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Transcript
Bell Work: 11/1/11 Please write the question, answer, and explain why you chose that answer (justify). Objectives • Differentiate among the characteristics of the earth’s three layers. (SPI 0707.7.4) • Recognize that lithospheric plates on the scale of continents and oceans continually move at rates of centimeters per year. (SPI 0707.7.5) Think, Pair, Share … Come up with an explanation to the following question, pair up with your elbow partner, & share: • How do we know so much about the mantle and the core? From our discussion… • How do we know so much about the mantle and the core? • Seismic waves, or vibrations produced from earthquakes, travel at different speeds through the Earth. Their speed depends on the density and composition of the material they pass through. • Traveling through a solid will go faster than through a liquid. Restless Continents • Look at pg. 400! • In the early 1900s, ___________ Wegener Alfred ___________ wrote about his hypothesis of continental ____________ ______. drift • Continental drift is the hypothesis that states that the _____________ continents once formed a single ______________, broke up, and landmass drifted to their present locations. • Continental drift also explained why __________ fossils of the same plant and animal species are found on continents that are on different sides of the Atlantic Ocean. Pangaea • Wegener thought that all of the present continents were once __________ joined in a single, huge continent called ______________. Pangaea • Pangaea is Greek for ______________. “all earth” You try it! Make Pangaea with the pieces of continents at your group. Challenging Question… Think, Pair, Share … • Based on what you know about tectonic plates, how would you prove Wegener’s theory to be true? Tracking Tectonic Plate Motion • Scientist use a system of satellites called global positioning system or GPS. • Radio signals are continuously beamed from satellites to GPS ground stations, which record the exact distance between the satellites and the ground stations. • Over time, these distances change slightly. • The movement is measured in centimeters per year. Events associated with movements of earth’s major plates: • • • • Sea-floor spreading Mountain building Earthquakes Volcanoes Sea-Floor Spreading • ____________ Mid-ocean __________, ridges or underwater mountain chains, are where Sea-floor spreading ____________ ___________ takes place. • Sea-floor spreading is the process by (or crust) which new oceanic Lithosphere ____________________ magma rises toward the forms as __________ surface and solidifies. • As ___________ tectonic __________ plates move away from each other, the sea floor spreads apart and magma fills the gap. Draw a picture of the sea floor spreading. Mountain Building • ______________ Mountains exist because tectonic plates are continually ______________ moving around and ___________ colliding with one another. • The Andes Mountains in South America formed where two tectonic plates converge or collide. • When tectonic plates undergo ________________ or ____________, tension they can compression form mountains in several ways. 3 types of mountains • Folded Mountains- form when rock layers are _______________ together and pushed squeezed ___________. upward Draw a picture • Example: Appalachian Mountains • Fault-Block Mountains- form when tectonic forces put ___________on the Earth’s crust tension causing large blocks of the Earth’s crust to_________ _________. drop down Draw a picture pg. 413 • Example: Tetons in Wyoming • Volcanic Mountains- form when _________ magma rises to the Earth’s surface and erupts. • Most of the world’s major volcanic mountains are located at convergent boundaries where oceanic crust sinks into the asthenosphere at subduction zones • Example: Mount St. Helens Draw a picture Earthquakes • The study of earthquakes is called ________________. seismology • Most earthquakes take place near the edges of __________ tectonic ___________. plates • As tectonic plates push, pull, or slip past each other, stress increases along breaks in the Earth’s crust, or ___________. faults • In response to this stress, rock in the plates _______________. deforms Elastic _______________ deformation leads to earthquakes. • __________ • It’s like a stretched rubber band, you can only stretch rock so far before it breaks. When the energy rock breaks, it releases ________________. • This energy is released in the form of seismic waves. Volcanoes • Tectonic plate boundaries are likely places for _____________ volcanoes to form. • ________ _____ which are The _________ Ring of _________, Fire plate boundaries surrounding the Pacific Ocean, contains nearly 75% _____ of the world’s active volcanoes. • About _____ 80% of active volcanoes on land form where plates ______________, and about collide 15% form where plates ____________. separate ______ • At these plate boundaries it is possible for _____________ to form and travel to the magma surface. Draw a picture of both types of volcano formations. Use pages 464-465. Let’s Review… 3-2-1 Reflection • 3 things that I learned… • 2 questions I have… • 1 way I can relate today’s lesson to my daily life…