| A | B |
|---|
| Seismic waves | Vibrations that travel through Earth carrying the energy released during an earthquake |
| Crust | the layer of rock that forms Earth's outer surface |
| Basalt | A dark, dense, igneous rock with a fine texture, found in oceanic crust |
| Mantle | the later of hot, solid material between Earth's crust and core |
| Lithosphere | a rigid layer made up of the uppermost part of the mantle together with the crust |
| Asthenosphere | the soft layer of the mantle on which the lithosphere floats |
| Outer core | a layer of molten iron and nickel that surrounds the inner core of Earth |
| Inner core | a dense sphere of solid iron and nickel at the center of Earth |
| Radiation | the transfer of energy through space |
| Conduction | the transfer of heat within a material or between materials that are touching |
| Convection | the transfer of heat by movement of a fluid |
| Density | the amount of mass in a given space |
| Convection current | the movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another |
| Pangaea | the name given to the single land mass that broke apart 200 million years ago and gave rise to today's continents |
| Fossil | a trace of an ancient organism that has been preserved in rock |
| Mid-ocean ridge | an undersea mountain chain where new ocean floor is produced; a divergent plate boundary |
| Sonar | a device that determines the distance of an object under water by recording echoes of sound waves |
| Sea-floor spreading | the process by which molten material adds new oceanic crust to the ocean floor |
| Deep-ocean trench | a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle |
| Subduction | the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary |
| Plate | a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental & oceanic crust |
| Plate tectonics | the theory that pieces of Earth's lithosphere are in constant motion, friven by convection currents in the mantle |
| Fault | a break in Earth's crust where masses of rock slip past each other |
| Divergent boundary | a plate boundary where 2 plates move away from each other |
| Rift valley | a deep valley that forms where 2 plates move away from each other |
| Convergent boundary | a plate boundary where 2 plates move toward each other |
| Transform boundary | a plate boundary where 2 plates move past each other in opposite directions |
