Grade 8 Earth's Moving Surface PDF

Grade 8 Earth's Moving Surface Chapter 3 Section 1 Instructions - Copy the notes into your notebook. - Leave a line or two in between each entry in case you want to add something later. - Answer all review questions in your notebook, you may need to refer to your textbook for some questions...

Grade 8 Earth's Moving Surface Chapter 3 Section 1 Instructions - Copy the notes into your notebook. - Leave a line or two in between each entry in case you want to add something later. - Answer all review questions in your notebook, you may need to refer to your textbook for some questions. - Watch all videos, there is important information in each one. You do not need to take notes on them but feel free to write down of interesting info. (Hint: You may change the speed while viewing or watch more than once) Some videos will be labeled “optional”. Essential Questions What is the theory of plate tectonics? What are the differences between divergent, convergent, and transform plate boundaries? What causes tectonic plates to move on Earth's surface? Earth’s Moving Surface The theory of plate tectonics states that Earth’s surface is broken into large, rigid pieces that move with respect to each other. Earth’s Moving Surface The pieces of Earth’s surface, called tectonic plates, move over Earth’s surface very slowly. Earth’s Moving Surface The motion of tectonic plates forms volcanoes and mountains and causes earthquakes. Earth’s Moving Surface Earth’s outermost layer is called the crust. Earth’s Moving Surface The crust and the uppermost part of the mantle make up the lithosphere. Earth’s Moving Surface The partially melted portion of the mantle below the lithosphere is the asthenosphere. Earth’s Moving Surface The asthenosphere can bend more easily than the lithosphere because it is hotter than the lithosphere. Earth’s Moving Surface Earth has 15 large tectonic plates, plus many smaller plates Earth’s Moving Surface Oceans completely cover some plates, but others are made of oceanic crust and continental crust. Plate Boundaries Scientists describe the movement of a tectonic plate as relative motion—how it moves in relation to another plate. Plate Boundaries The type of boundary between plates depends on the relative motion of the plates. Plate Boundaries A divergent boundary is a boundary where two plates move away from each other. Plate Boundaries As plates move apart, new crust forms between them Plate Boundaries A(n) convergent boundary is a boundary where two plates move toward each other. Plate Boundaries A(n) convergent boundary is a boundary where two plates move toward each other. Plate Boundaries The process that occurs when one tectonic plate moves under another tectonic plate is called subduction. Plate Boundaries A(n) transform boundary is a boundary where two plates slide past each other. Measuring Movement Tectonic plates move so slowly that geologists could not measure their movement until the mid-twentieth century. Measuring Movement New technology has determined that North America and Europe are separating from each other at an average rate of just 2.5 cm/y. Measuring Movement The network of satellites known as the Global Positioning System (GPS) can be used to accurately measure the position of any point on Earth’s surface. Measuring Movement Scientists can measure the speed and direction of plate movement by tracking tectonic plate positions over several years. Measuring Movement About 200 million years ago, North America and Europe were part of a large continent called Pangaea; when the plates moved apart, the Atlantic Ocean formed between the continents. Why Do Tectonic Plates Move? The amount of matter per unit of volume is called density. Why Do Tectonic Plates Move? When a fluid is heated, its molecules spread out and it becomes less dense. Why Do Tectonic Plates Move? When fluids heat unevenly, the warmer, less-dense fluid rises, and the cooler, denser fluid sinks. Why Do Tectonic Plates Move? Convection is the circulation within fluids caused by differences in density and thermal energy Why Do Tectonic Plates Move? Convection in the mantle can drag plates over Earth’s surface Why Do Tectonic Plates Move? Plates can also move as a result of subduction Why Do Tectonic Plates Move? When two plates collide, one can subduct or sink into the hotter, less-dense mantle. Alaska 1964 Why Do Tectonic Plates Move? The sinking part of a(n) plate pulls the rest of the plate along. Review Questions 1. What is the theory of plate tectonics? 2. What is a tectonic plate? 3. Name and describe the three types of plate boundaries. 4. What causes tectonic plate movement? The End