Plate Tectonics Mrs. Ramsey 6th Science

Inside the Earth Composition of earth: Divided into three layers Crust: 5-100 km think. Thinnest layer Mantle- thicker than crust, contains most of earth’s mass. Core- makes up 1/3 of earths mass

Inside the earth Physical structure of the earth Lithosphere- outermost layer; made of crust and mantle Asthenosphere- plastic layer where lithosphere moves Mesosphere- strong lower part of mantle Outer core- liquid layer of earth’s core that surrounds inner core Inner core- solid and dense center of planet

Inside the earth Tectonic plates Think of lithosphere as “Giant jigsaw puzzle” Major tectonic plates 1. Pacific plate 2. North American plate 3. Cocos plate 4. Nazca plate 5. South American plate 6. African plate 7. Eurasion plate 8. Indian plate 9. Australian plate 10. Antarctic plate

Inside the Earth Some tectonic plates have both oceanic and continental crust. Look at pg 195 for reference. Answers about our earth’s core sometimes come from earthquakes. When a earthquake happens seismic waves are produced resulting in vibrations. Their speed depends on density and composition of what they are traveling through. Seismograph can measure seismic waves