| A | B |
|---|
| atmosphere | gaseous envelope of air surrounding earth; one of the four spheres of the Earth system |
| biosphere | all living organisms on Earth and their environments; one of the four spheres of the Earth system |
| carbon cycle | the biogeochemical circulation of carbon through the Earth system |
| closed system | a system in which energy can enter or leave, but matter cannot |
| cycle | a sequence of events that repeats over a relatively short period of time |
| Earth system science | the study of Earth materials and processes subdivided into a group of four interconnected spheres of activity |
| energy cycle | the movement of energy into and out of the Earth system |
| evapotranspiration | the cycling of water vapor into the atmosphere by evaporation or transpiration |
| geosphere | the rocks and mountains of Earth |
| geothermal energy | heat energy that originates from within Earth |
| hydrosphere | all the water in the Earth system: gaseous, solid, liquid. |
| model | a simplified representation used for further study or investigation |
| open system | system with a free exchange of matter and energy with the surroundings |
| solar energy | energy emitted by the sun |
| system | a naturally occurring group of objects that share matter and energy |
| tidal energy | energy created by the gravitational pull of the sun and moon on Earth's surface |
| water cycle | the continual circulation of water through the hydrosphere |
