Slide 1 / 75 Slide 2 / 75 6th Grade PSI Earth's Materials and Systems Part I : The History of Planet Earth www.njctl.org Slide 3 / 75 Slide 4 / 75 Table of ontents: The History of Planet Earth lick on the topic to go to that section Earth's Layers Earth's Layers Three Types of Rocks Early Life on Earth / Fossils Rock Strata Return to Table of ontents Slide 5 / 75 Review Earth is a "terrestrial" or rocky planet. This means that it is made up of rocks and minerals. The rocks and minerals that now make up our Earth were once just small chunks revolving around our sun. Over billions of years, they combined to form the planet we live on today. What are the other rocky planets in our solar system? Slide 6 / 75 The Makeup of Earth s Earth grew larger, its gravity increased. Pressure beneath Earth's surface caused changes to the Earth's makeup. Distinct layers began to form. Do you remember any of the names of the layers? rainstorm with your table.
Slide 7 / 75 Slide 8 / 75 The Layers of Earth Earth's rust Our Earth is divided into four major layers: Think of the crust of Earth as the crust of a pizza pie. rust Mantle Inner ore Outer ore The crust is the outermost layer of Earth, just like the crust above is the outermost layer of the pizza! Slide 9 / 75 Slide 10 / 75 Earth's rust Earth's Mantle There are 2 parts to the crust. One is the land. What is the other part? The next layer down is the mantle. This is the largest layer - about 1,800 miles thick! This section is very thin compared to other layers of Earth (between 5 and 25 miles thick) and it is very hard and rigid. The mantle is made up of incredibly hot, semisolid rock (basically think of rock in a form sort of like pudding). The crust is composed of plates that slide around on top of the section below it. This portion is called the lithosphere. This layer makes up about 2/3 of Earth's mass. Slide 11 / 75 Slide 12 / 75 2 What is true of the mantle? It is the thickest layer of Earth. The layer of Earth that makes up the greatest mass. It is the top layer of Earth. layer of Earth that is made of a jello-like substance. D The plates of Earth that slide around the surface. The part of the atmosphere which we breathe. It is entirely made of liquid. D It is the least massive portion of Earth. 1 Which best describes the lithosphere?
Slide 13 / 75 Slide 14 / 75 3 The mantle is composed of Earth's land and oceans. 4 hoose the correct order of Earth's layers from outermost to most inner. True inner core, outer core, crust, mantle inner core, outer core, mantle, crust mantle, crust, inner core, outer core False D crust, mantle, outer core, inner core Slide 15 / 75 Slide 16 / 75 Earth's Inner ore Earth's Outer ore t the very center of Earth, you will find the Inner ore. The Outer ore is so hot that it is entirely liquid. It is the only liquid layer of Earth. Like the Outer ore, this layer is also extremely hot and is made of nickel and iron. It is made up of mainly nickel and iron. lthough the temperature is higher, the nickel and iron here are in solid form because of the intense pressure that this layer experiences. To give you an idea of how hot it is, nickel becomes a liquid at 2,650 degrees F and iron melts at 2,800 degrees F! What temperature does ice melt at? Slide 17 / 75 Slide 18 / 75 6 Which is the oldest layer of Earth? 5 What separates the Inner and Outer ore? crust The Inner ore is made of liquid; the Outer ore is solid. D The Outer ore is under more pressure than the Inner ore. The Inner ore is solid; the Outer ore is liquid. outer core D inner core mantle The Outer ore is hotter than the Inner ore.
Slide 19 / 75 Slide 20 / 75 Size of Earth's Layers Three Types of Rocks Return to Table of ontents Slide 21 / 75 Slide 22 / 75 Three Types of Rocks Formation of Rocks How a rock forms depends on what type of rock it is. There are three types of rocks: The energy of this heat and pressure results in the formation of rocks. The layers of Earth are constantly moving and changing due to intense heat and pressure. ut what exactly is a rock? lick on the rock type to see an example. With your table, come up with some characteristics of rocks. Igneous Slide 23 / 75 How Do Rocks Form? The three types of rocks on the previous page each form in different ways. The animation on the next slide will introduce you to the process behind the transformation of rocks from one type to another - a process known as the rock cycle. the questions on the accompanying worksheet while watching the animation. Slide 24 / 75
Slide 25 / 75 Slide 26 / 75 7 Which of the following is not a type ofrock? Glacier Igneous D "Sediments" are small fragments of rock. To form rock, these fragments combine together. Rock These rocks are typically multi-colored with many different textures. Slide 27 / 75 Igneous Rock "Igneous" has the same root word as "ignite." What does ignite mean? Slide 28 / 75 Types of Igneous Rock There are two types of igneous rock. "Intrusive" igneous rock is still inside Earth. Igneous rocks form when magma, which we can think of as "liquid fire," cools down. "Extrusive" igneous rock has exited Earth. These rocks are typically dark, very shiny, and made up of crystals. Slide 29 / 75 Metamorphosis "Metamorphosis" is when something changes into something new. You have learned about a few organisms which undergo metamorphosis in your science classes over the years. t your table, talk for a few minutes about the 2 organisms below and the metamorphosis they undergo during their lives. Slide 30 / 75 Rock Just like the frog, metamorphic rock is formed when another one type of rock changes into a new type of rock. rock forms when another type of rock changes its chemical makeup because of heat and pressure. These rocks are typically made up of layers that formed as the rock was squashed under pressure.
Slide 31 / 75 Slide 32 / 75 9 Which type of rock is formed of magma below the surface of Earth? Extrusive Igneous Extrusive Igneous Intrusive Igneous Intrusive Igneous D D Slide 33 / 75 Slide 34 / 75 Extrusive Igneous Intrusive Igneous D Extrusive Igneous Intrusive Igneous D Slide 35 / 75 Slide 36 / 75 12 This is an example of rock. 13 This is an example of rock. Igneous Igneous 11 Which type of rock is formed from magma cooling on Earth's surface? 10 Which type of rock is formed when other rocks undergo a transformation due to heat or pressure? 8 Which type of rock is made up of pieces of other rocks?
Slide 37 / 75 Slide 38 / 75 14 This is an example of rock. Igneous Igneous 15 This is an example of rock. Slide 39 / 75 Slide 40 / 75 The ge of Earth Early Life on Earth / Fossils Scientists estimate that the Earth formed around 4.6 billion years ago. We can learn about the history of Earth by studying rocks and fossils. Return to Table of ontents Slide 41 / 75 First Life on Earth There is evidence within the rocks on Earth that suggests that life first appeared on Earth about 3.6 billion years ago. Slide 42 / 75 Prokaryotes The first cells that existed on Earth were closely related to prokaryotes. These are cells that do not have a nucleus. Most prokaryotes are single-celled organisms. bacteria Why were the first organisms on Earth very simple? The image above is of stromatolites, the oldest fossils on record. They provide us with evidence of very simple life forms like bacteria as long as 3.5 billion years ago. What is a more common name for prokaryotes? Move the image once you come up with an idea.
Slide 43 / 75 Prokaryotes Slide 44 / 75 Photosynthetic Organisms Food was scarce on the early Earth. Why do you think this was? What do most organisms that we know of today eat? ome up with a theory at your table. Very specific conditions were needed for these living organisms to form. Organic chemicals (chemicals that include carbon) as well as some sort of heat were needed to form these cells. Slide 45 / 75 Photosynthetic Organisms Slide 46 / 75 How Do Scientists Reconstruct the Past? Scientists can estimate what life was like billions of years ago thanks to the discovery of fossils. What is a fossil? Food was scarce on the early Earth because there were only a few organisms to begin with! Some prokaryotes developed the ability to create their own food by converting sunlight, carbon dioxide, and water into sugar and oxygen. The creation of oxygen through this process led the way for more complex organisms, like animals, to evolve. Slide 47 / 75 How Do Scientists Reconstruct the Past? fossil is the preserved remains of an organism which is found in rock formations. The answer is under the photo to the right How Do Scientists Reconstruct the Past? The first fossils that hint at the existence of complex organisms are roughly 1.8 billion years old. The first algae appeared about 1.2 billion years ago. In what type of rock do you think fossils usually can be found? Think about how rocks are formed. Slide 48 / 75 Fossilized Seaweed Fossils are typically found in Rock Photo : Thomas resson
Slide 49 / 75 Slide 50 / 75 How Do Scientists Reconstruct the Past? ctivity - Fossil Layers How can scientists come up with the ages on the previous slide? Most fossils can be found in layers of sedimentary rock. Some can also be found in metamorphic rock, but they would be distorted due to heat and pressure. In this activity, you will create your own "sedimentary rock" full of fossils and then examine the affect that pressure has on them. It is difficult for scientists to figure out the age of the actual fossils, so instead they find the age of the sedimentary rock in which the fossil was found. The different colored layers in the picture above would help scientists estimate the age of fossils. Slide 51 / 75 Slide 52 / 75 Fossil Excavation 16 Fossils are usually found in rock. metamorphic sedimentary s was mentioned in the section on the Types of Rocks, the older rocks will be further down within Earth. Fossilized organisms will be about the same age as the layer of rock they are found in. igneous It is the job of a paleontologist to excavate, or dig up, these fossils and determine their ages. Slide 53 / 75 Slide 54 / 75 18 Scientists use to determine the age of fossils. 17 Old fossils will be found Earth than younger fossils. anywhere on chemistry microscopes rock layers on the surface of deeper down in
Slide 55 / 75 Slide 56 / 75 ctivity - ookie Excavation Vertebrate Fossil Webquest The work of a paleontologist is very delicate and difficult. It requires a lot of patience and care. In this activity, you will practice these skills on different types of cookies. an you excavate the chocolate chips from the cookies using only your paleontology tools? Now that the "fossils" have been excavated, how do they get from the site to the museum? Use the site above to track a vertebrate fossil! Slide 57 / 75 Slide 58 / 75 How Do We Determine a Fossil's ge? Rock Strata In our last section, we learned that we can tell a fossil's age based on the rock it is found in. This provides us with a general range for the age of the fossil. Return to Table of ontents The deeper it is within Earth, the older the fossil is. Slide 59 / 75 Slide 60 / 75 20 Which type(s) of rocks can contain fossils? Igneous Igneous 19 What kind of rock is featured on the previous page?
Slide 61 / 75 Life on Earth One goal of geology (the study of rocks) is to develop a timeline of Earth's past......and we can use this information to make connections between the first simple life forms to the diversity on Earth today. Slide 63 / 75 How Do Scientists Determine bsolute ge? Slide 62 / 75 bsolute ge Scientists use various techniques to determine the age of rocks. Sometimes, scientists are able to determine the absolute age, or the exact age, of a rock or fossil. The absolute age of the petrified wood above is 2,500 years old. Slide 64 / 75 Half Life When it comes to relative age, scientists analyze the amount of certain radioactive elements within the object. They then use the "half life" of the element to determine the object's age. The half life is the period of time it takes for half of the substance to decay. Scientists use a technique called radiometric dating to determine absolute age. Radiometric dating compares the ratio of a radioactive element with the amount that has decayed in the rock or fossil. Slide 65 / 75 arbon Dating radioactive version of the element arbon is known as arbon 14 because it has an atomic mass of 14 (rather than the usual 12). What is atomic mass? Slide 66 / 75 arbon Dating This means that if there are100 atoms of arbon 14 in the tree when itwas alive, there will be only50 left after it has been dead for 5,700 years. arbon 14 has a half life of about 5,700 years. arbon 14 is found in every living thing. So after onehalf life, the amount of arbon 14 is cut inhalf.
Slide 67 / 75 Slide 68 / 75 21 fter two half lives, how much arbon 14 would be left from the tree on the previous slide? (hint: what was arbon-14's half life?) 22 fter one half life, what percentage of arbon 14 remains? % Slide 69 / 75 Slide 70 / 75 arbon 14 23 fter two half lives, what percentage of arbon 14 remains? In organisms that were once living, the amount of arbon 14 will be cut in half every 5,700 years. % Scientists use this information to determine how long an organism has been dead... and therefore find out roughly how old it is! Slide 71 / 75 Webquest - The Radioactive Dating Game Slide 72 / 75 Relative ge When scientists cannot be exact, they try to determine an object's relative age. This is when they compare the age of an object or event to another object or event. In this activity, you will learn about different types of radiometric dating, such as carbon dating. Scientists can estimate the age of this volcano by looking at rocks and fossils found around its base. You will understand how decay and half life work to enable this dating. You will finish it up with a game that tests your ability to match the percentage of the dating element that remains to the age of the object! Why would they use the base of the volcano and not the top?
Slide 73 / 75 Slide 74 / 75 Index Fossils Layers of Rock What is anindex fossil? lick on the dinosaur below to uncover the definition! n index fossil is used to determine the age range of a rock layer. When new rock is formed on the surface of Earth, it settles on top of what was there before it. It is the fossil of an organism that existed only for a limited period of time. The deeper you dig into Earth's surface, the farther back in time you will see. Since scientists know that thestegosaurus lived between 150 and 155 million years ago, any rock layer containing a stegosaurus fossil will be around that age as well. Slide 75 / 75 Layer 1 Layer 2 Layer 3 24 In the diagram below, in what layer would the oldest rocks be found? Permission Granted: FL Museum of Natural History