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seismic waves

waves that produce when earthquakes occur


results from a force pressing on an area


the layer of rock that forms Earth's outer skin


a dark rock with a fine texture


usually a light colored rock with a course texture


a layer of hot, solid rock that is about 40 kilometers beneath the surface


the uppermost part of the mantle and the crust that is rigid


a soft layer of earth that is solid, but bendable

outer core

a layer of molten metal that surrounds the inner core

inner core

a dense ball of solid metal


The transfer of energy through space


heat transfer within a material or between materials that are touching


heat transfer by the movement of currents within a fluid


a mesure of how much mass there is in a volumeof a substance

convection current

the flow that transfers heat within a fluid

continental drift

Alfred Wegener's theory that the continents slowlymoved over Earth's surface


According to alfred, the continents drifted together to form this supercontinent


any trace of an ancient organism that has been preserved in rock

mid-ocean ridge

they wind beneath earth's oceans


a device that bounces sound wavesoff underwater objects and then records the echoesof these sound waves

sea- floor spreading

the sea floor spreads along both sides of the mid-ocean ridge as new crust is added

deep-ocean trench

the oceanic crust bends downward


the process by which ocean floor sinks beneath a deep-ocean trench and back into the mantle


according to J. Tuzo Wilson, the lithosphere is broken into sections called plates

scientific theory

a well tested concept that explains a wide range of observations

plate tectonics

this states that pieces of Earth's lithosphere are in slow, constant motion


breaks in eath's crust where rocks have slipped past eachother

divergent boundary

the place where two plates move apart

rift valley

forms along the divergent boundary

convergent boundary

the place where two plates come together

transform boundary

a place where two plates slip past eachother

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