The water cycle, also known as the hydrological cycle or the hydrological cycle, describes the continuous movement of water over, above and below the surface of the Earth. The water mass in the soil is kept quite constant over time, nevertheless the partition of water in the main reservoirs of ice, freshwater, salt water and atmospheric water is variable depending on a wide range of climatic variables. The water is moved from one depot to another, such as from the river to the ocean, or from the ocean to the atmosphere, by physical processes of evaporation, condensation, precipitation, infiltration, superficial cleavage, and underground flow. By doing so, the water passes through various forms: liquid, Solid (ICE) and steam.

The water cycle involves the exchange of energy, which leads to temperature changes. When the water is Évora, it takes energy from its environment and cool the environment. When Condensed, it releases energy and warms the environment. These heat changes influence the climate.

The evaporative Phase of the cycle purifies the water which then restores the earth with fresh water. The flow of liquid water and ice transports minerals every over the world. It Also participates in the remodeling of the geological characteristics of the earth, through processes such as erosion and sedimentation. The water cycle is also essential for the maintenance of most of the planet’s life and ecosystems.

The Sun, which propels the water cycle, warms the water in the oceans and seas. Water is like water vapor in the air. A little ice and snow sublimates directly into the water vapor. The evapotranspiration is the water that is transpiled from the plants and is evaporates from the soil. The Water molecule H2O has a lower molecular mass than the main components of the atmosphere, nitrogen and oxygen, N2 and O2, therefore, is less dense. Due to the significant difference in density, the buoyancy leads the highest moist air. As altitude increases, air pressure decreases and temperature drops (see gas laws). The lower temperature causes the water vapor to condense into tiny drops of liquid water that are heavier than air, and fall unless supported by an upward chain. A huge concentration of these drops in a large space in the atmosphere becomes visible as the cloud. Some condensation is close to ground level and is called fog.

Atmospheric circulation moves water vapor around the globe, particles in the cloud collide, grow and fall from the upper atmospheric layers like precipitation. Some precipitations fall like snow or hail, sleet, and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Most of the water falls in the oceans or on Earth as rain, where water flows into the ground as superficial cleavage. A portion of the cleavage enters rivers in valleys in the landscape, with water flowing into the oceans. The slag and water emerging from the soil (groundwater) can be stored as freshwater in the lakes. Not every plants flow into the rivers, much of which is absorbed into the soil as infiltration. Some waters infiltrate deep into the soil and replenish aquifers, which can store fresh water for long periods of time. Some infiltrations remain near the surface of the earth and can drain back into surface water bodies (and the ocean) as the discharge of groundwater. Some Underground waters find openings on the surface of the earth and come out as freshwater springs. In the river valleys and the alluvial plains, there are often a continuous exchange of water between the surface and groundwater in the area of Hiporheica. Over time, the water returns to the ocean, to continue the water cycle.
