What is the Inner Core?
Dense ball of solid metal
What is the Outer Core?
Layer of molten metal that surrounds the inner core
What is the lower mantle?
Solid material extending all the way to the earth’s core
What is the upper mantle?
Outermost layer of the two mantles. Includes the asthenosphere and lower lithosphere. Composed of solid rock, most of which flows due to convection currents within the mantel
What is the crust?
Layer of solid rock that forms earth’s outer skin. Includes both dry land and ocean floor. Oceanic crust (basalt) and continental crust (crust that forms continents)
What are plates?
Broken pieces of the lithosphere
What is plate tectonics?
Explains the formation, movement and subduction of the earth’s plates
What is radiation?
Transfer of energy through empty space, no direct contact between heat source and an object
What is conduction?
Heat transfer by direct contact of particles of matter
What is convection?
Transfer of heat by the movement of heated fluid (includes liquid and gas)
What are convection currents?
Flow in the mantle. Heat source is the earth’s core and mantle. Acts like a conveyor belt moving the lithosphere above.
What is continental drift?
Slow movement of earth’s contents moving away from each other
What is seafloor spreading?
New ocean floor is created as molten material from the mantle rises between plates or ridges and spreads out.
What are plate boundaries?
Where edges of plates meet at lines. When plates slip past each other along these boundaries, faults of breaks in crust occur.
What are transform boundaries?
Boundary where to plates slide past each other. Neither one is added to or destroyed but the sliding past each other creates a large amount of energy that is sometimes released as an earth quake.
What are divergent boundaries?
Two plates move apart. Occurs at mid-ocean ridges.
What are convergent boundaries?
Where two plates come together causing a collision.
What is stress?
Force that acts on rock to changes its shape or volume. Adds potential of stored energy to rock until it changes shape or breaks.
Three kinds: tension, compression and shearing
What is tension?
Pulls on the crust, stretching rock so it becomes thinner in the middle.
What is compression?
Squeezes rock until it folds or breaks
What is shearing?
Pushes a mass of rock in two opposite directions.
What is strain?
Changes in the shape of rock caused by stress. There are two kinds: elastic and plastic
What is elastic strain?
Change in rock that is not permanent. When stress is removed, the rock goes back to its original strain
What is plastic strain?
Permanent change in the shape of a rock. Usually occurs when rocks are weak or hot.
What is an earthquake?
Vibrations in the ground that result from movement along faults, or breaks in the earth’s lithosphere
What is a normal fault?
Form when forces pull rocks apart along divergent plate boundary; block of rock above fault moves down
What is a strike-slip fault?
Two blocks of rock slide horizontally past each other in opposite directions
What is a reverse fault?
Force pushes two blocks of rock together with the rock above the fault moving
What is focus?
Point beneath Earth’s surface where rock under stress breaks to cause an earthquake
What is epicenter?
Point on the surface directly above the focus