Inside the Earth - Pages 190-193 Chapter 7 Section 1 Inside the Earth - Pages 190-193

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Layers of the Earth Brown Blue

A. Composition of the Earth 1. The Earth is divided into 3 layers: -Crust -Mantle -Core 2. The Crust and Mantle are made of less dense compound. 3. The Core is more dense than the crust and mantle.

B. CRUST The outermost layer 5-100 km thick Thinnest layer 2 types of crust: Continental (land)- thick and Oceanic (under the ocean)-thin

C. MANTLE 2900 km thick Between the crust and core Thick Contains most of Earth’s mass Scientists study the mantle by looking at the composition of magma. Magma from volcanoes gives scientists clues about the composition of the mantle.

D. CORE Innermost layer Made mostly of iron and nickel Inner core solid Outer core liquid Core

E. Physical Properties of Earth Lithosphere Asthenosphere Mesosphere Outer Core Inner Core

F. Lithosphere Outermost layer of Earth Made of crust and upper mantle Divided into pieces called tectonic plates.

What are tectonic plates? 1. The Earth’s lithosphere, crust and upper mantle ,are divided into pieces called tectonic plates. 2. Think of the lithosphere like a jigsaw puzzle. 3. Each of the plates is a piece of the puzzle. 4. These plates move causing earthquakes, mountain building, seafloor spreading and volcanoes.

Tectonic Plates

G. Asthenosphere Layer below Lithosphere Pieces of lithosphere (tectonic plates) move along this layer. Made of solid rock, soft layer of the mantle Solid that acts like a liquid due to pressure and temperature.

Why is the asthenosphere considered “plastic”? Because it is very hot, and made of partially molten rock, it bends and can be pushed and deformed due to the pressure placed on it from deep within the Earth.

H. Mesosphere Below the asthenosphere Strong lower part of mantle Extends to the Earth’s core

I. Outer Core Liquid layer of Earth’s core Surrounds inner core

J. Inner Core Solid dense center

Convection Currents Cause plates to move very hot material in the mantle rising, then cooling, sinking again and then heating, rising and repeating the cycle over and over.

Earth’s Magnetic Field Magnets are simple examples of natural magnetic fields. Believe it or not, the Earth has a huge magnetic field. Because the core of our planet is filled with molten iron (Fe), there is a large field that protects the Earth from space radiation and particles such as the solar wind. When you look at tiny magnets, they are working in a similar way. The magnet has a field around it.

Earth’s Magnetic Field- Protection from Solar Radiation

Earth’s Magnetic Field- North and South Poles As mentioned earlier, the Earth is like a giant magnet because of its large iron content.  It has a north pole and a south pole.  This giant magnet is what makes a compass work.  No matter where you turn it, the needle of a compass will ALWAYS point to the north. https://www.youtube.com/watch?v=lxWBlJ1kB7Q

Quiz 1. Name the three main layers of the Earth. 2. Which layer is the most dense? 3. Which layer is the thinnest? 4. What are the two types of crust? 5. Which layer contains most of Earth’s mass? 6. What two layers make up the lithosphere? 7. The lithosphere is divided into pieces called: 8. Pieces of lithosphere move on top of this layer: 9. The Asthenosphere is said to be “plastic”. What does this mean? 10. Which layer, inner core or outer core, is liquid? 11. Which layer, the inner core or the outer core, is solid?

Answers 1.Crust, mantle and core 2. Core 3. Crust 4. Continental and oceanic 5. Mantle 6. Crust and upper mantle 7. Tectonic Plates 8. Asthenosphere 9. Because it is very hot and made of partially molten rock it bends and can be pushed and deformed due to the pressure placed on it from deep within the Earth. 10. Outer core 11. Inner core