Earth

By Tyler and Ashley

Introduction

The Earth is what we live on. It is made up of 4 main layers: crust, mantle, outer core, and inner core. Geologists think that when the Earth cooled from being an incandescent globe of hot gases, the lighter materials floated to the top while the heavier materials sank to the bottom. But there's more to Earth than that. That's why we have created this Smore just for you!
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Long ago

A long, long time ago, even before there were such things as continents, scientists thought that all the land on Earth was a big clump of land. A piece of land called Pangea. The scientist that proposed this idea was Alfred Wegener. They found a Mesosaurus fossil in both Africa and South America and used it as proof.

Mesosaurus fossil:

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Crust

Being the layer we live on, the crust is the most widely studied of all the layers. The crust is much thinner than the rest of the layers. It is also made of the lightest material; granite and basalt.

2 layers:

The oceanic layer and the continental layer are both parts of the crust. The oceanic crust varies from 5 to 10 kilometers depending on where it is while the continental layer varies from 35 to 70 kilometers depending on where it is. The oceanic layer consists of volcanic lava which is also known as basalt.

Temperature:

The temperature of the crust varies from air temperature at the top, to around 1600 degrees Fahrenheit near the bottom.

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Mantle

The mantle is much hotter than the crust with the ability to flow as well. There are thee parts to the mantle. There is the upper mantle, the middle mantle, and the lower mantle.

Thickness:

The mantle has a thickness of about 2900 kilometers.

Flow:

There are many theories to why the mantle flows. Some say that it is due to convection, the hot material floating, cooling, and sinking again and again. Some say that it is because the plates move, while others say that it is because the temperature of the top differs from the temperature at the bottom. Of course, no one certainly knows because no one's ever been there!

Temperature:

The temperature of the mantle varies from the top to the bottom. The top of the mantle can reach up to 1600 Fahrenheit, while the bottom of the mantle can reach up to 4000 Fahrenheit.

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Asthenosphere

The asthenosphere is basically another name for the middle mantle. Being part of the mantle, the asthenosphere is made of the same material, solid rock. The asthenosphere is where all of the convection occurs.

Lithosphere

The lithosphere consists of the oceanic and continental crusts, and most of the upper mantle. It is not a separate layer, it is just a layer grouping the crust and most of the upper mantle together.

Outer Core

The outer core is made of iron and nickel in the liquid state. It has much greater pressure than both the mantle and crust. The outer core has a pressure so rest that if one was to enter the outer core, they would be squeezed into a ball smaller than a marble.

Thickness:

The outer core has a thickness of about 2300 kilometers.

Temperature:

The temperature of the outer core can vary from 4000 Fahrenheit, to 9000 Fahrenheit.

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Inner Core

The inner core is the very center of Earth. The inner core has even greater pressure than the outer core so the iron and nickel that compose it are in the solid state.

Thickness:

The inner core has a thickness of about 1200 kilometers.

Temperature:

The inner core has a temperature that can reach up to 9000 Fahrenheit.

Pressure:

The pressure in the inner core is 45,000,000 pounds per square inch. That's 3,000,000 times greater than sea level!