Earth's Internal Heat Sources Flashcards

Vocabulary flashcards covering the layers of the Earth, internal heat sources, and mechanisms of heat transfer based on the lecture notes.

Crust

The outermost, rigid layer of Earth where life exists, ranging from $5$ to $70 km$ thick.

Mantle

The thick, semi-solid layer beneath the crust, approximately $2,900 km$ thick, with temperatures ranging from $500^{\circ}C$ to $4,000^{\circ}C$.

Outer Core

The liquid layer beneath the mantle, approximately $2,250 km$ thick, composed of liquid iron and nickel.

Inner Core

The solid, innermost layer of Earth with an average temperature of approximately $6,000^{\circ}C$, held solid by immense pressure.

Lithosphere

The rigid outer part of the Earth, consisting of the crust and the uppermost solid mantle.

Asthenosphere

The partially molten, plastic-like layer of the upper mantle below the lithosphere.

Moho

The boundary between the Earth's crust and the mantle.

Gutenburg discontinuity

The boundary separating the mantle from the outer core.

Geothermal Gradient

The rate of increasing temperature with respect to increasing depth in Earth's interior, typically $15^{\circ}$ to $30^{\circ}C/km$ within the crust.

Primordial Heat

Heat leftover from the Earth's formation and accretion that occurred about $4.6$ billion years ago.

Radioactive Decay

The natural breakdown of unstable atoms like Uranium-235, Uranium-238, Thorium, and Potassium that releases heat energy.

Gravitational Pressure

Heat produced by the enormous weight of overlying rocks and layers pressing down on materials deep within the Earth.

Planetary Differentiation

The process by which a planet separates into different layers based on the density of its materials during early formation.

Convection Currents

Circular movements of heated material caused by differences in temperature and density, acting as the main driving force for plate tectonics.

Conduction

The process of heat transfer through direct contact of particles without the movement of the material itself.

Convection

The transfer of heat by the movement of mass within fluids, such as liquids or gases; more efficient than conduction.

Radiation

The transfer of heat through electromagnetic waves without the need for a matter medium.

Half-life

The time needed for half of a radioactive substance to decay or change into another element.