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What Are Earths Layers Unit D, Chapter 1, Lesson 1, pD6-11.

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Presentation on theme: "What Are Earths Layers Unit D, Chapter 1, Lesson 1, pD6-11."— Presentation transcript:

1 What Are Earths Layers Unit D, Chapter 1, Lesson 1, pD6-11

2 Earths Layers Where does information about Earths structure come from? – Drills Samples taken from first km – Hypothesis Patterns of earthquake waves traveling through Earth Materials that come out of active volcanoes

3 Seismic Waves Pattern in Earth with no layers

4 Pattern of Seismic Waves in Earth with layers

5 Earths Layers Crust: Earths outermost layer – Continental crust made of granite Less dense – Oceanic crust made of basalt More dense Mantle: layer directly below the crust – 1600°C at the top and 4000°C at the bottom Hot enough to melt rock – Solid rock Intense pressure pushes rock into a solid Only upper mantle is partly melted

6 Earths Layers Core: innermost layer – Outer core Hot, liquid iron and nickel – Inner core Hotter than 5500°C – Hot enough to melt metal Solid iron – Intense pressure pushes metal into a solid

7 Earths Layers Zones – Lithosphere Includes all crust and part of upper mantle Cool, solid part of Earth – Lithos- Greek for stone – Asthenosphere Part of the upper mantle Partly melted rock in upper mantle – Asthenes- Greek for weak

8 Earths Plates 7 major lithospheric plates – Float on asthenosphere – partly melted rock Plasticity: it can flow (like silly putty) Convection currents in asthenosphere caused by heat from Earths center – Hot mantle Less dense hot mantle pushed up by more dense cooler rock – Hot rock spreads out & cools – Cooler, more dense rock sinks Lithospheric plates move asthenosphere flows – Plates constantly move – A few centimeters each year Lithospheric plates constantly change in shape and size – Plates slit across new lines – Combine with other plates – Slide under another plate to become mantle rock again Earthquakes and volcanoes usually found at plate boundaries

9 Earths Plates Major plates names after continents or oceans they carry – North American Plate: North America & Atlantic Ocean – South American Plate: South America & Atlantic Ocean – Australian-Indian Plate: Australia, India, & Indian Ocean – Antarctic Plate: Antarctica & Pacific, Atlantic, & Indian Oceans – Pacific Plate: Pacific Ocean – African Plate: Africa & Atlantic & Indian Oceans – Eurasian Plate: Europe & Asia & Atlantic Ocean

10 Earths Plates Plate tectonics: theory scientists use to explain plate movements – Tectonics Greek word meaning builder Plate movements build Earths largest landforms – Plates move, break apart, collide

11 Earths Plates Most plates contain both oceanic and continental crust – Oceanic crust Newer, thinner, under oceans – Continental crust Older, thicker, land

12 Changes to Earths Surface Earths surface is constantly being changed – Movement of plates Move continents around the globe – Form mountains – Causing earthquakes & volcanic eruptions – Erosion and deposition Water and wind erosion carve out valleys, cliffs, and caves Rivers deposit sand and rock on its banks & at mouth Wind picks up sand and deposits it on dunes

13 Changes to Earths Surface Earths surface is constantly being changed – Glaciers Erodes land and deposits rock, sand, and mud – Rocks & pebbles pulled by glacier act like sandpaper » Gravity pulls glacier downhill – Glaciers melt and deposit material » Form ridges, hills, gravel-covered plains – Objects from space Meteoroids – chunks of rock moving through solar system – Enter Earths atmosphere – Friction causes it to heat-up & burn » Meteor = streak of light, shooting star » Meteorite = meteoroid that hits the ground » Most too small to notice Comets & asteroids

14 Summary Earth is composed of inner core, outer core, mantle, & crust – Lithosphere = crust + part of upper mantle Theory of plate tectonics explains how lithospheric plates move causing changes to Earths surface Other changes to Earths surface caused by: – Wind & water – Glaciers – Space objects that hit Earth

15 Homework Read Unit D, Chapter 1, Lesson 1, pD6-11 Answer ?s on Google form

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