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Dive into the world of plate tectonics and explore the driving force behind Earth's dynamic movements. Learn about convection currents in the mantle and how they influence plate motions at different boundaries. Unravel the mysteries of divergent, convergent, and transform boundaries through engaging animations and demonstrations. Discover the connections between plate movements, seismic activity, and landform creation. Unveil the secrets of continental drift and sea-floor spreading in this interactive science lesson.
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Welcome to Science 9/20 • Get out your lab and your Ch. 7 Section 3 Notes and on your small paper answer the following question: • What do you think is the driving force that causes the Earth’s tectonic plates to move? • Today’s Schedule • 1. Ch. 7 Section 3 Notes/Discussion • 2. Review Sea-Floor Spreading Lab
What We Want To Know • What causes the plates to move? • THE answer to this question we believe is: convection currents in the mantle. • animation
Convection • Convection- heat transfer by the movement of currents within a fluid • Caused by differences of temp. and density within the fluid
Convection Currents in Earth • 1. What is the heat source? • 2. What is flowing? • Heat from the core and the mantle itself causes convection currents in the mantle. • Google Image Result for http://www.windows.ucar.edu/earth/interior/e_thermal_history_animated.gif
Convection Currents in the Earth • Animation • As the convection currents move through the mantle, it causes the plates to move in the lithosphere.
What do you see here? • Plate Boundaries
Plate Boundaries • Divergent Boundary- place where 2 plates move apart or diverge. • Most DB’s are at mid-ocean ridges. • On land DB’s form deep valleys called rift valleys • Fig. 19.21 - Evolution of a Divergent Plate Boundary • animation
Convergent Boundary • Place where 2 plates come together, or converge. • Oceanic plate + Continental plate = subduction • Continental plate + Continental plate =mountains • OptIPuter Outreach
Subduction at Trenches • Deep-ocean trench- underwater canyon where ocean crust sinks into the mantle. • Subduction- process by which ocean crust sinks beneath a deep-ocean trench and back into the mantle • Subduction Animation - Earthguide Online Classroom
Transform Boundary • Place where two plates slip past each other in opposite directions. • Transform Boundaries = Earthquakes • Observe animations of processes that occur along plate boundaries. • animation
land masses have slowly moved over time Plates move on top of asthenosphere Two plates slip past each other in opposite directions Happens at divergent boundaries, allows magma to rise to the ocean floor Two plates collide with each other Two plates separate with each other Convergent boundary Sea-floor spreading Plate tectonics Continental drift Divergent boundary Transform boundary Matching Game
Ch. 7 Section 3 The Theory of Plate Tectonics Things you should know: what plates are, directions plates move, and some landforms that plate movement creates. Now, you need to figure out what causes the plates to move. Observe these demonstrations to discover the answer.