The Layers of the Earth

Transcription

1 The Layers of the Earth HINT: Identify the layers you can in your picture. Record the thickness in km of the layers on your picture. Copyright M. J. Krech. All rights reserved. PowerPoint adapted from

2 The Four Layers Crust is the layer that you live on, and it is the most widely studied and understood. Mantle is much hotter and has the ability to flow. Outer Core & 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!

3 The Four Layers and Density Geologists theorize that as the Earth cooled the heavier, denser materials sank to the center and the lighter, less dense materials rose to the top. The Crust is made of the lightest materials (rock) and the Core consists of heavy metals (nickel and iron). HINT: Record the thickness in miles of the layers on your picture.

4 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 (8 kilometers) thick under the oceans (oceanic crust) and about 25 miles (32 kilometers) thick under the continents (continental crust). Temperatures vary from air temperature on top to about 1600 degrees (870 degrees Celsius) at the deepest parts.

5 The Lithospheric Plates The crust of the Earth is broken into many pieces called plates. The plates "float" on the soft, semi-rigid asthenosphere.

6 Lithospheric Plates Earth 100 Million Years From Now

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

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

9 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.

10 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.

11 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. Safety Caution: Don t get your face too close to the boiling water!

12 Convection Currents a path of heat flow 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. Convection Current example:

13 Mr. Parr- Changing Earth Song (YES, extra credit if all lyrics are copied and returned within 3 days of reading this) Layers of Earth MIT SciShow Earth s Not-So-Juicy Center Convection Currents & Plate Tectonics: Hot Cocoa & Convection 15 Things You Didn t Know About Earth

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15 How do Convection Currents work? The density of warm/hot fluid (gas, liquid or something that is semi-liquid like the material of the mantle of the Earth) is less dense than cooler material. The warmer material (fluid) will rise. As the warm fluid reaches a cooler area, it become more dense (because the molecule get closer together) and sink down. The convention currents in the asthenosphere of the mantle is the mechanism that moves the tectonic plates of the Earth s crust.

16 Fill in your picture!

17 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.

18 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.

19 Left Side Questions: Copy down each of these questions in your IAN. Discuss with your tablemates and answer in your IAN. Name the 4 layers of the Earth from the outside to the center of Earth. Have we ever seen part of the Mantle? Explain. What causes the mantle to flow? What are the two main metals that make up the outer and inner core? Describe how the Earth s layers were formed. Copyright M. J. Krech. All rights reserved.

20 Complete this list of tasks on the front of your IAN. Use your tablemates to assist you. Use a pencil in case changes need to be made. Identify following in this picture: asthenosphere, convection currents, continental crust, core, crust, inner core, lithosphere, lower mantle, mantle, ocean crust, outer core, and upper mantle. What is the core made of? List in order of most to least dense: core (inner & outer), crust (ocean crust, continental crust), mantle (upper, lower).

21 Complete this list of tasks on the front of your IAN. Use your tablemates to assist you. Use a pencil in case changes need to be made. ④ Color the four layers using this guide: inner core red, outer core red orange, lower mantle orange, middle mantle light orange, upper mantle yellow, oceanic crust light brown, continental crust light brown, ocean blue ⑤ Identify the composition, thickness, and state of matter of each of the 4 Layers of the Earth (inner core, outer core, mantle, and crust).

22 Check your results Least to most dense: inner core, outer core, lower mantle, upper mantle, ocean crust, continental crust