The Hydrologic Water Cycle
The water cycle, also known as the hydrologic cycle, is a continuous process that circulates water throughout Earth's systems. This cycle is essential for sustaining life and maintaining ecological balance.
Four Main Stages of the Water Cycle:
- Evaporation:
Water in oceans, lakes, and rivers is warmed by the sun and changes from a liquid to a gas state. This process is called evaporation.
Definition: Evaporation is the process where a liquid changes from its liquid state to a gaseous state.
- Condensation:
As water vapor rises into the cooler atmosphere, it condenses back into a liquid form, creating clouds or fog.
Definition: Condensation occurs when a gas is changed into a liquid. This process is the opposite of evaporation.
- Precipitation:
When the air can no longer hold more water, it falls back to Earth as rain, snow, sleet, or hail, depending on atmospheric temperatures.
Example: Rain forms when temperatures are above freezing, while snow, sleet, and hail result from freezing temperatures in the air.
- Transpiration:
Plants absorb water from the soil through their roots. This water moves up through the stems to the leaves, where some of it evaporates, adding to the water vapor in the air.
Highlight: Transpiration is a crucial part of the water cycle, as it returns significant amounts of water to the atmosphere through plant processes.
Additional Water Cycle Processes:
- Runoff: Precipitation that falls to the ground and flows downhill, attempting to return to oceans, lakes, rivers, or other water sources.
- Streamflow: Water moving across the Earth's surface in streams.
- Percolation: Rainwater that soaks into infiltrates the ground, entering the soil and underlying rock layers.
Vocabulary: Percolation is the process by which water moves downward through the soil and rock layers.
