Glossary of TermsContinental volcanic arc. Mountains formed in part by igneous activity associated with subduction of oceanic lithosphere beneath a continent.Convergent boundary. A boundary in which two plates move toward each other, causing one of the slabs of the lithosphere to subduct beneath an overriding plate.Crust. The outer portion of the earth.Continental Crust. The thick part of the Earth’s crust, not located under the ocean.Oceanic Crust. The thin part of the Earth’s crust located under the oceans.Divergent boundary. A region where the crustal plates are moving apart.Earthquake. Vibration of Earth due to the rapid release of energy.Fault. A break in a rock along which movement has occurred.Fracture. Any break in a rock in which no significant movement has taken place.Geology. The science that studies Earth.Hot spot. A concentration of heat in the mantle capable of creating magma.Magma. A mass of molten rock form from a depth, including dissolved gases and crystals.Mid-ocean ridge. A continuous mass of land with long width and height on the ocean floor.Plate. Rigid sections of the lithosphere that moves as a unit.Plate tectonics. A theory which suggests that Earth’s crust is made up of plates that interact in various ways, thus producing earthquakes, mountains, volcanoes and other geologic features.Primary (P) wave. The first type of seismic wave to be recorded in a seismic station. 24
Rocks. Consolidated mixture of minerals.Secondary (S) wave. Second type of earthquake wave to be recorded in a seismic station.Seismogram. A record made by a seismograph.Seismograph. A device used to record earthquake waves.Subduction. An event in which a slab of rock thrusts into the mantle.Transform fault boundary. A boundary produced when two plates slide past each other.Trench. A depression in the seafloor produced by subduction process.Volcanic Island arc. A chain of volcanoes that develop parallel to a trench. 25
References and LinksDepartment of Education, Bureau of Secondary Education. Project EASEIntegrated Science 1, Module 12: Inside the Earth.Department of Education, Bureau of Secondary Education (2013). ScienceGrade 8 Learner’s Module. Vibal Publishing House, Inc.Tarbuck, E.J. et al. (2009). Earth Science 12th ed. Pearson EducationSouth Asia Pte Ltd.http://www.skoool.ie/ accessed March 3, 2014http://earthds.info/ accessed March 3, 2014http://eqseis.geosc.psu.edu/ accessed March 4, 2014http://thehistoryofthephilippines.blogspot.com/ accessed March 4, 2014http://www.platetectonics.com/ accessed March 5, 2014http://geology.com/ accessed March 5, 2014http://www.nws.noaa.gov/ accessed March 6, 2014http://csep10.phys.utk.edu/ accessed March 6, 2014http://pubs.usgs.gov/ accessed March 6, 2014http://www.moorlandschool.co.uk/earth/tectonic.htm accessed March 7, 2014http://stream2.cma.gov.cn/pub/comet/Environment/TsunamiWarningSystems accessed March 3 2014http://marc.fournier.free.free.fr accessed July 1, 2014https://www.bucknell.edu/majors-and-minors/geology/location/geologic-history-of-central-pennsylvania/plate-tectonics.html accessed July 1, 2014http://www.adelaidenow.com.au/ accessed July 2, 2014http://www.wildjunket.com/ accessed July 2, 2014http://www.jnb-birds.com/ accessed July 2, 2014http://www.geo.hunter.cuny.edu/ accessed July 2, 2014http://wowlegazpi.com/mayon-volcano-interesting-facts/#sthash.Q3mSKqYG. dpbs accessed July 2, 2014 26
Unit 1 Suggested time allotment: 15 to 18 hoursMODULE The Earth’s Interior2Content Standard: Performance Standard:The learners shall demonstrate an The learners shall be able to:understanding of: 1. demonstrate ways to ensure The relationship among the disasterlocations of volcanoes, earthquakeepicenters, and mountain ranges preparedness during earthquakes, tsunamis, and volcanic eruptions; and 2. suggest ways by which he/she can contribute to government efforts in reducing damage due to earthquakes, tsunamis, and volcanic eruptions.Overview The topic on Plate Tectonics and the processes within the Earth’s interiorconclude the spiralling concepts in Geology. In fact, Geology is the only stranddiscussed in Grade 10 Science because of the topic’s broadness. In this module, we focus on the Earth’s interior structure and processes.It is also discussed how these processes could possibly have affected theEarth’s surface and caused its physical appearance. There are seven activities in this module which slowly develop theconcept of relating the Earth’s interior processes with the physical structure ofthe Earth’s surface. 27
After all these activities, a performance task is provided to connect andconclude the two modules for Earth and Space in this grade. The task is veryimportant for the learners to understand the nature of our home planet and toinstil in them how they could be part of reducing the risks brought by geologicphenomena. In the discussion, it would be best if the teacher focuses and directs thestudents towards the development of concepts by answering the following keyquestions:Learning Competencies In this module, you should be able to: 1. Describe the internal structure of the Earth. 2. Discuss the possible causes of plate movement. 3. Enumerate the lines of evidence that support plate movement. 28
Answers to Pre-AssessmentDirections:A. Choose the letter of the correct answer. For questions 1 and 2, refer to the figure below that shows the crosssection of the Earth as seismic waves travel through it. Seismic waves as they travel through the Earth 1. An S-wave shadow zone is formed as seismic waves travel through the Earth’s body. Which of the following statements does this S-wave shadow zone indicate? a. The inner core is liquid. b. The inner core is solid. c. The mantle is solid. d. The outer core is liquid. Answer: D 29
2. Why are there no P-waves or S-waves received in the P-wave shadow zone? a. P-waves are aboserbed and S-waves are refracted by Earth’s outer core. b. P-waves are refracted and S-waves are absorbed by Earth’s outer core. c. Both the P-waves and S-waves are refracted by Earth’s outer core. d. Both the P-waves and S-waves are absorbed by Earths outer core. Answer: B 3. What makes up the lithosphere? a. Continental crust b. Crust and the upper mantle c. Oceanic crust and continental crust d. Upper mantle Answer: B4. Miners dig into the Earth in search for precious rocks and minerals.In which layer is the deepest explorations made by miners?a. Crust c. Mantle b. Inner core d. Outer core Answer: A 5. How do you compare the densities of the Earth’s crust, mantle and core? a. The mantle is less dense than the core but denser than the crust. b. The mantle is less dense than both the core and the crust. c. The mantle is denser than the core but less dense than the crust. d. The mantle is denser than both the core and the crust. Answer: A 6. The movement of the lithospheric plates is facilitated by a soft, weak and plastic-like layer. Which of the following layers is described in the statement? a. Asthenosphere c. Lithosphere b. Atmosphere d. Mantle Answer: A7. Alfred Wegener is a German scientist who hypothesized that theEarth was once made up of a single large landmass called Pangaea.Which of the following theories did Wegener propose?a. Continental Drift Theory c. Plate Tectonics b. Continental Shift Theory d. Seafloor Spreading Theory Answer: A30
8. If you are a cartographer, what will give you an idea that the continents were once joined? a. Ocean depth b. Position of the south pole c. Shape of the continents d. Size of the Atlantic Ocean Answer: C 9. Which observation was NOT instrumental in formulating the hypothesis of seafloor spreading? a. Depth of the ocean b. Identifying the location of glacial deposits c. Magnetization of the oceanic crust d. Thickness of seafloor sediments Answer: B 10. As a new seafloor is formed at the mid-ocean ridge, the old seafloor farthest from the ridge is destroyed. Which of the stated processes describes how the oceanic crust plunges into the Earth and destroyed at the mantle? a. Convection b. Construction c. Diversion d. Subduction Answer: D 31
B. Answer briefly the following questions. 1. What are the different layers of the Earth? Answer: The different layers of the Earth are the crust, the mantle, and the core. The core is made up of a solid inner core and liquid outer core. 2. Why is there a need to study the Earth’s layers? Answer: We need to study the Earth’s layers because the mechanisms in the inner layers facilitate the slow changes that occur on the Earth’s surface. Although these changes takes millions of years to shape the Earth, the tectonic activities that go along with these changes affect us very much. 3. What proves the existence of the boundary between the crust and the mantle? Answer: As seismic waves pass from the crust to the mantle, the velocity increases. If the velocity of waves changes, it means that the density of the media where they travel through are different, and thus proves a boundary. 4. What are the characteristics of the asthenosphere? Answer: The asthenosphere is the soft weak layer below the lithosphere. It has a temperature that facilitates a small amount of melting that gives it the capability to flow. 5. What do the shapes of the continents now tell us about their past? Answer: The shape of the continents seems like a jigsaw puzzle when put together. A picture will be formed and indicate that the continents were once together in the past.Studying the Earth’s Interior The knowledge about seismic waves is very important in understandingthe discovery of the different layers of the Earth as well as in determiningthe properties of these layers. If the students are able to understand thecharacteristics of seismic waves, they will be able to relate how each layer ofthe Earth was discovered. The following activity will make the learners differentiate the types andunderstand the characteristics of seismic waves. It will prepare them in learningthe properties and composition of the different layers of the Earth. The teacher can make it as an individual activity for fast-paced learnersor as a group activity for those who are more inclined to group discussion. 32
Activity 1 Amazing Waves! In giving points to students’ responses, you may refer to the following:5 points – a graphic organizer that is complete and comprehensive4 points – one part of the organizer is not filled but the given ideas are correct3 points – two parts of the organizer is not filled but the given ideas are correct2 points – two parts of the organizer is not filled and some of the given ideas are not correct1 point – three parts of the organizer is not filled and some of the given ideas are not correct0 point – no effort exerted 33
Answers to questions:Q1. Differentiate surface waves from body waves. Surface waves travel only on the Earth’s surface like ripples of waterwhile body waves travel through the Earth’s body (interior). In addition, surfacewaves arrive last at seismic recording stations compared to the body waves.Q2. Which type of wave do you think were useful to seismologists in their study of the Earth’s interior? Explain your answer. The body waves were used by seismologists because they can passthrough the Earth’s interior. Allow to perform this activity in a way that the students will realize that ittakes different properties (like reflection and refraction properties of waves) andcharacteristics to analyze and differentiate the media where they travel through.Discuss the characteristics of the seismic waves and how these characteristicsled to the discovery of each layer of the Earth.The Composition of the Earth’s Interior As the teacher continues to discuss with the layers of the Earth, theteacher may opt to use a boiled egg that is cut across to represent the Earthand to demonstrate each layer. The teacher may ask the students to tell thelimitations of the model to determine their understanding. In describing the lithosphere and asthenosphere, the teacher may usethe cracked shell to represent the lithosphere and soft butter to represent theasthenosphere. Have the students slide the shell cracks over the soft butter.This will give them the idea how the lithosphere ride over the asthenosphere. The ability of the asthenosphere to flow slowly is termed as plasticity.To further demonstrate the characteristic of the asthenosphere, the teachermay do Predict-Observe-Explain for the following activity, before the readingsand discussion of the mantle. This is to affirm the correctness of ideas cited andrectify misconceptions that may arise upon doing the activity. Post the questions on the board: “How will the mixture of cornstarch andwater react? Will it act as liquid, solid or gas? The teacher writes the answersof the learners on the board but should not expect that they will give correctanswers. Let the learners observe as the teacher performs the activity. After theactivity is done, the teacher should correct the misconceptions of the studentsduring the discussion. 34
Demonstration: Simulating Plasticity(Adapted)Materials • 15 g cornstarch • 2 small cups • 20 ml tap water • medicine dropper • stirring rod or spoonProcedure: 1. Put 15 g cornstarch into one of the beakers. Put 10 ml water into the other beaker. 2. Add one drop full of water to the cornstarch. Stir the mixture. Ask the students the question: How does the mixture react like; solid, liquid or gas? 3. Continue to add water to the mixture, one drop full at a time. Stir the mixture after each addition. 4. Stop adding water when the mixture becomes difficult to stir. 5. Pour the mixture into your hand. 6. Roll the mixture into a ball and press it.Let the students explain what they have observed. Facilitate the students’reactions with the following questions: Q1. How does the mixture behave like? A1: It behaves like solid. Q2. How is the mixture of cornstarch and water similar to the Earth’s mantle? A2: The mixture of cornstarch and water behaves like the mantle. It has the ability to flow slowly.. Q3. How is it different from the Earth’s mantle? A3: The cornstarch gained mobility due to addition of water while the mantle’s plasticity is due to partial melting aided by the heat of the inner layers of the earth. Q4. How does the plasticity of the Earth’s mantle influence the movement of the lithospheric plates? 35
A4: Since the mantle is capable of flowing slowly, it carries and facilitates the movement of lithospheric plates above it as it moves.Activity 2 Our Dynamic Earth Activity 2 will test the learners’ understanding on the differentcharacteristics, properties and composition of the Earth’s layers. If possible,make it as an individual activity.Expected Output:Answers to questions:Q3. What element is the most abundant in the Earth’s crust? Oxygen is the most abundant element in the Earth’s crust.Q4. What elements make up most of the mantle? The elements silicon, oxygen, iron and magnesium make up the mantle. 36
Q5. What is the special feature of the upper mantle? The upper mantle has with it a soft weak layer called the asthenosphere, which is capable of flowing. This property facilitates the movement of the lithospheric plates.Q6. How did scientists discover that the outer core is liquid? The scientists were able to show that the outer core is liquid due to the fact that S- waves cannot travel through this Earth’s layer as proven by the S-wave shadow zone.Q7. What materials make up the inner core? The inner core is mostly made up of iron and nickel.Q8. Is the inner core solid, liquid or gas? What keeps it in this phase? The inner core is solid. This is due to the very high pressure that keepsit compacted together even if the temperature is really very high.Q9. Compare the inner core and the outer core. The outer and the inner core are made mostly of iron and nickel. The outer core reaches a temperature of 2000oC. With this temperature, the iron and nickel melt thus, this layer is liquid. The inner core has a temperature as high as 5000oC. It is compact despite of the very hot temperature because of the very great pressure that keeps this layer in the solid phase.The Earth’s Mechanism The teacher may introduce the lesson by linking the concept of theEarth’s interior structure with its interior processes, and then the effects ofthese processes. The teacher may ask this question: “Is the Earth’s interior processesrelated with the structure of the Earth’s surface?” Encourage responses fromthe students. 37
Activity 3 Let’s Fit it! Divide the class into groups of 3 to 4 students and perform the activity asa group. This will serve as the teacher’s springboard to the next activity. Thestudents’ reasoning ability will be enhanced. Conduct this activity as quickly aspossible.Answers to questions:Q10. What features of the newspaper helped you to connect the pieces perfectly? Pictures and words in the newspaper helped us to connect the pieces perfectly.Q11. How do the lines of prints or texts in the newspaper help you to confirm that you have reassembled the newspaper/magazine page? The lines of prints make sure that the newspaper is fitted well. The words written serve as clues in connecting the pieces of newspaper together. The completed/connected words confirm that the newspaper has been reassembled.Q12. Show proofs that the newspaper is perfectly reassembled. The answers may vary. - The picture in the newspaper if completed. - The broken words were completed/connected.Activity 4 Drifted Supercontinent!Answers to questions:Q13. What does the Glossopteris fossils tell us about the early positions of the continents? Since it is impossible for Glossopteris fossils found in different regions or continents to be blown by the wind or carried by ocean waves, the only possibility is that these regions were once connected. 38
Q14. If Glossopteris fossils were found in Antarctica, what does this indicate about the climate of this continent before? It proves that Antarctica had a tropical climate before.Q15. If the climate and the position of a place are relative to each other, where then was the initial location of Antarctica 250 million years ago? It tells us that Antarctica was nearer to the equator before as compared to where it is today.Q16. What does the presence of Mesosaurus fossils tell about the initial location and position of South America, Africa, and Antarctica? It tells us that these continents were connected before, since this kind of animal cannot swim across the vast ocean.Q17. What clues are useful in reconstructing Pangaea? The edges of the continents are useful in reconstructing Pangaea. Aside from the fitting of edges of the continents, the presence of evidences found in the same continents made the reconstruction easier.Q18. Which continents do you think were neighbors before? Possible answers: Europe and Asia were neighbors in the north. North America, South America and Africa in the middle. Australia and Antarctica, together with India in the South.Q19. Will there be a possibility that the current location of a continent would be different 100 years from now? Yes, if the continents continue to move. But it will not be very noticeable because it took 200 million years before the continents came to where they are now, based on the Continental Drift Theory.Q20. Where do you think was the Philippines located during the time that the Pangaea existed? Research on how the Philippine islands emerged. Knowing that the Philippines has or is near trenches, it could have not existed during the time of Pangaea but borne out of volcanic eruptions and other tectonic activities. 39
Q21. If the continents will continue to move, try to predict the Philippines’ location 100 million years from now. Answers may vary. For the purpose of facilitating learning and in preparation for the classdiscussion, the teacher must perform the activity first before letting the studentsdo it in the class.Activity 5 Split and Separate! (Adapted)Answers to questionsQ22. What do the stripes in the paper represent? The stripes represent the rocks with normal and reverse polarities.Q23. What does the middle slit represent? What occurs in this region? The middle slit represents the mid-ocean ridge where the actual seafloor - spreading occurs.Q24. What is the role of the mid–ocean ridge in the movement of lithospheric plates? The mid-ocean ridge serves as the origin of lithospheric movement. It is the place where the force that pushes the lithosphere originates.Q25. How does the new seafloor form at the mid-ocean ridge? Hot, less dense material below the Earth’s crust rises towards the mid-ocean ridge. As this material flows sideways, it creates a crack in the crust where magma will flow out. This magma cools down and becomes the new seafloor.Q26. What process/es happen at the side slits? The side slits serve as subduction zone where the old seafloor plunges beneath another tectonic plate. 40
Q27. Is the earth getting larger and wider when plates drift away from each other? Explain briefly. The Earth is not getting larger or smaller. If there is the production of a new seafloor in the mid-ocean ridge, there is a destruction of an old seafloor at subduction zones.Activity 6Adapted (Glencoe Earth Science student edition copyright 2002) In this activity, students will compute for the rate of seafloor spreading. After the activity, they will be able to determine the distance a continent movesfor every year. Reiterate to the students that NOT ALL plates move at the samerate. How fast does it go? Magnetic Polarity MapAnswers to questionsQ28. How far do the plates move away from each other every year? Answer: 2.5 cm per yearQ29. If Africa is approximately 2,400 km away from the Mid-Atlantic Ridge, how long ago was it when Africa was directly at or near the Mid-Atlantic Ridge? Answer: 96000000 years or 96 million years After the activity, the teacher must relate the creation of a new seafloorwith the one that causes it. This will pave the way to the concept of convectioncurrent. 41
Recall the mechanisms of the Earth’s interior structure and properties.The teacher must make a strong idea about the properties of the mantle andthe process it undergoes. This will lead the learners to connect the SeafloorSpreading Theory with the convection current that happens in the mantle. For Activity 7, the teacher must perform the activity first before letting thestudents perform so he could facilitate the class. The teacher must constantlyremind the students to be extra careful in handling heating materials.Activity 7(Adapted) Push me up and aside!Answers to questionsQ30. How does the food coloring react? The food color rises and moves to the sides of the beaker then sinks. It demonstrates a cyclic motion.Q31. What do you call this behavior? This is called convection current.Q32. Enumerate the factors that cause the formation of a current. The difference in density in the molecules is caused by the difference in temperature. The rate of heating at the bottom and the rate of cooling at the top. Amount of heat supplied to the substance.Q33. What happens to the blocks? What does this resemble? The blocks are pushed up to the middle of the boiling water and then swayed towards the sides of the beaker. The small, light wood blocks resemble the lithospheric/tectonic plates that moved about slowly along the tectonic boundaries, pushing, sliding past and drifting away from each other because of convection current. 42
The teacher should explain that these are the possible causes of tectonicactivities. Again, reiterate that the processes/activities in the Earth’s interiorplay a role in the processes along Earth’s surface. The teacher may opt to end the lesson with a video presentation on theevolution of the Earth or a video on how magnificent the Earth is if there areavailable videos that can be downloaded from the internet. The teacher should also emphasize that it is impossible to stop thesetectonic activities from happening, but we can do something to mitigate theireffects.Performance Task This is the performance task for the students. This activity shows theeffects of geologic activities like volcanic eruptions and earthquake. This couldbe an individual or a group activity which aims to motivate students to be partin mitigating the effects of tectonic activities. 1. The teacher gives a situation where the students acts as a project engineer who wants to develop a subdivision, a realtor who sells a house & lot, a geologist visiting his/her hometown or simply a student seeking to help the government. However, the students are given an option to choose other characters in the society. 2. The performance task must be given at the start of the first grading period. 3. This should be presented at the end of the grading period. 4. The teacher must set a date for the learners’ to present their outputs in class. 43
5. The teacher may consider the following rubric in rating the students.Criteria 4 3 2 1 ScoreDetails and Has included 5 Has included Has included Has included 2information things or more to 4 things to 3 things to things to remember remember before, remember before, remember before, during and during and after during and after before, during after any tectonic any tectonic any tectonic and after any activity. activity. activity. tectonic activity.Method of The method of The method of The method of The method ofPresentation presentation presentation presentation is presentation is not is easy to is unique and organized but organized and not understand, organized. not unique. unique. unique and outstanding.Technique/ The presentation/ The presentation The presentation The presentation /Creativity medium includes / medium includes / medium include medium does not unusual and some unusual unusual and include unusualAccuracy interesting and interesting interesting or interesting features and features that features, but they features.Feedback components interest the do not add to its that excite the audience and meaning. audience about relate to the the topic and add meaning. to the meaning. Information Information Information Information contains no error. contains minimal contains minimal contains many error, none of errors, of which errors. which interferes interferes with with the clarity of the clarity of communication communication The clientele The clientele The clientele The clientele understood well understood a understood the ignored the the purpose and little the purpose purpose. purpose. objective was and objective attained. was somewhat attained. 44
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