Elemsci Volume 3

Writers Elvira R. Galvez

Grace R. Sumayo

Coordinator Nora Cordero

Reviewers Evelina M. Vicencio, PhD

Elvira R. Galvez

Editors Josefina G. Belen, PhD

Graphic Artist Redd Macaranas

Elena Cutiongco, PhD

TSM First Edition

Writers: Carolette B. Bacani, Camp Crame Elementary School, QC; Leticia P. Cortes, University of the East, Manila; Silverio O. Estorco, Lagro Elementary School, QC; Sonia V. Estrella, San Agustin Elementary School, QC; Mario Jose V. Malabunga, Jr., U.P. Integrated School, QC; Ritchie T. Manzano, U.P. Integrated School, QC; Violeta S. Martinez, Commonwealth Elementary School, QC; Eusebia P. Matute, North Fairview Elementary School, QC: Noreen Marie M. Nunez, LINC International; Emely M. Pelobello, Camp Crame Elementary School, QC; Rachel Patricia B. Ramirez, U.P. Integrated School, QC; Eugenio C. Ticzon, Bagong Barangay Elementary School, Manila; Evelina Maclang Vicencio, PhD, University of the Philippines, Diliman, QC.

Content Editors: Noel G. Cuizon, MD, PhD, University of the Philippines. Manila; Aurora A. Lianko, PhD, U.P. Integrated School; Edmund M. Rosales, National Institute for Science and Mathematics Development; John Vincent D. Salayo, Miriam College High School; Rosanelia T. Yangco, PhD, U.P. Integrated School

Coordinator: Evelina M. Vicencio, PhD

Artists: Maximo de Jesus; Addie Saliva

Volume 3 Contents Page

Theme 6. Earth Episode 33 The Living Planet 1 Episode 34 The Precious Soil 15 Episode 35 Water: The Drop of Life 25 Episode 36 Atmosphere: The Earth’s Shield 36 Episode 37 The Restless Earth 51

Theme 7. Earth and Space Episode 38 The Great Triumvirate: Earth, Moon, and Sun 69 Episode 39 The Solar System 88 Episode 40 Beyond the Solar System 108

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VOLUME 6. EARTH EPISODE 33. THE LIVING PLANET

OVERVIEW OF THE EPISODE This episode describes the three layers of the Earth: the crust, the mantle, and the core. Minerals and rocks are also discussed as well as the theory on the origin of the planet Earth.

SCIENCE CONCEPTS Earth has four major zones: the atmosphere, lithosphere, hydrosphere, and biosphere. The solid Earth, the lithosphere, is made up of three layers, namely the crust, the mantle, and the core. Minerals are composed of an element or a group of elements. Rocks are made up of natural aggregates of minerals.

There are three types of rocks based on mode of formation: igneous, sedimentary and metamorphic. The rock cycle summarizes the sequence of events in which rocks are formed, destroyed, altered, and reformed by geological processes.

Earth is believed to have formed from the accretion and condensation of hot gases and dusts resulting from a supernova explosion. This model is called the Nebula model.

The early Earth consists of rock-forming elements like iron, magnesium, calcium, silica, sodium, potassium, and aluminum. The heavy elements, like iron and magnesium, settled into the core and the lighter elements were pushed upward to the surface. This resulted to the layered structure of the Earth.

The hydrosphere and atmosphere have changed in composition from the early Earth to the present-day Earth.

OBJECTIVES 1. Identify the internal layers of the solid Earth. 2. Differentiate the layers in terms of composition, density, and

thickness. 3. Identify the three rock types. 4. Differentiate the rock types in terms of formation and appearance. 5. Relate the evolution of the Earth.

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SCIENCE PROCESSES Observing, describing, identifying, comparing, classifying, naming, measuring, and inferring.

VALUES Care for our planet Earth

LIFE SKILLS Empathy with our changing and dynamic planet Effective communication in taking care of the planet.

INTEGRATION WITH OTHER EPISODES Episode 22 (Solids, Liquids, and Gases- Phases of Matter)

CONTENT BACKGROUND FOR TEACHERS Earth’s Three Major Layers by Chemical Composition A lot of what we know about the Earth’s interior is based on the study of earthquake waves, laboratory experiments, and comparisons with meteorites. The solid Earth is chemically divided into three layers. These are—from the surface going to the center—the rocky crust, the mantle, and the core (Figure 33.1). These layers differ in terms of composition, density, and thickness.

Figure 33.1 Structure of the Earth (Not drawn to scale) (Source: http://www.uwsp.edu/geo/faculty/ritter/glossary/l_n/lithosphere.html)

Episode 33. The Living Planet

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The Earth’s Three Major Layers Defined by Physical Properties The other way by which the internal structure of the Earth may be described is by using the property called “rigidity,” or how hard or solid a material is. The lithosphere (sphere of rock) refers to the outer rigid layer of the Earth composed of the crust and the upper mantle. The lithosphere is “floating” over the hot and plastic (not molten, very much like clay) asthenosphere (weak sphere). From the lower mantle in the region between the asthenosphere and the outer core, is the mesosphere. The outer core is in a liquid state and is about 2,260 km thick. The inner core (which has a radius of about 1,228 km) is solid due to the extremely high pressure brought about by the weight of the overlying materials.

Materials of the Earth: Rocks and Minerals There are three rock types based on formation:

1. Igneous rocks formed when molten rock mass called magma cools and solidifies, forming crystals. When crystallization occurs at the surface through volcanic eruptions, volcanic igneous rocks or extrusive rocks are formed. Rocks formed are fine-grained or glassy. On the other hand, when crystallization happens beneath the surface, plutonic igneous rocks or intrusive rocks.

2. Sedimentary rocks formed when the sediments were compacted and cemented together.

3. Metamorphic rocks formed as pre-existing rocks respond to changing form and composition.

When identifying rock types, you may find it useful to have students follow an identification key like Figure 33.2 below.

The Rock Cycle The rock cycle (Figure 33.3) links the principal sedimentary, metamorphic, and igneous rocks together in an idealized view of the sequential evolution of rocks in Earth's crust. The Rock Cycle is a group of changes. Igneous rock can change into sedimentary rock or into metamorphic rock. Sedimentary rock can change into metamorphic rock or into igneous rock. Metamorphic rock can change into igneous or sedimentary rock.

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Figure 33.3 The Rock Cycle (Source: http://www.mhhe.com/earthsci/geology/mcconnell/ram/rcycle.htm)

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VOCABULARY WORDS asthenosphere atmosphere basalt biosphere chemical weathering continental crust core crust hydrosphere igneous rocks inner core lithification

lithosphere magma mantle mineral Moho ( Mohorovicic

discontinuity) oceanic crust outer core physical or mechanical

weathering rock sedimentary rocks

PRE-VIEWING ACTIVITIES

Activity 1. What Is Inside the Earth? Show a globe, hold it up, and say that the globe represents Earth. Have the children draw a picture of what they think is found inside Earth.

Explain that Earth is like a ball and you want to know what they think is inside it .

Activity 2. Egg-zactly Materials 5 hard-boiled chicken eggs cut vertically into equal halves.

Procedure 1. Divide the class into groups of 5. 2. Have the groups examine the cross-section of an egg and ask

them the following questions: a. How many layers do you see? b. Describe each layer as to its color, thickness, and density.

(Density may be determined by separating the layers carefully and gauging the relative “weights.”)

3. Ask them to give their observation by completing the table below with matching drawing or sketch of the cross section.


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Table 33.1 Characteristics of the Layers of an Egg

LAYER COLOR THICKNESS DENSITY HARDNESS OTHER PROPERTIES

Shell

Egg white

Egg yolk

4. With a marker, have them make a dot about the size of a pea at the center of the yolk. This represents the solid inner core of the Earth. The rest of the yolk is the outer core. The white is the semi-solid mantle, and the shell is the crust. The relative proportion in size between shell, white, and yolk is a fairly accurate representation of the Earth's layers.

Activity 3. Look, Listen, and Learn 1. Give short introductory lecture of what they can expect to view on

the CD.

2. Explain that the Earth is very much like an egg... The shell is thin and can be cracked easily. They can go ahead and do this, but tell them not to peel the shell off yet. Explain that the cracks are similar to plate boundaries, faults and mountain belts within the Earth's crust.

3. Hand out a blank diagram (see below) of the interior of the earth and ask the students to complete the figure by filling out the blanks on the diagram as the different layers are mentioned in the film.

4. Ask the students to complete the table below while viewing the film:

Table 33.2 Characteristics of Earth’s Layers

Layer Composition Thickness* Phase of Matter (solid, gas or liquid)

Crust Mantle Outer Core Inner Core

*The thickness may be calculated from the blank diagram given.

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Figure 33.4 Internal Structure of the Earth (Source: EnchantedLearning.com)

VIEWING ACTIVITIES

PLAY segment 6:54-8:52 (How the Earth Works). PAUSE video to allow students to take down the answers

PLAY the segment again if majority of the pupils did not understand what they viewed


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Crust

Mantle

Outer Core

Inner Core

Post -Viewing Activity

Activity 4. Let’s Find Out After viewing the segment, let the pupils label the diagram of the Earth’s interior and fill out the characteristics of each layer in the table provided.

Table 33.3 Characteristics of Earth’s Layers

Figure 33.5 Internal Structure of the Earth (Source: EnchantedLearning.com)

Layer Composition Thickness*

(in kilometers)

Phase of Matter (solid, gas, or

liquid) Crust Granite and Basalt 5-40 Solid Mantle Peridotite 2900 Solid Outer Core Fe-Ni (with sulfur and

silicon) Alloy 2272 Molten

Inner Core Fe-Ni (with sulfur and silicon) Alloy

1200 Solid

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PRE-VIEWING ACTIVITY

Activity 1. Rock and Tell Materials

Different rock specimens. Ask students to bring some rock samples. Procedure

1. Divide the class into groups of 5. 2. Give each group a rock sample to examine and describe. 3. Have them record their observations in the table below. 4. Have them set aside their observation tables for the post-viewing

activity on rocks. Table 33.4 Rock Observations

Sample No. Color Grain size Hardness Others (fossils present)

Activity 2. Look, Listen. and Learn 1. Tell the students that they will watch a video on the different types

of rocks and the how these rocks are formed. 2. Prepare copes of this fill-in puzzle and give a copy per student. 3. Tell them to get ready to complete the puzzle with letters as they

view the segment.

S I E N R Y

M G M G E U

M T M O P C O K C L E


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4. Have the students copy the table:

Table 33.5 Classifying Rocks

Igneous Rocks Sedimentary Rocks

Metamorphic Rocks

Source of materials Process/es Examples

VIEWING ACTIVITY Show the segment starting at 11:01. Pause the film to allow students to complete the word puzzle and complete their table. Play the segment again if majority of the students failed to do their activity.

POST-VIEWING ACTIVITIES

Activity 3. Let’s Find Out Let the class work on the puzzle and table cooperatively on the board.

Table 33.6

Igneous Rocks Sedimentary Rocks Metamorphic Rocks Source of materials

Magma Sediments from any pre-existing rocks

Pre-existing rocks

Process/es Crystallization Lithification Metamorphism

Examples Granite Sandstone Slate

S E D I M E N T A R Y

M A G M A I G N E O U S

M E T A M O R P H I C R O C K C Y C L E

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Activity 4 Rock and Tell Rock identification and classification

Materials rock identification kit

sets of rocks containing one of each type on flow chart, if possible.

Procedure Review the identification key and flowchart with the pupils. 1. Depending on the number of rock samples, group the class

accordingly. 2. Ask the students to describe the rock samples based on the

criteria in the identification key. 3. Using their observation in the Pre-viewing activity on rocks

guide the students through the process of identification and classification.

EVALUATION 1. What is the name of the thin, outermost rocky layer of the Earth?

A. Crust B. Inner core C. Outer core D. Mantle

2. Which is the heaviest layer of the solid earth? A. Continental crust B. Core C. Mantle D. Oceanic crust

3. Which layer constitutes the thickest portion of the earth? A. Continental crust B. Inner Core C. Mantle D. Outer Core

4. What is the core of the earth made of? A. Basaltic rock B. Granitic rock C. Peritonitis rock D. Iron-Nickel Alloy


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5. If you were able to dive into the center of the earth through a drilled hole, in what order you would encounter the various layers of the earth? A. crust-mantle-outer core- inner core? B. crust-outer core-inner core-mantle C. inner core-outer core-mantle-core D. outer core-mantle-inner core-crust

6. What type of rock has been changed by high temperatures and pressures? A. Igneous B. Sedimentary C. Metamorphic

7. Which of the following statements is true? A. The lithosphere contains the crust. B. The crust contains the lithosphere. C. The lithosphere and crust are different terms for the same part

of the Earth. D. The lithosphere and crust are separate parts of the Earth.

8. Which type of rock is produced through weathering and erosion? A. Igneous B. Sedimentary C. Metamorphic

9. Which type of rock originates from magma? A. Igneous B. Sedimentary C. Metamorphic

10. What is the process of breaking down rocks by mechanical or chemical means A. Lithification B. Melting C. Metamorphism D. Weathering

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ANSWERS KEY 1. B 2. C 3. D 4. A 5. C

6. A 7. B 8. A 9. D

10. D BIBLIOGRAPHY Tarbuck, E. and Lutgens, F.K. (2005). Earth: An introduction to physical

geology. NJ: Pearson Prentice Hall.

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VOLUME 6. EARTH EPISODE 34. THE PRECIOUS SOIL

OVERVIEW This episode focuses on soil as a precious natural resource—its importance, composition and formation, conservation and the measures mitigating its erosion. It also explains the impact of soil conservation on sustainable food production.

SCIENCE CONCEPTS 1. Soil plays a significant role in providing a basic source of our

nourishment through plant growth. 2. Soil consists of unconsolidated particles of rocks and minerals mixed or

chemically combined with decayed organic materials called humus. 3. Soil forms by the processes of weathering, erosion, deposition, and

humification. 4. The layering of the soil profile shows different stages of soil

development. 5. Different kinds of soil may be characterized by the humus content, the

texture, and chemical composition. 6. Soil degradation happens when soil erosion occurs faster than soil

formation. 7. Soil conservation is the key to sustainable food production.

OBJECTIVES Identify the different types of soil Differentiate the types of soil from one another. Explain the different soil forming processes: weathering, erosion, deposition, and humification. Explain the development of a soil profile. Explain the different ways of soil conservation

SCIENCE PROCESSES Observing, describing, identifying, comparing, classifying, naming, measuring and inferring.

VALUES Conservation of soil Appreciation of soil-forming processes

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LIFE SKILLS Self – awareness Empathy Problem solving

INTEGRATION WITH OTHER EPISODES Episode 23 Changes. The different soil-forming processes are chemical and physical change.

CONTENT BACKGROUND FOR TEACHERS Soil is the portion of the Earth’s surface where plants grow. It plays a vital role in supporting plant growth that provides nourishment of both human beings and domesticated animals. Soil is made up of a mixture of decomposed rock particles and organic matter. It is formed by the combination of chemical and physical breakdown of rocks, erosion, and deposition. These geologic processes occur at or near the surface.

In areas where removal of soil is minimal one would see a vertical layering of soil from the surface downwards. This is the soil profile. Each layer is characterized by different compositions.

In contrast, some areas have relatively fast rate of erosion which leads to the decrease of productivity. This is more commonly known as soil erosion or soil degradation. To mitigate soil erosion man must adopt some measures like crop rotation, terracing, contour plowing, shelterbelts and strip cropping.

Soil and Its Composition Soil is a mixture of (1) unconsolidated particles of various sizes, (2) decayed plant and animal matter called humus, (3) moisture in the form of a thin film of water coating the rock particles and humus, (4) air filling the spaces among the rock particles. By volume, a good typical soil is made up of 45% rock and mineral particles, 25% water, 25% air and 5% humus.

VOCABULARY WORDS A horizon B-horizon bedrock C-horizon contour plow erosion gully erosion

humus leaching rill erosion sheet erosion shelterbelt soil soil erosion

soil profile terracing topsoil weathering zone of accumulation zone of leaching

EPISODE 34. THE PRECIOUS SOIL

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Activity 1. Soil Particles

Materials a handful of soil (pupils may be asked to bring some soil from their

backyard) a magnifying lens (for each group of 5 pupils) a sheet of white paper

Procedure 1. Spread the soil thinly on the white paper. 2. Examine the soil using the magnifying lens. 3. Describe the soil in terms of color, particle size, presence or

absence of organic remains and moisture. 4. Ask the pupils to summarize their observations by filling up the

table below:

Table 43.1 Characteristics of Soil Samples Sample No. 1 2 3 4

Color Particles Pebble Sand Clay Humus (present/ not present)

Moisture (dry/wet/very wet)

Activity 2. Look, Listen and Learn Tell the pupils that they will watch a videolesson on soil formation and composition. Have the pupils copy the following questions:

1. Arrange the following words to show the flow of nutrients from soil to man. Use arrows to show directions.

PLANT, ANIMAL, SOIL, MAN 2. What is soil? 3. What happens to rocks when exposed to hot weather? 4. What happens to soil during cold weather?

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Tell the pupils to answer the questions after viewing the video.

VIEWING ACTIVITY

Let the pupils view the segment on how soil is formed. PAUSE the film to allow pupils to answer the given questions.You may REPLAY the segment if majority of the pupils failed to understand what they have viewed.


Activity 3 Let’s Find Out Discuss with the pupils what they have just viewed. During the discussion you may also answer the questions posted earlier.

1. Arrange the following words to show the flow of nutrients from soil to man. Use arrows to show directions.

SOIL → PLANT→ ANIMAL→ MAN 2. What is soil?

Soil is made up of unconsolidated rock particles and decayed organic materials.

3. What happens to rocks when exposed to hot weather? Heat expands rocks.

4. What happens to soil during cold weather? Rocks contracts under cold temperature.

Activity 4 Soil Sample Description Ask the pupils to describe the soil sample they have been working on before the film showing.

Ask: Based on your observation of the soil samples and what you have seen on the video, what is soil made of?

What is the dark /black soft material present in your sample?


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Activity 1. Picture Study Show pictures of the following scenarios:

A. River B. Sandstorm or wind in action C. Landslides

Ask the pupils to describe how the soil particles are moved from one place to another. Activity 2. Look, Listen and Learn Tell the pupils that they will watch a video on soil formation and composition of soil. Have the pupils copy the following questions:

1. What is soil erosion? What is removed when you have soil erosion? 2. What are the 3 different types of erosion? 3. Aside from water, what is another agent of erosion? 4. Give examples of how human can cause soil erosion. 5. What are ways by which we can conserve soil?

Tell the pupils to answer the questions after viewing the video.

VIEWING ACTIVITY PLAY the segment on soil erosion and how to prevent soil erosion. PAUSE the film to let the pupils answer the questions given and discuss briefly what have just been viewed. REPLAY the segment if majority of the pupils failed to understand what they have viewed.


Activity 3. Let’s Find Out 1. Discuss what was viewed in the segment by answering the questions

posted earlier. What is soil erosion? What is removed when you have soil erosion?

Soil erosion is the removal of topsoil due to water or wind.

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What are the three different types of erosion? · Sheet erosion · Rill erosion · Gully erosion

Aside from water, what is another agent of erosion? Wind

Give examples of how people can cause soil erosion. · Farming · Grazing of cattle · Construction of buildings · paving of roads and highways · Mining-related activities

How can we conserve soil? · Reduced tillage farming · Crop rotation · Terracing · Contouring · Shelterbelt · Wooden benches · Earth banks

Ask the pupils how they can prevent soil erosion in their communities.

Activity 4 Water and Wind Erosion and Contouring Break the class into small groups to perform the following activities:

1. Rain as an agent of erosion (Note: needs to be performed outside the classroom)

Materials A pail of soil Sprinkler

Procedure 1. Pile the soil into a mound. 2. To simulate rainfall, fill up the sprinkler with water and pour

it on the surface of the soil. 3. Observe what happens. 4. What happened to the soil particles when water was poured

onto the surface? 5. Explain how the soil particles were carried away from one

place to another.


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Explanation Water as falling rain is one of the most effective agents of soil erosion especially for areas where there is no vegetative cover. The erosive energy of water varies with respect to its volume and velocity. The bigger the amount of water and the faster its velocity (such as during flashfloods), water can carry larger particles.

2. Wind as an agent of erosion Materials

half kilo of dry sand hand fan or cardboard used folder

Procedure 1. Pile the sand into a mound on the used folder. 2. Fan the soil with the cardboard. Vary the speed of fanning. 3. Observe what happens. 4. What happened to the soil particles when you fanned the

sand? 5. Explain how the sand particles were carried away from one

place to another. 6. Did the sand particles vary with the change of distance it

traveled away from the mound? 7. What did the fan activity represent?

Explanation In dry areas, wind is the most effective erosion agent. However, unlike water, which is able to carry large boulders during flash floods, The wind can move only fine particles.

3. Contour plowing to prevent soil erosion Materials

2 identical shoebox covers aluminum foil (big enough to cover the box cover) soil (enough to fill up the shoebox cover) 2 basins (large enough to hold the length of the shoebox cover) 2 blocks of wood sprinkler pencil or ruler

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Procedure 1. Cover the shoebox covers completely with the aluminum foil. 2. Fill up the shoebox cover with the soil. 3. With the pencil or ruler, make vertical grooves on the soil

surface of Shoebox Cover A and horizontal grooves on the soil surface of Shoebox Cover B.

4. Position the shoebox covers using the wood blocks such that one end rests on the top of the basin. See to it that the position slightly slants from the woodblock to the basin.

5. With the sprinkler, pour water onto Shoebox Cover A. Observe what happens to the soil particles.

6. Do the same to Shoebox Cover B. 7. What did you observe when water was poured onto Cover A?

Cover B? 8. Which basin had more soil particles? 9. What do you think prevented particles to flow more easily

from Shoebox Cover B. Explanation

Contouring is an effective measure to prevent soil erosion in mountainous areas.

EVALUATION 1. Which process leads to soil formation?

A. volcanism C. weathering B. erosion D. growth of plants

2. What do you call the soil that is made up of fine, loose particles? A. loam C. sandy soil B. humus D. clay

3. Soil is made up of loose particles and decayed organic matter. What do you call this decayed plant and animal remains? A. loam C. sandy soil B. humus D. clay


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4. What is the richest and most productive layer of soil called? A. topsoil C. subsoil B. pebbles D. bedrock

5. Which kind of soil is best for growing plants? A. gravel C. clay B. sand D. loam

6. Which of these is NOT an effect of soil pollution? A. increase in crop production C. food shortage B. water pollution D. air pollution

7. Which of the following helps in preventing soil pollution? A. Mining C. Proper garbage disposal B. C. Use of pesticide D. Overuse of inorganic fertilizer

8. Which of the following does NOT help in soil conservation? A. Crop rotation B. Burning of trees C. Proper garbage disposal D. Selective cutting of mature trees

9. What do you call the succession of distinctive horizons in the soil from the surface down to the unchanged parent material beneath it? A. Soil gradient B. Soil profile C. Soil superposition D. Soil zonation

10. Which factor is the most important in determining soil characteristics? A. climate B. time C. topography D. type of bedrock

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ANSWER KEY 1. C 2. C 3. B 4. A 5. D

6. A 7. C 8. B 9. C

10. C

BIBLIOGRAPHY Press, F., & Siever, R. (1998). Understanding Earth. NY: W.H. Freeman &

Company. Tarbuck, E., & Lutgens, F. K. (2005). Earth: An introduction to physical geology.

NJ: Pearson Prentice Hall. Villona, H. M., & Adduru, M. Q., Ocampo, L. V., Silas-Cunanan, C., &

Valencia, N. G. Catris, L. C. (Coordinator). (2007). RBS Science and Health Series, CyberScience 4 (1st Ed.). Manila: Anvil Publishing.

Wicander, R., & Monroe, J. S. (1998). Essentials of geology. Southern Africa, International Thomson Publishing.

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VOLUME 6. EARTH EPISODE 35. WATER: THE DROP OF LIFE

OVERVIEW The episode discusses the water cycle, bodies of water, sources of potable water, and water contamination and purification

The presence of water on Earth is one primary reason for the existence of life as we know it on Earth. Water is distributed on Earth through the water cycle. This cycle shows the movement and changes in state of water from the atmosphere to the lithosphere to the hydrosphere with active participation of the biosphere.

Water covers 70% of the Earth’s surface. As precipitation falls onto the Earth’s surface almost 97% infiltrates the ground and occupies the pore spaces in the rock layers. This comprises what is called “groundwater”. A small part of precipitation flows on the Earth’s surface forming oceans, lakes and rivers. Groundwater accounts for largely the supply for potable water. It is less prone to contamination and changes in temperature compared with surface water.

As water flow from its source, debris and chemicals may be added into it resulting to water contamination or water pollution. In such way the water become unsafe for human consumption. The water supply of Metro Manila is first collected in the La Mesa Dam. From here, it undergoes several stages to purify and treat the water before it reaches our home.

SCIENCE CONCEPTS 1. The Earth’s surface is covered with 70% water. 2. The existence of water is one of the primary reasons why there is life on

Earth. 3. The hydrologic or water cycle summarizes the movement of water from

the atmosphere to the continents and biosphere and back to the atmosphere.

4. As water flows from one place to another, contamination is inevitable. 5. To make water suitable for drinking, it has to go through a rigorous

procedure of collection, purification and treatment.

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OBJECTIVES 1. Explain the processes in the water cycle. 2. Describe the changes in water as it moves through the water cycle. 3. Form a hypothesis on how/why the water cycle works. 4. Explain how acid rain forms. 5. Cite possible sources of water pollution. 6. Explain the steps in water purification and treatment. 7. Give measures on how to conserve water.

SCIENCE PROCESSES Observing, describing, identifying, comparing, classifying, naming, measuring and inferring.

VALUES Appreciation of the existence of water in our planet. Commitment to practice water conservation. Commitment to adopt measures to prevent water pollution.

LIFE SKILLS Empathy Effective communication Problem-solving Decision making Critical thinking Interpersonal relationship

INTEGRATION WITH OTHER EPISODES Episode 22 - Solids, Liquids, and Gases: Phases of Matter Episode 23 - Changes Water undergoes changes in its phases in the hydrologic cycle. These phases and the different changes of phases are tackled in the above mentioned episodes.

CONTENT BACKGROUND FOR TEACHERS

Water Cycle The hydrologic cycle is a summary of the circulation of Earth’s water supply. It is powered by the sun or solar energy. The cycle links oceans to continents to the biosphere.

Episode 35. Water: The Drop of Life

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Several processes make up the water cycle, namely: – Precipitation – Evaporation – Infiltration – Runoff – Transpiration

Precipitation includes both rain and snow in some places. Once precipitation reaches the Earth’s surface water may move into rocks or soil through cracks and pore spaces percolating down into the ground. This is the process of infiltration. A part of the precipitation flows over the surface referred to as runoff. All surface runoffs eventually are dumped into the oceans. Water goes back to the atmosphere through the process of evaporation from the ground and water bodies. Plants, through evapotranspiration, also cycle back the water to the atmosphere.

Figure 35.1 A schematic diagram showing the water cycle http://www.epa.gov/climatechange/effects/images/watercycle.jpg

Sources of Potable Water Potable water or drinkable water essentially comes from groundwater, the part of the precipitation that percolates down into the Earth’s ground. There

http://www.epa.gov/climatechange/effects/images/watercycle.jpg


















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is a misconception that there is a body of water underground. Groundwater refers to the water that occupies the pore spaces between rock particles. This may be extractable using pumps or if hydrostatic. In other cases, water pressure is high enough, water may freely flow out of the well producing an artesian well.

Rock layers, which have large number of pore spaces, are said to be porous. However, if the rock layers although porous will not allow the water in between the particles to flow are not good reservoir of groundwater. A rock layer has to be permeable that allows water to flow through. This allows withdrawal of water from the ground to the surface.


Activity 1: Word Game Give out flash cards on which the first letters of the following words are written. Ask them to stick the cards on the board as soon as they know the answer. The “Word Starts With This Letter Hint” answers follows:

W --------- A substance that is very important to us. We need it to live, and it covers over two thirds of the surface of the Earth.

O --------- A large body of water on the surface of the Earth. E --------- A process in which liquid water turns into water vapor (a

gas). P --------- In transpiration, water from these objects evaporates into

the atmosphere. C --------- A fluffy-looking object in the sky that contains tiny water

droplets or ice particles. It is formed when water vapor condenses.

R ---------- This type of precipitation is water that falls from clouds in a liquid state. ________________________

W --------- The process in which water circulates from the oceans to the clouds to the land to the rivers, and then accumulates back into the oceans.

Activity 2: Look, Listen, and Learn Briefly explain to the pupils the concept of water cycle and that water moves from the continents to the atmosphere to the hydrosphere. Tell them that you will show them a short film clip on the water cycle. Ask the pupils to label the water cycle diagram as they watch the video. Give them the word bank below to help them out.


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VIEWING ACTIVITY

POST-VIEWING ACTIVITY Activity 3. Let’s Find Out Using an enlarged version of the water cycle diagram, discuss with the pupils the different processes of the cycle.

Figure 35.2 A water cycle diagram for labeling (top); with labels (bottom)

Precipitation

Surface Runoff

Condensation

Evaporation

Inflitration Accumulation

Evapotranspiration

Condensation

PLAY the segment on the water cycle. PAUSE the film to allow the pupils to write down the labels on the hydrologic cycle. You may re-play the segment if most pupils failed to understand what they have viewed

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Activity 4. Making a Model of the Water Cycle Materials

soil water small margarine bowl large, clear plastic container or an old aquarium plastic wrap plastic trees, animals, boat, etc. are optional tape or large elastic band bag of ice (optional) heat lamp (optional)

PROCEDURES 1. Arrange the soil in the container to make mountains, plateaus, hills,

etc., and a lake basin. Place the margarine bowl in the lake basin. Fill up the bowl with water. The plastic toys may be added to appeal to the children's imagination. Cover the container tightly with plastic wrap and secure it with masking tape.

2. Discuss what is expected to happen in the container. 3. A bag of ice may be placed on one end of the covered container,

while a heat lamp is focused on the other. 4. Watch for condensation on the plastic "sky" of the container. When

enough moisture collects, it will fall onto the landforms as precipitation.

5. Compare the hypothesis with the actual results. 6. Encourage the pupils to draw the water cycle using arrows to show

the flow.

Activity 1. Pre-Viewing Activities 1. Ask the pupils what they think is dirty water. 2. Ask them how water may be contaminated. 3. Tell them that the you will take them out on a field trip to the La

Mesa Water Treatment Plant to observed the steps in purifying water and make it safe enough to drink.


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Activity 2: Word Game Give the pupils the word puzzle worksheet and tell them to watch out for the word/s as they view the video. L __ M __ __ A __ A __ Where water from the upland is accumulated and treated P__P__ S Water from the dam travels through these

to the filter systems B__ __A __ __ One of the water filtering system SC__ E__ N__ __G Prevents entry of large floating objects M__ __ __ NG Uniformly disperses chemicals to cause

suspended particles of clumping together __L__ C__ __L__T__ __N The process of gently agitating the water

causing small clumps to form larger clumps

F__ __ __ Larger clumps S__ __ __ M__ __ T__ __ I __ N Allows heavy floc particles to settle at the

bottom of an open basin which allows clean water to flow through at the top

__ __ __ T__ __ T__ __ N the process by which water flows through a series of filter beds consisting of layers of graded gravel, anthracite or coal, and sand.

C__ __ __ __ I __E Added to the water to prevent bacterial contamination

VIEWING ACTIVITY Show the segment on water contamination and purification, ending with the “field trip” to La Mesa Water Treatment Plant. Pause the film to stress vital information and to allow pupils to answer their word puzzle:

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Activity 3: Let's Find Out Discuss with the pupils what was viewed. With the discussion, answer the word puzzle as follows: L A M E S A D A M Where water from the upland is accumulated and treated P I P E S Water from the dam travels through these

to the filter systems B A L A R A One of the water filtering system S C R E E N I N G Prevents entry of large floating objects M I X I N G Uniformly disperses chemicals to cause

suspended particles of clumping together F L O C C U L A T I O N The process of gently agitating the water

causing small clumps to form larger clumps

F L O C Larger clumps S E D I M E N T A T I O N Allows heavy floc particles to settle at the

bottom of an open basin which allows clean water to flow through at the top

F I L T R A T I O N the process by which water flows through a series of filter beds consisting of layers of graded gravel, anthracite or coal, and sand.

C H L O R I N E Added to the water to prevent bacterial contamination

Activity 4. Making a Water Purification Setup Materials

plastic tubing, 25 mm diameter and 330 mm long (may be purchased from a hardware)

10 cotton balls gravel, 250 ml sand, 250 ml charcoal, 250 ml water methylene blue, 5 drops graduated 1-liter clear container for mixing water and contaminant


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graduated 1-liter clear container for containing outflow of filtration process

Procedure 1. Position the plastic tubing firmly in one of the containers (outflow

of filtration) 2. Push 5 cotton bolls into one end of the tubing. 3. Over the cotton bolls, pour the charcoal pieces, then the sand,

followed by the gravel and then the remaining cotton balls (Figure 35.3).

Figure 35.3 Setup for water purification activity

4. Prepare the “contaminated water” by mixing the methylene blue with the water.

5. Pour the contaminated water into the tubing to simulate purification.

6. Ask the pupils to check for impurities in the filtered water.

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7. Ask the pupils to identify and be ready to explain what they have observed.

Explanation This activity aims to involve the pupils in the problem of environmental pollution in the form of contaminated water.

VOCABULARY WORDS

acid rain condensation evaporation evapotranspiration

hydrologic cycle infiltration potable water precipitation

surface runoff vapor (water) water cycle water pollution

EVALUATION

1. What do you call the water that does not infiltrate the ground in the hydrological cycle? A. magmatic C. runoff B. meteoric D. saturated

2. Which is the correct sequence of processes as water moves from the ocean to land in the hydrologic cycle? A. evaporation, condensation, precipitation, runoff B. evaporation, precipitation, runoff, condensation C. precipitation, evaporation, condensation, runoff D. runoff, precipitation, evaporation, condensation

3. What happens to most of the water that falls as rain? A. It stays in the soil. B. It runs off the land in rivers. C. It sinks into the groundwater zone. D. It returns to the atmosphere by evapotranspiration.

4. Which one of the following is NOT one of the processes included in the hydrologic cycle? A. condensation C. evaporation B. erosion D. precipitation

5. Which of the of the following can pollute water? A. fertilizers and pesticides C. water that has been filtered B. people conserving water D. trees growing near the river

6. How can you show that you care for water? A. Using only the amount of water they really need.


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B. Leaving faucets dripping when water is not being used. C. Taking long, hot showers. D. Watering the garden plans everyday in hot weather.

7. What is another name for rain? A. evaporation C. infiltration B. groundwater D. precipitation

8. Which of the following is NOT a significant part of the hydrologic cycle? A. runoff C. precipitation B. infiltration D. advection

ANSWER KEY 1. C 2. A 3. C 4. B

5. A 6. A 7. D 8. D

BIBLIOGRAPHY Arce-Flores, S., McFarlin, C., Pilzer, S., & Vigil, S. (2006). Working with

watershed: An educational resource binder for the environmentally aware educator.

Tarbuck, E. and Lutgens, F.K. (2005). Earth: An Introduction to Physical Geology, Pearson Prentice Hall, New Jersey.

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VOLUME 6. EARTH EPISODE 36. ATMOSPHERE: THE EARTH’S SHIELD

OVERVIEW OF THE EPISODE The episode deals with the study of the atmosphere of the Earth. The discussion focuses on (1) air composition, (2) the factors that affect atmospheric conditions, and (3) important environmental issues and concerns such as air pollution and the greenhouse effect.

SCIENCE CONCEPTS 1. The atmosphere is made up a mixture of gases covering the entire Earth. 2. The three most plentiful permanent gases in the atmosphere are

nitrogen (N2), 78%; oxygen (O2), 21%; and argon (Ar), 0.93%. The two most plentiful variable gases are water vapor (H20), 0-4%; and carbon dioxide (CO2), 0.036%.

3. The temperature of the atmosphere varies with distance from the ground, dividing the Earth into layers.

4. Weather is the specific condition of the atmosphere at a particular place and time.

5. Factors that affect the weather are: wind, temperature, humidity, atmospheric pressure, cloudiness, and precipitation.

6. The atmosphere shields us from extreme temperature changes through the greenhouse effect, making life possible on Earth.

7. The accumulation of carbon dioxide and water vapor in the atmosphere resulting from human activity causes a steady increase in the Earth's surface temperature.

8. This increase in the surface temperature may have adverse effects on Earth such as global warming and varied weather conditions.

9. The atmosphere shields the Earth from the harmful ultraviolet radiation from the Sun.

OBJECTIVES 1. Identify the important gases that make up the atmosphere 2. Describe the vertical layered structure of the atmosphere in terms of

elevation, temperature, and composition 3. Explain the greenhouse effect 4. Discuss the various causes for the greenhouse effect 5. Explain the different factors affecting the weather 6. Describe how to use instruments that record and predict the weather

http://www.ucsd.tv/moleculesforthemedia/lesson_atmosphere_study.asp

EPISODE 36. ATMOSPHERE: THE EARTH’S SHIELD

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7. Predict the weather of the day from observed atmospheric conditions such as temperature and cloud formation.


VALUES Awareness of and sensitivity to changes in the natural world Skills in applying concepts on atmospheric changes to one’s daily life Ability to adjust to the continually changing weather conditions Awareness of the impacts of daily activities to the atmosphere

LIFE SKILLS Appreciation Problem-solving Empathy

INTEGRATION WITH OTHER EPISODES The following episodes discuss concepts which are very much relevant to the different processes and events discussed in the current episode.

Episode 22. Phases of Matter Episode 23. Changes Episode 25. Energy: Forms and Transformation Episode 31. Heat and Temperature

CONTENT BACKGROUND FOR TEACHERS The atmosphere is the layer of gases that envelopes the Earth. The Earth’s atmosphere is vertically layered from the ground to space. The layers differ in terms of temperature and structure. The layers from the surface to space are as follows: troposphere, stratosphere, mesosphere, and the ionosphere. These layers protect the Earth from bombardment by objects from space and all life from harmful radiations from space.

The greenhouse effect is the process by which heat accumulates in the Earth's atmosphere instead of being released out into space. This process occurs naturally and keeps the Earth warm enough to sustain life. Scientific evidence shows that human activity intensifies this natural process. The increase in the emission of CO2, H2O, NO2, CH4, and chlorofluorocarbons or CFC, blocks the escape of heat from the atmosphere. The continuous increase may lead to drastic consequences to life on Earth. The melting of

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polar caps and glaciers result in an increase in sea level and more variability in weather patterns.

The atmosphere protects us from extreme temperature changes. It provides us with the right mixture of gases needed for life. The ozone layer shields us from the harmful ultraviolet radiation from the sun. Without the atmosphere, the Earth would be as lifeless as the Moon.

As a gaseous envelope, the atmosphere is one primary reason that life as we know it exists on Earth. The atmosphere also provides an efficient shield from the harmful ultraviolet radiation from the Sun. This is one primary reason that life exists on Earth. No other planet in the solar system is known to nurture life. The atmosphere also distributes the heat supplied to our planet, hence, providing temperate climate conditions over large areas of the Earth’s surface that would otherwise be inhabitable to human life.

The Atmosphere and Its Composition The atmosphere is the gaseous layer that surrounds the entire Earth. It is made up of a mixture of gases in different amounts. Dry air (that is, air without water in any form) is made up of the following gases:

Table 36.1 Composition of air Gas (% by volume)

Nitrogen Oxygen Argon Carbon dioxide Helium

78.084 20.946 0.934 0.033 0.005

Other gases in the atmosphere include neon, krypton, hydrogen, xenon, ozone, methane, and nitrous oxide. Aside from these gases, the atmosphere also contains water in its three forms (vapor, liquid, and solid), dust, plant pollen, bacteria and other microorganisms, soot and ash, and salt particles from the ocean.

Although animals inhale oxygen and exhale carbon dioxide, the relative percentage of oxygen in the atmosphere is maintained at a nearly constant value as a result of photosynthesis. In this process, oxygen is returned to the atmosphere by plants and at the same time, carbon dioxide and water are converted into sugars.


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Figure 36.1 Layers of the Atmosphere

The Layered Atmosphere The Earth’s atmosphere in divided into vertical layers (Figure 36.1). The layers differ in terms of temperature and composition. The layers—from the surface of the Earth going up—are as follows:

The troposphere refers to the lower 16 km of the atmosphere. In this region the temperature drops with increase in altitude at a rate of 6.5oC/km. Almost all weather activities take place here. We interact and live in the troposphere.

The stratosphere starts at about 16 km to a height of about 50 km. Here the temperature increases as the altitude increases but in a nonuniform rate. The thin ozone layer in the upper stratosphere has a high concentration of ozone, a particularly reactive form of oxygen. This layer is primarily responsible for absorbing the ultraviolet radiation from the Sun.

Above the stratosphere is the mesosphere. Above the mesosphere is the ionosphere (or thermosphere), where many atoms are ionized (gained or lost electrons so they have a net electrical charge). The ionosphere is very thin. It contains many ions and free electrons (plasma). The ions are created when sunlight hits atoms and tears off some electrons.

The exosphere is the outermost layer of the Earth's atmosphere. The exosphere goes from about 640 km (400 miles) to about 1,280 km (800 miles) high. The lower boundary of the exosphere is called the critical level of escape, where atmospheric pressure is very low (the gas atoms are very widely spaced) and the temperature is very low.

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Weather and Its Properties Weather refers to the general atmospheric conditions of the lower troposphere over a specified area within a specified period of time. These conditions include air temperature, atmospheric pressure, humidity, cloudiness, wind direction and speed or strength, and precipitation or rainfall. A cloud is a large collection of very tiny droplets of water or ice crystals. The droplets are so small and light that they can float in the air. All air contains water, but near the ground it is usually in the form of an invisible gas called water vapor. When warm air rises, it expands and cools. Cool air cannot hold as much water vapor as warm air, so some of the vapor condense on tiny particles of dust that float in the air and form tiny droplets around the dust particles. When billions of these droplets stick together they become a visible cloud. Clouds are classified according to shape and altitude. Cirrus, cumulus, stratus, and nimbus are root words used in naming clouds (Figure 36.2).

Figure 2. Photographs of different types of clouds. (Source: http://geography-info.com/physical/)


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The Greenhouse Effect and the Greenhouse Gases The greenhouse effect is an increase in the temperature of Earth as the gaseous atmosphere traps heat energy from sunlight. Examples of greenhouse gases are carbon dioxide, CFC, and water vapor.

Solar energy is short-wavelength radiation, which easily penetrates the Earth's atmosphere and warms the Earth; the atmosphere reflects only about one quarter of incoming sunlight. The warmed Earth emits long-wavelength radiation (infrared waves or heat energy) back into space; these longer waves are mostly reflected back to Earth by the atmosphere.

The three main gases in our atmosphere that contribute to the greenhouse effect are carbon dioxide, methane and water vapor. With increasing carbon dioxide emissions from humans (Figure 36.3), the greenhouse effect has become drastically exaggerated. This has caused an alarming global warming process that is threatening our present environment by melting polar ice caps and raising sea levels around the globe.

Figure 36.3. A schematic diagram showing the greenhouse effect on the atmosphere. (Source: http://www.global-greenhouse-warming.com/graphs-diagrams-of-global-warming-and-climate.html)

http://www.global-greenhouse-warming.com/graphs-diagrams-of-global-warming-and-climate.html

http://www.global-greenhouse-warming.com/graphs-diagrams-of-global-warming-and-climate.html

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Air Pollution Air pollution is a growing problem today. Air pollution is caused by toxic contaminants or Volatile Organic Compounds (VOCs) which have been released into the air. All over the world, fuel, in the form of oil and coal, is burned to run factories, machinery, and all forms of transportation. The burning of these fuels creates byproducts, such as smoke and invisible irritants, which contaminate our atmosphere. Many consumer products such as hair spray, paint, cleaners, windshield washers, etc. release high levels of VOCs into the atmosphere. The cumulative effect of air pollution destroys our environment and poses health threats to humans.

Sources of air pollution include cars, consumer products, gas stations, power stations, agriculture and forestry, and chemical industry. Air pollution is a major threat to our health. It is a one of the leading causes of lung disease, following smoking. It has also been implicated in the rising occurrence of asthma, bronchitis, and emphysema.

Air pollution effects on our environment are immense. Contaminating particles from sulfur dioxide emissions which are released into the air by factories, power plants, and cars combine with water particles in the atmosphere and fall to the Earth in the form of rain or snow. This is called acid rain. The acidity or basicity of this precipitation is dependent upon the concentration and type of contaminants with which the water particles have been combined. When oceans, lakes. and streams absorb acid rain, their support structure of algae, plankton, and other aquatic life, which provide food and nutrients for fish, is destroyed. Acid rain damages trees and plants. Roofs of buildings are also damaged by acid rain.

Another form of pollutant in our air known as CFCs, or chlorofluorocarbons, does major damage to our environment. CFCs are chemicals created by industrial usage such as solvents, refrigerant gases, and paints. CFCs combine with the Earth's upper atmosphere, attaching themselves to the molecules of ozone. The ozone layer protects the Earth from ultraviolet radiation of the Sun. The CFCs transform and destroy the ozone layer. If the ozone shield gets too thin or disappears, exposure to ultraviolet radiation can cause crop failures, skin cancer, and other environmental and health disasters.


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VOCABULARY WORDS air pollution air pressure anemometer atmosphere barometer cirrus clouds clouds condensation cumulus clouds evaporation

greenhouse effect greenhouse gases humidity ionosphere mesosphere monsoon nimbus clouds ozone layer precipitation psychrometer

stratus clouds thermometer thermosphere tornado troposphere typhoon vapor (water) weather wind vane


Activity 1: Look Up the Sky! Begin by asking the pupils what happens as you go farther up in the sky. See if they know anything about layers, air pressure, or temperature. Discuss what they know and how they found out.

Activity 2: Look, Listen, and Learn Tell the pupils that you will let them watch a video clip showing the changes in the atmosphere with altitude increase. Provide them with the blank diagram igure 36.4) and ask them to watch out for the different layers of the atmosphere while watching the film.

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Figure 36.4 Diagram of the Layers of the Atmosphere for Labeling

VIEWING ACTIVITY


Activity 3. Let’s Find Out Discuss what have been viewed giving the characteristics of each layer. With the discussion, label the diagram provided to the pupils as follows:

Figure 36.5 Labelled Diagram of the Layers of the Atmosphere

PLAY the segment, Layers of the Atmosphere. While watching the video, ask the pupils to label the different parts of the diagram showing the layers of the atmosphere. PAUSE the video to allow the pupils to label their diagram. You may PLAY the segment again if most of the pupils did not understand what they watched.


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CHALLENGE Ask the pupils to write the name of the layer or part of the atmosphere that answers the riddles.

1. I have the coldest temperature of the atmosphere. Who am I?_______________________________

2. I am where most of the weather occurs. Who am I?_______________________________

3. I contain most of the ozone layer. Who am I?_______________________________

4. I protect the Earth from ultraviolet rays given off by the sun. Who am I?_______________________________

5. I extend to an average altitude of about 12 km. Who am I?_______________________________

6. My temperature may reach as high as 2000 degrees celsius. Who am I?_______________________________

7. I am the layer that touches the surface of the Earth. Who am I?_______________________________

8. I am the layer that reaches the highest altitude. Who am I?_______________________________

9. I extend to an alititude from about 50 km to 80 km. Who am I?_______________________________

10. I am the layer that interacts with living things. Who am I?_______________________________

11. I extend upwards from an altitude of about 550 km to 1000 km. Who am I?_______________________________

12. The air pressure is the greatest here. Who am I?_______________________________

13. Electrically charged particles called ions are found here. Who am I?_______________________________

14. My temperature drops about 6.5 degrees Celsius per km. Who am I?_______________________________

15. I extend to an altitude of about 12 km to 50 km. Who am I?_______________________________

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PRE-VIEWING ACTIVITY

Activity 1: “Weather-weather lang”! Begin the lesson by discussing the weather at the time. Ask probing questions like, What is the weather like today? What is the difference between the weather today and the weather yesterday? What are the conditions by which you have just described the weather?

Activity 2: Look, Listen, and Learn

Tell the pupils that you will show them a video clip about the weather and different factors that affect weather conditions. Prepare an illustration on which the following the following questions are written down for easy reference by the pupils while watching the video clip.

1. What is weather?

2. What are the different factors affecting the weather?

3. What is “air temperature”?

4. Why is Baguio colder than Metro Manila?

5. What is “air pressure”?

6. What instrument is used to measure air pressure?

7. What are cyclones?

8. What is the difference between a hurricane and a typhoon?

9. What is another name for southwest monsoon?

10. What instrument is used to measure wind direction?

11. What instrument is used to measure wind speed?

12. What is “humidity”?

13. What do you call the visible masses of water and ice crystals?

14. Which type of cloud is most likely to bring rain?

VIEWING ACTIVITY

Let the pupils view the segment on Weather Forecasting. Pause the film to allow the pupils to write down their answers to the given questions. You may re-play the segment if most pupils cannot understand what they have viewed.


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Activity 3. Let’s Find Out Discuss with the pupils what was viewed. Have the pupils answer the questions posted.

1. What is weather? Weather is the atmospheric condition at a specific time and area.

2. What are the different factors affecting the weather? Air temperature, air pressure wind, humidity, rain, and cloudiness.

3. Why is Baguio colder than Metro Manila? Because the warming of the atmosphere occurs from the surface going up, Baguio City, being higher in elevation gets less of the reflected heat from the ground than in Manila, which is nearer the ground.

4. What is air pressure? Air pressure is the weight of the overlying layer of air.

5. What instrument is used to measure air pressure? Mercury barometer.

6. What are cyclones? Cyclones are an area of closed fluid motion that is characterized by inwardly spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

7. What is the difference between a hurricane and a typhoon? Hurricanes are intense cyclones that occur over the Atlantic Ocean and eastern North Pacific whereas typhoons occur over the tropics.

8. What is another name for southwest monsoon? “Hangin habagat.”

9. What instrument is used to measure wind direction? Wind vane.

10. What instrument is used to measure wind speed? Wind anemometer.

11. What is humidity? Amount of water in the air.

12. What do you call all the visible masses of water and ice crystals? Clouds.

13. Which type of cloud is most likely to bring rain? Nimbus cloud.

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Activity 4: Constructing an Anemometer Materials

5 paper cups 2 straight plastic straws a pin scissors paper punch small stapler sharp pencil with an eraser

Procedure 1. Using the paper punch, punch one hole in of the paper cups,

about a half inch below the rim. 2. Take the fifth cup. Punch four equally spaced holes about 1 cm

below the rim. Then punch a hole in the center of the bottom of the cup.

3. Take one of the four cups and push a plastic straw through the hole. Fold the end of the straw, and staple it to the side of the cup across from the hole. Repeat this procedure for another one-hole cup and the second straw.

4. Now slide one cup and straw assembly through two opposite holes in the cup with four holes. Push another one-hole cup onto the end of the straw just pushed through the four-hole cup. Bend the straw and staple it to the one-hole cup, making certain that the cup faces in the opposite direction from the first cup. Repeat this procedure using the other cup and straw assembly and the remaining one-hole cup.

5. Align the four cups so that their open ends face in the same direction (clockwise or counterclockwise) around the center cup. Push the straight pin through the two straws where they intersect. Push the eraser end of the pencil through the bottom hole in the center cup. Push the pin into the end of the pencil eraser as far as it will go. The anemometer is ready to use.

Explanation The anemometer is useful because it rotates with the wind. To calculate the velocity at which the anemometer spins, determine the number of revolutions per minute (RPM). Next calculate the circumference (in centimeters) of the circle made by the rotating paper cups. Multiply the RPM value by the circumference of the


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circle, and an approximation of the velocity of at which the anemometer spins (in cm per minute) may now be calculated.

EVALUATION Multiple Choice. Choose the letter of the correct answer.

1. What percent of the air we breathe in is oxygen? A. 5 C. 75 B. 21 D. less than 1

2. Which lone substance is found naturally in the atmosphere as a solid, a liquid, and a gas? A. carbon dioxide C. oxygen

B. nitrogen D. water

3. Which of the following layers of the atmosphere are listed in order of increasing altitude? A. mesosphere, stratosphere, ionosphere A. stratosphere, ionosphere, mesosphere, exosphere B. troposphere, mesosphere, stratosphere C. troposphere, stratosphere, mesosphere

4. In which part of the atmosphere do we live in? A. exosphere C. stratosphere B. ionosphere D. troposphere

5. Energy is trapped in the troposphere by what process? A. Earth’s solar energy C. ozone layer B. greenhouse effect D. thermosphere conversion

6. Which part of the atmosphere shields Earth’s surface from harmful ultraviolet radiation? A. ionosphere C. ozone layer B. mesosphere D. troposphere

7. Which of the following is a greenhouse gas? A. CO2 C. methane B. KFC D. nitrogen

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8. Which one of the following statements is false? A. Weather is caused by air that stays in the same place for a long

time. B. Weather results from the movement of air and changes in

temperature, air pressure, and humidity. C. A weather report can include temperature, humidity, air pressure,

wind speed and direction, cloud cover and precipitation. D. Werather is a record of the atmospheric conditions over a long

period of time.

9. Which cloud indicates rainfall will likely occur? A. nimbus C. stratus B. cumulus D. cirrus

10. What instrument is used to measure atmospheric pressure? A. anemometer C. psychrometer B. barometer D. thermometer

ANSWERS 1. B 2. D 3. D 4. D 5. B

6.C 7.A 8.C 9.A

10. B

BIBLIOGRAPHY Cortes, L. P., Basa, E., Estrera J. A., Galvante, W. P. & Rodriguez, V. L.

(2003). Earth science: The Philippines in focus (5th ed.). QC: University of the Philippines National Institute for Science and Mathematics Education Development.

Tarbuck, E., & Lutgens, F. K. (2005). Earth: An introduction to physical geology. NJ: Pearson Prentice Hall.

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VOLUME 6. EARTH EPISODE 37. THE RESTLESS EARTH

OVERVIEW OF THE EPISODE The episode discusses how and why our planet Earth is continuously changing as a result of ongoing geological processes. Described and illustrated are the following processes or forces that shape and alter the Earth’s surface: isostasy, continental drift, plate tectonics, faults, volcanic eruptions, and earthquakes.

Precautionary measures before, during, and after an earthquake and a volcanic eruption are discussed as well.

SCIENCE CONCEPTS 1. The theory of isostasy proposes that continents, ocean basins,

mountains, and plains are all in a state of balance. 2. The theory of continental drift states that the continents were once

joined into “Pangaea,” which broke into several fragments and moved into their present positions.

3. The theory of plate tectonics states that the upper rigid layer of the Earth, the lithosphere, is broken into several “plates,” which are moving over the hot, weak asthenosphere. At their boundaries, the plates either collide, move away, or slide past each other.

4. As a response to stress, rock layers break. Breaks in rock layers without movement are called fractures or joints. When rocks break with movement or displacement, a fault occurs.

5. When a fault moves, it releases stored elastic energy which causes rocks nearby to shake generating an earthquake.

6. Seismic waves that travel through the Earth’s body are referred to as “body waves.” These consist of the Primary or P-waves and Shear/Secondary or S-waves.

7. Seismic waves that travel on the surface or along discontinuities are called “surface waves.”

8. A volcano is a mountain or hill formed around a vent on the Earth’s surface through which molten rock mass and other hot materials are ejected. Volcanic eruptions may either be strong or mild.

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OBJECTIVES 1. Explain the different processes that change the Earth’s surface 2. Explain the distribution of earthquake epicenters and volcanoes 3. Differentiate between magnitude and intensity of earthquakes 4. Describe how a volcanic eruption occurs 5. Explain the factors that control the explositivity of a volcanic eruption. 6. Practice precautionary measures before, during, and after an earthquake

and a volcanic eruption. 7. Show pupils how theories are formed and supported through scientific

methodology


VALUES Survival during disasters Diligence in practicing precautionary measures before, during, and after

a disaster

LIFE SKILLS Empathy Effective communication Problem solving Decision making Coping with stress Interpersonal skills

INTEGRATION WITH OTHER EPISODES Episode 33 deals with the internal structure of the Earth, which provides the background information pupils need to understand the different forces that change the Earth’s surface.

CONTENT BACKGROUND FOR TEACHERS Isostasy refers to the state of gravitational equilibrium between Earth's lithosphere and asthenosphere such that the tectonic plates "float" at an elevation which depends on their thickness and density. It is invoked to explain how different topographic heights can exist at the Earth's surface.

Episode 37. The Restless Earth

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The continental drift theory refers to the movement of the Earth's continents relative to each other. In this theory, a supercontinent, called Pangaea, was proposed to have existed 200 million years ago. The theory of continental drift was followed by the theory of seafloor spreading. Together, they led to the theory of plate tectonics. In the continental drift theory, the continental crust plowed over the oceanic crust. In the plate tectonics theory, the Earth's lithosphere is broken into “tectonic plates” moving over the plastic asthenosphere. The ocean floors are continually moving, spreading from the center, sinking at the edges (subduction), and regenerating (magmatism). Mantle convection currents beneath the plates move the tectonic plates in different directions.

Plate boundaries are defined by the occurrences of earthquakes and volcanoes. Together with other surficial and internal forces, the forces associated with earthquakes and volcanism are responsible for shaping the surface of the Earth. An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Most earthquakes occur along plate boundaries and faults. Faults are fractures in rocks layers with displacement. Movement may either be vertical or horizontal or a combination of the two. Earthquakes are recorded with a seismograph. The strength of an earthquake can be measured either as intensity (perceived strength based on damage) or magnitude (energy released).

A volcano is an opening, or rupture, in a planet's surface or in the Earth’s crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic eruption varies from mild to explosive. The main factor that controls the explositivity of a volcanic eruption is the magma composition. This in turn affects the viscosity of the magma. A viscous magma has high silica content, and combined with high gas content, results to a pressure buildup underneath the volcano which leads to an explosive type of eruption.

Precautionary measures must be taken before, during, and after an earthquake and a volcanic eruption. People should remain calm and have presence of mind.

ADDITIONAL CONTENT INFORMATION

Continental Drift Theory In 1912, Alfred Wegener, a German meteorologist, proposed a radical new theory, the theory of continental drift. In his theory, Wegener hypothesized

http://en.wikipedia.org/wiki/Earth

http://en.wikipedia.org/wiki/Crust_(geology)

http://en.wikipedia.org/wiki/Seismic_wave

http://en.wikipedia.org/wiki/Crust_(geology)

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that 200 million years ago, the continents were once assembled into one supercontinent which he called “Pangaea,” meaning “all lands” in Greek. Pangaea broke into several fragments and the continents slowly drifted towards their present-day position.

Fossils of Glossopteris and Mesosaurus were discovered in South America and Africa which are not separated by the vast, deep and cold Atlantic Ocean (Figure 37.1). Wegener believed that the seeds of Glossopteris are too large to be carried by the winds and that Mesosaurus, being a freshwater reptile, could not have swum across the Atlantic Ocean. However, if the continents were assembled back to Pangaea then the occurrences of the fossils may be explained.

Wegener, however, failed to explain convincingly why and how the continents drifted. He suggested that the continent crusts plowed over the oceanic crust. Wegener continued looking for more evidence to support this theory but failed; the evidence came after World War II.

Figure 37.1 Occurrences of fossils supported the existence of Pangaea.


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Seafloor Spreading Theory Scientists observed that underneath the major oceans is a long chain of mountains (running to a total length of 70,000 km). Rocks across the ridge were older and denser symmetrically away from the ridges. These mountain ranges are called mid-oceanic ridges and are active volcanoes. Harry Hess and Robert Dietz proposed a radical new theory called seafloor spreading: sea floor splits apart and rocks move away from each other. This theory provides clues to the mechanism driving the continental drift. The continents, instead of moving on top of the oceanic crusts as postulated by Wegener, are pushed as the seafloor moves laterally. Ocean ridges are above mantle upwellings, which cause seafloor to spread, like a conveyor belt. Magma replaces seafloor as it moves away, becoming new oceanic crusts.

(Correction Note: The demonstration of seafloor spreading in the videolesson should be part of the segment on the plate tectonics theory).

Plate Tectonics Theory Scientists then combined the two theories—the continental drift and the seafloor spreading—into one theory, the theory of plate tectonics. This unifying theory explains the mechanisms of continental drift, seafloor spreading, and subduction. It also explains global patterns of earthquakes, including deep subduction zone quakes, volcanism, and mountain building.

In the plate tectonics theory, the lithosphere is broken into fragments called tectonic plates (Figure 37.2). A tectonic plate may be made up of oceanic and continental crust (North American Plate) or a purely oceanic crust (Pacific Plate). If it is of the former, it carries the name of the continent. There are seven major plates (classified based mainly on size) and several minor plates. The Philippine Sea Plate is a minor plate.

At the boundaries of these plates, intense geologic processes and events occur. Earthquakes and volcanic eruptions mark the plate boundaries. There are three types of plate boundaries (Figure 37.3). Along divergent margins, two plates move away from each other.

When two plates move towards each other, their boundary is called convergent margins. When an oceanic crust is involved in the collision of plates, subduction occurs. Subduction is the process by which one of the colliding plates dive underneath the other plates. The boundary of the subducting plate and the overlying plate is marked by a trench. When two oceanic crusts collide, the slower plate subducts, forming a volcanic island

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Figure 37.2 Map showing the different tectonic plates (Source: http://Earthsci.org/education/teacher/basicgeol/platec/fg1.jpe)

Figure 37.3. Occurrences of fossils supported the existence of Pangaea

arc. The Philippine Trench marks the subduction of the Philippine Sea Plate underneath the Eurasian plate, forming the Philippine Archipelago. Volcanoes in the Philippines formed as the subducted oceanic lithosphere partially melts in the hot mantle region. (Correction Note: Not as undersea volcanoes as given in the telelesson, segment 8:41-8:46).

At the boundaries of these plates, intense geologic processes and events occur. Earthquakes and volcanic eruptions mark the plate boundaries. There are three types of plate boundaries (Figure 37.3). Along divergent margins, two plates move away from each other. When two plates move towards each other, their boundary is called convergent margins. When an oceanic crust is involved in the collision of


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plates, subduction occurs. Subduction is the process by which one of the colliding plates dive underneath the other plates. The boundary of the subducting plate and the overlying plate is marked by a trench. When two oceanic crusts collide, the slower plate subducts, forming a volcanic island arc. The Philippine Trench marks the subduction of the Philippine Sea Plate underneath the Eurasian plate, forming the Philippine Archipelago. Volcanoes in the Philippines formed as the subducted oceanic lithosphere partially melts in the hot mantle region. (Correction Note: Not as undersea volcanoes as given in the telelesson, segment 8:41-8:46).

Earthquakes Movements within the Earth that cause earthquakes happen very suddenly since the pressure or stress which has been building slowly is suddenly released. The study of seismic waves is called seismology. The instrument used to detect and record an earthquake is the seismogram and the record of the arrival of the seismic waves is the seismograph.

Most strong earthquakes occur when a fault moves. A fault is defined as a break in the rock layers where there is displacement. Movement may be vertical (up or down), lateral (left or right), or a combination of vertical and lateral.

Primers on precautionary safety measures to be done before, during, and after an earthquake and a tsunami published by the Philippine Institute of Volcanology and Seismology (PHIVOLCS) is given at the end of this episode. A flyer giving instructions on how to conduct an earthquake drill in schools is also available.

Volcanism There are 200 volcanoes in the Philippines, 20 of which are classified as active (Figure 4. The most active Philippine volcano is the Mayon Volcano with 49 eruptions up to 2010. Volcanoes are edifices on the Earth’s surface through which magma are ejected. Aside from lava (magma found on the Earth’s surface), ash or cinder, pyroclasts or tephra (solid rock fragments), and gases are also spewed during a volcanic eruption. A PHIVOLCS primer giving some vital information on active Philippine volcanoes is found at the end of the episode. Some eruptions may be mild that one may watch safely while the volcano is erupting as in the case of Hawaiian eruptions. Some volcanoes have explosive eruptions like that of 1991 Mt. Pinatubo eruption. How explosive an eruption would be is determined by two factors: the composition of the magma involved and the occurrence of magma-water

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interaction. If the magma is fluid, the bubbles would simply push the magma out of the volcano, resulting to mild and non-explosive eruption. In contrast to a magma which is viscous, the escaping gases is trapped in the magma which may result to a buildup of pressure. With the increase in pressure, an explosive eruption may occur. An explosive eruption also occurs when the hot ascending magma comes in contact with groundwater.

Figure 37.4 Volcanoes in the Philippines


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VOCABULARY WORDS active volcano ash asthenosphere continental crust continental drift theory convergent margins divergent margins earthquakes epicenter eruption fault focus fossil intensity isostasy lava lithosphere magma magnitude

mantle Mercalli intensity scale oceanic crust Pacific ring of fire Pangaea plate tectonics pyroclastics Richter scale seafloor spreading seismic waves seismogram seismograph subduction subduction zone tectonic plate transform fault boundary trench tsunami volcano

THE MOVING CONTINENTS

PRE-VIEWING ACTIVITIES Activity 1. Show and Tell 1. Review the internal structure of the Earth. 2. Begin the lesson by showing the class a standard physical map of the

world. Ask the pupils to look closely at the continents, particularly those across the Atlantic Ocean. Ask the pupils if they notice anything “strange” about the shapes of South America and Africa.

Activity 2. Look, Listen, and Learn Ask the pupils to copy the following questions.

1. What is the continental drift? 2. What do you call the supercontinent that existed 200 million years ago? 3. Name six continents that made up this supercontinent.

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VIDEO VIEWING

POST-VIEWING ACTIVITIES Activity 3. Let’s Find Out 1. What is the continental drift? (Answer: The continental drift is a theory that

proposes that there once a supercontinent which existed 200 million years ago.) 2. What do you call the supercontinent that existed 200 million years ago?

(Answer: This supercontinent was called Pangaea.) 3. Name eight continents that made up this supercontinent. (Answer: The

eight continents that made up Pangaea were: 1) North America with Greenland 2) Eurasia 3) South America 4) Africa 5) India 6) Australia 7) Madagascar 8) Antarctica

Activity 4. Challenge: Pangaea Puzzle Materials

cutout jigsaw puzzle pieces of “Pangaea” puzzles with Pangaea only (no features) Pangaea puzzle pieces that show the continents with evidence for

continental drift Procedure

1. Group the pupils and ask them to work out the puzzles. 2. Ask the pupils to stick on the board the completed puzzle. Start with

the puzzle that does not show any feature (ie, the blank Pangaea puzzle).

3. Ask the group that worked on the blank Pangaea puzzle if they found it easy to assemble the puzzle. Ask them what they used to help them reconstruct Pangaea. Ask the group if the pieces they used formed the correct image of Pangaea.

PLAY the segment titled The Moving Continents. PAUSE the video to allow the pupils to write down their answers to the questions. You may RE-PLAY the segment if majority of the pupils failed to understand what they have just viewed.


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PLAY the segment on Earthquake. PAUSE the VIDEO to allow pupils to write down their answers to the questions. You may RE-PLAY the segment if majority of the pupils failed to understand what they have viewed. Ask pupils to take down notes on what to do before, during, and after an earthquake

4. Next, ask the other groups to stick on the board their respective puzzles.

5. Ask the pupils to tell the class what features in the puzzle they used to put the pieces together. Ask them what they used to help them reconstruct Pangaea. Ask the group if they are confident that the image they came up with is the correct image for Pangaea.

6. Tell the pupils that what they have done is similar to how scientists worked to collect evidence used to support the theory of continental drift.

EARTHQUAKES


Activity 1 Ask the pupils if they have ever experienced an earthquake. Ask them to describe the experience.

Activity 2. Look, Listen, and Learn Display these questions on the board for pupils to answer as they view the segment:

1. What is an earthquake? 2. What is a fault? 3. Name the fault that cuts through Metro Manila 4. What should you do before an earthquake? 5. If an earthquake occurs while you are at home what should you do? 6. What should you do after an earthquake?

VIEWING ACTIVITY

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Activity 3. Let’s Find Out 1. Discuss the segment viewed. 2. Have the pupils answer the questions on precautionary measures

before, during and after an earthquake. a. What is an earthquake? (Answer: An earthquake is the shaking of the

ground resulting from the sudden release of energy stored in rocks along faults.

b. What is a fault? (Answer: A fault is a break in rock layers that show some movement.)

c. Name the fault that cuts through Metro Manila. (Answer: The fault that runs through Metro Manila is the Marikina Valley Fault. This is now called Valley Fault System.)

d. What should you do before an earthquake? (Answer: Prepare your house and its contents by securing objects and furniture which may fall during an earthquake. Prepare an emergency kit.)

e. If an earthquake occurs while you are at home, what should you do? ( Answer: Don’t panic. Duck, cover, and hold.)

f. What should you do after an earthquake? (Answer: Check yourself and other people for injuries; treat minor injuries; check for damages; If you are inside a building, look for the safest exit.)

Activity 4. Shifting Vertical Layers To demonstrate what may happen when an earthquake occurs, do this activity.

Materials 2 strips of cloth or plastic a rectangular cake pan or a cardboard box small plastic toy houses, cars and bridges.

Procedure Lay two separate strips of cloth or plastic next to each other on the bottom of a cake pan. Let the end of one strip hang out from one side of the pan, and let the other end of the other strip hang out from the opposite side of the pan. Cover the strips with damp soil up to the edge of the pan and pack it down firmly. Place small plastic toys on the soil to represent houses, cars, and bridges. Now pull the strips protruding from the sides of the pan simultaneously. Ask the pupils


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to describe what happens. Ask them to predict what may happen if a similar event occurs.

Emphasize the do’s and don’t’s before, during, and after an earthquake. Use the PHIVOLCS posters or primers.

EVALUATION Direction: Choose the letter of the best answer.

1. It is a theory that states that 200 million years ago, a supercontinent broke up and the resulting fragments started to drift apart. A. Continental Drift C. Plate Tectonics B. Isostasy D. Seafloor Spreading

2. Which theory states that the lithosphere is divided into a number of plates? A. Seafloor Spreading C. Continental Drift B. Plate Tectonics D. Plutonism

3. While new lithosphere is created at mid-oceanic ridges, where is older lithosphere destroyed? A. at island arcs C. at subduction zones B. at spreading centers D. at transform faults

4. At which type of boundary is the Philippines located? A. convergent C. transform B. divergent D. divergent and transform

5. To what does the magnitude of an earthquake refer? A. its intensity c. the duration of its trembling B. the damage it created d. the energy released

6. Kiko was studying for his science exam when he felt a sudden movement. . What do you call this ground measurement? A. epicenter C. intensity B. focus D. magnitude

7. What do you call the point of origin of seismic waves? A. center C. focus B. epicenter D. starting point

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8. Any molten silicate material, whether below the surface or on top in known as a what? A. intrusion C. magma B. lava D. pluton

9. What should you do when an earthquake occurs? A. Run out of the house or building. B. Quickly cross a bridges or overpass. C. Stand under a power line or post. D. Protect your body from falling debris.

10. Which is TRUE about volcanoes? A. steep-sided high mountains of any origin B. places where magma originates and comes out of the earth C. typically mountains built up of countless layers of volcanic flows

and pyroclastics D. giant hills or mountains that have been pushed up like giant

bubbles by the pressure of magmas underneath

ANSWER KEY 1. A 2. B 3. C 4. A 5. D

6. C 7. C 8. C 9. D

10. B BIBLIOGRAPHY Tarbuck, E., & Lutgens, F. K. (2005). Earth: An introduction to physical geology.

N J: Pearson Prentice Hall.

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VOLUME 7. EARTH AND SPACE EPISODE 38. THE GREAT TRIUMVIRATE (EARTH, MOON, SUN)

OVERVIEW OF THE EPISODE The episode is about the Earth and its moon and the Sun. It presents the characteristics of the Moon, the Sun, and Earth. It discusses the three theories on the origin of the Moon, the features of the Moon, its orbit, and its phases. It presents the origin of the Sun, the length of sunlight, how day and night, a solar eclipse, and a lunar eclipse happen.

The episode begins with a presentation of three theories about the origin of the Moon. This is followed by a discussion of the features of its surface and the phases of the Moon. A demonstration of the Moon’s phases is presented. The cause of tides in the Earth’s seas is graphically illustrated. Segments on the Sun describe how seasons, solstices, and eclipses happen. A procedure for observing an eclipse safely is demonstrated.

SCIENCE CONCEPTS 1. The escape, capture, and moon formation theories are ideas about the

origin of the Moon. 2. Craters are the most numerous features on the Moon’s surface. 3. The Moon’s orbit around Earth is elliptical. At apogee, it is about 404 336

km. At perigee it is about 354 341 km. 4. The shape of the Moon appears to change because different amounts of

its illuminated part face Earth as it revolves around Earth. 5. Tides are caused by the attraction of the Moon and the Sun on Earth and

the Earth’s rotation. 6. The rotation of Earth on its axis causes day and night. 7. An eclipse may occur during the Moon’s revolution around Earth and

Earth’s revolution around the Sun.

OBJECTIVES 1. Use a model to demonstrate Earth’s rotation on its axis 2. Explain the changing shapes of the Moon seen on many nights. 3. Illustrate the position of the Moon relative to Earth during a high tide

and a low tide. 4. Show through a model how a solar and a lunar eclipse occur.

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Figure 38.1 Features of the Moon

SCIENCE PROCESSES Observing, communicating, using a model, using an illustration, inferring

VALUES Appreciation of the orderliness of natural phenomena Working in harmony with members of one’s group

LIFE SKILLS Making models Recording observations Making illustrations

INTEGRATION WITH OTHER EPISODES Episode 35 titled Water: The Drop of Life discusses places on Earth where oceans and seas are located. This relates to the topic on tides in the present episode.

CONTENT BACKGROUND FOR TEACHERS

Origin of the Moon The Moon is Earth’s nearest neighbor. There are theories about the Moon’s origin. Scientists believe that the Moon was formed from the material ejected after the Earth collided with a Mars-sized object. This ejected material merged with the Moon and went into orbit around Earth. This catastrophic collision occurred about 60 million years after Earth was formed (about 4.3 billion years ago). In several missions to the Moon, NASA astronauts have collected 382 kg of moon rocks. Studies of these rocks show that the composition of the moon rocks is very similar to that of Earth rocks. Using radioisotope dating, moon rocks are determined to be about 4.3 billion years old.

Features of the Moon In the past, astronomers thought that the Moon was a ball of rocks. They believed that there were valleys and mountains on the Moon’s surface. The black areas seen from Earth were thought to be bodies of water and so it was named maria, meaning seas. They

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are actually plains on the Moon. Maria are concentrated on the side of the moon that faces the Earth; the far side has very few of these plains. Using powerful telescopes, astronomers observed the rugged surface of the Moon. They think the surface of the Moon is scarred by millions of (mostly circular) impact craters caused by asteroids, comets, and meteorites. There is no atmosphere on the Moon to protect it from bombardment by impactors (most objects from space burn up in our atmosphere). Also, there is no erosion by wind or precipitation and little geologic activity to wear away these craters, so they remain unchanged until another new impact changes it. These craters appear as bright spots on the surface. These craters are up to many hundreds of kilometers, but the largest craters have been flooded by lava, and only parts of the outline are visible. The low elevation maria have fewer craters than other areas because they were formed more recently, and have had less time to be hit. The biggest intact lunar crater, Clavius is 100 miles (160 km) in diameter.

The Moon’s Orbit The Moon’s orbit around Earth is an ellipse. When the Moon is closest to Earth at 356,410 km that position is termed perigee. Its farthest distance from Earth at 406,700 km is its apogee. The Moon revolves around Earth in a counterclockwise direction at the speed of 3,520 km per hour. At perigee, the Moon’s revolution is a bit faster. The Moon rotates on its axis. It rotates once in one revolution.

Phases of the Moon As the Moon circles the Earth, the shape of the Moon appears to change (Figure 38.3). This is because different amounts of the illuminated part of the Moon face us. The shape varies from a full Moon when the Earth is

Figure 38.2 The Moon’s orbit

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between the Sun and the Moon to a new Moon when the Moon is between the Sun and the Earth.

Figure 38.3 Phases of the Moon

Explanation of Figure 38.3. Sunlight is shown coming in from the right. Earth is at the center of the diagram. The Moon is shown at eight key stages during its revolution around Earth. The dotted line from Earth to the Moon represents one’s line of sight when looking at the Moon. To help visualize how the Moon would appear at that point in the cycle, look at the larger Moon image. The Moon phase name is shown alongside the image.

Exactly one half of the Moon is always illuminated by the Sun. It is necessary for pupils to visualize this in order to understand the phases. At certain times, we see both the sunlit portion and the shadowed portion—and that creates the various Moon shapes (phases). Note that the shadowed part of the Moon is invisible to the naked eye (in the diagram it is only shown for clarification purposes).


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So the basic explanation is that the Moon’s phases are created by relative positions of the Earth, the Moon, and the Sun, as the Moon orbits Earth.

It may be easier to understand the Moon cycle in this order: new Moon and full Moon, first quarter and third quarter, and the phases in between.

As shown in the diagram, new Moon occurs when the Moon is between Earth and the Sun. The three celestial bodies are in approximate alignment (why "approximate" is explained below). The entire illuminated portion of the Moon is on the back side of the Moon, the half that we cannot see.

At full Moon, Earth, Moon, and Sun are in approximate alignment, just as the new Moon, but the Moon is on the opposite side of the Earth, so the entire sunlit part of the Moon is facing us. The shadowed portion is entirely hidden from view.

The first quarter and third quarter Moons (both often called a "half Moon"), happen when the Moon is at a 90-degree angle with respect to Earth and the Sun. So we are seeing exactly half of the Moon illuminated and half in shadow.

Once the four key Moon phases is understood, the phases between will be easier to visualize, as the illuminated portion gradually changes between them.

A way to remember and understand those "between" lunar phase names is by breaking out and defining four words: crescent, gibbous, waxing, and waning. The word crescent refers to the phases where the Moon is less than half illuminated. The word gibbous refers to phases where the Moon is more than half illuminated. Waxing means "growing" or expanding in illumination, and waning means "shrinking" or decreasing in illumination.

Thus we can simply combine the two words to create the phase name, as follows: After the new Moon, the sunlit portion is increasing, but less than half, so it is waxing crescent. After the first quarter, the sunlit portion is still increasing, but now it is more than half, so it is waxing gibbous. After the full Moon (maximum illumination), the light continually decreases. So the waning gibbous phase occurs next. Following the third quarter is the waning crescent, which wanes until the light is completely gone—a new Moon.

Moon and Tides Tides are the daily rise and fall of water level caused by the gravitational force of the Moon and the Sun on Earth and by Earth’s rotation. Since Earth is rotating, two tides occur each day. In one rotation a side on Earth’s

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surface is exposed to the greatest attraction of the Moon when directly facing it and to its least attraction when facing away from it. Thus two high tides on opposite sides of Earth of about 12 hours apart are formed. The Moon’s attraction on Earth is greater than that of the Sun because the Moon is nearer. Water on Earth’s surface is pulled toward the side directly facing the Moon and humps up. Water on the side of Earth away from the Moon is left behind because the Moon’s attraction is weaker there. The water that is not pulled away therefore has a higher water level than the waters on the part of the Earth at right angle to the Moon (Figure 38.4). The knowledge of the height of tides, both low and high, is vital for many functions, including navigation, fishing, and the construction of coastal facilities.

Figure 38.4 Tides

Spring Tide A spring tide occurs when the Sun and the Moon are in line with Earth, and their gravitational pulls reinforce each other (Figure 38.5, left). It is a tide in which the difference between high and low tide is the greatest. It occurs when the Moon is either new or full, and the Sun, the Moon, and Earth are aligned. When this is the case, their collective gravitational pull on Earth's water is strengthened. Neap Tide

LOW TIDE

HIGH TIDE HIGH TIDE

LOW TIDE


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A neap tide occurs when the Sun, the Moon, and Earth form a right angle and the gravitational pull of the Sun counteracts the pull of the Moon (Figure 38.5, right).

Figure 38.5 Spring tide (left) and neap tide (right)

The Sun A theory holds that the Sun and its planets formed from the mixed debris of a supernova that exploded 5 billion years ago. The Sun is considered a middle-aged, medium-sized, yellow star. Like other stars, the Sun undergoes continuous nuclear reactions at its center. The reactions change hydrogen into helium. These reactions produce the heat and light given off by the Sun. It is theorized that the Sun will last for 4 to 5 billion years. As the star grows older, either the nuclear reactions stop and the star collapses, or the reactions become greater and the star explodes.

Day and Night Earth’s rotation causes day and night. Earth rotates or spins on its axis (an imaginary line passing through the North and South Poles (Figure. 38.6) may help illustrate to pupils the meaning of axis. Earth rotates slowly all the time, but we don't feel any movement because it turns smoothly and at the same speed. Earth takes a whole day (24 hours) to make a complete rotation. At any time half of Earth faces the Sun. This part has day. The other half of Earth faces away from the Sun. It receives no light. It is dark and has night.

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Figure 38.6 Examples to illustrate the meaning of axis

Eclipse As the Moon revolves around Earth and Earth revolves around the Sun, an eclipse may occur. Either the Sun is blocked or the Moon is blocked. When the Moon passes directly between the Sun and Earth, the Moon casts a shadow on Earth. All solar eclipses involve the Moon passing between Earth and the Sun, and casting a shadow on Earth. However, the type of eclipse which can be seen from a given location depends on whether the Moon passes directly, or only partly, between Earth and the Sun; but also on places on Earth where people observe it.

The Moon blocks the Sun’s light from reaching Earth. This is called solar eclipse. A solar eclipse occurs when the Moon passes between Earth and the Sun, blocking all or a portion of the Sun. A total solar eclipse occurs only over the areas on Earth covered by the umbra of the Moon. It happens only during a new Moon. (Figure 38.7) A partial solar eclipse occurs on those areas covered by the penumbra of the Moon.

When Earth is between the Sun and the Moon, Earth casts its shadow on the Moon. This is a lunar eclipse. When Earth casts its shadow on just a part of the Moon’s visible surface, a partial lunar eclipse occurs. When the Moon is completely covered by Earth’s shadow, a total lunar eclipse occurs.


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Figure 38.7 Total solar eclipse

A lunar eclipse occurs when the Moon passes behind Earth such that Earth blocks the Sun’s rays from striking the Moon. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with Earth in the middle. Hence, there is always a full Moon the night of a lunar eclipse (Figure 38.8). Unlike a solar eclipse, which can only be viewed from a certain relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A lunar eclipse lasts for a few hours, whereas a total solar eclipse lasts for only a few minutes at any given place.

Figure 38.8 Schematic diagram of the shadow cast by Earth

A lunar eclipse occurs at night and a solar eclipse occurs during the day. We can see lunar eclipses more readily than solar eclipses, and it has to do with proximity. The Moon is much closer to Earth (over 300 times closer than the

http://en.wikipedia.org/wiki/Sun

http://en.wikipedia.org/wiki/Earth

http://en.wikipedia.org/wiki/Moon

http://en.wikipedia.org/wiki/Full_moon

http://en.wikipedia.org/wiki/Solar_eclipse

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Sun), so Earth has a much greater chance of blocking sunlight to the Moon, compared to the Moon blocking light from the Sun. Also, a lunar eclipse can be seen from a greater portion of Earth. Solar eclipses, on the other hand, are rarer and when they do happen, they can only be seen by a very narrow segment of Earth for a short period of time.

It is safe to watch a lunar eclipse with the naked eye, but watching a solar eclipse without eye protection can seriously damage the eyes.

Looking at a Solar Eclipse Safely Looking directly at the photosphere of the Sun (the bright disk of the Sun itself), even for a few seconds, can cause permanent damage to the retina of the eye because of the intense visible and invisible radiation that the photosphere emits. This damage can result in blindness. The retina has no sensitivity to pain, and the effects of retinal damage may not appear for hours, so there is no warning that injury is occurring.

Under normal conditions, the Sun is so bright that it is difficult to stare at it directly, so there is no tendency to look at it in a way that might damage the eye. However, during an eclipse, with so much of the Sun covered, it is easier and more tempting to stare at it. Unfortunately, looking at the Sun during an eclipse is just as dangerous as looking at it outside an eclipse, except during the brief period of totality, when the Sun's disk is completely covered (totality occurs only during a total eclipse and only very briefly; it does not occur during a partial or annular eclipse). Viewing the Sun's disk through sunglasses, binoculars, a telescope, a camera viewfinder, a black color slide film is extremely hazardous.

The safest way to view the Sun's disk is by indirect projection. This is by projecting an image of the disk onto white paper using a pair of binoculars (with one of the lenses covered), a telescope, or another piece of cardboard with a small hole 1 mm in diameter (also called a pinhole camera). The projected image of the Sun on the paper can then be safely viewed. This technique can be used to observe sunspots as well as eclipses. It is safe to observe the total phase of a solar eclipse directly with the unaided eye, a binoculars, or a telescope, only when the Moon completely covers the Sun's photosphere. During this period, the Sun is too dim to be seen through filters. The Sun's faint corona will be visible. But viewing the Sun after totality can be dangerous.


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VOCABULARY WORDS axis counterclockwise Earth’s rotation first quarter Moon

full Moon last quarter Moon Moon’s revolution new Moon

umbra solar eclipse lunar eclipse total solar eclipse

PRE-VIEWING ACTIVITIES The following activities may be done to introduce the pupils to the video segment on day and night.

Activity 1. Acting Out You may do this short motivation. Ask several pupils to act out activities they do during the day and at night (they may demonstrate sleeping and waking up the following morning). They will stay in front. The rest of the class will guess which activity is done during the day and at night. Then ask the whole class: How does our surrounding look at daytime? (Bright.) How does it look at nighttime? (Dark.)

Activity 2. Watch, Listen, and Learn Tell the pupils that they will watch a video about the Earth, Moon, and Sun. Have them copy the following questions which they will answer as they view the video.

1. Where does light that brightens our surrounding come from? 2. What causes day and night? 3. Why is the Moon located at different places each night? 4. What are the spots and shadows on the Moon? Are there living things on the Moon? 5. Why does the level of water in seas rise and fall? How many times in a day does this event happen?

VIDEO VIEWING

Have the pupils view the following segments: Lunar Features, Phases of the Moon, Tides, and Earth’s Rotation. After each segment, PAUSE the videolesson to give the pupils time the questions related to the segment.

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POST-VIEWING ACTIVITIES Activity 3. What Happens When Earth Rotates?

Materials 1 big round fruit, such as pomelo (suha) or watermelon (pakwan) to

represent Earth 1 banana cue stick black marker (pentel pen) styropor pad flashlight to represent the Sun

Procedure 1. Put a dot on one side of the big fruit to mark the place where you

live. 2. Push a banana cue stick through the center of the big fruit. The

stick represents Earth’s axis. 3. Make a dot mark on one side of the fruit to mark the part you can

see from Earth. 4. Stick the pointed end of the stick on the styropor pad in a slanting

position. 5. Put the flashlight on the table and switch it on. Focus its light on

the big fruit. 6. Hold the big fruit in front of the flashlight. 7. Turn the big fruit on its axis (rotate) counterclockwise. Ask: How

does the side with the dot facing the light look? (Answer: Bright.)

Tell them that it is daytime on that side of Earth. Ask: How does the side with the dot that is turned away from the light look? (Answer: Dark.)

Activity 4. Kinesthetic Modeling of Day and Night Note: Kinesthetic learning is a teaching and learning style in which learning takes place as the student actually carries out a physical activity, rather than listens to a lecture or watches a demonstration.

Pupils will play Earth to learn more about day and night. Darken the room, and turn on the lamp. Say that the lamp represents the Sun.

1. Ask a pupil to be Earth. Wrap a whole manila paper around the pupil. Draw a small school on the paper so that it is on the pupil’s chest. The pupil should be seen by the whole class.

2. Ask the class to focus on the drawing as the pupil-Earth rotates.

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3. Begin with the pupil-Earth’s back to the lamp. Ask the class if they think it is day or night in their school’s town. (It is night.)

4. Have pupil- Earth rotate slowly in a counterclockwise direction, until the left arm is pointed to the Sun. Ask the class: Do you think it is sunrise or it is still night?

5. Pupil-Earth continues the counterclockwise rotation until he or she faces the lamp directly. Ask the class: What time is it now in the town? Pupils can see that it is noon, the middle of the day, when the town gets the most light from the Sun. You may need to prompt with additional questions.

6. Ask pupil-Earth to rotate a little more. Have the pupil stop when his or her right arm points toward the Sun. Ask: What time of day is it? (Sunset.)

7. Complete the day-and-night cycle by having pupil-Earth return to his or her original position (that is with his or her back to the Sun). The class should be able to tell you that is midnight.

8. Ask the class: What time of day it is on the other side of Earth (pupil’s back faces the Sun and it is noon)? Explain that one half of Earth is always in the light while the other is in the dark. Emphasize that it is Earth's own shadow that makes the night side of the Earth dark.

9. Repeat this demonstration. Call other volunteers so that the class will get a chance to view the day-and-night cycle several times. Explain that it takes 24 hours for Earth to rotate (spin on its axis) completely.

Activity 5. Why Does the Moon’s Shape Change? Materials Materials

big rectangular box flashlight black paint, white paint piece of wood paint brush masking tape styropor ball (bigger than a pingpong ball) cardboard as wide as the top of the box 2 cm wire

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Procedure 1. Cut off all the flaps of one end of the box. Cut another cardboard to

fit the opening of the box to replace the removed flaps. This will serve as the cover of the box. Using masking tape, fasten one length of the flap to one side of the box.

2. Paint the inside of the box black. 3. Paint the pingpong ball gray (mix some black and white paint).

4. Make 8 holes the size of one peso coin, 3 each on the wider side and 1 each on the narrower sides of the box.

5. Make a smaller hole the size of a 25-centavo coin 2 cm from the hole on the narrower side.

6. Mark the holes A, B, C, D, E, F, G, and H starting from the side opposite the smaller hole.

7. Fasten the styropor ball with wire to the center of the flap cover, letting it hang parallel to the holes of the box.

8. Remove the head cover of the flashlight, leaving the bulb exposed. Switch on the flashlight and insert the lighted bulb through the small hole.

9. Have the pupils do the following: 9.1 Make a chart with labels A to H.

A. B. C. D. E. F. G. H.

9.2 Peep through all the 8 holes starting from A. 9.3 Draw the lighted part of the ball as seen through each hole. 9.4 Answer the following questions:

9.4.1 What does the changing size of the lighted part of the ball indicate?

9.4.2 The Moon has completed one revolution around Earth. How long does it take the Moon to make one revolution?


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Activity 6. Label the Moon Phases Read the descriptions in Table 1, then label the Moon phases diagram.

Table 38.1 Descriptions of the Moon Phases

Crescent Moon - we can see only a sliver of the Moon's disk (the side of the Moon facing us)

New Moon - the Moon's disk is dark (and invisible to us) because the Moon is between the Sun and Earth

Full Moon - the Moon's disk is light because Earth is between the Sun and the Moon

Quarter Moon - also called half Moon; we see one half of the Moon's disk or one-quarter of the entire Moon's surface

Gibbous Moon - we see roughly three-quarters of the Moon's disk

Waning Moon - the Moon seems to be getting smaller, going from full to gibbous to half to crescent to new

Half Moon - also called quarter Moon; we see one half of the Moon's disk or one-quarter of the entire Moon's surface

Waxing Moon - the Moon seems to be getting bigger, going from new to crescent to half to gibbous to full

Figure 38.9 Unlabelled Diagram of the Moon’s Phases

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Answer to Activity 6

Figure 38.10 Labelled Diagram of the Moon’s Phases Activity 7. How Does a Solar Eclipse and a Lunar Eclipse Occur?

Materials pingpong ball with a piece of string tied to it; this will represent the

Moon flashlight to represent the Sun globe or ball bigger than a pingpong ball to represent Earth

Procedure Darken the room. You can cover the windows with dark curtain or black garbage bags. Have each group set up the materials and answer the questions.

1. Dangle the pingpong ball between the bigger ball and the flashlight.

2. Turn on the flashlight.

Question: Can you see the shadow of the pingpong ball on the globe? Discussion: From Earth we will not see the Sun as a whole circle because part of it is covered by the Moon. This is how a solar eclipse occurs.


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1. Have the groups move the pingpong ball around the globe in a counterclockwise direction. Stop when the globe is between the flashlight and the pingpong ball.

Question: Can you see the shadow of the globe on the pingpong ball? This is how a lunar eclipse occurs.

Activity 8. Labeling an Eclipse Diagram Have the pupils label the diagram (Figure 38.11).

Figure 38.11 An Eclipse Diagram

Answers to Activity 8 A. Sun - the star in our Solar System B. Earth - the planet on which we live C. Moon - the natural satellite of Earth D. Umbra - the area in which the shadow of an object (in this case, the

Earth, on the Moon) is total. When the entire Moon is in Earth's umbra, we experience a total lunar eclipse. When part of the Moon is in Earth's umbra, we experience a partial lunar eclipse.

E, F. Penumbra - the area in which the shadow of an object (in this case, the Earth, on the Moon) is partial.

EVALUATION Read each question. Choose the answer from the four options.

1. Every how many hours does a high tide occur? A. 3.5 hours C. 12.42 hours B. 6 hours. D. 24 hours

A B

C

D

E

F

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2. Why does the Moon seem to move to the west? A. Earth rotates from west to east. B. Earth revolves around the Sun. C. The Moon revolves around Earth. D. The Moon rotates on its axis once in 29 1/2 days. 3. How long does it take for the Moon to complete its phase from full Moon to the next full Moon? A. 271/2 days C. 29 1/2 days B. 28 days D. 30 days 4. The phase of the Moon when it passes between the Sun and Earth is A. full Moon C. last quarter Moon B. new Moon D. first quarter Moon 5. The Moon at perigee means that it is

A. in its full Moon phase. B. in its new Moon phase. C. at its farthest point from Earth. D. at its nearest point from Earth.

6. A lunar eclipse occurs when Earth passes between the Moon and the

Sun, and Earth's shadow obscures the Moon or a portion of it A. the Earth passes between the Moon and the Sun. B. the Moon passes between the Earth and the Sun. C. the Sun passes between the Earth and the Moon. D. the Moon’s shadow obscures the Sun.

7. The craters on the Moon’s surface are caused by

A. lack of water. B. running water. C. lack of atmosphere. D. the impact of meteorites

8. Compared to other stars, the Sun is __________________ .

A. the biggest C. not as hot B. the smallest D. the hottest


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9. What will likely occur when the Moon passes between the Sun and Earth? A. solar eclipse C. first quarter Moon B. lunar eclipse D. last quarter Moon

10. What causes day and night?

A. tilting of Earth’s axis B. Earth’s rotation on its axis C. Moon’s rotation on its axis D. Earth’s rotation and revolution

ANSWERS TO EVALUATION QUESTIONS 1. C 2. A 3. C 4. B 5. D

6. A 7. D 8. C 9. A

10. B

BIBLIOGRAPHY Center for Science Education at Space Sciences Laboratory (CSE@SSL),

University of California at Berkeley (UCB). (2009). What Makes Day and Night? The Earth's Rotation. Retrieved from http://eyeonthesky.org/lessonplans/05Sun_daynight.html

Cortes, L. P., Basa, E., Estrera J. A., Galvante, W. P. & Rodriguez, V. L. (2003). Earth science: The Philippines in focus (5th ed.). QC: University of the Philippines National Institute for Science and Mathematics Education Development.

Lunar Eclipse. (modified 29 April 2012). Wikipedia, The Free Encyclopedia. Retrieved from

http://en.wikipedia.org/wiki/Lunar_eclipse Lunar Tides. (n.d.). Astronomy 161 Lectures. [Online]. Retrieved from www.cmdowns.com/tides-notes.htm Smith, I. C. (modified May 3, 2008). The Earth and Moon. [Online] Retrieved

from <www.hermit.org/Eclipse/why_solsys.html> Spring Tide. (Updated 2009). The Free Dictionary. Retrieved from http://www.thefreedictionary.com/spring+tide

mailto:[email protected]

http://eyeonthesky.org/lessonplans/05sun_daynight.html

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VOLUME 7. EARTH AND SPACE EPISODE 39. THE SOLAR SYSTEM

OVERVIEW OF THE EPISODE This episode focuses on the Solar System. It presents the nine planets, the Sun, and other celestial bodies. It demonstrates a procedure for making a classroom mobile of the planets to show their relative sizes.

The episode begins with a presentation of the nine planets, their groupings into two based on size. This is followed by a discussion of the profile of each planet, such as its distance from the Sun, revolution, rotation, orbital speed, diameter, tilt, and number of moons. It also discusses the asteroids, comets, and meteoroids that comprise the celestial bodies in the Solar System. The use of an actual telescope for observing the surface of the Sun is shown to emphasize the danger of looking at the Sun directly.

SCIENCE CONCEPTS 1. Our Solar System consists of the Sun, the eight planets and their moons,

and other objects that orbit the Sun. 2. The planets in our Solar System are Mercury, Venus, Earth, Mars,

Jupiter, Saturn, Uranus, and Neptune. 3. The asteroids, meteoroids, and comets compose the other celestial

bodies in the Solar System. 4. The planets rotate on their axis, revolve around the Sun and are

illuminated by light from the Sun. 5. The Sun is the center and the largest object in our Solar System. It gives

off light, heat, and other forms of energy that make life on Earth possible.

OBJECTIVES 1. Recognize that the Solar System is an orderly arrangement of heavenly

bodies 2. Identify the Sun as the center of the Solar System 3. Identify the planets in the Solar System according to their characteristics,

such as size, orbit, distance from the Sun, number of moons, temperature, and component material

4. Use a diagram to demonstrate the rotation of the planets and their revolution around the Sun

5. Describe the asteroids, comets, and meteoroids

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SCIENCE PROCESSES Observing, communicating, comparing, measuring, showing relationship, interpreting data, inferring, predicting

VALUES Realize the significance of Earth maintaining its distance from the Sun Recognize the importance of keeping an open mind about changes in

established information about the Solar System

LIFE SKILLS Communicating effectively Improvising things Analyzing information

INTEGRATION WITH OTHER EPISODES Episode 38 The Great Triumvirate: Earth, Moon, Sun. Use the segment on characteristics of the Sun, such as its size, composition, origin, and the heat and light that it produces as additional background information

CONTENT BACKGROUND FOR TEACHERS Our Solar System

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Figure 39.1 Diagram of the Solar System

The phrase solar system refers to the Sun and all the objects that travel around it. Our Solar System is made up of the Sun, eight planets, 167 moons, dwarf planets, comets, asteroids, and other space rocks. The Sun is the center of the Solar System. Scientists think that the Solar System formed 4.5 billion years ago. The Sun contains 99.8% of all of the mass in our Solar System. This mass has a tremendous gravitational pull on the objects around it. Astronomers and other sky watchers observe comets with sparkling tails, and meteors or shooting stars apparently falling from the sky. Asteroids and comets orbit our Sun in a flattened circle called an ellipse.

The Sun The Sun is composed mainly of hydrogen and helium. Its gravity holds these spinning gases within the core. Nuclear reactions that continuously occur in its core change hydrogen into helium. These reactions produce the heat and light the Sun emits.

The Planets A planet is a large space body which reflects the light of a star around which it revolves. The eight planets that make up our Solar System are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. They are named after Roman deities—Jupiter, king of the gods; Mars, the god of war; Mercury, messenger of the gods; Venus, the goddess of love and beauty; and Saturn, father of Jupiter and god of agriculture.

Not all planets are the same. Some of them are not even solid. The planets in our Solar System are classified as inner planets and outer planets. The inner planets, the closest to the Sun, are Mercury, Venus, Earth, and Mars. For their first 600 million years, these inner planets were constantly bombarded by asteroids and meteorites. That is why there are craters of varying sizes on the surface of the inner planets and their satellites. Think of the craters on the Moon and Mars. Man stepped onto the Moon in 1969 to study the rocks and craters. NASA's Mars Exploration Rovers are sending back information about the craters on Mars. The Cassini spacecraft is providing a new look at spectacular craters recently found around the moons of Saturn. There are craters on Earth. Over millions of years, wind, rain, ice, and water have changed the surface of Earth since the craters were formed. In the USA, there is the Meteor Crater in Arizona.

The outer planets are large gaseous planets with rings. These are Jupiter, Saturn, Uranus, and Neptune. Saturn is not the only planet with rings.


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Jupiter, Uranus, and Neptune have rings, but they are very dark and millions of times less massive than the rings of Saturn. Jupiter's rings are made of bits of dust that fly off Jupiter's moons when they were struck by meteorites. It is not known yet what made the black rings of Neptune and Uranus.

Between the inner and outer planets (between Mars and Jupiter) is an asteroid belt. Some of the planets have naturally occurring satellites, or moons, while others do not.

Why Pluto Is No Longer a Planet by Fraser Cain, April 10, 2008 http://www.universetoday.com/2008/04/10/why-pluto-is-no-longer-a-planet/

This is one of the most heartbreaking questions I get asked, "Why Isn't Pluto a Planet"? And I get it a lot. I was expecting that a few years after the International Astronomical Union's controversial decision, the debate would have settled down and people would finally accept it. But no, it's still a sore point for many people that Pluto is not a planet. In this article, I'll explain the events that led up to the decision, the current state of planetary definition, and any hope Pluto has for the future. Let's find out why Pluto is no longer considered a planet.

Pluto was first discovered in 1930 by Clyde W. Tombaugh at the Lowell Observatory in Flagstaff Arizona. Astronomers had long predicted that there would be a ninth planet in the Solar System, which they called Planet X. Only 22 at the time, Tombaugh was given the laborious task of comparing photographic plates. These were two images of a region of the sky, taken two weeks apart. Any moving object, like an asteroid, comet, or planet, would appear to jump from one photograph to the next.

After a year of observations, Tombaugh finally discovered an object in the right orbit, and declared that he had discovered Planet X. Because they had discovered it, the Lowell team were allowed to name it. They settled on Pluto, a name suggested by an 11-year old school girl in Oxford, England (no, it wasn't named after the Disney character, but the Roman god of the underworld).

The Solar System now had nine planets.

Astronomers weren't sure about Pluto's mass until the discovery of its largest Moon, Charon, in 1978. By knowing its mass (0.0021 Earths), they could more accurately determine its size. The most accurate measurement currently gives the size of Pluto at 2,400 km (1,500 miles) across. Although it is small

http://www.universetoday.com/2008/04/10/why-pluto-is-no-longer-a-planet/

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http://www.universetoday.com/guide-to-space/pluto/

http://www.universetoday.com/guide-to-space/the-solar-system/planet/

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http://www.universetoday.com/guide-to-space/the-sun/solar/

http://www.universetoday.com/guide-to-space/asteroid/

http://www.universetoday.com/guide-to-space/comets/

http://www.universetoday.com/guide-to-space/astronomy/orbit/

http://www.universetoday.com/guide-to-space/the-solar-system/

http://www.universetoday.com/guide-to-space/the-solar-system/9-planets/

http://www.universetoday.com/guide-to-space/pluto/interesting-facts-about-pluto/

http://www.universetoday.com/guide-to-space/pluto/plutos-moon-charon/

http://www.universetoday.com/guide-to-space/pluto/plutos-moon-charon/

http://www.universetoday.com/guide-to-space/pluto/diameter-of-pluto/

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(Mercury is only 4,880 km or 3,032 miles in diameter), Pluto was considered larger than anything else past the orbit of Neptune.

Over the last few decades, new ground and space-based observatories have changed previous understanding of the outer Solar System. Instead of being the only planet in its region, like the rest of the Solar System, Pluto and its moons are now known to be just a large example of a collection of objects called the Kuiper Belt. This region extends from the orbit of Neptune out to 55 astronomical units (55 times the distance of the Earth to the Sun).

Figure 39.3 Diagram showing the location of the Asteroid Belt and the Kuiper Belt

Astronomers estimate that there are at least 70,000 icy objects with the same composition as Pluto that measure 100 km across or more in the Kuiper Belt (shown on the far right in the diagram). According to the new rules, Pluto is just another Kuiper Belt object.

Astronomers realized that it was only a matter of time before an object larger than Pluto was discovered in the Kuiper Belt. And in 2005, a team of astronomers dropped the bomb. They had discovered an object, farther out than the orbit of Pluto that was probably the same size, or even larger. Officially

Figure 39.2 Pluto and its moon

http://www.universetoday.com/guide-to-space/mercury/

http://www.universetoday.com/guide-to-space/space/

http://www.universetoday.com/guide-to-space/the-solar-system/other-solar-system/

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http://www.universetoday.com/guide-to-space/pluto/moons-of-pluto/

http://www.universetoday.com/guide-to-space/outer-solar-system/kuiper-belt/

http://www.universetoday.com/guide-to-space/astronomy/astronomical-units/

http://www.universetoday.com/guide-to-space/earth/

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named 2003 UB313, the object was later designated as Eris. Since its discovery, astronomers have determined that Eris' size is approximately 2,600 km (1,600 miles) across. It also has approximately 25% more mass than Pluto.

With Eris being larger, made of the same ice/rock mixture, and more massive than Pluto, the concept that of the nine planets in the Solar System began to fall apart. What is Eris—planet or Kuiper Belt object? What is Pluto? Astronomers decided they would make a final decision about the definition of a planet at the XXVIth General Assembly of the International Astronomical Union, which was held from August 14 to August 25, 2006 in Prague, Czech Republic.

Astronomers from the association were given the opportunity to vote on the definition of planets. One version of the definition would have actually boosted the number of planets to 12; Pluto was still a planet, and so were Eris and even Ceres, which had been thought of as the largest asteroid. A different proposal kept the total at nine, defining the planets as just the familiar ones we know without any scientific rationale, and a third would drop the number of planets down to eight, and Pluto would be out of the planet club. But, then … what is Pluto?

In the end, astronomers voted for the controversial decision of demoting Pluto (and Eris) down to the newly created classification of "dwarf planet."

Is Pluto a planet? Does it qualify? For an object to be a planet, it needs to meet these three requirements defined by the IAU:

· It needs to be in orbit around the Sun – Yes, so maybe Pluto is a planet. · It needs to have enough gravity to pull itself into a spherical shape – Pluto,

check. · It needs to have "cleared the neighborhood" of its orbit – Uh, oh. Here's the

rule breaker.

According to these, Pluto is not a planet.

What does "cleared its neighborhood" mean? It means it should orbit the Sun in isolation, as opposed to sharing its orbit with many similar-sized objects. There are many other objects whose size and mass are similar to Pluto that are in its orbit. And so it is excluded from full-fledged planethood, making it instead a dwarf planet.

Even though Pluto is a dwarf planet, and no longer officially a planet, it'll still be a fascinating target for study. NASA has sent the New Horizons spacecraft which will reach Pluto in July 2015, and capture the first close-up images of the (dwarf) planet's surface.

http://www.universetoday.com/guide-to-space/the-solar-system/2003-ub313/

http://www.universetoday.com/guide-to-space/pluto/what-is-pluto-made-up-of/

http://www.universetoday.com/guide-to-space/the-solar-system/planets-in-the-solar-system/


http://www.universetoday.com/guide-to-space/the-solar-system/number-of-planets/

http://www.universetoday.com/guide-to-space/asteroids/ceres/

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http://www.universetoday.com/guide-to-space/the-solar-system/planets-in-the-solar-system/

http://www.universetoday.com/guide-to-space/the-solar-system/dwarf-planets/

http://en.wikipedia.org/wiki/Dwarf_planet

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Space enthusiasts will marvel at the beauty and remoteness of Pluto, and the painful deplaneting memories will fade. We'll just be able to appreciate it as Pluto, and not worry how to categorize it. At least now we know why Pluto was demoted.

The Planets’ Orbits The orbits of the planets are ellipses with the Sun at one focus. They all orbit in the same direction (counterclockwise). Orbit means the gravitationally curved path of one object around a point (+ mark in the diagram below). Ellipse means a closed, symmetric curve shaped like an oval. The diagrams (Figure 39.4) may be useful to pupils’ understanding of the terms.

Figure 39.4 Diagram of the orbit of two balls (left) and an ellipse (right)

Other Characteristics of the Planets The inner planets are dense, composed of rock and metal unlike the outer planets which are gaseous with no solid surface.

Mercury. It is closest to the Sun, the smallest (only about one-tenth the size of Earth), has too little gravity to keep much of an atmosphere.

Venus. It is about the size of Earth, the hottest, with an average temperature of 460°C.

Earth. It is the largest of the inner planets, the densest planet with 70% of its surface covered in water. Earth's average temperature is 13 to 17 degrees Celsius. The hottest temperature ever recorded on Earth was in

http://www.nineplanets.org/help.html#ellipse

http://www.nineplanets.org/sol.html

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2005 in the Lut Desert in Iran at 70.7°C. The coldest temperature recorded on Earth was in Vostok, Antarctica at –89.2°C. Earth is sometimes called the Blue Planet although Uranus and Neptune are also blue.

Mars. This famous Red Planet, has captivated people for centuries. Its red color is caused by the rusting of metals on its surface. Life on it has not been detected.

Jupiter. It is the largest in the Solar System, its size and mass is overwhelming (Earth looks like a speck in comparison); 1321 Earths could fit inside; it is also called the gas giant.

Saturn. It is the second largest planet in our Solar System; it has the most extensive planetary ring system, these rings can be seen with a simple telescope.

Uranus. It has a bright blue coloring from the methane in its atmosphere; it is colder than Neptune.

Neptune. It is the farthest planet from the Sun but not the coldest; its temperature can drop to –221.4°C. It has bright blue coloring from the methane in its atmosphere.

The Ancient Greeks and Romans wrote about the planets many centuries ago. Because the planets move in the sky, they were termed wandering stars. The term planet comes from the Greek word for wanderer, "planetes." Ancient people thought that the planets were gods, so they gave them names of their gods. All of the planets, except Earth, have names of Roman deities.

Because Neptune cannot be seen without a telescope, it was not discovered until after 1610 when Galileo created the telescope. Pluto was discovered in 1930 by the astronomer Clyde Tombaugh.

Sizes A way to visualize the relative sizes in the Solar System is to imagine a model in which everything is reduced in size by a factor of a billion. In such a model:

- The Earth would be about 1.3 cm in diameter (the size of a grape). - The Moon would be about 30 cm (about a foot) from the Earth. - The Sun would be 1.5 m in diameter (about the height of a man) and

150 m (about a city block) from Earth. - Jupiter would be 15 cm in diameter (the size of a large grapefruit—

suha) and 5 city blocks away from the Sun.

http://www.universetoday.com/guide-to-space/neptune/uranus-and-neptune/

http://www.universetoday.com/guide-to-space/mars/red-planet/

http://www.universetoday.com/guide-to-space/the-solar-system/gas-giant/

http://www.universetoday.com/guide-to-space/the-solar-system/what-is-the-second-biggest-planet-in-the-solar-system/

http://www.universetoday.com/guide-to-space/telescopes/

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http://www.universetoday.com/guide-to-space/telescopes/

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- Saturn (the size of an orange) would be 10 city blocks from the Sun. - Uranus and Neptune (lemons) would be 20 and 30 city blocks from

the Sun. - A person on this scale would be the size of an atom.

Table 39.1 shows ways in which the eight planets can be further classified.

Table 39.1 Other bases for classifying the planets

I. By composition A. Rocky planets: Mercury, Venus, Earth, and Mars

The rocky planets are composed of rock and metal, have relatively high densities, slow rotation, solid surfaces, no rings, and few satellites.

B. Gas planets: Jupiter, Saturn, Uranus, and Neptune

The gas planets are composed primarily of hydrogen and helium, have low densities, rapid rotation, deep atmospheres, have rings and many satellites.

II. By size A. Small planets with diameters less than 13000 km: Mercury, Venus, Earth,

and Mars. B. Giant planets with diameters greater than 48000 km: Jupiter, Saturn,

Uranus, and Neptune.

III. By position relative to the Sun A. Inner planets: Mercury, Venus, Earth, and Mars B. Outer planets: Jupiter, Saturn, Uranus, Neptune

The asteroid belt between Mars and Jupiter forms the boundary between the inner planets and the outer planets.

IV. By position relative to Earth A. Inferior planets: Mercury and Venus

Closer to the Sun than Earth Show phases like the Moon's when viewed from Earth

B. Superior planets: Mars through Neptune Farther from the Sun than Earth Always appear full or nearly full


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Moons A moon is a natural satellite rotating around a planet. Table 339.2 lists the planets’ moons.

Table 39.2 The Planets and Their Moons

Planet Number of

Moons

Name of the moons

Mercury 0

Venus 0

Earth 1 Moon

Mars 2 Phobos, Deimos

Jupiter 63 Io, Europa, Ganymede1, Callisto, Amalthea, Himalia, Elara, Pasiphae, Sinope, Lysithea, Carme, Ananke, Leda, Metis, Adrastea, Thebe, Callirrhoe, Themisto, Kalyke, Iocaste, Erinome, Harpalyke, Isonoe, Praxidike, Megaclite, Taygete, Chaldene, Autonoe, Thyone, Hermippe, Eurydome, Sponde, Pasithee, Euanthe, Kale, Orthosie, Euporie, Aitne, plus others yet to receive names

Saturn 61 Titan2, Rhea, Iapetus, Dione, Tethys, Enceladus, Mimas, Hyperion, Prometheus, Pandora, Phoebe, Janus, Epimetheus, Helene, Telesto, Calypso, Atlas, Pan3, Ymir, Paaliaq, Siarnaq, Tarvos, Kiviuq, Ijiraq, Thrym, Skadi, Mundilfari, Erriapo, Albiorix, Suttung, plus others yet to receive names4

Uranus 27 Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel, Umbriel, Titania, Oberon, Caliban, Sycorax, Prospero, Setebos, Stephano, Trinculo, plus others yet to receive names

Neptune 13 Triton, Nereid, Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, plus others yet to receive names

1 the largest moon (diameter: 3,280 miles) in the Solar System 2 the second largest (diameter: 3,200 miles), half as large as Earth's Moon 3 a very tiny moon (diameter: 20km) 4 Names are assigned by the nomenclature committee of IAU.

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The Cassini spacecraft that arrived at Saturn in 2004 found two small moons about 2 miles and 2.5 miles in diameter. They turned out to be the smallest bodies seen until then around the ringed planet.

Of all the known moons in the Solar System, only three are in the inner region (Earth has one, and Mars has two).

The moons of the outer planets are popular targets of spaceflight researchers. More moons are discovered each year in the outer Solar System by astronomers using ever more powerful equipment.

Jupiter has more moons than any other planet. Its best known moons are the four large planet-sized bodies Io, Europa, Ganymede, and Callisto. Callisto is the outermost of the four and the most cratered body in the Solar System. Io is innermost of the four. It has hundreds of volcanoes.

Uranus' moons have very tall mountains towering more than ten miles high, very deep valleys, and huge plains.

Other Objects in the Solar System The first thing that observers notice through their telescopes is that the Solar System is mostly empty space. The planets are very small compared to the space between them. The large number of asteroids orbit the Sun, mostly between Mars and Jupiter in a region called the asteroid belt.

The main asteroid belt (shown in white at left) is located between the orbits of Mars and Jupiter. It is occupied by numerous irregular rocky bodies called asteroids,

Figure 39.5 Asteroid belt and some asteroids

http://www.nineplanets.org/asteroids.html

http://en.wikipedia.org/wiki/Mars

http://en.wikipedia.org/wiki/Jupiter

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Figure 39.6 A comet

Meteoroids These are chunks of metal or rock smaller than asteroids. When meteoroids fall into Earth’s atmosphere, they break up and burn. As that happens, they form bright streaks of light called meteors (popularly called shooting stars or falling stars). When meteors reach the ground they are referred to as meteorites.

Comets (bulalakaw in Tagalog) Comets are small icy bodies that come and go from the inner parts of the Solar System in highly elongated orbits. When a comet gets close to the Sun some of the ice turns into gas. The gas and bits of dust shoot out of the comet. Solar wind carries them outward, forming a long tail. Many comets are located beyond Neptune. By far the most famous comet is Comet Halley. Comets have been known since ancient times. There are Chinese records of Comet Halley going back to 240 BC. Many comets are first discovered by amateur astronomers. Since comets are brightest when near the Sun, they are usually visible only at sunrise or sunset. The dust tail up to 10 million km long is the most prominent part of a comet to the unaided eye. It is composed of smoke-sized dust particles.

VOCABULARY WORDS asteroids atmosphere comets elliptical

orbit planet revolve rotate

satellite solar wind

PRE-VIEWING ACTIVITIES Activity1. How Am I Moving? Ask 9 pupils to come to the front and form a line as shown: * * * * * * * * *

1 2 3 4 5 6 7 8 9

http://www.solarviews.com/cap/comet/west.htm

http://www.nineplanets.org/halley.html



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Pupil 1 will act as the middle object. Pupils 2 to 9 will act as objects that will move counterclockwise around number 1 in concentric circles (Figure 39. 7). As they move around Pupil 1 each of them will also turn around (rotate).

The rest of the class will watch. Back in their seats ask the volunteers their experience. Could they move easily? Ask the observers: Could classmates 2 to 9 keep their positions as they move? Inform the class that they will watch the video about the Solar System. They will find out how objects in the Solar System move, what kinds of movement they make, and other interesting

Figure 39.7 Concentric circles

VIEWING ACTIVITY

Activity 2. Watch, Listen, and Learn Tell the class they will watch a video showing movement in the universe. Have the pupils copy the following questions and answer them as the video is viewed:

1. Which is the biggest planet? 2. Which is the smallest planer? 3. What planet is closest to the Sun? 4. What planet is farthest from the Sun? 5. What are the two ways in which the planets move? 6. Which planet moves the fastest around the Sun? 7. How can planets be grouped?

Have the pupils watch the following sections of the episode: segment 6.54 for the description of the small planets; and segment 11.12 – 28.02 for the description of the large planets and the profile of each planet. You may have the pupils make a mobile of the Solar System as shown in the video (segment starting at 7.19) It is very important to show the segment on safe ways to observe the features of the Sun. Note: When the video episodes were written and produced in 1996, certain facts were true then based on the information at the time. Since that time much has been discovered by astronomers and space studies. Updated information about the number of moons is included in the content background of this episode. Every day brings new theories, new discoveries, and new questions.


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8. Besides the planets what other objects move around the Sun?

POST-VIEWING ACTIVITIES Activity 1. Parts of the Solar System Discuss answers to the questions listed in Pre-Viewing Activity 2. Ask the pupils to summarize information about the Solar System by filling up column 2 of the chart below. (The expected answers are in italics):

Members of the Solar System

Name of our star Sun Name of inner planets Mercury, Venus, Earth, Mars Name of outer planets Jupiter, Saturn, Uranus, Neptune Name of other bodies Moons, asteroids, comets

Activity 2. Locating the Planets Procedure

Ask the pupils to read the descriptions in Table 39.3, then label the diagram in Figure 39.8.

Table 39.3 Characteristics of the Planets Planet Characteristics Mercury The planet closest to the Sun. Venus The second planet from the Sun. It is the hottest planet. Earth The third planet from the Sun and the planet we live on. Mars A red planet and the fourth planet from the Sun. Jupiter The fifth planet from the Sun. This gas giant is the largest

planet. Saturn The sixth planet from the Sun. This gas giant has large, beautiful

rings. Uranus A gas giant and the seventh planet from the Sun. Neptune A gas giant and is the eighth planet from the Sun.

http://www.enchantedlearning.com/subjects/astronomy/planets/mercury/

http://www.enchantedlearning.com/subjects/astronomy/planets/venus/

http://www.enchantedlearning.com/subjects/astronomy/planets/earth/

http://www.enchantedlearning.com/subjects/astronomy/planets/mars/

http://www.enchantedlearning.com/subjects/astronomy/planets/jupiter/

http://www.enchantedlearning.com/subjects/astronomy/planets/saturn/

http://www.enchantedlearning.com/subjects/astronomy/planets/uranus/

http://www.enchantedlearning.com/subjects/astronomy/planets/neptune/

http://www.enchantedlearning.com/label/

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Figure 39.8 Unlabelled Diagram of the Solar System

Answer to Activity 2

Figure 39.9 Labelled Diagram of the Solar System

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Activity 3. Classifying the Planets From the information in the video (the host’s discussion and tabulated profile of planets) and the data in Table 39.3 used in Activity 2, ask the pupils to classify the planets. You may group the pupils and each group can use a different basis for classifying the planets such as size (diameter), distance from the Sun, composition, temperature, speed of revolution, and number of moons. The pupils may come up with classification similar to those given in Table 39.1 (in Content Background).

Activity 3. A Model of the Solar System Instead of showing the demonstration on making a mobile of the Solar System, you may have the pupils make the model themselves based on the scale used in the video using cartolina of different colors. Tell them that their model will show only the eight planets and the dwarf planet Pluto but not the other bodies in Solar System such as asteroids and meteoroids. Also ask: Is it possible to include the Sun? Why? (No, the model of the Sun will be too big to fit inside the classroom).

At this point you may narrate the events that led to the reclassification of Pluto in 2004 into a dwarf planet but is discussed in the video (made in 1985) as the ninth planet. Such is the nature of science. Observatories continue to provide much information. Getting close to the planets using interplanetary spacecraft in the space program of some countries has revolutionized planetary science. Activity 4. What Is an Orbit?

Materials white bond paper 2 thumbtacks 25 cm string thick cardboard (corrugated board) pencil

Procedure 1. Lay the bond paper on top of the cardboard. 2. Push 2 thumbtacks 5 cm apart on the paper. 3. Make a loop in the string and tie its end. 4. Place the loop around the 2 thumbtacks. 5. Stretch the loop with a pencil in a vertical position and move it all

the way around. Question: What is the shape of the figure made by the pencil?

http://astro.nineplanets.org/bigeyes.html

http://www.jpl.nasa.gov/

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Activity 5. Comparing the Planets Have pupils study Table 39.4.

Table 39.4 Some facts about the planets

Planet Distance from Sun Million km

Mass X10 22kg

Length of 1 revolution (in days)

Length of 1 Rotation Number of moons

Mercury 58 33.0 88.0 175.940 days 0 Venus 108 487 224.7 116.75 days 0 Earth 150 598 365.2 24 hr 1 Mars 228 64.2 687.0 24 hr 39 min 35.24 sec 2 Jupiter 778 190,000 4,332 9 hr 55 min 33 sec 63 Saturn 1,429 56,900 10,760 10 hr 32 min 36 sec 61 Uranus 2,871 8,690 30,700 17 hr 14 min 23 sec 27 Neptune 4,504 10,280 60,200 16 hr 6.6 min 13

1. Which planet revolves the fastest around the Sun? Which revolves the

slowest? 2. Which planet has the longest day? 3. Which planet has the shortest day? 4. Which is the densest planet 5. Which planet is nearest the Sun? 6. Which planet is farthest from the Sun? 7. Which planet has the most moons?

Activity 6. Classifying the Planets Group the pupils and ask them to group the planets using some basis such as the data in Table 39.4. One group may use size as basis. Others can work on relative distance to the Sun (less than 1000 km vs more than 1000 km, length of rotation (1 day and less vs many days), length of revolution such as less than 1000 days to many thousand days.

EVALUATION Choose the letter of the correct answer.

1. What planet is nearest the Sun?

A. Earth C. Venus B. Mercury D. Mars


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2. Why do the planets not collide as they revolve around the Sun?

A. The planets are not of the same sizes. B. The planets move in different directions. C. The planets have their own orbits. D. The planets move at different speeds.

3. Why is Venus described as the hottest planet in the Solar System?

A. It is nearest the Sun. B. It has a very high interior temperature. C. It has a layer of thick clouds containing carbon dioxide. D. Both a and b.

4. With the exception of Venus what factor affects the surface temperature of the planets?

A. size B. distance from the Sun C. magnetic pull of the planets D. presence of an atmosphere

5. Why did the International Astronomical Union (IAU) decide to name Pluto a dwarf planet?

A. Its orbit includes other bodies. B. It is very far from the Sun. C. It does not have enough gravity to make it a perfect sphere. D. It is very small.

6. Why do planets have different orbits?

A. They are at different distances from the Sun. B. They are of different sizes. C. They move at different speeds. D. They have different weights.

7. What are the planets’ satellites called?

A. spacecrafts C. meteoroids B. asteroids D. moons

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Questions 8 to 10 are based on this information: The planets in the Solar System are: Earth, Mars, Mercury, Jupiter, Neptune, Saturn, Uranus, and Venus.

8. Which are called the inner planets?

A. Mercury, Venus, Earth, and Mars B. Jupiter, Saturn, Uranus, and Neptune C. Mars, Venus, Uranus, and Neptune D. Earth, Mercury, Jupiter, and Saturn

9. Which are called the outer planets?

A. Mercury, Venus, Earth, and Mars B. Earth, Mercury, Jupiter, and Saturn C. Mars, Venus, Uranus, and Neptune D. Jupiter, Saturn, Uranus, and Neptune

10. Rings have been observed around which planets?

A. Saturn B. Saturn and Venus C. Saturn and Jupiter D. Saturn, Jupiter, Uranus, and Neptune

ANSWER KEY

1. B 6. A 2. C 7. D 3. C 8. A 4. B 9. D 5. A 10. D

REFERENCES Brown, M. E. (n.d.). The Dwarf Planets. Retrieved Jan. 26 2008. Available at

http://web.gps.caltech.edu/~mbrown/dwarfplanets/ Bruton, D. (n.d.).Conversion of Absolute Magnitude to Diameter for Minor

Planets. Retrieved June 6, 2008. Available at http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). July 7, 2011. Planetary Names: Planet and Satellite Names and Discoverers. Retrieved 2008-07-13. Available at http://planetarynames.wr.usgs.gov/append7.html#DwarfPlanets

http://en.wikipedia.org/wiki/Michael_E._Brown

http://web.gps.caltech.edu/~mbrown/dwarfplanets/

http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html

http://planetarynames.wr.usgs.gov/append7.html#DwarfPlanets


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International Astronomical Union. (Aug. (16, 2006). The IAU draft definition of “planet” and "plutons." Retrieved June 6, 2008. Available at http://www.iau.org/public_press/news/release/ iau0601

Salazar, J. (Nov. 30, 2009). Alan Stern: ‘A Chihuahua is still a dog, and Pluto is still a planet. In EarthSky. Retrieved Dec. 12 2009) http://www.earthsky.org/interviewpost/space/alan-stern-%E2%80%98a-chihuahua-is-still-a-dog-and-pluto-is-still-a-planet.

InnerSolarSystem-en.png URL: http://www.EnchantedLearning.com mhttp://www.spacenewsfeed.co.uk/index.php/space-newsfeed-3?gclid=CIeK9czkpKACFQhB6wodHWMrZw http://www.bing.com/images/search?q=solar+system&FORM=BIFD

http://www.iau.org/public_press/news/release/

http://www.earthsky.org/interviewpost/space/alan-stern-%E2%80%98a-chihuahua-is-still-a-dog-and-pluto-is-still-a-planet

http://www.earthsky.org/interviewpost/space/alan-stern-%E2%80%98a-chihuahua-is-still-a-dog-and-pluto-is-still-a-planet

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VOLUME 7. EARTH AND SPACE EPISODE 40. BEYOND THE SOLAR SYSTEM

OVERVIEW OF THE EPISODE This episode is about the universe beyond the Solar System. The different segments discuss the characteristics of the Sun and other stars. A simple demonstration activity simulating the twinkling of stars and an activity to view different star patterns are presented. The episode also discusses the theories about the birth and death of stars.

The episode begins with a description of the Sun in the Solar System and a demonstration simulating the twinkling of stars. It discusses the different star patterns and demonstrates a procedure for making a constellarium. Differences in colors of stars are explained. The video describes theories about the birth and collapse of stars. It presents how the Hubble space telescope was able to see the black hole. It presents other nearby galaxies and the different shapes that are used for classifying galaxies.

SCIENCE CONCEPTS 1. Stars differ in size, color, temperature, brightness, and distance to Earth. 2. The color of stars indicates their relative temperature, age, composition,

and size. 3. The distance of the stars from Earth is measured in light-years. 4. A light-year means it takes one year for the light from a star or other

celestial body to reach Earth. 5. Dust and other particles in Earth’s atmosphere make the stars appear to

twinkle. 6. Groups of stars form patterns which people in early times use as guide

for navigation, for telling time and season to plant crops. 7. The North Star or Polaris, being always in the north, is useful in finding

directions. 8. A galaxy is a big group of stars numbering billions. 9. The Milky Way is a galaxy where the Solar System is located 10. There are different shapes of galaxies: spiral, elliptical, and irregular. 11. The universe is composed of the vast space and all the bodies that move

in it. 12. The Big Bang Theory and the Nebular or Dust Cloud Theory are theories

on the origin of the universe.

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13. The Big Bang Theory states that the universe began as a huge explosion from which all matter in the universe, such as stars, planets, and galaxies were created.

OBJECTIVES 1. Compare stars according to color, size, brightness, and distance to Earth 2. Describe the relationship between the color and the temperature of a star 3. Describe a constellation as a grid-like area or segment of the celestial

sphere which contains stars and other bodies 4. Identify star patterns in some constellations 5. Describe how constellations are useful to people 6. Discuss the use of astronomical instruments

SCIENCE PROCESSES Communicating, comparing, organizing, classifying objects and illustrations into categories based on shared characteristics, analyzing categorized data, looking for patterns, inferring

VALUES Marvel at the vastness of the universe Working wi h a team in doing a group activity Being resourceful

LIFE SKILLS Determining direction Seeing patterns Grouping things

INTEGRATION WITH OTHER EPISODES This episode can use the information about the Sun in Episode 38. The Great Triumvirate: Earth, Moon, Sun in relation to the topic on the heat and light produced by the Sun.

Episode 39. Solar System (Grade 5) is a helpful review of the information about the position of our Sun as a star in the Milky Way Galaxy.

CONTENT BACKGROUND FOR TEACHERS The Stars A star is an enormous body of glowing gases. It has observable characteristics that make it distinct from other celestial bodies. These characteristics are color, size, and brightness. Due to their great distance

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from Earth, all stars except the Sun appear to the human eye as shining points in the night sky that twinkle because of the effect of the Earth's atmosphere. The colors vary from red to orange, yellow, blue, bluish white, and white. There are giant stars, dwarf stars, supergiants, and giants. Some stars appear bright because they are nearer Earth. The actual brightness of a star is called luminosity. Usually the brightest stars are blue and the least bright are red. The Sun is the star closest to Earth. It is close enough to Earth that it appears as a disk and provides heat and light. The Sun's color is white, although from the surface of the Earth, it may appear yellow because of atmospheric scattering. It is informally designated a yellow star, because majority of its radiation is in the yellow-green part of the visible spectrum. Why Stars Flicker or Twinkle Temperature variations in the air distort the light coming from a star. Air temperature varies. It typically decreases by 6.5 Celsius degrees for every kilometer going up (this agrees with the experience that it feels cooler up in the mountains). Also, on a hot day, we see shimmering waves (thermals) that come off a heated road and make a distant car appear wavy. (Thermals are unstable air caused by heating.)

How do temperature variations cause twinkling? When light enters a transparent medium, such as air, it generally changes direction, i.e., it is scattered. By how much it changes direction however, depends on the temperature. Warm air bends light less, while cool air bends it more because in warm air, the air molecules are further apart from each other, producing less scattering.

Any star, except the Sun, is so far away that it practically sends only a single ray of light towards us. As that ray enters the atmosphere, it is scattered differently as it passes through air of different temperatures. When it is scattered away from us, the star seems to disappear for a moment. When it is scattered toward our eyes, it seems to reappear, resulting in a twinkle. Life Cycle of Stars Scientists have theories about the life of stars. What eventually happens to a star depends on how massive it is. It may become a supernova, a pulsar (pulsating star), or a black hole. Future trends At present, most star formation occur in smaller galaxies where cool gas is not so depleted. Spiral galaxies, like the Milky Way, only produce new generations of stars as long as they have dense molecular clouds of interstellar hydrogen in their spiral arms. Elliptical galaxies are already

http://en.wikipedia.org/wiki/Scintillation_%28astronomy%29

http://en.wikipedia.org/wiki/Star

http://en.wikipedia.org/wiki/Scattering

http://www.hko.gov.hk/education/edu06nature/ele_star_e.htm#q5

http://en.wikipedia.org/wiki/Molecular_cloud


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largely devoid of this gas, and so form no new stars. The supply of star-forming material is finite; once stars have converted the available supply of hydrogen into heavier elements, new star formation will end. The current era of star formation is expected to continue for up to one hundred billion years, and then the "stellar age" will wind down after about ten trillion to one hundred trillion years (1013 to 1014 years), as the smallest, longest-lived stars in our astrosphere, tiny red dwarfs, begin to fade. At the end of the stellar age, galaxies will be composed of compact objects: brown dwarfs, white dwarfs that are cooling or cold ("black dwarfs"), neutron stars, and black holes. Eventually, as a result of gravitational relaxation, all stars will either fall into central supermassive black holes or be flung into intergalactic space as a result of collisions.

Constellations In casual, informal usage, a constellation is a group of celestial bodies, usually stars, which appear to form a pattern in the sky. Astronomers today still use the term, though the current system focuses primarily on constellations as grid-like segments of the celestial sphere rather than as patterns. In 1922, Eugène Delporte aided the International Astronomical Union (IAU) divide the celestial sphere into 88 official constellations. Each constellation has exact boundary. Every place in the sky is within one constellation (Figure 40.1). Typically, these current constellations share the names of their Graeco-Roman predecessors, such as Orion, Leo, and Scorpius. While such celestial formations were originally linked to a mythical event, creature or person, the categorization of the night sky into recognizable patterns was important in early land and naval navigation before the invention of the compass. With the technical advancement of astronomy, it became important to move from a pattern-based system of constellations to one based on area-mapping.

A star-pattern that is not officially classed as a constellation is referred to as an asterism, a term used by the IAU to refer to stars considered part of the larger constellation of Ursa Major. One famous example of an asterism is known as the Big Dipper (Figure 40.2).

http://en.wikipedia.org/wiki/Red_dwarf

http://en.wikipedia.org/wiki/Compact_star

http://en.wikipedia.org/wiki/Brown_dwarf

http://en.wikipedia.org/wiki/White_dwarf

http://en.wikipedia.org/wiki/Black_dwarf

http://en.wikipedia.org/wiki/Neutron_star

http://en.wikipedia.org/wiki/Black_hole

http://en.wikipedia.org/wiki/Relaxation_time

http://en.wikipedia.org/wiki/Orion

http://en.wikipedia.org/wiki/Leo

http://en.wikipedia.org/wiki/Scorpius

http://en.wikipedia.org/wiki/Compass

http://en.wikipedia.org/wiki/Asterism

http://en.wikipedia.org/wiki/Ursa_Major

http://en.wikipedia.org/wiki/Big_Dipper

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Figure 40.1 Division of the celestial sphere into constellations

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Figure 40.2 Ursa Major (The Great Bear) has seven stars of the pattern, Big Dipper. Ursa Major is visible throughout the year in most of the northern hemisphere. Its name means The Great Bear in Latin. It is dominated by the widely recognized asterism known as the Big Dipper or Plough, which is a useful pointer toward north and which has mythological significance in numerous world cultures.

Stars and constellations once guided people in finding directions. By following the two stars of the Big Dipper we can see Polaris. Cassiopea also faces Polaris. The longest distance between the four stars of Crux can help mark the South Pole (Figure 40.3).

Figure 40.3 Crux is the smallest of the 88 modern constellations, but it is one of the most distinctive. Its name is Latin for cross. It is dominated by a cross-shaped asterism that is commonly known as the Southern Cross. It is easily visible from the Southern Hemisphere at practically any time of year. Crux is bordered by the constellations Centaurus, which surrounds it on three sides, and Musca.

http://www.enchantedlearning.com/subjects/astronomy/activities/dots/bigdipper.shtml

http://www.enchantedlearning.com/subjects/astronomy/activities/dots/bigdipper.shtml

http://en.wikipedia.org/wiki/Northern_hemisphere


http://en.wikipedia.org/wiki/Latin

http://en.wikipedia.org/wiki/Asterism_%28astronomy%29

http://en.wikipedia.org/wiki/Big_Dipper

http://en.wikipedia.org/wiki/North

http://en.wikipedia.org/wiki/List_of_constellations_by_area

http://en.wikipedia.org/wiki/Constellation


http://en.wikipedia.org/wiki/Cross

http://en.wikipedia.org/wiki/Asterism_%28astronomy%29

http://en.wikipedia.org/wiki/Southern_hemisphere

http://en.wikipedia.org/wiki/Southern_hemisphere

http://en.wikipedia.org/wiki/Centaurus

http://en.wikipedia.org/wiki/Musca

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The brightest star in Crux is Acrux, which is really two stars going around each other, but they are so far away that we see them as one star. Explorers of the Southern Hemisphere use Crux to guide them when sailing. By looking at Crux, they can figure out in which direction to sail without getting lost.

Other constellations are shown in Figures 40.4, 40.5, 40.6, and 40.7. You can use them for the patterns when pupils make their constellarium in Activity 2.

Figure 40.4 Canis Major is a constellation included in the second century astronomer Ptolemy's 48 constellations, and is still included among the 88 modern constellations. Its name is Latin for greater dog, and is commonly represented as one of the dogs following Orion, the hunter. Canis Major contains Sirius, the brightest star in the night sky, known as the dog star; the star is part of the asterism known as the Winter Triangle in the Northern Hemisphere, or the Summer Triangle in the Southern Hemisphere.

Figure 40.5 Leo lies between dim Cancer to the west and Virgo to the east. Leo contains many bright stars, such as Regulus and Denebola.

http://en.wikipedia.org/wiki/Constellation

http://en.wikipedia.org/wiki/Ptolemy


http://en.wikipedia.org/wiki/Orion_%28mythology%29

http://en.wikipedia.org/wiki/Sirius

http://en.wikipedia.org/wiki/List_of_brightest_stars

http://en.wikipedia.org/wiki/Asterism

http://en.wikipedia.org/wiki/Winter_Triangle

http://en.wikipedia.org/wiki/Cancer_%28constellation%29

http://en.wikipedia.org/wiki/Virgo_%28constellation%29

http://en.wikipedia.org/wiki/Regulus

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Figure 40.6 Gemini is Latin for "twins," and it is associated with the twins Castor and Pollux in Greek mythology. Its symbol is . It lies between Taurus to the west and Cancer to the east, with Auriga and Lynx to the north and Monoceros and Canis Minor to the south.

Figure 40.7 Taurus is the Latin word for "bull." The astrological symbol for the constellation is , a stylized bull's head. Taurus is a large and prominent constellation in the northern hemisphere's winter sky, between Aries to the west and Gemini to the east; to the north lie Perseus and Auriga, to the southeast Orion, to the south Eridanus, and to the southwest Cetus. The brightest member of this constellation is Aldebaran, an orange-hued, giant star. The name Aldebaran is Arabic and translates literally as "the follower." Aldebaran forms the bull's


http://en.wikipedia.org/wiki/Castor_and_Pollux

http://en.wikipedia.org/wiki/Castor_and_Pollux

http://en.wikipedia.org/wiki/Greek_mythology

http://en.wikipedia.org/wiki/File:Gemini.svg

http://en.wikipedia.org/wiki/Taurus_%28constellation%29

http://en.wikipedia.org/wiki/Cancer_%28constellation%29

http://en.wikipedia.org/wiki/Auriga_%28constellation%29

http://en.wikipedia.org/wiki/Lynx_%28constellation%29

http://en.wikipedia.org/wiki/Monoceros

http://en.wikipedia.org/wiki/Canis_Minor

http://en.wikipedia.org/wiki/Cattle

http://en.wikipedia.org/wiki/Astrology

http://en.wikipedia.org/wiki/File:Taurus.svg


http://en.wikipedia.org/wiki/Aries_%28constellation%29

http://en.wikipedia.org/wiki/Gemini_%28constellation%29

http://en.wikipedia.org/wiki/Perseus_%28constellation%29

http://en.wikipedia.org/wiki/Auriga_%28constellation%29

http://en.wikipedia.org/wiki/Orion_%28constellation%29

http://en.wikipedia.org/wiki/Eridanus_%28constellation%29

http://en.wikipedia.org/wiki/Cetus

http://en.wikipedia.org/wiki/Aldebaran

http://en.wikipedia.org/wiki/Giant_star

http://en.wikipedia.org/wiki/Arabic_language

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bloodshot eye, which has been described as "glaring menacingly at the hunter Orion," a constellation that lies just to the southwest.

Figure 40.8 Orion, a hunter in Greek mythology. It is one of the largest and beautiful constellations in the night sky and one of the easiest to find. Two of the brightest stars in the evening sky lie at opposite corners of the rectangle: Betelgeuse at the northeastern corner and even brighter Rigel at the southwest. Near the center of the rectangle, are the short diagonal line of three stars—Orion's belt. And extending south from the belt is another, fainter line of stars that forms


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Orion's sword. One of the objects in Orion's sword is not a star but a nebula—a cloud of gas and dust that is like a giant fluorescent bulb. Hot young stars inside the nebula pump energy into its gas, causing the gas to glow. Patterns in the sky have influenced people’s actions in early times. People learned about the Sun and other stars by observing patterns repeating over time. They used these patterns to make predictions about the seasons and to find directions. They developed calendars, told time, and planted crops using patterns in the sky. All cultures imagined constellations and used them to navigate and make star maps.

Celestial navigation is an ancient art, one that may seem antiquated in this modern era, yet it remains a valuable tool. For example, the North Star appears in the same place all the time. It always points north, at least in the Northern Hemisphere. Locating the North Star is wonderfully easy. A person can follow these steps and will always know which direction is north, which can then give a rough idea of east, south, and west.

The Big Dipper can also be used as a compass and a clock. A compass shows which direction is north. It can be a clock because it circles the North Star every 24 hours.

The Big Dipper, which is part of the constellation Ursa Major, is visible for nine months in the Philippines.

Galaxies A galaxy is a massive, gravitationally bound system that consists of stars, stellar remnants, an interstellar medium of gas and dust, and dark matter. Typical galaxies range from dwarfs with as few as ten million stars to giants with one trillion stars, all orbiting the galaxy's center of mass. Galaxies contain many star systems, star clusters, and various interstellar clouds.

Historically, galaxies have been categorized according to their apparent shape. A common shape is the elliptical galaxy, which has an ellipse-shaped light profile. Spiral galaxies are disk-shaped with dusty, curving arms. Galaxies with irregular or unusual shapes are called peculiar galaxies and typically result from disruption by the gravitational pull of neighboring galaxies. Such interactions between nearby galaxies may result in galaxies merging. There could be more than 170 billion (1.7 × 1011) galaxies in the observable universe. Observational data suggests that massive black holes exist at the center of many galaxies. The Sun of our Solar System is one of the stars in the Milky Way galaxy.

http://en.wikipedia.org/wiki/Gravitation

http://en.wikipedia.org/wiki/Star

http://en.wikipedia.org/wiki/Stellar_remnant

http://en.wikipedia.org/wiki/Interstellar_medium

http://en.wikipedia.org/wiki/Cosmic_dust

http://en.wikipedia.org/wiki/Dark_matter

http://en.wikipedia.org/wiki/Dwarf_galaxy

http://en.wikipedia.org/wiki/Trillion

http://en.wikipedia.org/wiki/Center_of_mass

http://en.wikipedia.org/wiki/Star_system#Multiple_star_systems

http://en.wikipedia.org/wiki/Star_cluster

http://en.wikipedia.org/wiki/Interstellar_cloud

http://en.wikipedia.org/wiki/Elliptical_galaxy

http://en.wikipedia.org/wiki/Ellipse

http://en.wikipedia.org/wiki/Spiral_galaxy

http://en.wikipedia.org/wiki/Peculiar_galaxy

http://en.wikipedia.org/wiki/Observable_universe

http://en.wikipedia.org/wiki/Supermassive_black_hole

http://en.wikipedia.org/wiki/Sun

http://en.wikipedia.org/wiki/Milky_Way

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The word galaxy comes from the Greek term for our own galaxy, galaxias or galaktikos, meaning "milky circle" for its appearance in the sky. Here’s an interesting story: In Greek mythology, Zeus places his infant son, Heracles, on the breast of Hera, a mortal woman, while she is asleep. By feeding on Hera’s divine milk, Heracles becomes immortal. When Hera wakes up, she realizes she is breastfeeding an unknown baby. As she pushes the baby away, a jet of her milk sprays the night sky, producing the faint band of light now called the Milky Way.

Galaxy written with the capital letter G is used to refer to our galaxy, the Milky Way, to distinguish it from the billions of other galaxies. The term Milky Way first appeared in the English language in a poem by Chaucer:

"See yonder, lo, the Galaxyë Which men clepeth the Milky Wey, For hit is whyt."

—Geoffrey Chaucer. The House of Fame, c. 1380.

The three main types of galaxies according to the Hubble classification scheme are: ellipticals, spirals, barred spiral, and irregulars. An E indicates a type of elliptical galaxy; an S is a spiral; and SB is a barred-spiral galaxy (Figure 40.9).

Figure 40.9 Galaxy classification: the Milky Way is an E-type galaxy (Source: http://www.edwinhubble. com/hubble_classification.htm)

Many things have been discovered about space but many questions have yet to be answered. The Hubble Space Telescope (HST) is a space-based telescope that was launched from the space shuttle in 1990. From its

http://en.wikipedia.org/wiki/Greek_language

http://en.wikipedia.org/wiki/Greek_mythology

http://en.wikipedia.org/wiki/Zeus

http://en.wikipedia.org/wiki/Heracles

http://en.wikipedia.org/wiki/Milky_Way

http://en.wikipedia.org/wiki/Geoffrey_Chaucer

http://en.wikipedia.org/wiki/The_House_of_Fame

http://en.wikipedia.org/wiki/Galaxy_morphological_classification


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position 380 miles above Earth's surface, the HST has expanded our understanding of the universe, in particular, star birth, star death, galaxy evolution, and black holes.

Scientists have built spacecrafts that transport observers to space and return them to Earth. They have designed these vehicles that allow astronauts to cope with weightlessness and other conditions in space.

In the Philippine Science Centrum (an interactive science museum) in Marikina City is a Space Gallery with hands-on exhibits such as Artificial Gravity, Human Gyro, Astronaut, and Your Weight on Other Planets, Refracting and Reflecting Telescopes. The Department of Science and Technology (DOST) funded the development and construction of the gallery to create public awareness about space science and raise students’ interest in this field. VOCABULARY WORDS

star star pattern Milky Way constellation galaxy light-year

PRE-VIEWING ACTIVITIES Activity 1. Where Are the Stars? Before pupils enter the room, tape six 7-cm squares of white paper against five various colored background, such as brown cabinet, black umbrella, yellow poster, beige wall, and one white background, such as white blank cartolina.

Tell the pupils that there are six white squares in various places in the room and that you will be asking volunteers to look for the squares. The volunteers simply have to note where these are; they are not to show nor tell any of their classmates where the squares are when they find any. When all are seated ask volunteers to locate these squares. Ask: Which square is the easiest to spot? Why? Which square is difficult to spot? Why? Their answer should point to color of background.

Next, have the pupils look out the window and the sky. Ask: What do you see in the sky? (clouds, sun). At night when you look at the sky what do you see? (stars) Why do you see stars at night and not during the day? Do you think the stars disappear during the day? Accept any answers, and then tell them they will watch a video on stars. First, have them copy the first five questions which they will answer as they view the particular video segments.

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cardboard with a hole

lamp

electric stove

1. What is a star? 2. What is the nearest star to Earth? What is the next nearest star to Earth? 3. How do stars differ? What are the colors of stars? What do the colors of

stars indicate? 4. Why do stars twinkle? 5. What are constellations? How have they helped people? 6. What are some of the brightest stars? 7. Where is a star born? 8. How old is the sun? How long will the sun last? 9. What is a nebula? What is a Black Hole? 10. What is a galaxy? What galaxies are near the Milky Way? What are the

shapes of galaxies?

VIEWING ACTIVITY Have the pupils view the following parts of the episode:

Segment on The Sun. Pupils may do the activity to simulate the twinkling of stars shown in the segment (Why stars twinkle) or prepare a setup similar to the one described in Activity 1. Pupils may also do the activity on viewing constellations demonstrated in the segment on Constellations and another activity on star colors. PLAY segment on Birth of Stars, changes that happen to them, and how they end. PLAY segment on the Milky Way, other galaxies, and shapes of galaxies.

POST-VIEWING ACTIVITIES Activity 1. What Is a Star? Discuss pupils’ answer to questions 1 to 3. Activity2. Why Do Stars Twinkle? You may have the pupils do the activity as demonstrated in the video for inferring the apparent twinkling of stars.

Here is another simple hands-on activity to simulate the effect of the Earth’s atmosphere on observing stars. Use a heat source (for example, an electric stove), a cardboard with a small hole at the center and a light bulb.


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Place the cardboard between the lighted bulb and the electric stove. Darken the room and switch on the stove.

The pupils can take turns in looking through the hole. They will see the light from the flashlight coming through the hole flicker.

Activity 3. Star Pictures Materials

paper and pencil Procedure The pupils will work in pairs. Tell the pupils in each pair to close their eyes and quickly make 20 dots on the paper. Imagine these to be stars. They will connect the dots to create a picture formed by their stars. They just made their own constellation! They will name their constellation. They will show each other their pictures. Ask:

Do your their partners see the same or a different picture? If pupils from another country will look at your stars picture will they see the same or different picture? Why do you think ancient people saw kings, queens, animals in star patterns? What do you think people today would see in them?

Activity 3. Shoebox Constellation Materials

shoe box or cardboard rolled into a tube black paper or cloth glue or stapler push pin a photocopy of constellations given in the Content Background

Procedure 1. Make a square hole on one end of the box and a peep hole on the

other end. Line the inside of the box with black cloth or staple black paper to it.

2. Lay a copy of the constellation diagram flat on a small piece of black paper

3. Prick the big and small dots in the diagram using pushpins. 4. Place the pricked diagram on the end with the square hole. 5. Hold the box to a bright light and look through the peephole.

What do you see? What do the big and small dots represent?

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Activity 4. Locating North and Other Directions

Procedure 1. Find the familiar seven-star pattern of the Big Dipper, also known

as Ursa Major, in the star map for March. The Big Dipper has three stars that form the handle and four that make the cup portion. The stars run from left to right, with the "handle" on the left and the "cup" on the right.

2. Locate the two "Pointer Stars" of the Big Dipper. These are two stars that form the outer portion of the cup of the Dipper.

3. Trace a straight line up from the Pointer Stars. The first star the line hits is Polaris, the North Star. Polaris is the last star at the handle of the Little Dipper in the constellation, Ursa Minor. If the North Star points north, where are South, East, and West?

Figure 40.10 Star map for March Source: Pyxis Astronomy Educational Services

Activity 3. What Are Galaxies? Procedure

1. Look at the Galaxy Classification Chart. They are pictures of actual galaxies.

2. Pretend that a NASA astronomer comes to your school and ask:


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Name the galaxies pictured in the diagram based upon their resemblance to common objects. What would you name them? Write your suggestions for each picture.

a. Which galaxies look similar to each other? Which of them will you group together? How many groups do you have? Give each group a name. Write the basis that you used.

o Group name of galaxy: _______________________________________ Basis: _____________________________________________________ _______________________________________________________

o Group name of galaxy: _______________________________________ Basis: _____________________________________________________ _____________________________________________________

o Group name of galaxy: _______________________________________ Basis : ____________________________________________________ ____________________________________________________

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o Group name of galaxy: _______________________________________ Basis: ____________________________________________________ _____________________________________________________

Answers to Activity 3

Source: NASA Goddard Space Flight Center

EVALUATION 1. What is a light-year?

A. name for a kilometer in space B. distance from the Sun to Earth C. distance traveled by light in one year D. same distance as one trillion kilometers

2. What is the best indication of a star’s temperature? A. size C. brightness B. color D. distance from Earth

3. What is an object that travels in orbit around the Earth? A. rocket C. space probe B. satellite D. telescope


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4. What were invented to deal with problems when living inside a spacecraft?

A. smoke detectors B. freeze-dried foods C. plastic lenses of eyeglasses D. athletic shoes with cushioned soles

5. Which of the following could form as a result of a supernova? A. nebula c. neutron star B. black hole d. all of the above

6. Why does a constellation appear in a slightly different place at the same time each night? A. Earth rotates B. constellations rotate C. stars revolve around Earth D. Earth revolves around the Sun

7. Which of the following are designed to return to Earth? A. satellites C. space shuttles B. space probes D. space stations

8. According to a theory how are stars formed? A. supernova occurs B. layers of gas start to cool C. gravity pulls hydrogen gas and dust apart D. gravity pulls hydrogen gas and dust closer

9. The following has so far been provided by space explorations except________

A. new medical techniques B. more information about the universe C. definite evidence of life on other planets D. new inventions that make life easier

10. Astronomers get detailed information about other planets from _____________ . A. rockets C. space probes B. satellites D. telescopes

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ANSWER KEY 1. C 2. B 3. B 4. B 5. D

6. D 7. C 8. D 9. C

10. C

BIBLIOGRAPHY NASA's Goddard Space Flight Center. (Last updated Feb. 09, 2012). Imagine

the Universe. [Online]. Available http://imagine.gsfc.nasa.gov/docs/teachers/galaxies/imagine/act_classifying_galaxies.html

Pyxis Astronomy Educational Services. (2010). Philippine Starmaps. [Online]. Available http://www.pyxis.astronomy.com.ph/starmaps/?map=08

The Hubble Classification. [Online]. Available http://www.edwinhubble.com/hubble_classification.htm University of the Philippines Science Education Center. Earth Science. The

Philippines in Focus. (1983). Diliman, QC: Author. Wolke, R. L. (Last revised Oct. 03, 2009). What Einstein told his barber. [Online].

Available http://www.enchantedlearning.com/subjects/astronomy/stars/constellations.shtml

Young, H. D. (1992). Physics (8th ed.). Reading, MA: Addison-Wesley.

http://www.nasa.gov/goddard/

http://imagine.gsfc.nasa.gov/docs/teachers/galaxies/imagine/act_classifying_galaxies.html

http://imagine.gsfc.nasa.gov/docs/teachers/galaxies/imagine/act_classifying_galaxies.html

http://www.pyxis.astronomy.com.ph/starmaps/?map=08

http://www.edwinhubble.com/hubble_classification.htm

http://www.enchantedlearning.com/subjects/astronomy/stars/constellations.shtml

http://www.enchantedlearning.com/subjects/astronomy/stars/constellations.shtml

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Elemsci Volume 3