Earth's Interior Summarize the three layers of Earth- crust, mantle, core- on the basis of relative position, density, and composition.

Objectives: 1.What do geologists do? What are the characteristics of Earth's crust, mantle, and core? geologists- scientists study forces that make and shape Earth. chemical/ physical makeup of rocks map location of types of rock on Earth describe landforms search for clues about Earth's history Earth looks very different today!

Constructive forces- shape surface by building mountains Destructive forces- wear away mountains and landmasses (wind, water- ocean waves) 200 years ago- what geologists knew: Earth is a sphere 6,000 km radius 7 continents made up of rock

What's inside the Earth? deepest mine in the world 3.8 kilometers (6,000 km to center of Earth) Indirect method to find out Earth's interior Seismic waves- waves of energy produces by Earthquakes. Geologists study: 1. how the waves travel 2. speed of the seismic waves 3. paths that the waves take ** determined that Earth's interior is made up of many layers

Journey to the Center of the Earth! Temperature surface rock cool, 20 meters down it is warmer After 40 meters decent, 1°C increase Pressure- force per unit of area force pushing on a surface or area weight & pressure of rock increases as descend

Crust, Mantle, Core Crust- "outer skin" 5 to 40 km thick Basalt- dark, dense rock under oceans, fine texture Granite- less dense continental rock, coarse texture

Mantle- lithosphere- "lithos" Greek for stone layer of mantle that is solid rock 100 km thick asthenosphere- Greek for weak soft flowing rock rock bends like plastic due to high heat and pressure lithosphere floats on top of asthenosphere mantle is 3 000 km thick

Core- outer core- molten iron and nickel, behaves like thick liquid inner core- extreme pressure forms solid iron and nickel inner and outer core slightly smaller than the moon! 1/3 Earth's mass Earth's Magnetic Field iron and nickel very magnetic- responsible for producing Earth's magnetic field

Middle layer, thickest layer; top portion called the lithosphere Position Density Composition Crust Outermost layer, thinnest under the ocean, thickest under the continents; crust and top of mantle called the lithosphere Least dense layer overall; oceanic crust=dense basalt, continental crust=less dense granite Solid rock Mantle Middle layer, thickest layer; top portion called the lithosphere Density increases with depth because of increasing pressure Hot softened rock; contains iron & magnesium Core Inner layer; consists of two parts- outer core & inner core Heaviest material; most dense layer Mostly iron & nickel; outer core- slow flowing liquid, inner core- solid