Chapter 15, Section 1: Inside the Earth What we are going to learn: 1. Identify the layers of the Earth by their chemical composition. 2. Identify the layers of the Earth by their physical properties. 3. Describe a tectonic plate. 4. Explain how scientists know about the structure of Earth’s interior.

Three Layers of the Earth  The Crust is the outermost layer km thick but is the thinnest layer.  The Mantle is the layer between the crust and the core. This is where magma is found.  The Core is the center part of the Earth and is made of two parts, inner core and outer core.

Outer Part of the Earth  The Crust is where we live.  Next is the Lithosphere. Made from the crust and the hard outer part of the mantle.  Next is the Asthenosphere. This is the soft layer of the mantle where the lithosphere “floats”.

Middle Earth  The Mesophere is the strong lower part of the mantle between the asthensophere and the core.  The Outer Core is the outer part of the core and is liquid.  The Inner Core is the most center part of the Earth and is made from solid iron.

How do we know for sure what’s under us???  How can we know what each part is made from if we haven’t been there?  Scientists use vibrations called Seismic Waves created during earthquakes to determine thickness and composition.  Waves move through solid and liquid material at different speeds.

Tectonic Plates  The lithosphere is divided into puzzle like pieces called Tectonic Plates.  On the edge of these plates we get mountains, earthquakes, volcanoes, and sea floor spreading.

Convergent Boundaries  A Convergent Boundary is formed when two plates collide with one another.  This can be two contiential plates, two ocean plates, or one contiential plate with an ocean plate.

Divergent and Transform Boundaries  A Divergent Boundary is where two tectonic plates are moving away from one another.  A Transform Boundary is where two plates are sliding horizontally or beside one another.

Sea Floor Spreading  At divergent boundaries in the ocean magma is pushed up and new ocean crust is formed pushing the old crust outward.  This process is constantly making new ocean crust.

Deforming the Earth’s Crust  Deformation – when the shape of a rock changes due to stress.  Tension stress- pulling apart.  Compression stress- pushing together.

Folding Rocks  Folding – the bending of rock layers due to stress.  Types of folds….

Faults in Rocks  Fault – is a break in a body of rock where one side moves against the other side.  Types of faults…

Mountain Building  Folding and faulting can build mountains  Types of mountains… Folded Mountains

Mountain Building  Fault- Block Mountains

Mountain Building  Volcanic Mountains

Uplift  Uplift – the rising of regions of the Earth’s crust to higher elevations.

Subsidence  Subsidence – the sinking of regions of the Earth’s crust to lower elevations.