Water is a main component of nature and is the main source of life in our ecosystem. It covers 70% of the earth's total surface but actually represents 0.05% of the earth's total mass. The total volume of water on the Earth's surface is approximately 1,386 billion cubic kilometers (333 million cubic miles). Of this volume, 97.5% is salt water and 2.5% is fresh water. Only 0.03% of fresh water is present in the earth in liquid form. The water cycle is a closed water system because the amount of water involved does not change but can be changed from one state to another. It involves the movement of water in the earth in a cyclical form through a series of processes. The processes involve the input, output, transport and storage of water. Exit - precipitation. Input: evaporation, transpiration and sublimation. Water storage: interception, artificial vegetation, storage, surface storage and groundwater storage. Also, water transport runoff, stem flow, percolation, channel flow, infiltration, and groundwater flow. The main processes involve evaporation, sublimation, hydration and transpiration considered as the first phase, then followed by condensation, precipitation, percolation and infiltration. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay To begin with, evaporation, transpiration, sublimation, and hydration are the first processes of the water cycle. These processes cause the water present on the Earth's surface to disperse into the atmosphere. They change water from a liquid state to a vapor or gaseous state. Here's how it happens; water in its liquid state has a closed molecular arrangement that prevents water from rising. When the sun shines on the earth the temperature rises causing the water to absorb heat. This heat breaks down the molecular arrangement of liquid water making it looser and less heavy to flow, turning the water into gas or vapor and begins to rise and move upward in the atmosphere. Water escapes into the atmosphere through evaporation. Man-made things such as fabrics, buildings, dams, among others, found on earth serve as a medium for water storage and lose water to the atmosphere as the temperature increases through evaporation. Additionally, bodies of water found on the earth's surface and below the surface such as the sea, lakes, rivers, and aquifers lose water to the atmosphere through evaporation. During precipitation, water penetrates the vegetation through the leaves through interception. These waters stored in vegetation are lost to the atmosphere through the stomata of leaves during high temperatures, this process is called transpiration. In the cold regions of the earth such as the Arctic and Antarctic, the polar and temperate zones, and places at high altitudes, such mountainous regions have water stored in the ice and ice sheet. They lose water directly from their solid state to their gaseous state without melting when they absorb heat. This process is called sublimation. Finally, humans and animals also serve as a means of storing water. During high temperatures they lose water to the atmosphere through hydration. Secondly, condensation is the second phase of the water cycle. This process transforms water from a vapor state to a liquid state. According to the law that says that "the higher you go, the colder it gets" when the water vapor escaping into the atmosphere reaches the highest troposphere since the temperature is very low in that.