Name ________________ # ___ Changing Earth Study Guide I. Journey to the Center of the Earth (C14) a. The Earth has ____4_____ layers. b. Write the number of the definition to each vocabulary word. crust ___2___ 1. solid because of extreme pressure, the hottest layer mantle ___4___ 2. made of rock, the part scientists know the most about outer core __3____ 3. liquid rock, very, very hot inner core ___1___ 4. soft rock, like melted candy, this part sometimes reaches the Earth’s surface through volcanoes Label the layers of the Earth crust inner core mantle outer core II. Plate Tectonics (C15) a. The theory of Plate Tectonics states that the Earth’s crust is not a single piece, but is actually 12 large pieces called plates. b. Scientists believe that currents cause the plates to move across the Earth’s surface. c. A fault is a large crack in the Earth’s crust. This is where earthquakes can occur. d. There are three different types of boundaries between plates. They are named based on how they move. Convergent boundaries – when two plates collide (come together) Divergent boundaries – two plates moving in opposite directions Transform (sliding) boundaries – two plates are sliding past each other III. Volcanoes (C16-17) a. A volcano is any opening in the Earth’s crust that allows hot gases , rocks , and melted materials to pass through into the atmosphere . b. What two things cause rock to melt? Heat (high temperature) and pressure . c. Melted rock found INSIDE the volcano is called magma . d. When this melted rock reaches the surface, it is called lava . e. The opening in the Earth’s crust is called the volcanic vent . IV. Mountains, Volcanoes, and Earthquakes (C16-18) a. MOUNTAINS: The highest mountains form where continental plates collide. b. When continental and oceanic plates collide, the continental plate moves over the oceanic plate. The Cascades Mountains were formed this way. c. Some mountains form where pressure from movement at the boundaries push rock upward. This pressure forms at the middle of the plates. d. Sometimes plates pull apart and leave big gaps. Magma can bubble to the surface and cause mountains to form under the ocean. e. VOLCANOES: When plates collide, chains of volcanoes can form. f. Sometimes they form in the middle of plates when magma comes to the surface. g. EARTHQUAKES: caused by a sudden release of energy in the Earth’s crust. h. Plates can crush together, scrape past each other, or bend along boundaries. i. The places where the crust moves are called faults . j. An instrument called a seismograph is used to measure the magnitude of an earthquake. The numbers on the Richter Scale describe the magnitude of the earthquake. V. Changes to the Earth’s Surface (C6-11) a. Landforms are physical features on the Earth’s surface. They are constantly changing whether we realize it or not. b. Weathering is the process of changing rock into sediments . c. After the rock has been broken down into smaller pieces, erosion takes place, which moves the sediment to a new location. d. Finally, the sediment is deposited in a new location. We call this process deposition . River deltas are formed when sediment builds up at the mouth of a river. e. The chief agents of weathering and erosion are water , wind , and ice . f. Mass movement is the downhill movement of rock and soil because of gravity. Some examples of FAST changes are sink holes , mudslides , and landslides . An example of a SLOW change is creep . VI. How the Earth’s Surface Has Changed (C22-25) a. The Theory of Continental Drift suggests that the Earth’s continents have moved over the years. It suggests that about 225 million years ago, the Earth was one big super continent called Pangea . b. Fossils are traces and remains found in some rocks. c. Younger rock layers are found on top of older rock layers. d. Take the Grand Canyon for instance, the oldest rock layers would be found at the bottom of the canyon. e. Fossils are not actual remains of once living things, they are just traces left behind when dead plants and animals decay or dissolve .