Joe’s Journey to the Center of the Earth Reynolds

Title Your Journal… Layers of the Earth Notes Q: How is a peanut m&m like the layers of the earth? (2 similarities) 2

Hey Joe! What’s Up? Heard you were going to the center of the Earth… So I wanted to study up. Get prepared. 3 t.com/clip/journey-to- center-of-earth- 3d/magnetic-rocks

Yea, well that’s a good idea Joe… but I don’t know if that movie is the best way to study Joe…. Whateverrrrr. The movie was awesome! But now I’m hittin’ the sack. 4

Later that night… AHHHHHHH! 5

Poor Joe…having nightmares from that movie.. 6

Hey Fred… where did you come from? I just got back from the Inner Core and I wanted to scare Joe. Haha Yea, that’s not necessary…I think he can do that on his own..haha 7

We can leave Fred and Joe to their dreams and dinosaurs for a while… 8

What evidence supports the idea that Earth has layers? The behavior of seismic waves generated by earthquakes give scientists some of the best evidence about the structure of Earth. (a) If Earth were uniform (homogeneous) throughout, seismic waves would radiate from the site of an earthquake in straight lines. (b) If the density, or rigidity, of Earth increased evenly with depth, seismic wave velocity would increase with depth, and the waves would bend smoothly upward toward the surface. (c) If Earth were layered inside, some seismic waves would be reflected at the boundaries between layers while others were bent. Seismic evidence shows that Earth is layered.

The Four Basic Layers The Earth is composed of four different layers. The crust is the layer that you live on, and it is the most widely studied and understood. The mantle is much hotter and has the ability to flow. The outer core and inner core are even hotter with pressures so great you would be squeezed into a ball smaller than a marble if you were able to go to the center of the Earth! 10

The Crust The Earth's Crust is like the skin of an apple. It is very thin in comparison to the other three layers. The crust is only about 3-5 miles thick under the oceans (oceanic crust) and about 25 miles thick under the continents (continental crust). 11

Write this down Layers of the Earth Notes I. Layers of the Earth A. Crust- very thin uppermost layer of the Earth. (Where we live) 12

The Crust The crust is composed of two rocks. The continental crust is mostly granite. The oceanic crust is basalt. Basalt is much denser than the granite. Because of this the less dense continents ride on the denser oceanic plates. 13

The Lithospheric Plates The crust of the Earth is broken into many pieces called plates. The plates "float" on the soft, semi-rigid asthenosphere. Remember this- we will learn about this later… 14

The Lithosphere The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere. 15

Write this down Layers of the Earth Notes I. Layers of the Earth A.Crust- very thin uppermost layer of the Earth. (Where we live) B.Lithosphere- part of the crust and upper mantle that is rigid brittle rock. 16

The Mantle The Mantle is the largest layer of the Earth. The middle mantle is composed of very hot dense rock that flows like asphalt under a heavy weight. The movement of the middle mantle (asthenosphere) is the reason that the crustal plates of the Earth move. 17

Write this down Layers of the Earth Notes I. Layers of the Earth A.Crust- very thin uppermost layer of the Earth. (Where we live) *Continental (25 mi.) – granite *Oceanic (3-5 mi.) – basalt *broken into plates B.Lithosphere- part of the crust and upper mantle that is rigid brittle rock. C.Mantle- the largest layer of Earth. It is divided into three sections called Lithosphere, Asthenosphere, and Mantle 18

The Asthenosphere The asthenosphere is the semi-solid or semi-rigid part of the middle mantle that flows like hot asphalt under a heavy weight. 19

A.Crust- very thin uppermost layer of the Earth. (Where we live) B.Lithosphere- part of the crust and upper mantle that is rigid brittle rock. C.Mantle- the largest layer of Earth. It is divided into three sections called Lithosphere, Asthenosphere, and Mantle *Asthenosphere- the middle of the mantle. CONVECTION 20

Convection Currents 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. 21

Convection Currents The next time you heat anything like soup or water in a pan you can watch the convection currents move in the liquid. When the convection currents flow in the asthenosphere they also move the crust. The crust gets a free ride with these currents, like the cork in this illustration. 22

B.Lithosphere- part of the crust and upper mantle. Rigid brittle rock. C.Mantle- the largest layer of Earth. It is divided into three sections called Lithosphere, Asthenosphere, and Mantle *Asthenosphere- semi-solid middle of the mantle. -CONVECTION -Plasticity- able to be molded 23

The Outer Core The core of the Earth is like a ball of very hot metals. 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. 24

* Asthenosphere- the middle of the mantle. This is where CONVECTION happens. 1. Convection Currents flow in the Asthenosphere causing this layer to have semi-solid properties. 2. Plasticity- able to molded. D. Core * Outer Core- The liquid layer that surrounds the inner core. 25

The Inner Core The inner core of the Earth has temperatures and pressures so great that the metals are squeezed together and are not able to move about like a liquid, but are forced to vibrate in place like a solid. 26

D. Core * Outer Core- The liquid layer that surrounds the inner core. *Inner Core- The very center of the Earth. This layer is very hot and has pressure pushing on it to make it stay in solid form. 27

How HOT is it? Surface of Sun! 5,500°C Sun Core 15,000,000°C

II. Temperatures of Inner Layers A. The temperature increases as you get closer to the inner core. B. The inner core is said to be as hot as the Sun’s surface (5,000 o C)! 29

The End 30