Internal Structure of the Earth Flashcards
Identify, draw and label internal structure of the earth ○ Characteristics of ALL LAYERS (depth, temperature, density etc)
Layers of the Earth
The Earth is made up of four main layers, each with distinct characteristics. These layers are arranged from the outermost to the innermost part of the Earth
Crust
Definition: The Earth’s outermost layer.
Thickness: It’s the thinnest layer, ranging from about 5 km beneath the oceans (oceanic crust) to 70 km beneath the continents (continental crust).
Composition: Made of solid rock, primarily silicate minerals such as granite (continental crust) and basalt (oceanic crust).
Properties: It’s rigid and brittle, meaning it can crack and break, which leads to the formation of earthquakes and volcanoes
Mantle
Definition: The thick layer beneath the Earth’s crust.
Thickness: About 2,900 km thick.
Composition: Made of silicate rocks that are rich in magnesium and iron. The mantle is semi-solid, meaning that it behaves like a solid but can flow slowly over time.
Properties:
Upper Mantle: The uppermost part of the mantle is rigid and interacts with the crust to form the lithosphere (the rigid outer shell of the Earth). Beneath this is the asthenosphere, where the rocks are partially melted and can flow.
Lower Mantle: The lower part of the mantle is denser and more solid
Outer Core
Definition: The liquid layer beneath the mantle.
Thickness: About 2,200 km thick.
Composition: Composed mainly of iron and nickel, along with small amounts of lighter elements like sulfur and oxygen.
Properties: The outer core is liquid due to the high temperatures that prevent the metals from solidifying. This layer is responsible for the Earth’s magnetic field, as the movement of molten iron creates electric currents.
Lithosphere
This is the rigid outer part of the Earth, consisting of the crust and the uppermost part of the mantle. It is broken into tectonic plates that float on the semi-fluid asthenosphere beneath them.
Inner Core
Definition: The innermost layer of the Earth.
Thickness: About 1,200 km thick.
Composition: Composed primarily of solid iron and nickel.
Properties: Despite the extremely high temperature, the inner core is solid due to immense pressure that prevents the metals from melting. Temperatures here can reach up to 5,500°C, similar to the surface of the sun!
Asthenosphere
A layer in the upper part of the mantle that is semi-fluid and allows the tectonic plates to move. It’s like a “conveyor belt” that moves the plates slowly over time.
Tectonic Plates
Large pieces of the Earth’s lithosphere that move and interact with each other. Plate movements are responsible for the creation of earthquakes, volcanic activity, and mountain formation.
Earthquakes and Volcanoes
The movement of tectonic plates along fault lines causes earthquakes, and volcanic eruptions occur when magma from the mantle rises to the surface.
Plate Tectonics
The theory that explains how the Earth’s plates move and how they interact with each other. This movement shapes the Earth’s surface, causing mountains to form, ocean basins to open, and continents to drift.
Magnetic Field
The movement of molten iron in the outer core generates the Earth’s magnetic field, which is vital for life on Earth, protecting us from harmful solar radiation.
