Water is essential to life on earth. We have limited amount of water on earth. Nature is always moving water through the air and land, so that the water we use is constantly recycled. This is important because humans, animals, and plants all need water to survive. Since there is a continuous movement of water on, above, and below the surface of the Earth, there is no beginning or end. This phenomenon of continuous circulation of water in the Earth-atmosphere system is called a water cycle. Water cycles have been taking place on the surface of the earth over millions of years. Water Cycle
Earth's water is always in movement, and the water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Since the water cycle is truly a "cycle," there is no beginning or end. Water can change states among liquid, vapor, and ice at various places in the water cycle, with these processes happening in the blink of an eye and over millions of years. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go in a hurry. The earth has a limited amount of water, that keeps going around and around and around and around and (you get the idea) in what is called the "Water Cycle". This cycle is made up of a few main parts:
evaporation (and transpiration)
Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air. Condensation:
Water vapor in the air gets cold and changes back into liquid, forming clouds. This is called condensation. Precipitation:
Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow....
Please join StudyMode to read the full document