Earth & its Layers Allison Morton Adv. Earth Science 2 ND Period

Earth’s Inside Layers Earth has 3 layers in the inside- the crust, mantle, and core. The lightest materials make up the outermost layer, and densest materials make up the inner layers. This is because lighter materials tend to float up, while heavier materials sink. Earth’s layers are made of different physical mixtures of elements. This means that the layers have different compositions. Temperature, pressure, and density are the three things that increase as you go inside the Earth.

The Crust The crust is the outermost layer of the Earth. It is also the thinnest layer. This is the rocky layer that we live on. Since we live on this layer, we would know more about it than the others. Oxygen and silicon are two of the most abundant elements found in the Earth’s crust.

The Mantle The mantle is the layer of the Earth between the crust and the core. Compared to the crust, the mantle is extremely thick and contains most of the Earth’s mass. It makes up 80% of the Earth’s total value.

The Core The core is the central part of the Earth below the mantle. The core extends from the bottom of the mantle to the center of the Earth. Since the core is so hot it radiates a natural heat to the upper layers. Earth’s core mainly contains iron.

Earth’s Structure The Earth is divided into 5 main physical layers- the lithosphere, asthenosphere, mesosphere, outer core, and inner core. Each of these layers have their own unique characteristics about themselves.

Lithosphere The lithosphere is the outermost layer of Earth. A.K.A “Rock Sphere” This layer is made of two parts - the crust and the rigid upper part of the mantle. The lithosphere is the layer that we walk on. The lithosphere is divided into pieces called tectonic plates.

Plate Tectonics Plate tectonics- is the theory that the Earth’s lithosphere is divided into tectonic plates that move around on top of the asthenosphere. Tectonic Plates- are actual pieces of the lithosphere that moves around on top of the asthenosphere. Don’t get the two confused!!!!!

Sea-floor Spreading Sea-floor spreading is the process by which new oceanic lithosphere is created, older materials are moved away from the mid-ocean ridge. Sea-floor spreading takes place at mid- ocean ridges. At mid-ocean ridges new lithosphere is formed. As the tectonic plates move away from the mid-ocean ridge, magma rises to fill the gap. The crust increases in age the farther it is from the mid-ocean ridge. The oldest crust in the Atlantic Ocean is found along the edges of the continents.

Diagram of Sea-floor Spreading Youngest Oldest AB Mid- Atlantic Ridge

Where is new rock being made? –Mid-Atlantic Ridge Where is old rock being destroyed? –Marianas Trench

Asthenosphere The asthenosphere is a soft layer of the mantle on which pieces of the lithosphere move. A.K.A. “Weak Sphere” This sphere is made of solid rock that flows very slowly. It flows about the same rate your fingernails grow. Also the asthenosphere contains convection currents.

Outer Core The Earth’s core is divided into 2 parts- the outer core and the inner core. The outer core is the liquid layer of the Earth’s core, that lies beneath the mantle and surrounds the inner core.

Inner Core The inner core is the solid, dense center of our planet that extends from the bottom of the outer core to the center of the Earth. The inner core is hotter than the liquid outer core. The immense pressure from all of the Earth’s layers keeps it in a solid state. The inner core was discovered in 1936.

Works Cited Earth Science Textbook Recent tests,quzzes,and warm-ups

Made By: Allison Morton