Earth's Layers, Heat Sources, and Density

Vocabulary flashcards reviewing the formation of Earth, heat sources, density, and the classification of Earth's layers by composition and physical properties.

Early Earth Heat Sources

The three factors that made planet Earth hot in the beginning: collision, gravity, and radioactive decay.

Earth's Ongoing Internal Heat

The heat currently in the center of the Earth, caused by leftover heat from planetary formation as well as ongoing radioactive decay.

Density

The amount of matter or mass packed into a given space.

Planetary Differentiation

The process where the early liquid and uniform Earth separated as gravity caused high-density material to sink to the center and low-density material to rise to the surface before cooling into distinct layers.

Composition

What something is composed of or made out of.

Layers of Earth by Composition

The three Earth layers classified by what they are made of: the crust, mantle, and core.

Physical Properties Classification

The classification of Earth's layers based on how they act rather than what they are made of.

Layers of Earth by Physical Properties

The five Earth layers classified by how they act: the lithosphere, asthenosphere, mesosphere, outer core, and inner core.

Asthenosphere

A layer of the Earth categorized by its physical properties where internal movement causes processes like seafloor spreading.

Seafloor Spreading

A geological process occurring on the ocean floor, visible as a scar in the middle of the Atlantic Ocean, driven by movement in the asthenosphere.