10 Science Quarter 1 – Module : 4 Earth’s Internal Structure Science – Grade 10 Alternative Delivery Mode Quarter 1 – Module 4: Title: Earth’s Internal Structure First Edition, 2020 Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio Development Team of the Module Authors: Lesson 1 & 2 - Hellen M. Dizon Lesson 3 - Lilibeth B. Montemayor Lesson 4 - Patty M. Canyong Lesson 5 & 6 - Dulce S. Ortega Lesson 6 - Nilo Salazar Lesson 7 - Marygin T. Joson Lesson 8 - Helen Rose A. Ferrancullo / Shirlie G. Custodio Editor: Rebecca M. Roxas, EPS Reviewers: Arlene Gatpo, PSDS Illustrator: Layout Artist: Management Team: Malcolm S. Garma, Regional Director; Genia V. Santos, CLMD Chief; Dennis M. Mendoza, Regional EPS in Charge of LRMS and Regional ADM Coordinator; Maria Magdalena M. Lim, CESO V, Schools Division Superintendent; Aida H. Rondilla , CID Chief; Lucky S. Carpio, Division EPS in Charge of LRMS and Division ADM Coordinator Printed in the Philippines by ________________________ Department of Education – Region NCR Office Address: Telefax: E-mail Address: ____________________________________________ ____________________________________________ ____________________________________________ nilo.salazar001@deped.gov.ph 10 Science Quarter 1 – Module : 6 Earth’s Internal Structure Introductory Message For the facilitator: Welcome to the Science Grade 10 Earth’s Internal Structure. Alternative Delivery Mode (ADM) Module on This module was collaboratively designed, developed and reviewed by educators both from public and private institutions to assist you, the teacher or facilitator in helping the learners meet the standards set by the K to 12 Curriculum while overcoming their personal, social, and economic constraints in schooling. This learning resource hopes to engage the learners into guided and independent learning activities at their own pace and time. Furthermore, this also aims to help learners acquire the needed 21st century skills while taking into consideration their needs and circumstances. In addition to the material in the main text, you will also see this box in the body of the module: Notes to the Teacher This contains helpful tips or strategies that will help you in guiding the learners. As a facilitator you are expected to orient the learners on how to use this module. You also need to keep track of the learners' progress while allowing them to manage their own learning. Furthermore, you are expected to encourage and assist the learners as they do the tasks included in the module. 2 For the learner: Welcome to the Science 8 Alternative Delivery Mode (ADM) Module on Earth’s Internal Structure! The hand is one of the most symbolized part of the human body. It is often used to depict skill, action and purpose. Through our hands we may learn, create and accomplish. Hence, the hand in this learning resource signifies that you as a learner is capable and empowered to successfully achieve the relevant competencies and skills at your own pace and time. Your academic success lies in your own hands! This module was designed to provide you with fun and meaningful opportunities for guided and independent learning at your own pace and time. You will be enabled to process the contents of the learning resource while being an active learner. This module has the following parts and corresponding icons: What I Need to Know This will give you an idea of the skills or competencies you are expected to learn in the module. What I Know This part includes an activity that aims to check what you already know about the lesson to take. If you get all the answers correct (100%), you may decide to skip this module. What’s In This is a brief drill or review to help you link the current lesson with the previous one. What’s New In this portion, the new lesson will be introduced to you in various ways such as a story, a song, a poem, a problem opener, an activity or a situation. What is It This section provides a brief discussion of the lesson. This aims to help you discover and understand new concepts and skills. What’s More This comprises activities for independent practice to solidify your understanding and skills of the topic. You may check the answers to the exercises using the Answer Key at the end of the module. What I Have Learned This includes questions or blank sentence/paragraph to be filled in to process what you learned from the lesson. What I Can Do This section provides an activity which will help you transfer your new knowledge or skill into real life situations or concerns. 3 Assessment This is a task which aims to evaluate your level of mastery in achieving the learning competency. Additional Activities In this portion, another activity will be given to you to enrich your knowledge or skill of the lesson learned. This also tends retention of learned concepts. Answer Key This contains answers to all activities in the module. At the end of this module you will also find: References This is a list of all sources used in developing this module. The following are some reminders in using this module: 1. Use the module with care. Do not put unnecessary mark/s on any part of the module. Use a separate sheet of paper in answering the exercises. 2. Don’t forget to answer What I Know before moving on to the other activities included in the module. 3. Read the instruction carefully before doing each task. 4. Observe honesty and integrity in doing the tasks and checking your answers. 5. Finish the task at hand before proceeding to the next. 6. Return this module to your teacher/facilitator once you are through with it. If you encounter any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator. Always bear in mind that you are not alone. We hope that through this material, you will experience meaningful learning and gain deep understanding of the relevant competencies. You can do it! 4 What I Need to Know This module was constructed and written with the learner and its status in mind. This will help you understand better the characteristics of each of the Earth’s internal structure. The scope of this module permits it to be used in many different learning situations. The language used recognizes the diverse vocabulary level of students. The lessons are arranged to follow the standard sequence of the course. But the order in which you read them can be changed to correspond with the textbook you are now using. The module is consist of a single lesson entitled: Earth’s Internal Structure which is about describing the mantle, outer core and inner core and relating them to geological events happening on Earth’s surface. (S10ES –Ia-j-36.4) After going through this module, you are expected to: 1. Explain how scientists used seismic waves to describe internal structure of the Earth. 2. Characterize internal layers of the Earth in terms of the composition and densities of materials within it. 5 What I Know Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. Which term is used to collectively refer to crust and upper mantle? A. asthenosphere B. inner core C. lithosphere D. mesosphere 2. Which layer is composed mostly of iron and nickel? A. asthenosphere B. core C. crust D. mantle 3. Which of these solid layer of the Earth has the ability to flow very slowly? A. asthenosphere B. crust C. hydrosphere D. lithosphere 4. Arrange the layers on which the seismic waves will travel slowest to fastest. I. Asthenosphere II. Crust III. Upper mantle IV. Lower mantle A. I, II, III, and IV B. II, I, III, and IV C. III, I, II, and IV D. IV, III, II, and I 5. Which seismic wave will not pass through outer core? A. Love wave C. S wave B. P wave D. Surface wave 6 Lesson 1 Earth’s Internal Structure Isaac Newton was one of the first scientists to theorize about the structure of Earth. Based on his studies of the force of gravity, Newton calculated the average density of Earth and found it to be more than twice the density of the rocks near the surface. From these results, Newton realized that the interior of Earth had to be much denser than the surface rocks. What’s In In your grade 8 science you have learned that there are several types of seismic waves; Primary waves (P-waves), Secondary waves (S-waves), and surface waves. Pwaves and S-waves are known as body waves because they move through the solid body of the Earth. To have a better understanding about Earth’s internal structure, you must know first the characteristics of each body wave. Notes to the Teacher/Parent The lesson involves figure and data analysis, if learner found some difficulty in analyzing, you may guide them 7 What’s New Communication P-waves are fastest, traveling at about 6 to 7 kilometers per second, so they arrive first at the seismometer. P-waves move in a compression/expansion type motion, squeezing and unsqueezing Earth materials as they travel. This produces a change in volume for the material. P-waves bend slightly when they travel from one layer into another. Seismic waves move faster through denser or more rigid material. Compression Rarefaction S-waves on the other hand are about half as fast as P-waves, traveling at about 3.5 km (2 miles) per second, and arrive second at seismographs. S-waves move in an up and down motion perpendicular to the direction of wave travel. This produces a change in shape for the Earth materials they move through. Only solids resist a change in shape, so S-waves are only able to propagate through solids. Swaves cannot travel through liquid. 8 In 1909, after a large earthquake, a Croatian scientist named Andrija Mohorovicic studied seismograph data gathered from various stations. He realized that the velocity of a seismic wave is related to the density of the material that it is moving through. He interpreted the acceleration of seismic waves observed within Earth's outer shell as a compositional change within the Earth. The acceleration must be caused by a higher density material being present at depth. (You can watch this link) https://www.visionlearning.com/library/animations/Seismic_Wave/Seismic_Wave.html What is It Critical Thinking/Collaboration Analyze the graph below showing the change in velocity of P waves with various depths of the Earth’s interior. Q1. From the graph, which depth shows a sudden increase in velocity of the P waves? Q2. Using your observation from Q1, compare the density of materials on point A and point B. A Q3. What happened to P wave’s velocity at 120 km – 180 km depths? B Q4. What is happened at P wave’s velocity below 200 km? C D Point A of the graph which shows a little change on velocity of P waves suggests that the materials within this depth are uniform in terms of density and composition. Meanwhile, the sudden increase of velocity of seismic wave at point B indicates that both the composition and density of materials there are totally different compared with the materials above 9 them. These differences prompt the scientists to consider another layer on Earth’s interior; MANTLE. The boundary between the crust and mantle, as inferred from the change in the speed of body waves (point B), is called the Mohorovicic discontinuity or simply referred as the Moho. How about the materials at 120-180 km depth that shows decreasing wave velocity upon passing them? The slowing down of waves at those depths is because of the lower rigidity and compressibility of the rocks in the layer below the lithosphere. The zone below the lithosphere where seismic waves travel more slowly is called the low velocity zone. The low velocity zone is probably coincident with the asthenosphere. What’s More Critical Thinking/Collaboration Activity 1.1 Because S-waves are able to travel through Earth's Asthenosphere scientists infer that it is nearly solid. However, one of the fundamental concepts of plate tectonics is that this hot, weak solid flows over long periods of time (a property generally associated with liquids). At this point you might be confused by the idea of flowing solids, so, to have a better understanding on the properties of materials in the asthenosphere you must perform the next activity. Materials • 1 cup of water • 1 to 2 cups of cornstarch • Mixing bowl • Food coloring (optional) Preparation • Pour one cup of cornstarch into the mixing bowl, and dip your hands into it. Can you feel how smooth the powder is? It's made up of super-fine particles. • Now pour the water in, mixing slowly as you go. Keep adding more water until the mixture becomes thick (and hardens when you tap on it). Add more cornstarch if it gets too runny, and more water if it becomes too thick. 10 • Add a few drops of food coloring if desired. (If you want to turn your material another hue, it’s easier to add the coloring to the water before you mix it with the cornstarch.) Q5. Roll the mixture around in your hands. characteristics of this substance? What are the Q6. When does it act more like a solid? Q7. When does it act more like a liquid? Roll the mixture into a ball and then break the ball apart. Let each piece of the ball sit in your hand. Describe its behavior. Substance Conditions Cornstarch and water Roll mixture around in hands Behavior Acts like a: Solid Liquid Let piece just sit in the palm of your hand Other observations Activity 1.2 Like the material in your previous experiment, rocks in the asthenosphere are solids but they have the ability to flow mainly because of high temperature. The asthenosphere together with the overlying crust constitute what we call lithosphere. The lithosphere is rigid and brittle, when stresses act on the lithosphere, it breaks. This is what we experience as an earthquake. 11 If you’re going to analyze again the previous graph (shown on the left), point A is part of the crust while below point B (including the asthenosphere) up to point D is part of the upper mantle. How about below point D? At 660 km depth, marks the beginning of the lower mantle. The increase in wave velocity will give you an idea that the materials here are denser compared with the materials in the upper mantle. Although materials in both mantle are similar, they differ in density because of the difference in pressure exerted by materials above. The deeper the materials the more pressure exerted on it, thus, becomes a lot denser. Asthenosphere 12 Critical Thinking Layer A B C Above is a cross-sectional diagram of the Earth showing how seismic waves (P and S waves) travel through its interior as recorded by seismographs from different parts of the world. Here, P waves are represented by blue lines while S waves are represented by red lines. Q8. On which layer did both P and S waves passed through? Q9. Which wave was able to pass through layer B? Q10. Which phase of matter is present on layer B based from your answer in Q9? 13 The diagram shows layer A as the mantle since both P and S waves were able to pass through it. On the other hand the next layer (B) shows that only P waves were able to penetrate it which suggests that it is liquid in form, Remember that S waves cannot pass through liquids unlike P waves. Also, there is a sudden large reduction in the speed of P-waves, as they enter the liquid layer where there is no rigidity to contribute to P-wave speed. This liquid layer is called outer core. As for layer C of the diagram, scientists determine that materials here are solids and the densest as suggested by refraction of P-waves passing through this part of the core, due to an abrupt increase in their speed, which was not shown by P-waves traveling through only the outer part of the core. This innermost layer is termed as the inner core. Materials on the inner core remains solid despite of very hot temperature due to immense pressure exerted on it. In terms of the kind of materials present in the core, scientists suggested that it is made mostly of iron and abundant nickel as well. This idea comes from the fact that since members of the solar system like asteroids and other planets has much higher percentage of iron and nickel in their composition than is found in the Earth’s crust, it is most likely that these elements are deposited in the innermost part of the Earth. What I Have Learned Primary waves (P waves) are the fastest type of seismic waves and move in a compression/expansion type motion. It can travel on any state of matter. S-waves are about half as fast as P-waves, and arrive second at seismographs. S-waves move in an up and down motion perpendicular to the direction of wave travel. It could not pass through liquids. The boundary between the crust and mantle, as inferred from the change in the speed of body waves, is called the Mohorovicic discontinuity or simply referred as the Moho. Asthenosphere is part of the upper mantle that is made up of solid rocks that are able to flow. The asthenosphere together with the overlying crust constitute the lithosphere. Only P waves travel along the outer core suggesting that it is made up of liquid iron and nickel. While the sudden increase in velocity of P waves, gives us the idea that the inner core is made up of solid iron and nickel. 14 Assessment Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. Which term is used to collectively refer to crust and upper mantle? A. asthenosphere B. inner core C. lithosphere D. mesosphere 2. Which layer is composed mostly of iron and nickel? A. asthenosphere B. core C. crust D. mantle 3. Which of these solid layer of the Earth has the ability to flow very slowly? A. asthenosphere B. crust C. hydrosphere D. lithosphere 4. Arrange the layers on which the seismic waves will travel slowest to fastest. I. Asthenosphere II. Crust III. Upper mantle A. I, II, III, and IV C. III, I, II, and IV B. II, I, III, and IV D. IV, III, II, and I 5. Which seismic wave will not pass through outer core? A. Love wave C. S wave B. P wave D. Surface wave 15 IV. Lower mantle Additional Activities Describe the change in velocity of P wave and S wave on each layer of Earth’s interior. 16 Answer Sheet Name_________________________ Grade and Section___________ Score________ Teacher_______________________ School___________________ Date________ Note: Submit this answer sheet to your teacher. What I Know 1. 2. 3. 4. What is it Assessment Q1. 1. Q2. 2. 3. Q3. 4. Q4. 5. 5. What's More Q5. Q6. Q7. Q8. Q9. Q10. 17 Substance Conditions Behavior Acts like a: Solid Cornstarch and water Roll mixture around in hands Let piece just sit in the palm of your hand Other observations 18 Liquid Cornstarch and water Roll mixture around in hands 19 Feel hard √ Solid Substance Conditions Behavior Liquid Acts like a: What's More Q5. It has the characteristics of solids. Q6. When it is being rolled in your hands or pressure is applied. Q7. When there’s less pressure on the material. Q8. Layer A Q9. P waves Q10. Liquid What I Know 1. 2. 3. 4. 5. C B A B C What is it Q1. Q2. Q3. Q4. Assess ment 40-50 km Point B has denser materials Decreased with depth Increased 1. 2. 3. 4. 5. C B A B C Answer Key Let piece just sit in the palm of your hand It can flow Other observations 20 √ References https://www.visionlearning.com/ https://courses.lumenlearning.com/ https://www.scientificamerican.com/ https://pubs.usgs.gov/gip/interior/ 21
