| A | B |
|---|
| 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 |
| convection current | The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another |
| density | The amount of mass in a given space; mass per unit volume |
| continental drift | The hypothesis that the continents slowly move across Earth’s surface |
| Pangaea | The name of the single landmass 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 |
