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BCLN Science 7 - Rev. Sept/2015 Unit 8 ~ Learning Guide Name: ______________________________ Instructions: Using a pencil, complete the following notes as you work through the related lessons. Show ALL work as is explained in the lessons. You are required to have this package completed BEFORE you write your unit test. Do your best and ask questions if you don’t understand anything! Earth's Layers Questions 1. Create a labelled diagram showing the 4 layers of the earth (crust, mantle, outer core, inner core). Label the layers then write two pieces of information about each layer. Four Layers of the Earth Information About Each layer Crust: 1. 2. Mantle: 1. 2. Outer Core: 1. 2. Inner Core: 1. 2. 2. What is the temperature range and depth for each part of the four layers of the Earth? The first one is done for you. Earth's Layers Crust Mantle Outer Core Inner Core Depth (km) (kilometers) 0-40 Temperature Range C (degrees Celsius) 0-870 BCLN Science 7 - Rev. Sept/2015 3. What two different plates float on the Earth's mantle? Pangaea Questions 1. What is plate tectonic theory and how does it relate to a jigsaw puzzle? 2. Watch the "Continental Drift" video Complete the table with the 4 different continental drift eras (time periods) and their land masses. The first one is done for you. Continental Drift Land Masses Pangaea Continental Drift Eras 225 Million years Ago 3. Identify and explain the four pieces of evidence that support the theory of "Continental Drift". Evidence 1: Evidence 2: Explanation 1: __________________________________ Explanation 2: __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ Evidence 3: Evidence 4: Explanation 3: __________________________________ Explanation 4: __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ __________________________________ BCLN Science 7 - Rev. Sept/2015 Plate Tectonics Questions 1. What startling discovery did the seismometers after World War II show scientists? 2. What are the two different parts of the Earth's crust called and how are they different? 3. Name the different tectonic plates. BCLN Science 7 - Rev. Sept/2015 4. What new evidence have scientists discovered that supports plate tectonic theory? Complete the questions in the diagram below. What new evidence did scientists find by mapping the ocean floor? _________________________________ What new evidence did scientists find by studying the ages of the rocks on the ocean floor? _________________________________ _________________________________ _________________________________ _________________________________ _________________________________ _________________________________ _________________________________ What new evidence did scientists find by studying the Earth’s magnetic fields? _________________________________ What new evidence did scientists find by studying the locations of earthquakes and volcanoes? _________________________________ _________________________________ _________________________________ _________________________________ _________________________________ _________________________________ _________________________________ 5. What instrument do scientists use to measure the movement of tectonic plates? How much do the plates move each year? BCLN Science 7 - Rev. Sept/2015 Answer Key Earth's Layers Answers: 1. Four Layers of the Earth Information About Each layer Crust: Thin layer of solid rock, Broken into may parts called plates Mantle: Largest layer on the earth, mostly solid rock but has some melted material at the bottom Outer Core: Allot of pressure, temperature over 4000 degrees, liquid and flows like the bottom of the mantle, liquid iron and nickel Inner Core: Hot as surface of the sun, more pressure, may be made of iron and nickel 2. Depth (km) Temperature Range C (kilometers) (degrees Celsius) Crust 0-40 0-870 Mantle 40-2700 870-3700 Outer Core 2890-5150 3700-4300 Inner Core 5150-6378 43007200 3. The plates on the Earth's crust are divided up into Oceanic Plates and Continental Plates. Earth's Layers Pangaea Answers: 1. Plate tectonic theory is the idea that there used to be one singular land mass and slowly over time the land separated into different continents. Our current continents and land masses look like they fit together like a jig saw puzzle. 2. Continental Drift Land Masses Pangaea Laurasia, Gondwanaland North America, South America, Eurasia, Africa, India, Antarctica, Australia North America, South America, Africa, India, Antarctica, Australia Continental Drift Eras 225 million years ago 135 million years ago 65 million years ago Present BCLN Science 7 - Rev. Sept/2015 3. Evidence 1: Shape of continents Explanation 1: The shapes of the continents would fit together like pieces of a puzzle if they were cut out. Evidence 3:Landforms Explanation 3: Mountains in eastern North America are made of the same rock as a mountain range in Britain and Norway. Mountain ranges in South Africa line up with mountains in Argentina. Evidence 2: Fossils Explanation 2: Paleontologists had found that there were fossils of similar species found on continents that are now separated by great geographic distance. These organisms couldn't have travelled the long distance between these continents, supporting his theory that they were once joined. Evidence 4: Ice Age Explanation 4: Scientists found identical marks caused by the movement of glaciers along the coasts of Africa and South America. It was also found that glaciers covered large areas of the world which also are now separated by great geographic distances. Plate Tectonics Answers: 1. 2. The seismometers showed scientists that that earthquakes, volcanoes, and other active geologic features for the most part aligned along distinct belts around the world, and those belts defined the edges of tectonic plates. This supported the theory of plate tectonics, which suggests that the surface of the Earth is made up of about a dozen large plates that are continually moving. Oceanic Crust (ocean floor) and Continental Crust (contents) 3. South American Plate North American Plate Caribbean Plate Juan de Fuca Plate Cocos Plate African Plate Eurasian Plate Arabian Plate Philippine Plate Pacific Plate Indian Australian Plate Antarctic Plate Scotia Plate BCLN Science 7 - Rev. Sept/2015 4. What new evidence did scientists find by mapping the ocean floor? -They found that the Earth’s longest mountain range underwater! -Mountains and valleys mark the edge of a plate where the Earth’s crustal plates are moving apart Scientists also found evidence of long, narrow, deep depressions in the sea floor called trenches. Many trenches are found around the edges of the Pacific Ocean plate. What new evidence did scientists find by studying the Earth’s magnetic fields? -Further paleomagnetic studies revealed a striped pattern of magnetic reversals in the crust of the ocean basins -the lava from spreading centers in the oceans forms and cools, these minerals align to the north pole -the Earth has undergone several magnetic reversals in the past, in which the north and south poles are reversed for a period of time -geologists and geophysicists discovered that the crust in the ocean recorded these reversals, it was even more positive proof that the lithosphere had to be in motion, otherwise there would be no "stripes" of normal and reversed polarity crust. 5. What new evidence did scientists find by studying the ages of the rocks on the ocean floor? -thin crust and low amounts of sediment make parts of the ocean floor seem very young compared to other parts of the Earth's crust -if it was older the layers of sediment would have been much thicker What new evidence did scientists find by studying the locations of earthquakes and volcanoes? -It revealed earthquakes, volcanoes, and other active geologic features for the most part aligned along distinct belts around the world, and those belts defined the edges of tectonic plates Scientists use satellites to track the movement of the tectonic plates. They have found the plates move anywhere from 1 to 12 centimeters per year.