Hydrologic Cycle Vocabulary

A set of vocabulary flashcards covering key terms and processes related to the Earth’s hydrologic (water) cycle.

Water Cycle (Hydrologic Cycle)

The continuous circulation of water among Earth’s land surface, oceans, and atmosphere through processes such as evaporation, condensation, precipitation, and runoff.

Evaporation

The process by which liquid water gains enough kinetic energy to change into water vapor, transferring water from the Earth’s surface to the atmosphere.

Transpiration

The evaporation of water through tiny openings (stomata) in plant leaves.

Evapotranspiration

The combined loss of water to the atmosphere through evaporation from surfaces and transpiration from plants.

Sublimation

The direct conversion of water from solid (snow or ice) to vapor without passing through the liquid phase.

Condensation

The transition of water vapor to liquid water when air becomes saturated, leading to cloud, dew, fog, and ultimately precipitation formation.

Condensation Nuclei

Microscopic particles in the air on which water vapor condenses to form fog and cloud droplets.

Precipitation

Water released from clouds that falls to Earth’s surface as rain, snow, sleet, or hail.

Runoff (Surface Runoff)

The portion of precipitation that flows over land surfaces directly into streams, rivers, or the sea.

Infiltration

The downward movement of water from the surface into the soil.

Groundwater

Subsurface water stored in soil and rock layers, derived mainly from infiltrated precipitation.

Groundwater Runoff

Groundwater that later emerges to feed streams and rivers.

Hydrograph

A graph showing stream discharge (runoff) plotted against time to illustrate changes in flow.

Tracer Technique

A method for studying groundwater movement by tracking introduced or natural tracers through subsurface flow paths.

Remote Sensing

The acquisition of information about Earth processes—such as groundwater or ice—using instruments on satellites or aircraft.

Troposphere

The lowest layer of the atmosphere (up to about 10–13 km) that contains nearly all atmospheric water vapor.

Permafrost

Ground that remains at or below 0 °C for at least two consecutive years, typically found in tundra climates.

Glacier

A large, persistent body of dense ice on land formed from accumulated snow, such as Argentina’s Perito Moreno glacier.

Sea Ice

Frozen ocean water that forms a floating ice cover on the sea surface.

Frost

Ice crystals deposited directly from water vapor onto surfaces when air temperatures drop below the freezing point.