| A | B |
|---|
| asthenosphere | the soft layer of the mantle on which the lithosphere floats |
| conduction | the transfer of heat by direct contact of particles of matter |
| continent | a great landmass surrounded by oceans |
| continental drift | the hypothesis that the continents slowly move across Earth's surface |
| convection | the transfer of heat by movements of a heated fluid |
| convection current | the movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another |
| convergent boundary | a plate boundary where two plates move toward each other |
| crust | the layer of rock that forms Earth's outer surface |
| density | the amount of mass in a given space; mass per unit volume |
| destructive force | a force that slowly wears away mountains and other features on the surface of Earth |
| divergent boundary | a plate boundary where two plates move away from each other |
| fault | a break in Earth's crust where slabs of rock slip past each other |
| granite | a usually light-colored rock that is found in continental crust |
| heat transfer | the movement of energy from a warmer object to a cooler object |
| lithosphere | a rigid layer made up of the uppermost part of the mantle and the crust |
| mantle | the layer of hot, solid material between Earth's crust and core |
| mid-ocean ridge | the undersea mountain chain where new ocean floor is produced |
| outer core | a layer of molten iron and nickel that surrounds the inner core of Earth |
| Pangaea | the name of a single landmass that broke apart 200 million years ago |
| plate | a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust |
| plate tectonics | the theory that pieces of Earth's lithosphere are in constant motion driven by convection currents in the mantle |
| radiation | the transfer of energy through empty space |
| scientific theory | a well-tested concept that explains a wide range of observations |
| subduction | the process by which oceanic crust sinks back into the mantle |
| transform boundary | a plate boundary where two plates move past each other in opposite directions |
