Topic 1.7: Hydrologic (Water) Cycle Vocabulary

Vocabulary flashcards covering key terms, processes, and reservoirs in the hydrologic cycle from the AP Environmental Science Topic 1.7 lecture.

Hydrologic Cycle

The movement of water in different states (solid, liquid, or gas) between different sources and reservoirs, driven by energy from the sun.

Ocean

The largest reservoir of water on Earth, containing saltwater that cannot be directly used by humans for drinking or agriculture.

Freshwater Sources

Water reservoirs that humans can use for drinking and agriculture, including polar ice caps, glaciers/ice caps on mountains, and groundwater.

Precipitation

The process of water moving from a gas in the atmosphere as it condenses into clouds and falls back down to Earth's surface as a liquid.

Evaporation

The process driven by the sun's energy where liquid water on Earth warms up and transforms into a gas or vapor that enters the atmosphere.

Transpiration

The process by which plants draw water up from the ground through their roots and stems to their leaves, where water evaporates into the atmosphere through open stomata.

Stomata

Little pores in plant leaves that open up to allow water vapor to evaporate into the atmosphere, creating a low water pressure system that pulls groundwater up through the roots.

Evapotranspiration

The total amount of water leaving an ecosystem through the combined processes of evaporation (from soil and water bodies) and transpiration (from plants).

Runoff

Precipitation that flows across Earth's surface until it reaches surface bodies of water like lakes, rivers, or ponds, often gathering pollutants along the way.

Infiltration

The process where precipitation slowly trickles or soaks into the ground to reach underground water stores.

Aquifers

Underground water stores that hold groundwater and are recharged by the process of infiltration.

Permeability

The ability of a ground cover to allow water to soak through it and recharge the underground aquifers beneath.