Educational Description of a Water Cycle and Its Main Processes

Water is a principal component of nature and it is the major source of life in our ecosystem. It covers 70% of the total earth surface but actually, represents 0.05% of the earth's total mass. The total volume of water present on the earth's surface is about 1,386 billion cubic kilometers 333 million cubic miles. Out of this volume, 97.5%is salt water, and 2.5% is fresh water. Only 0.03 percent of freshwater is present as a liquid form in the earth. The water cycle is a closed system of water because the amount of water involved does not change but can be changed from one state to the other. It involves the movement of water in the earth in a cycle form through series of processes. The processes involve the input, output, transport, and storage of water. Output- precipitation. Input- evaporation, transpiration, and sublimation. Water storage- interception, artificial things 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 stage, then followed by condensation, precipitation, percolation, and infiltration.

To begin with, evaporation, transpiration, sublimation, and hydration are the first processes of the water cycle. These processes make water found on the surface of the earth lose into the atmosphere. They change water from its liquid state to a vapor or gaseous state. This is how it occurs; water in its liquid state has a closed molecule arrangement which makes the water not rise. When the sun shines on the earth the temperature rises making the water absolves heat. This heat breaks the molecule arrangement of the water at its liquid state making it wider and less heavy to flow this changes the water into gaseous or vapor and begins to rise and move upward into the atmosphere. Water escapes into the atmosphere through evaporation. Man-made things like cloths, buildings, dams among others found on the earth serve as a medium for water storage they lose water into the atmosphere when the temperature rises through evaporation. Also, water bodies found on the earth’s surface and below the surface like the sea, lakes, rivers, and groundwater loses water into the atmosphere through evaporation. During precipitation, water gets into vegetation through its leaves through interception. These waters stored in the vegetation lose into the atmosphere through the stomata of the leaves during high temperature, this process is called transpiration. In the cold regions of the earth such as the Arctic and Antarctic, polar and the temperate zones and places on high elevation such mountainous region have water stored in ice and Ice Cap. They lose water directly from their solid-state to gaseous states without melting when they absolve heat. This process is called sublimation. Lastly, humans and animals also serve as a medium for water storage. During high temperatures, they lose water to the atmosphere through hydration.

Secondly, condensation is the second stage of the water cycle. This process changes the water in the vapor state into the liquid state. According to the law which states that “the higher you go the cooler it becomes” when the water vapor which escapes into the atmosphere reaches the higher troposphere since the temperature is very low at that point the molecule which is wide apart coming closer to form a water droplet. The help of dust and volcanic ashes that are ejected into the atmosphere serves as a platform or surface for these water droplets to settle on for a given time to form clouds.

Moreover, precipitation is the next stage of the water cycle. It occurs when the water droplets become so heavy that they cannot hold themselves together anymore due to lower temperature at the place then they fall in many forms like rain, snow, and according to the temperature it reaches. For instance, when the temperature reaches zero degrees the precipitation will be snow. Before precipitation, clouds can separate and move to the other part of the hydrologic drainage basin under the influence of wind and then precipitate. This process is called advection. When advection occurs, clouds move to the sea, the land, and also to the mountainous regions or the colder regions and then precipitate. As I said early on, the kind of precipitation that will occur depends on the temperature of the place mostly in the mountainous regions their precipitation that occurs is mostly snow.

Also, runoff is the fourth stage of the water cycle. It is the movement of water on the surface of the earth. When there is precipitation, some of the water flows on and below the earth’s surface in the form of flooding channel flow, river flow, groundwater, and infiltration. Some flow into lakes, ponds, oceans, and rivers depending on the relief and channels of the place or field. Runoffs also happen when ice caps on mountains absolves heat, melt and flow down onto the nearby lower lands and into, rivers, ponds, lakes to be mentioned but few.

Lastly, percolation and infiltration are the last states of the water cycle. It occurs when water gets into the ground during precipitation. During precipitation, some water is able into the earth's crust. Infiltration happens when water sinks into the soil for a short distance depending on the nature of the soil mostly in sandy and loamy soil, water infiltration is very high. When water gets into the soil through infiltration depending on the nature of the rock inside the crust water can penetrate deeper into the soil and eventually into the groundwater. In places where there is an aquifer that is very porous water can penetrate or percolate inside very easily and flow within it along slopes into the nearby streams.

In conclusion, the hydrological or water cycle is a closed system of water because the amount of water involved does not change but changes from one state to another and involves the movement of water in the earth in a cycle form through series of processes. They are the loss of water in the earth's surface through many forms with the aid of heat, condensation, precipitation, runoff, and percolation and the process starts all over again.