Water is found in the all three states of matter in everyday life. It is found in the solid state as ice form, in the liquid state as water and in the gaseous state as water vapour.
Different forms of water influence the earth and the living beings.
Water is found in glaciers, oceans, rivers and streams and in the form of water vapour.
Global water balance is maintained by the flow of the water in and out of the system.
Major inflow in the system is through precipitation and the outflow is through evapo-transpiration. It is also referred as water or hydrological cycle. The interchange of the different states of water between the ocean, land and air is called hydrological cycle.
Physical processes of water cycle are evaporation, precipitation and condensation.
Evaporation is the process by which water is transformed into the water vapours by the sun’s heat. The factors affecting evaporation are temperature, dry air, clear sky and winds.
When the air is holding maximum amount of water it can hold, the air is said to be saturated. The temperature at which the air gets saturated is known as dew point.
Condensation is the process by which water vapour is converted into water. The various forms of condensation are cloud, mist, fog, dew and frost.
Precipitation is the process through which water from the atmosphere falls down on the earth. The various forms of precipitation are rain, drizzle, snow, sleet and hail.
In evaporation, water changes into water vapour. In condensation, water vapour changes into the water. In precipitation, water falls down on the earth’s surface.
Heat is absorbed in the process of evaporation. Heat is released in the process of condensation. No absorption or release takes place in the process of precipitation.