What is it? And what makes it work?

 Our Earth  Not a solid ball of rock  Composed of distinct layers  Three main layers based on composition:  Crust  Mantle  Core  The lightest materials make up the outer layers.  The densest materials make up the inner layers.

 Outermost layer of the Earth.  Two types of crust  Continental  Less dense than oceanic crust.  Contains the Earth’s continents.  Oceanic  Found primarily under the ocean.  Most dense type of crust.

 Layer between the crust and the core.  Flows very slowly.

 The innermost part of the earth.  Very dense.  Composed of iron and nickel.  About the size of the planet Mars.

 Outermost rigid layer.  Made of 2 parts: the crust and rigid upper part of the mantle.  Divided into pieces called tectonic plates.

 There are approximately 30 plates on the Earth’s surface.  The plates move on a layer of rock that is so hot it flows, even though it remains solid.  The plates are moving at speeds up to 10 cm per year.

 The force responsible for plate movement.

 Divergent Boundary – move _____  Convergent Boundary – move _____________  Transform Fault Boundary – move ___________________ apart together (collide) sideways past each other

 Places where two plates move apart or diverge.  Divergent boundaries of two continental plates creates a ________.  Example: Great Rift Valley of Africa  Divergent boundaries of two oceanic plates creates a _____.  Example: Mid-Atlantic Ridge rift valley ridge (sea-floor spreading)

 Places where two plates come together, or converge.  Convergent boundaries of two continental plates creates _________.  Example: Himalaya Mountains  Convergent boundaries between a continental plate and an oceanic plate forms a __________________ and a ______.  This process is called ___________.  Example: Coast of Chile mountains trench subduction volcanic mountain range

 Convergent boundaries of two oceanic plates creates ________ and a _____.  Example: Islands of Japan island arc trench

 Places where two plates slip past each other, moving in opposite directions.  Example: San Andreas Fault in California

 Places where plates move apart are called ________ boundaries.  When continental plates diverge a ________ is formed.  When two oceanic plates converge a ___________________ is formed.  The force moving the plates is _________.  ________ is the process where a denser ______ plate slides under a ________ plate. divergent rift valley an island arc and a trench convection Subduction ocean continent