Water is a fundamental element for life because, thanks to it, living beings can hydrate ourselves, perform our vital functions and obtain nutrients. Planet Earth or also known as the blue planet because of the large amount of water it contains, is the only one of the known planets where there is liquid water and life. Water can be in three different states (liquid, solid or gaseous) depending on the phase of the water cycle.
Where is the water
We can find water in different parts of the Earth. It is found in the seas and oceans, in rivers, streams, lakes, lagoons and can also be found in the soil, either forming aquifers (large masses of water under the ground) or between the pores of the earth when it infiltrates it, for example , after raining. The water found in these spaces is liquid water , but we can also find water in other states. Water also appears in solid form such as ice that we can find in glaciers, icebergs or hail, or in the form of snow . In addition, although we may not always be able to see it, it is also in a gaseous stateFor example, in the atmosphere and in the air we breathe, there is water vapor. Water vapor also escapes from geysers or volcanic eruptions.
In addition, the water can be sweet like that normally found in rivers, lakes or icebergs or salty like that of the seas and oceans. The main difference is that salt water contains a lot of salt or sodium chloride, like the salt we use at home for cooking (in fact, that salt comes from the sea) and fresh water has much less concentration and that is why when we drink water we do not feel that salty taste.
As the name indicates, it is a cycle and that means that each of the processes that occur in it are repeated from time to time . When explaining the water cycle, any step would serve as a starting point, but the sea is normally used as a starting point.
First of all, the sun’s rays heat the surface of the sea water or also of rivers and lakes. Due to this, the water heats up and evaporates , that is, it turns into water vapor. In the case of the poles, the ice melts into a liquid state and finally evaporates into a gaseous state. Living beings also evaporate water, in the case of animals it is known as sweating and in the case of plants as perspiration. On the other hand, the sum of the evaporation produced by transpiration and that produced by the warming of the soil is known as evapotranspiration , and it can suppose a great amount of water loss in the continents.
However, the water is not exactly lost, it is only transformed. The water vapor obtained by the previous processes becomes part of the atmosphere . As it is lighter, it ascends and gradually cools down. This cooling results in the condensation of water , a process by which the water goes from being in a gaseous state to a liquid, which in this case would be small drops of water that when they come together begin to form clouds . Thanks to the action of the wind, the clouds disperse and move towards the continents.
Clouds continue to cool until precipitation occurs . Depending on climatic factors, precipitation can take the form of rain, sleet, snow or hail.
In a way, precipitation returns the water to the land (in liquid or solid state) and thus the water cycle can start all over again. Once the water reaches the continents it forms the rivers and lakes on the surface and infiltrates the ground. Thanks to infiltration, plants can use water to carry out photosynthesis and it can also accumulate in the ground in the form of aquifers. Finally, inland waters flow into the sea, closing the cycle.
The water cycle is a fundamental process since we could understand it as the water recycling process . As the water changes its state, its properties change and it is purified. In addition, water is once again available so that living beings can use it and thanks to the wind, for example, it can be distributed throughout the planet.
The water is essential for life , but not only serves to hydrate. Water is also a means of transport and a storage system. In water there are also essential elements that both animals and plants need to live (salts, iron, nutrients) and thanks to the water cycle and its movement they are distributed and reaching almost all parts of the planet. And, of course, water also constitutes the medium where many organisms live and depending on the quantity and chemical composition of the water, some communities of living beings or others may develop, just as it could influence the terrestrial ecosystems that are close to them.