Bellringer On Friday you wrote about taking a

Bellringer • On Friday you wrote about taking a journey to the center of the earth. Do you think it would really be possible to journey to the center of the earth? Why or Why Not? • What were the 3 main layers of the earth by composition? • What are the 5 physical layers of the earth?

Inside the Earth

Density and Earth’s materials • Scientists conclude that Earth formed from the gas and dust that surrounded our young sun. • At first, Earth’s surface was made of the same materials as its center. • Later, the materials melted and became fluid. • More dense materials settle toward the center. • Less dense materials rose toward the surface. • This created the “layers” of the earth.

Layers by Composition (What it is made of) • Crust • Mantle • Core

The Crust • • Thin, outer layer. less than 1% of Earth’s mass 5 -70 km thick Part of the lithosphere. • Continental Crust - thick (10 -70 km) - buoyant (less dense than oceanic crust- it “floats”) - mostly old • Oceanic Crust • - thin (~7 km) - dense (sinks under continental crust) - young

The Mantle • Layer beneath the crust • 64% of mass of Earth • 2, 900 km thick • Made of – lithosphere – asthenosphere – mesosphere

Convection Currents COOL HOT -The middle mantle "flows" because of convection currents. - Convection currents are caused by the very hot material at the deepest part of the mantle rising, then cooling and sinking again --repeating this cycle over and over.

Core • 3, 248 km radius • sphere of hot, dense nickel and iron • 4, 000 - 5, 000 °C • 1/3 of the Earth’s mass • Made of – Outer Core – Inner Core

Physical Structure of the Earth (5 Layers) -Lithosphere -Asthenosphere Mesosphere -Outer Core -Inner Core

The Lithosphere The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere. Earth’s lithosphere is broken into about 19 pieces called tectonic plates.

Asthenosphere • 250 km thick • solid, plastic layer made of rock • flows very slowly and allows tectonic plates to move across

Mesosphere • 2, 250 km thick • “middle” sphere • lower part of mantle

The Outer Core - The outer core is so hot that the metals in it are all in the liquid state. - The outer core is composed of the melted metals of nickel and iron.

The Inner Core - The inner core of the Earth is a solid layer of iron and nickel. - It has temperatures and pressures so great the metals are squeezed together too tight to move like a liquid, but are forced to vibrate in place like a solid.

Throw Your Hands Up For the Layers of the Earth! Chorus Throw your hands up for the layers of the earth • Throw ‘em up for what’s below the surface Throw your hands up, and let’s discuss • The inner core, outer core, mantle, and crust Verse I The layer we’ll discuss first Is the central inner core, in the center of the earth A solid ball buried below the dirt We believe it’s primarily metallic iron You could never take a trip to the inner core, right? The heat will burn you up, 9, 000º Fahrenheit 4, 000 miles below the Earth’s crust One down three to go y’all. 1, 800 miles from the tip top The outer core is hard at work and it don’t stop. It’s busy spinning around the inner core, and listen, This steady movement causes Earth’s magnetism. Ranging from 4 to 9, 000 degrees, It contributes 1/5 of the heat flowin’ to you and me. • It’s liquid metals that violently flow So let it settle… and when you’re ready let me know. Just… Chorus Verse II The mantle layer is the largest of the class. About half of our planet’s mass. The mantle is composed of very hot dense rocks, That move and flow, always on the go, they never lock, Never stop, and they’re responsible for tectonic shift Please believe the Earth’s plates are adrift It’s pretty thick and the heat is awesome 1, 600 at the top, 4, 000 at the bottom The continental crust’s surface is where we breathe A lot of rock up to 25 miles deep. The oceanic crust is next door It’s 3 -5 miles thick below the ocean floor. Earth’s surface: 70% H 20. Where do you get all that water? Salty sea flow, fresh water’s in the glaciers, ice caps, and snow. Chorus