Earth’s Interior Layers © Copyright 2006.  M. J. Krech. All rights reserved. http://oceansjsu.com/images/exp5_interior_earth.gif

The Four Layers http://mail.colonial.net/~hkaiter/Aaa_web_images2012/earth.gif

How do scientists know and learn about Earth’s interior? Direct Evidence rock samples and lava **Indirect Evidence seismic waves https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTLDhFLpi-Kiopnlw3qPlm7Wscho1PypijQROBDtY7tXf8V9D-r http://www.iris.edu/hq/files/programs/education_and_outreach/lessons_and_resources/images/ExplorEarthPoster.jpg

The Crust *like the skin of an apple - very thin in comparison to other layers * only about 3-5 miles (8 kilometers) thick under oceans (oceanic crust) * about 25 miles (32 kilometers) thick under the continents (continental crust). http://www.enchantedlearning.com/egifs/Earthscrust.GIF

The Crust composed of two main types of rock https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcSizQbYp-vEQH7vQ7eQi09Xg1SB39nSJN2Y37SZAlGseRviKKyS composed of two main types of rock continental crust is mostly granite & oceanic crust is basalt basalt is much denser than the granite less dense continents ride on the denser oceanic plates.

Lithosphere crust and the upper layer of the mantle together make up this zone of rigid, brittle, solid rock https://nees.org/site/images/stories/Figure_2.jpg

The Lithospheric Plates https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQKjW9bHa-P4K4HmO5Z7n3mtFuHs-KRCJoQFlJyGYIfjwlFrbVHtg The crust of the Earth is broken into many pieces called tectonic plates. These plates "float" on the asthenosphere.

Scientists think that movement here is the reason tectonic plates move Asthenosphere semi-rigid part of the middle mantle that flows like hot asphalt or plastic Scientists think that movement here is the reason tectonic plates move http://www.gly.uga.edu/railsback/1121CrMaLiAsthenosphere.jpeg

The Mantle largest layer of the Earth composed of very hot dense rock that is capable of flow like asphalt under a heavy weight The movement of the middle mantle (asthenosphere) is the reason that the tectonics plates of the Earth move. http://www.classroomatsea.net/general_science/images/upper_structure.jpg

Convection Currents What is convection? Where is the heat source? http://study.com/cimages/videopreview/videopreview-small/screen_shot_2013-02-03_at_8.03.47_am_106385.jpg https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcT-GzyGr9eL_0rgreNgkqrRww7U7_j6ZN568Gilea5LPWHKoUkwx3iKtXQ Asthenosphere "flows" because of convection currents. What is convection? Where is the heat source?

The Outer Core ball of very hot metals http://science.howstuffworks.com/environmental/29143-100-greatest-discoveries-earths-magnetic-field-video.htm ball of very hot metals so hot that the metals in it are all in the liquid state The outer core is composed mainly of liquid nickel and iron. http://www.isaveearth.org/earthinterior1.jpg Scientists think that spinning movement in the liquid outer core is the reason for Earth’s magnetic field.

The Inner Core temperatures and pressures so great that metals are squeezed together and are not able to move about like a liquid, but are forced to vibrate in place like a solid. http://academic.evergreen.edu/g/grossmaz/temp.jpeg

Earth's Interior Interactive Click the links below for more about Earth’s Interior and plate tectonics! Earth's Interior Interactive Earth's Interior Rap :) Bill Nye video clip (12 min) http://www.amnh.org/ology/features/stufftodo_earth/images/ediblelayers.gif