Layers of the Earth

Vocabulary flashcards covering the structure, composition, properties, and key facts about the layers of the Earth.

Crust

The thinnest, outermost solid layer of the Earth where life exists, ranging from $5\,\text{km}$ to $50\,\text{km}$ thick and composed mainly of oxygen, silicon, aluminum, and small amounts of other elements.

Types of Crust

The two types of Earth's crust, identified as continental and oceanic.

Mantle

The thickest layer of the Earth (about $2,900\,\text{km}$ thick) composed of semi-solid, molten rock rich in magnesium and iron, making up nearly $\frac{2}{3}$ of Earth's mass with temperatures ranging from $500\,^\circ\text{C}$ to $4,000\,^\circ\text{C}$.

Outer Core

A liquid layer surrounding the inner core, estimated to be about $2,300\,\text{km}$ thick, composed of molten iron, with temperature ranges from $4,000\,^\circ\text{C}$ to $5,000\,^\circ\text{C}$.

Inner Core

The innermost solid layer of the Earth, estimated to be about $1,2500\,\text{km}$ thick, composed of iron under extreme pressure with a temperature of nearly $6,000\,^\circ\text{C}$, about the same as the surface of the Sun.

Lithosphere

The Earth's crust and upper portion of the mantle.

Asthenosphere

The portion of Earth's mantle where convection occurs.

Earth's Magnetic Field

A field caused due to the inner core spinning at a different speed than the rest of the planet.

Seismic Waves

Waves from earthquakes and volcanic eruptions used by scientists to study the Earth.

Diameter of the Earth

The measurement across the Earth, recorded as $12,742\,\text{km}$ ($7,917.5\,\text{miles}$).