4 th Grade PSI. Slide 1 / 107 Slide 2 / 107. Slide 3 / 107. Slide 4 / 107. Slide 5 / 107. Slide 6 / 107. The History of Planet Earth

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1 Slide 1 / 107 Slide 2 / th Grade PSI The History of Planet Earth Slide 3 / 107 Slide 4 / 107 The History of Planet Earth The Structure of Earth Rock Layers Fossils and Relative Time Tectonic Plates Earth's Visible Features Patterns of Earth's Features Click on the topic to go to that section The Structure of Earth Return to Table of Contents Slide 5 / 107 The Structure of Earth When you look at the world around you, have you ever asked How did the Earth get to be the way it is today? Slide 6 / 107 The Structure of Earth The things that we see today on the surface of the Earth exist for many reasons, and they can teach us many things. The structures we can see on the surface and things underneath the surface tell us about the Earth's history.

2 Slide 7 / 107 The Structure of Earth Working with your table, come up with a list of structures on Earth that you think might tell some of the story of Earth's past. Slide 8 / 107 The Structure of Earth The things we see on the surface of Earth today have gotten to be that way over many, many years. The surface of Earth - what we see with our eyes - is the outermost layer of Earth and is called the crust. crust Even though the crust is the outer layer, there are still parts of the crust that are too deep for us to see. Slide 9 / 107 The Structure of Earth Earth has other layers underneath the crust. These are called the mantle and the core. Slide 10 / 107 The Structure of Earth Most of the crust is made up of rock. Much of this rock is sedimentary rock. But when we talk about the history of Earth, it is the crust - the outer layer - that can tell us the most. mantle core Sedimentary rocks are one of the main reasons why the crust tells us so much about Earth's history. Why do we rely on the crust to tell us the story and not the mantle or the core? Slide 11 / 107 Slide 11 () / Can the things we see on Earth's surface can tell us about Earth's history? 1 Can the things we see on Earth's surface can tell us about Earth's history?.

3 Slide 12 / 107 Slide 12 () / Is it possible Earth's surface has gotten to be the way it is within the past 50 years? 2 Is it possible Earth's surface has gotten to be the way it is within the past 50 years?, Earth's surface has gotten to be the way it is over many, many years. Slide 13 / 107 Slide 13 () / The outer layer of Earth is called the: 3 The outer layer of Earth is called the: A skin B mantle C crust A skin B mantle C crust D core D core C Slide 14 / 107 Slide 14 () / We can see all of Earth's crust with our eyes. 4 We can see all of Earth's crust with our eyes., we cannot see all of the Earth's crust with our eyes because the crust is thick.

4 Slide 15 / 107 Slide 15 () / Which layer of Earth tells us the most about Earth's history? 5 Which layer of Earth tells us the most about Earth's history? A the core B the mantle C the outside A the core B the mantle C the outside D the crust D the crust D Slide 16 / 107 Rock Layers Return to Table of Contents Slide 17 / 107 Rock Layers Sedimentary rock, which makes up much of Earth's crust, is made from sediment. Sediment is broken down pieces of rock and other solid material that settles to the bottom of a liquid. Sediment is often dirt and rock particles that settle at the bottom of bodies of water, but it also refers to any solid material that settles at the bottom of a liquid, such as these particles in this glass of water. sediment Slide 18 / 107 Rock Layers Sedimentary rock is formed over many years. Slide 19 / 107 Rock Layers So here's how it happens: Can you brainstorm any ways sedimentary rock could come to be? Remember our definition of sediment. Sediments are deposited (usually by water). Sediments build up in layers - a process called sedimentation. Sediments are compacted as the weight of the sediments on top squash the sediments at the bottom. Where on Earth might we see evidence of layering? How could that have happened? Sediments are cemented by crystals of salt that are left after the water has been squeezed out of the rocks.

5 Slide 20 / 107 Rock Layers deposition sedimentation compaction cementation Slide 21 / 107 Rock Layers Sedimentary rocks provide a history of the evolution of Earth, especially within the past billion years. When sediments are deposited and compacted to form sedimentary rock, sediments are accumulated in beds one on top of another - in layers. This means that when cut deep into the crust, below the surface we can see with our eyes, we find layers of different rocks that have formed over a long period of time. txstate.edu deposition sedimentation compaction cementation Slide 22 / 107 Rock Layers Which layer of rock in this diagram do you think is the youngest? Which is the oldest? Label the top and bottom layers and then move the boxes to reveal the answers. This is called the Law of Superposition. Slide 23 / 107 Rock Layers Geologists study ancient sedimentary rocks to determine what environment they formed in. Determining ancient environments is very important to understand the history of Earth. move for It helps geologists understand how Earth's surface has changed over time. answer One way to study this is to compare the sedimentary structures in ancient rocks with sedimentary structures in modern environments. move for answer Slide 24 / 107 Slide 24 () / The most important characteristic of a sediment is: A that it settles to the bottom of a liquid B that it floats in liquid 6 The most important characteristic of a sediment is: A that it settles to the bottom of a liquid B that it floats in liquid C its color C its color D that it is small D that it is small A

6 Slide 25 / Order the following steps from first to last in the process of sedimentary rock formation (enter all 4 letters on your responder in the correct order): A compaction Slide 25 () / Order the following steps from first to last in the process of sedimentary rock formation (enter all 4 letters on your responder in the correct order): A compaction B deposition C cementation B deposition C cementation B, D, A, C D sedimentation D sedimentation Slide 26 / 107 Slide 26 () / Sedimentary rocks form in layers. 8 Sedimentary rocks form in layers.. Slide 27 / 107 Slide 27 () / The Law of Superposition says: A rock layers that are closer to the surface are old B old and new rocks are found in the same place C rock layers get older as you go further down D rock layers that are deep down are the most recent 9 The Law of Superposition says: A rock layers that are closer to the surface are old B old and new rocks are found in the same place C rock layers get older as you go further down D rock layers that are deep down are the most recent C

7 Slide 28 / 107 Slide 28 () / Geologists study ancient rocks to learn about: A people B environments C sediments D cementation 10 Geologists study ancient rocks to learn about: A people B environments C sediments D cementation B Slide 29 / 107 Slide 30 / 107 LAB: Rock Layers In this lab, we will look more at how sedimentary rocks form, focusing on the questions: How are different sediments deposited differently? How do sedimentary rocks form? Fossils and Relative Time Return to Table of Contents Slide 31 / 107 Fossils and Relative Time Sedimentary rocks not only contain sediments such as dirt, sand, and pebbles, but also fossils - preserved remains of plants or animals. Slide 32 / 107 Fossils and Relative Time Rocks of the same age contain the same, or very similar, So, for example, very recently formed rocks may have a lot of these fossils, fossils. while in rocks from an older time period there may be none of those fossils, but many of these fossils, Fossils come in many forms. They can be bones, tracks, plants, or bodies of animals, among other things. and in rocks from an even older time period, there may be lots of these fossils, but none of the types found in the more recent rock.

8 Slide 33 / 107 Fossils and Relative Time When the same kind of fossils are found in rocks in different places - for example, fossils of an organism that no longer exists - we know that the rocks are the same age. How? Slide 34 / 107 Fossils and Relative Time This means that the age of a rock can be determined by the fossils that are found in it. A rock can also be compared to other rocks by the fossils the rocks contain. The types of fossils in the rocks being compared So if fossils of this organism are found in these three places, then the rocks they were found in are all the same age. will show which rock is older than the other. Slide 35 / 107 Fossils and Relative Time When we compare fossils, we can form a general timeline of organisms that existed throughout history! Slide 36 / 107 Fossils and Relative Time The kinds of fossils found in rocks from different time periods change because animals and plants change through time. These patterns of fossils exist globally. But in certain places, fossils are also found in different rock layers because the environment of that particular place changed throughout history. very long time ago long time ago recent Slide 37 / 107 Fossils and Relative Time For example, imagine that a long time ago there was a lake, and many fish and shell fossils were left in that rock. Slide 38 / 107 Fossils and Relative Time Fossils can tell us many things about the the history of: Many years later, something happened in that area and the rocks from that later time had many plant fossils, but no fish or shell fossils. one place, one region, What do you think scientists would be able to tell happened in that place based on what they learned from the fossils? Come up with an idea in your group you can share with the rest of the class. or the entire planet.

9 Slide 39 / Fossils are: (choose all that apply) Slide 39 () / Fossils are: (choose all that apply) A found in sedimemtary rocks B living organisms C able to help determine how old rocks are D preserved remains of plants and animals A found in sedimemtary rocks B living organisms C able to help determine how old A, rocks C, & are D D preserved remains of plants and animals Slide 40 / 107 Slide 40 () / Is it possible to tell if one rock is older or younger than another rock by looking at their fossils? 12 Is it possible to tell if one rock is older or younger than another rock by looking at their fossils?. Slide 41 / 107 Slide 41 () / Rocks of the same age contain very different fossils. 13 Rocks of the same age contain very different fossils..

10 Slide 42 / 107 Slide 42 () / Why do rocks from different time periods have different Students kinds type their of answers fossils? here (discuss as a class, do not answer with responders) 14 Why do rocks from different time periods have different Students kinds type their of answers fossils? here (discuss as a class, do not answer with responders) Rocks from different time periods have different types of fossils because plants and animals change through time or in certain places because the environment has changed over time so the organisms that lived there changed. Slide 43 / 107 ACTIVITY: Sediment Fossil Surprise In this activity we will explore how fossils are deposited in rock layers. We will make our own models to better understand how fossils work and what they tell us. Slide 44 / 107 ACTIVITY: Relative Age with Edible Rocks In this activity we will closely examine the inside of edible rocks to learn about their "sediments" relative age based on patterns of their deposition. We will focus on the question: How is relative age dating used when observing rock layers? We will focus on the question: How are fossils deposited in sediment layers? Slide 45 / 107 Rock Formations and Earth Forces Slide 46 / 107 Sometimes rock layers are disturbed by different Earth forces. This means that the pattern we typically see in rocks - of older rocks being farther underground and newer rocks being closer to the surface - can sometimes be mixed up, with rock layers existing in different formations. What do you think might cause this? Return to Table of Contents

11 Slide 47 / 107 Earth forces can disturb the Law of Superposition. Slide 48 / 107 EARTHQUAKES Patterns in rock formations can show where earthquakes - shaking caused by the movement of rock under Earth's surface - occurred and layers are no longer aligned. fault line Some Earth forces include earthquakes, rivers, and erosion. Rock layers impacted by an earthquake will often show distinct change at the fault line where the earthquake occurred. Slide 49 / 107 RIVERS Rivers are strong forces that can impact rocks. Often times rivers will cut through rocks, leaving rock layers exposed. Slide 50 / 107 EROSION Different forces such as rain, wind, flowing water, and living animals can make rocks erode, or wear down. This erosion wears down rocks and creates new patterns in rock layers. eroded rock layers Rivers may also deposit new sediment in the middle of old rock layers. Slide 51 / 107 Often the cause of Earth forces that disrupt rock patterns is plate tectonics, the movement of plates that make up Earth's crust. Slide 52 / 107 It is broken into sections called plates. crust Remember, we said the crust is not a solid layer on the outside of Earth. geology.er.usgs.gov You can see the plates here with a map of the continents underneath. These plates move slowly and interact at their boundaries.

12 Slide 53 / 107 Tectonic plates fit closely together along their boundaries. The plates are many miles thick. They bump and rub agains each other, while pulling apart, and pushing together. Slide 54 / 107 So in a cross-section under Earth's surface, the layers of rock that make up the crust are floating on top of the thick mantle of liquid rock. Earth's surface Earth's surface mantle crust crust The plates float on top of Earth's mantle which is made up of liquid rock. mantle mantle Slide 55 / 107 Earthquakes are one example of Earth forces caused by tectonic plate movement. Slide 56 / 107 Tectonic plates can also cause rock layers to bend and fold. Earthquakes occur when the plates interact - typically when they are pushing together or sliding past each other - and, as we saw, they disturb rock layers. Earthquakes often leave visible marks on Earth's surface, but especially leave visible marks on rock layers. Slide 57 / 107 When Earth forces disturb typical rock formations, it can be trickier to understand what has happened in Earth's history. But using fossils and other clues can help scientists understand rocks and their ages even in these cases when the layers are mixed up and not in straight lines. Slide 58 / 107 For instance, if these fossils were found in these layers, we could figure out which layers were oldest and youngest even though the layers are diagonal. oldest youngest recent very old old

13 Slide 59 / 107 Slide 59 () / If Earth forces have impacted rocks in an area, will younger rocks still always be located on top of older ones? 15 If Earth forces have impacted rocks in an area, will younger rocks still always be located on top of older ones?. Slide 60 / Earth forces can cause rock layers to: (choose all that apply) Slide 60 () / Earth forces can cause rock layers to: (choose all that apply) A disappear A disappear B fold up B fold up C unalign C unalign B, C, & D D swap D swap Slide 61 / 107 Slide 61 () / What Students may type have their answers happened here to these rocks? (discuss as a group, not a responder question) 17 What Students may type have their answers happened here to these rocks? (discuss as a group, not a responder question) These rock layers may have been laid a long time ago, but more recently had a river cut through them. The river dried up and new sediment was deposited in the space it eroded.

14 Slide 62 / 107 Slide 62 () / The crust is a solid layer on the outside of Earth. 18 The crust is a solid layer on the outside of Earth.. Slide 63 / 107 Slide 63 () / The crust is broken into pieces called: 19 The crust is broken into pieces called: A continents B regions C plates A continents B regions C plates D shells D shells C Slide 64 / Tectonic plates: (choose all the apply) Slide 64 () / Tectonic plates: (choose all the apply) A never move A never move B interact at their boundaries C can cause earthquakes D are very thin B interact at their boundaries C can cause earthquakes D are very thin B & C

15 Slide 65 / 107 Slide 66 / 107 Tectonic Plates The crust is divided into two types: oceanic and continental. Tectonic Plates If you look closely at this map of tectonic plates, you can see that parts of the plates are covered with water and parts are covered with land. Return to Table of Contents geology.er.usgs.gov Slide 67 / 107 Tectonic Plates OCEANIC CRUST Where do you think oceanic crust is found? Slide 68 / 107 Tectonic Plates CONTINENTAL CRUST Where do you think continental crust is found? It is made of dense rocks such as basalt. This means that oceanic crust is heavy. oceanic crust ocean floor It is made of less dense rocks such as granite. This means continental crust is light. Its thickness varies between 6 to 47 miles. continental crust Oceanic crust is about 4 miles thick. mantle Continental crust is almost always much older than oceanic crust. mantle Slide 69 / 107 Tectonic Plates There are three types of tectonic plate boundaries: convergent, divergent, and transform. If you look closely at this map of tectonic plate movement, you can see arrows showing that different plates move in different directions relative to each other. geografas.eu Slide 70 / 107 Tectonic Plates CONVERGENT BOUNDARIES At convergent boundaries, plates collide with one another. The collision causes the edge of one or both plates to buckle, or causes one plate to move underneath the other, a process known as subduction. At convergent boundaries, continental crust is created and oceanic crust is destroyed as it subducts, melts, and becomes magma.

16 Slide 71 / 107 Tectonic Plates DIVERGENT BOUNDARIES At divergent boundaries, plates separate. Slide 72 / 107 Tectonic Plates TRANSFORM BOUNDARIES At transform boundaries, plates slide past one another. Here, geysers spurt super-heated water, and magma, or molten rock, rises from the mantle and solidifies to form new crust. At divergent boundaries, oceanic crust is created. Here, earthquakes tend to occur when plates move and rub against one another. New crust is neither created or destroyed at transform boundaries. Slide 73 / 107 Tectonic Plates Here is a diagram of the three types of plate boundaries. Slide 74 / 107 Tectonic Plates Can you find the 3 different types of plate boundaries on this diagram? USGS.gov geografas.eu (The lithosphere and asthenosphere are parts of the mantle. The asthenophere is made of molten rock.) Slide 75 / 107 Tectonic Plates On this diagram each type of boundary is shown in a different color. Did you correctly identify some of these boundaries in the last diagram? Slide 76 / The Students two types their of answers crust hereare and. (not a responder question)

17 Slide 76 () / 107 Slide 77 / The Students two types their of answers crust hereare and. (not a responder question) 22 Oceanic crust is heavier than continental crust. True False continental crust and oceanic crust Slide 77 () / 107 Slide 78 / Oceanic crust is heavier than continental crust. 23 When tectonic pates move apart, it is called a: True False A divergent boundary B transform boundary C convergent boundary True D subducting boundary Slide 78 () / 107 Slide 79 / When tectonic pates move apart, it is called a: A divergent boundary B transform boundary C convergent boundary 24 This shows a boundary. A divergent boundary B transform boundary C convergent boundary D subducting boundary A D subducting boundary

18 Slide 79 () / 107 Slide 80 / This shows a boundary. A divergent boundary B transform boundary Earth's Visible Features C convergent boundary D subducting boundary C Return to Table of Contents Slide 81 / 107 Earth's Visible Features Some rock layers indicate Earth forces that happened a long time ago, but there are also many features on Earth's surface that are visible signs of Earth forces today. This is because tectonic plates are still moving. Slide 82 / 107 Earth's Visible Features MOUNTAIN RANGES Where plates collide or push together, mountain ranges form. These visible features include mountain ranges, ocean trenches, mid-ocean ridges, rift valleys, and volcanoes, all existing due to the movement of tectonic plates. You can see that as the plates push together, the top layer of rock crunches up to form mountains. Sometimes one plate moves under the other plate - subducts - and the other plate pushes upwards. Sometimes both top layers are pushed upwards. Slide 83 / 107 Earth's Visible Features MOUNTAIN RANGES When a oceanic and continental plate converge, the oceanic plate subducts and the continental crust crunches up, forming a mountain range. Slide 84 / 107 Earth's Visible Features MOUNTAIN RANGES The Himalayas, shown here, are an example of this. quake.eas.gatech.edu Where two continental plates converge, they are likely to bothbuckle, or crunch up, forming a mountain range. shanahan2.pbworks.com

19 Slide 85 / 107 Earth's Visible Features OCEAN TRENCHES Where oceanic plates converge and one plate subducts underneath the other, ocean trenches are formed. Slide 86 / 107 Earth's Visible Features MID-OCEAN RIDGES Where oceanic plates diverge, mid-ocean ridges are formed. Trenches mark the position at which the flexed, subducting crust begins to descend under the crust it is colliding with. Oceanic trenches typically extend 1.9 to 2.5 miles below the level of the surrounding oceanic floor. trench Hot magma from Earth s mantle bubbles to the surface where plates diverge. This magma is then cooled by seawater and forms new crust. The newest oceanic crust is located near the center of the ridge. Over time, new oceanic crust pushes older crust farther away. magma Slide 87 / 107 Slide 88 / 107 Earth's Visible Features RIFT VALLEYS Where continental plates diverge, rift valleys are formed. Rift valleys are often narrow, with steep sides and a flat floor. Rift valleys can lead to the creation of entirely new continents, or deepen valleys in existing ones. Earth's Visible Features VOLCANOES Where tectonic plates push together, volcanoes - mountains that erupt with lava - often form. Where plates collide, pressure is built up in Earth. Magma - a mixture of gases and hot molten rock - builds up in the mantle and pushes up into rock layers. The magma opens cracks in weak spots in rocks, and eventually pushes all the way to the surface. Slide 89 / 107 Earth's Visible Features VOLCANOES When the magma erupts on Earth's surface, it is called lava. The place it erupts is the volcano. lava Slide 90 / Mountain ranges form where tectonic plates diverge. volcano magma

20 Slide 90 () / 107 Slide 91 / Mountain ranges form where tectonic plates diverge. 26 Subduction is when: A two plates buckle up when they collide B a colliding plate goes under another C continental crust moves under oceanic crust D two plates diverge Slide 91 () / 107 Slide 92 / Subduction is when: 27 Mid-ocean ridges form where: A two plates buckle up when they collide B a colliding plate goes under another C continental crust moves under oceanic crust A oceanic and continental crust converge B oceanic crust converges with oceanic crust C continental or oceanic plates diverge D two plates diverge B D oceanic crust diverges Slide 92 () / Mid-ocean ridges form where: A oceanic and continental crust converge B oceanic crust converges with oceanic crust C continental or oceanic plates diverge D oceanic crust diverges D Slide 93 / Which of the following are true of volcanoes: (choose all that apply) A they form where plates converge B they do not need magma to form C they erupt with lava D pressure in the earth helps to cause them

21 Slide 93 () / Which of the following are true of volcanoes: (choose all that apply) A they form where plates converge Slide 94 / 107 ACTIVITY: Where Plates Meet In this activity we will explore tectonic plate boundaries across the globe. We will focus on the question: What do we find on Earth s surface at tectonic plate boundaries? B they do not need magma to form C they erupt with lava D pressure in the earth helps to cause them A, C, & D Slide 95 / 107 Slide 96 / 107 Patterns of Earth's Features Patterns of Earth's Features The features we see on Earth, both visible and underground, occur in patterns. Think about what causes earthquakes and volcanoes. Where do you think earthquakes and volcanoes are most likely to occur? Return to Table of Contents geology.er.usgs.gov Slide 97 / 107 Patterns of Earth's Features Here is a map of earthquake locations over a 15 year period. black = earthquakes close to the surface (0-70km) green = earthquakes a bit farther down (70-300km) red = earthquakes farther down in the crust ( km) Slide 98 / 107 Patterns of Earth's Features If you place the map next to a map of the tectonic plates, you can see that earthquakes are most likely to occur along plate boundaries. What do you notice? This is because earthquakes are caused by plates interacting at their boundaries. geology.er.usgs.gov

22 Slide 99 / 107 Patterns of Earth's Features We know that volcanoes occur where plates are converging. Slide 100 / 107 Patterns of Earth's Features Here is a map of volcano locations around the world. From looking at this map, can you guess where volcanoes are located? geografas.eu Are any of the volcanoes where you guessed they would be? Slide 101 / 107 Patterns of Earth's Features Similar to earthquakes, volcanoes are also found along plate boundaries. Slide 102 / 107 Patterns of Earth's Features Many volcanoes are found around the edges of the 5 main plates in the Pacific Ocean. This area is known as The Ring of Fire. Why is it called this? geografas.eu More specifically, volcanoes exist where plates converge. Slide 103 / 107 Patterns of Earth's Features A map of tectonic plates and their movements can help us predict and know many things about Earth's features. Slide 104 / Earthquakes occur in completely random locations that could never be predicted. True False geografas.eu

23 Slide 104 () / 107 Slide 105 / Earthquakes occur in completely random locations that could never be predicted. True False 30 Earthquakes are likely to occur: A anywhere B in random places C where plates diverge False D around plate boundaries Slide 105 () / 107 Slide 106 / Earthquakes are likely to occur: A anywhere 31 What Students is The type their Ring answers of here Fire? (not a responder question) B in random places C where plates diverge D around plate boundaries D Slide 106 () / What Students is The type their Ring answers of here Fire? (not a responder question) Slide 107 / 107 ACTIVITY: Finding Plates by Mapping Quakes In this activity we will map earthquakes across the globe and compare their locations to the location of plate boundaries. We will think more about the question: What can the location of earthquakes help us understand? The Ring of Fire is an area around the tectonic plate edges in the Pacific Ocean where many volcanoes are located.