Unit C: Earth Science Chapter 1: The Changing Earth

Transcription

1 Unit C: Earth Science Chapter 1: The Changing Earth Lesson 1: Layers of the Earth 1. Atmosphere is the layer of gases that surrounds the planet 2. Clouds are in this layer 3. Atmosphere contains gases that organisms, need to live 4. Most of the atmosphere is close to the surface of the earth Hydrosphere is the layer beneath the atmosphere: it is the water part of the earth's surface 1. It includes oceans, lakes, rivers, streams, and glaciers 2. Water covers 75% of the earth's surface 3. Without water life could not exist Lithosphere is the solid surface of the earth it includes the continents and the ocean floors 1. Our homes are attached to the lithosphere 2. The atmosphere, hydrosphere, and lithosphere form layers, but parts of each layer can be found in others Crust, Mantle, Core 1. Crust: earth's outer rock layer 2. Mantle: is the rock layer beneath the crust the Upper part of the mantle is solid 3. The middle portion of the mantle is partly melted 4. The lower portion of the mantle is solid and can flow slowly 5. Core: the center part of the earth made of iron and nickel 6. In the outer part of the core, the iron and nickel are melted

2 7. As you go deeper into the outer part of the core the temperature continues to rise 8. As you go deeper more of the earth is above you and the pressure is so great it forces the iron and nickel to become solid

3 Lesson 2 How Does the Earth's Crust Move? Moving Continents 1. Scientist think the continents were once part of a single land mass that began separating 150 to 200 million years ago 2. Evidence that supports the continents were once connected: 3. Mountain ranges on five continents fit together in a jigsaw puzzle and ancient rock formations of these mountains match 4. Coal deposits in North America match identical deposits in Europe 5. Discovery of warm-weather organisms in cold climates 6. Glacial deposits in warm climates Plate Tectonics 1. This is the theory of how continents move 2. The earth's surface is broken into about twenty sections or plates 3. Plates are large sections of the earth's surface made of the crust and the top rigid portion of the mantle 4. They fit together but keep changing because they are slowly moving Events Caused by Plate Movements 1. Earthquakes 2. Volcanic Eruptions 3. Mountain Formations 4. These events are most common along plate boundaries

4 Lesson 3 What Changes the Earth's Surface? Weathering 1. Weathering is the process that breaks down and changes rocks 2. Rocks can slowly be broken down by air, ice, water, chemicals, and living things 3. There are two types of weathering 4. Physical Weathering: breaks down rock without changing the substance that makes up the rock 5. Can be caused by freezing water, waves, windblown particles, and plant roots 6. Chemical Weathering: breaks down rock by changing the substance that makes up the rock 7. Water combines with chemicals such as weak acid to cause chemical weathering 8. Air pollution and living things can cause chemical weathering Erosion 1. Erosion is the process of moving weathered rock and soil by wind, water, and ice 2. Flowing water is main cause of erosion 3. Wind can also cause erosion Deposition 1. Deposition is the dropping of materials moved by erosion 2. Over time deposition may build new features such as: deltas, beaches, and dunes

5 Lesson 4 How Do Rocks Reveal Changes on the Earth? How Rocks Change Form 1. Rocks can be heated, compressed, cemented, twisted and even melted 2. These changes that rocks go through make up the rock cycle 3. Igneous rocks are rocks formed from melted mantle that comes from deep inside the earth when it cools the melted material hardens into igneous rock 4. Metamorphic rock is formed by the application of heat and or pressure to sedimentary rock or igneous rock 5. Sedimentary rock is formed by the pressing and the cementing of layers of sediments 6. Most rocks are made of one or more minerals 7. A mineral is a natural, nonliving solid with a definite chemical structure 8. Different minerals have different properties including: color, luster, hardness, magnetism, crystal pattern, and breakage pattern 9. The Mohs Hardness Scale measures the hardness of minerals Fossils That Indicate Changes 1. A river carries sediments into a shallow sea and deposits them on the bottom. Layers build up. 2. Dead animals sink to the bottom. Layer after layer of sediments are deposited on top. 3. Over time, the lower layers form sedimentary rock. The remains of the dead animals form fossils. 4. Fossils in rock layers tell about changes in the earth's climate and land features.