them to write sentences using each term. Alternatively, give them several sentences using the terms (with some sentences using the incorrect term) and ask them to identify the correct and incorrect uses.

Time 45–60 min Vocabulary • solar eclipse • lunar eclipse Assessment Resources

Assessment Rubric 1: Knowledge and Understanding Assessment Summary 1: Knowledge and Understanding Other Program Resources

BLM 0.0-3 Compare and Contrast Chart

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Gizmo: Eclipse; 3D Eclipse

Bob Riddle.Scope on the skies: You’re blocking my view, Science Scope, 2005. Science Connections 9 ExamView® Test Bank

Literature Connection

Solar and lunar eclipses appear in the literature and oral histories of many cultures. Have students research myths, fairy tales, or other stories that feature eclipses. Ask them to summarize their findings in a report, poster, or video.

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9.8 Expansion of the Universe

OVERALL EXPECTATIONS: A1, A2, D2, D3 SPECIFIC EXPECTATIONS

Scientific Investigation Skills: A1.5, A1.8, A1.10 Career Exploration: A2.2

• Scientists have strong evidence that the Universe began around 14 billion years ago.

• describe the evidence for the expansion of the Universe • summarize the Big Bang theory

• The red shift is an example of a phenomenon known as the Doppler effect. The Doppler effect is the apparent change in frequency of waves that occurs because of the movement of the source of the waves relative to the observer.

• The most commonly observed example of the Doppler effect is the change in the pitch of a police, fire, or ambulance siren as the vehicle approaches and then speeds away. As the vehicle approaches the observer, the pitch of the siren sounds higher. As it moves away from the observer, the pitch sounds lower. • The Doppler effect can be observed for

all energy travelling as waves. When the source and the observer are moving toward one another, the observed wave

frequency increases. For sounds, a higher frequency corresponds to a higher pitch; for visible light, a higher frequency corresponds to a shift toward the blue end of the electromagnetic spectrum. When the source and the observer are moving apart, the observed wave frequency decreases. For sound, this results in a lower pitch; for visible light, it produces a shift to the red end of the spectrum (red shift). • The Doppler effect can occur only when

the relative velocity of the source and observer is a significant fraction of the speed of the wave. We cannot observe red shift on everyday objects because they travel much more slowly than the speed of light. Stars and galaxies are moving much more quickly, so they exhibit a visible red shift.

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– Identify: Students may think that, because all observed galaxies are moving away from us, the Solar System is at the centre of the Universe.

– Clarify: Because the Universe is expanding in all directions, all objects appear to moving away from all other objects. This is similar to the motion of raisins in raisin bread dough as the dough rises. All the raisins move away from each other; none stays stationary at the centre of the dough. – Ask What They Think Now: At the end of the lesson ask, If you were an

astronomer in the Andromeda galaxy, how would all other galaxies appear to be moving? (All the other galaxies, including the Milky Way, would seem to be moving away from you.)

• Review with students what they learned in Section 8.1 about the Universe. Write the word Universe on the board. Ask students to list examples of objects that are part of the Universe. Conclude by asking, Is there anything that is not part of the Universe? (no)

• Relate red shift to Doppler shift in sound waves. Ask, When a police car goes past, what happens to the sound of the siren? (It sounds higher pitched the closer it gets, and then lower pitched the farther it moves away again.) Explain that this apparent change in pitch happens when the sound waves are stretched or compressed because of the movement of the source. When the siren is moving away from you, the sound waves are stretched out and the siren sounds lower pitched. Explain that the same thing happens to light from distant galaxies. Because the light from distant galaxies is shifted toward lower frequencies (the red end of the electromagnetic spectrum’s rainbow colours), we know the light waves are stretched out, which indicates that the galaxies are moving away from us.

• Explain that red shift is one of the pieces of evidence for the Big Bang theory. Scientists think that the motions of the galaxies are the result of the initial expansion that happened during the early moments of the formation of the Universe.

• Have students complete Try This: Model the Expanding Universe on page 355 of the Student Book

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TRY THIS: MODEL THE EXPANDING UNIVERSE

Skills: Performing, Observing, Analyzing, Communicating

Purpose

• To model the expansion of the Universe

Equipment and Materials (per student): marker; tape measure; round balloon

Notes

• Adding many more galaxies in different directions will help to illustrate the point that space is expanding at the same rate in all locations and that all galaxies are expanding away from all others, even though none is the centre of the Universe.

A. The distances between the galaxies on the balloon increased as the balloon was inflated. B. Galaxy D would appear to move away from you most quickly.

C. Galaxy B would appear to move away from you most slowly.

• Have students work in pairs to generate a summary of this section. Consider distributing copies of BLM 0.0-5 Concept Map for students to use in making their summaries.

•

1. Observing a red shift in the light spectrums of distant galaxies indicates to astronomers that the galaxies are moving away from Earth rather than simply being stationary or moving towards it.

2. Based on his observation of the red shifting of spectrums in galaxies increasing as the galaxies’ distance from Earth increased, Hubble realized that objects farther away from one another in the Universe were moving away from one another faster than objects that were closer together. From this, he concluded that the Universe itself is expanding.

3. No. Stars and galaxies did not form immediately after the Big Bang. They are thought to have started forming a billion years later.

4. Cosmologists study the makeup and origins of the Universe.

• Group students with different learning styles and ask them to prepare an informative documentary about the Big Bang theory and the expansion of the Universe. Allow students with different learning styles to contribute in different ways. For example, verbal learners might write a script for a video; interpersonal learners might conduct interviews; and mathematical/logical learners might prepare diagrams or charts.

LITERACY TIPS AND ENGLISH LANGUAGE LEARNERS • Have English language learners identify parts of this section they do not

understand. Pair each student with a native English speaker and ask them to discuss the section, focusing especially on parts that are not clear.