Mr. Matthews's Restless Earth Vocab

Seismic Waves

energy released in the form of waves due to the shifting of the Earth's interior.

P Waves (Primary)

the fastest seismic wave travels through solids and liquids. A longitudinal wave.

S Waves (Secondary)

the second fastest seismic wave, travels through solids only. A transverse wave.

Surface Waves

the slowest of the seismic waves, but the most destructive. Travel at Earth's surface.

Seismograph

A device that records ground movements caused by seismic waves as they move through Earth

Lithosphere

the rigid outer part of the earth, consisting of the crust and upper mantle.

Asthenosphere

the upper layer of the earth's mantle in which thigh temps and pressure cause plastic flow and convection is thought to occur.

Medium

matter through which a wave travels

Transverse Wave

A wave in which the particles of the medium move perpendicularly to the direction the wave is traveling

Longitudinal Wave

a wave in which the particles of the medium move parallel to the direction of wave motion

Reflection

The bouncing back of a wave when it hits a surface through which it cannot pass.

Refraction

The bending of a wave as it passes at an angle from one medium to another

Convection

The transfer of thermal energy by the circulation or movement of a liquid or gas

Theory of Continental Drift

Idea that at one point in time all of the continents were one super continent, they broke up and moved to their current locations.

Pangaea

The name of the single landmass that broke apart over 200 million years ago and gave rise to today's continents

Plate Tectonics

The theory that Earth's lithosphere is divide into large pieces or plates and are in constant motion, driven by convection currents in the mantle.

Convergent Boundary

A tectonic plate boundary where two plates collide or converge on each other.

Divergent Boundary

The boundary between two tectonic plates that are moving away from each other

Transform Boundary

The boundary between tectonic plates that are sliding past each other horizontally

Tectonic Plate Boundary

The location where two or more tectonic plates meet.

Mesosphere

The strong, lower part of the mantle between the asthenosphere and the outer core

inner core

A dense sphere of solid iron and nickel at the center of Earth

outer core

the liquid layer of the Earth's core that lies beneath the mantle and surrounds the inner core

Mantle

The layer of hot, solid material between Earth's crust and core.

Crust

The thin and solid outermost layer of the Earth above the mantle

celestial bodies

all objects seen in the sky (the Sun, Moon, stars, and planets)

pressure

the amount of force exerted per unit area of a surface

radioactive decay

the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element

Primordial heat

heat remaining from collisions during Earth's formation

Seismic Shadow Zones

the result of S-waves' inability to pass through liquids leaving areas of the internal Earth unseen by seismographs