Warm-up: If you journeyed to the center of the Earth, what do you think you would observe along the way? Draw an illustration of your journey in your science journal.

Ch. 7 Plate Tectonics This is a satellite image of the San Francisco Bay area. The row of lakes below marks the line of the San Andreas fault, a crack in Earth's crust. (New Theory)

Standard S6E5.a – Compare and contrast the Earth’s crust, mantle, and core including temperature, density, and composition. (p ) Essential Questions How do scientists know what’s inside the Earth? How do the layers change as you descend into the Earth? Why is there a magnetic field around the Earth? S6E5.a – Compare and contrast the Earth’s crust, mantle, and core including temperature, density, and composition. (p ) Essential Questions How do scientists know what’s inside the Earth? How do the layers change as you descend into the Earth? Why is there a magnetic field around the Earth?

What You Will Learn Identify the layers of the Earth by their chemical composition & physical properties. Explain how scientists know about the structure of Earth’s interior. Identify the layers of the Earth by their chemical composition & physical properties. Explain how scientists know about the structure of Earth’s interior.

7.1 Inside of the Earth Discover Activity Canisters with different items What is inside? Guess what is inside by shaking, rolling, etc Discuss with your team and jot observations on paper. Do not open until told to do so.

Finding Indirect Evidence Geologists use an indirect method of studying Earth’s interior. Hanging a picture on a wall Geologists use seismic waves.

Finding Indirect Evidence Seismic waves - A vibration that travels through Earth carrying the energy released during an earthquake. Seismographs measure seismic waves which can tell the distance and travel times to calculate the density & thickness of each physical layer.

A Journey to the Center of the Earth Book written in 1864 Scientists knew nothing at that time. Was the Earth hot, cold, solid, or hollow?

A Journey to the Center of the Earth You would need a vehicle that could travel through solid rock. The vehicle would carry scientific instruments to record changes in temperature and pressure as you descend toward the center of Earth. You would need a vehicle that could travel through solid rock. The vehicle would carry scientific instruments to record changes in temperature and pressure as you descend toward the center of Earth.

Temperature As you start to tunnel beneath the surface, you might expect the rock around you to be cool. At first, the surrounding rock is cool. At 20 meters…getting warmer Every 40 meters…goes up 1 degree Celcius. As you start to tunnel beneath the surface, you might expect the rock around you to be cool. At first, the surrounding rock is cool. At 20 meters…getting warmer Every 40 meters…goes up 1 degree Celcius.

Pressure During your journey to the center of Earth, your instruments also record an increase in pressure in the surrounding rock. The deeper you go, the greater the pressure. Why do you think this is the case? During your journey to the center of Earth, your instruments also record an increase in pressure in the surrounding rock. The deeper you go, the greater the pressure. Why do you think this is the case?

Inside the Earth Scientists think about the physical layers in two ways: Chemical composition Physical properties Scientists think about the physical layers in two ways: Chemical composition Physical properties

The Chemical Composition Three main layers make up Earth's interior: the crust, the mantle, and the core.

The Crust Outermost layer of the Earth km thick Less than 1% of Earth’s mass Temp – degree C Thinnest layer like an onion Two types Continental crust Oceanic crust

The Crust Both types are made of: Oxygen - O Silicon – Si Aluminum – Al

The Crust The oceanic crust is denser and has twice as much: Iron – Fe Calcium – Ca Magnesium - Mg

The Crust Oceanic crust is made up of mostly basalt (A). Basalt is dark, dense, and has a fine texture. Continental crust is mainly made up of granite (B). Granite forms continents, is less dense, large crystals, light colored, and coarse- grained.

The Mantle Between the crust and core Never been visited. Volcanoes on the surface and underwater observations have given scientists many clues on the composition. Some material gets pushed up to the surface, allows direct observation of rock composition

The Mantle 67%of Earth’s mass 2900 km thick Denser than crust due to magnesium content Temperatures degrees Celsius

The Core The Earth’s core consists of two parts - a liquid outer core and a solid inner core. Iron and nickel (metals) make up both parts of the core. Makes up 1/3 of Earth’s mass.

The Core Radius of 3,430 km Temperatures in the core range from 3, degrees Celsius It is as hot as the sun’s surface!

The Physical Structure of the Earth Divided into five layers Lithosphere Asthenosphere Mesosphere Outer Core Inner Core

Lithosphere The outermost, rigid layer of the Earth. Made of two parts Crust and upper part of mantle Divided into tectonic plates

Asthenosphere Plastic layer of the mantle on which pieces of the lithosphere move. Made of solid rock that flows very slowly.

Mesosphere Strong, lower part of the mantle. Extends from the bottom of the asthenosphere to the Earth’s core

Outer Core The Earth’s core is divided into two parts: Outer core - liquid Inner core

Inner Core Solid, dense center of our planet that extends from the bottom of the outer core to the center of Earth, which is about 6, 380 km.

Earth’s Magnetic Field Currents in the liquid outer core force the solid inner core to spin at a slightly faster rate than the rest of the planet. These currents in the outer core also create Earth's magnetic field, which causes the planet to act like a giant bar magnet.

Earth’s Magnetic Field

This concept is important because it is yet another way scientists gather information about Earth’s history. Since the magnetic field is present, it helps people navigate around the world and find their way back home. Later in the unit, we will discuss how the magnetic field serves as evidence for sea- floor spreading. This concept is important because it is yet another way scientists gather information about Earth’s history. Since the magnetic field is present, it helps people navigate around the world and find their way back home. Later in the unit, we will discuss how the magnetic field serves as evidence for sea- floor spreading.

Show What You’ve Learned Review activity, Promethean board. Work with your partner to complete the graphic organizer on the chemical/compositional layers of the earth Review activity, Promethean board. Work with your partner to complete the graphic organizer on the chemical/compositional layers of the earth