Vesifivaiheet

Vesifivaiheet, also known as the water cycle or hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. This fundamental process is driven by solar energy and gravity. The cycle begins with evaporation, where solar energy heats water in oceans, lakes, rivers, and soil, turning it into water vapor that rises into the atmosphere. Transpiration, the release of water vapor from plants, also contributes to atmospheric moisture.

As the water vapor ascends, it cools and undergoes condensation, transforming back into liquid water droplets or ice crystals, forming clouds. When these clouds become saturated, precipitation occurs, releasing water back to the Earth's surface in the form of rain, snow, sleet, or hail.

Once on the surface, water can follow several paths. It can flow over the land as surface runoff, collecting in streams, rivers, and eventually returning to oceans and lakes. Some water infiltrates the ground, becoming groundwater. This groundwater can slowly move through the soil and rock layers, eventually rejoining surface water bodies or being stored in aquifers. Water can also be stored in ice caps and glaciers for extended periods. The entire process then repeats, ensuring a continuous supply of fresh water.