THE Water is a substance found on our planet in the form solid, net and gaseous and which is characterized by being formed by two hydrogen atoms and an oxygen atom (H2O). This substance is essential for life on our planet, since it is part of the composition of the body of living beings and also acts in the different reactions that occur in these beings.
→ water formula
Water is a substance made up of two hydrogen atoms and one oxygen atom that are joined by bonds called a simple covalents. The chemical formula of water is therefore H2O. THE water molecule is a molecule polar and has a shape similar to a V. See the following figure:
The water molecule is formed by two hydrogen atoms bonded to one oxygen.
One water molecule binds to another through bonds called a hydrogen bonds. When we observe the water in the solid state, these links stand out for being more durable that in the liquid state, where the links are fragile and quickly undone and redone. This ability to undo and remake itself guarantees the fluidity from water. Unlike what is observed in the liquid state and in the solid state, in the gaseous state the molecules meet in a way individual, that is, there are no connections between them.
Read too:Atoms and molecules
→ water properties
Water is a substance that has some important properties. See, below, some of them:
Cohesion of molecules: The water molecules stay next one of the others because of the bonds they establish (hydrogen bonds). This property is known as cohesion and it is essential for living things. An example of this is the fact that water moves through plants due to its cohesion property.
Temperature moderation: Water has an ability to absorb and release heat. This property is extremely important when we think about cooling our body. O sweat it is rich in water, and as it evaporates, the body temperature decreases.
Floating ice over liquid water: Water is a substance that in its solid state floats on the liquid state. This is because ice is less dense than water in its liquid form. This property allows, for example, that, in frozen lakes, there is life under the surface.
Universal solvent: Water is an important solvent, that is, it is capable of dissolving substances. This ability is important, for example, to ensure that substances are transported by our body.
→ water in the human body
In the human body, water is essential for the performance of various functions of the body, besides, of course, being part of the body composition. The human body has about 70% of water, this amount varies according to the individual's stage of life, being higher in the first six months of age.
Water is essential for the performance of several functions, its main ones are:
Thermoregulation: Water acts to maintain our body temperature. The release of sweat ensures the reduction of our body temperature.
Transport of substances: Many substances are transported in a dissolved form. Blood plasma, for example, is rich in water and ensures the transport of various nutrients throughout the body.
Participation in chemical reactions: As many reactions take place only in an aqueous medium, water is essential in these processes.
Protection: Water protects our body in several ways, as it is part, for example, of the tear composition, which protects the eyes; the aminotic fluid, which protects the fetus in the mother's uterus; and synovial fluid, which acts as a lubricant protecting the joints.
Know more about: Human Body
→ Water loss by the human body
The human body uses water for the most diverse activities and also loses a large amount of this substance during some processes. Here are some of the main ways our body loses water:
Breathing: During the process of breathing, a considerable amount of water is lost. in people sedentary, the breath loss is believed to be approximately 300 ml of water per day. This value is increased in people who practice activities.
Urine: Via urine, a large amount of water is lost daily, which is the main form of water loss by the body. It is estimated that a person loses, in this way, between 1000 ml and 2000 ml of water daily. It is noteworthy that this will depend on several factors, such as room temperature and the amount of water consumed by a person. On cold days, for example, people tend to lose more water through urine, due to the reduction in sweat loss.
Elimination of feces: In faeces, little water is lost, however, this type of water loss should be watched carefully when a person has diarrhea. At diarrhea, the large elimination of liquid stools can trigger, for example, the dehydration.
Sweat:Sweat is also an important form of water loss, and its elimination is related to the reduction of our body temperature. We lose more water through sweating on hot days and when we do physical activities.
One of the ways our body loses water is through sweat.
Faced with so many losses and functions that water plays in our body, it is clear the need to ingest an adequate amount daily. The recommendation of the Ministry of Health is that, every day, at least, two litters of water. This value can be increased in situations of extreme heat and physical activity practices, for example.
→ the water on the planet
We inhabit planet Earth, also known as “Water planet”. This name is due to the fact that about 71% gives terrestrial surface is covered by water, corresponding to approximately 1.4 billion km3. The Earth is constituted by water in its three physical states:
Liquid |
Gaseous |
Solid |
Water is found in oceans, seas and continental waters. The oceans represent more than half of the water available on Earth. these are a big water mass responsible for gaseous envelope and by climate control, because absorb and reflect most of the solar energy. The seas are also large bodies of salt water and considered part of the oceans, which enable fishing and maritime transport, provide minerals, among other functions used by humans. You rivers, lakes, groundwater (continental waters) and glaciers are of paramount importance for living beings as they provide fresh water.
Of the total water that covers the earth's surface, about 97,5% corresponds to salt water, and only 2,5% corresponds to fresh water. Look:
The available fresh water corresponds to the bodies of water intended for human consumption (remembering that sea water can be consumed as long as it goes through the process of desalination). Fresh water is distributed in glaciers, eternal snow, groundwater, rivers, lakes, soils and swamps.
THE distribution of fresh water in the world varies according to presence of ecosystems in different regions, therefore, it's not uniform. Therefore, some areas have greater availability of water than others.
Some countries (such as Russia, Brazil, Canada, United States, India, Peru and Colombia) present big reserves of fresh water, concentrating, approximately, 60% of full availability. The countries most vulnerable to water scarcity are in the Middle East, such as Qatar and Kuwait.
→ Concentration of fresh water by continent, according to the National Water Agency:
America: 39.6%
Asia: 31.8%
Europe: 15%
Africa: 9.7%
Oceania: 3.9%
→ Potable water
First, it must be emphasized that not all fresh water is drinkable. Easily accessible water, such as that from rivers and lakes, is not necessarily of good quality. In order to be considered potable, the water needs to be free from contamination.
Water suitable for consumption is called potable water and poses no health risks.
According to the Ministry of Health, drinking water is defined as:
“water that meets the standard of potability and that does not pose a risk to health”. |
Therefore, it corresponds to the water that can be consumed by meeting the physical requirements, chemicals and biological that establish its quality and guarantee the safety and well-being of the consumer.
Know more:How is the water treatment?
In order to be considered potable, water must also meet certain requirements, such as being odorless, colorless and have indefinable flavor, and also can not present pathogenic organisms (organisms that cause disease).
→ water cycle
THE replacement of fresh water in the world is only possible due to the cycle from water. But what does this mean? water cycle corresponds to the set of transformations of the water between the terrestrial surface and the atmosphere. During this circulation, water can be found in different physical states.
Watch:
The water cycle represents the water transformation process that takes place between the earth's surface and the atmosphere.
The water present on the earth's surface (in oceans, seas, lakes and rivers) undergoes the so-called process of evaporation. This is possible due to the solar energy that reaches the surface, turning liquid water into steam. This steam rises and forms clouds. Due to weather conditions, these clouds, sometimes loaded with moisture, precipitate (in liquid form, snow or hail), then returning to the surface. Some of this water evaporates before reaching the ground; part returns to the oceans, seas, rivers and lakes; and part infiltrates the soil, supplying the underground reservoirs, such as aquifers.
→ water use
Water, in addition to being essential for the survival of living beings, is used for several activities that are important to the development of a society. According to the Secretariat of the Ministry of the Environment, the water use can be classified as follows:
→ Consumptive use: it corresponds to the direct use of water (affecting the amount of water available), such as in human supply, animal watering, irrigation, among other activities.
→ non-consumptive use: corresponds to the indirect use of water (affecting the quality of available water), such as in use for leisure, navigation and energy generation.
According to the Food and Agriculture Organization of the United Nations (FAO), about 70% of water consumption corresponds to agricultural sector. already the industrial sector it uses, approximately, of 22% water consumption; followed by domestic supplies, which consumes about 8% of water, according to the Ministry of the Environment.
Read too:The activities that consume the most water
→ lack of water in the world
Water scarcity is already a reality in many parts of the world, causing many conflicts.
The issue of water is already the subject of debate among several countries, the scientific community and society in general, which is already feeling the effects caused by the scarcity of water and by floods that provoke countless tragedies. Climate change is already being felt in a large part of the planet (although sometimes contested). Many countries are already experiencing the reality of water shortages. According to the Unesco report of 2018, about 30% gives world population lives in areas that are affected or by floods or by extreme drought.
The report also estimates that the population affected by floods will increase from 1.2 billion for 1.6 billion in 2050. Already the people affected by drought and desertification will reach 1.8 billion. It is estimated that about 3.6 billion of people inhabit areas that have potential for water scarcity, and this number may reach up to 5.7 billion in 2050.|1|
There are several factors related to the possible lack of water in the world, such as the waste, O population increase, a urbanization, at climate changes, a pollution, O logging, and the intensification of industrialization. These are, therefore, worrying and the agenda of several conferences about the environment.
According to the United Nations (UN), more than 2 billion people in the world do not have access to safe drinking water. The organization also alerts to the inequalities found in the countries, as each one of them lives a different reality regarding the consumption and availability of water. Although not evenly distributed, the United Nations Educational, Scientific and Cultural Organization (UNESCO) points out that there is, in the world, enough water to meet the demand of the population that grows more and more, especially in developing countries. However, this last organization warns of the need to change the issue of use, of management It's from share From water resources.
Regarding the Brazil, according to the Ministry of the Environment, between 20% and 60% of the water intended for consumption are wasted along the distribution. You habits of a large part of the Brazilian population don't cooperate for water preservation. It is therefore necessary to rethink consumption, avoid waste and promote actions that project resources anywhere in the world, in order not only to avoid water shortages but also possible conflicts between nations.
→ water preservation
We know that the availability of water is increasingly reduced worldwide, due to issues such as use irrational, pollution, waste, contamination, among other problems associated with resources water.
Unesco, through this water issue, released a report in 2018, during the Forum World Water, which brings alternatives that help in the management of water in the world and preserve this resource Natural. These solutions are based on nature itself, so there is no need for major works to achieve this goal. Some of them are: expansion of dry toilets, reforested areas, restoration of riparian forests, spring recovery etc.
Preserving water is fundamental to sustaining life, especially that of future generations. And there are many actions that we can take with the objective of saving water resources, not delegating this function only to the government or to agencies and institutions. A change of habit is extremely necessary, starting with small actions, such as:
don't take long showers and turn off the taps while brushing your teeth;
don't throw garbage in the toilet;
do not use soap, excessively, when washing clothes, to avoid greater use of water;
reuse the water used to wash clothes and use it for other cleaning activities;
do not wash sidewalks under running water;
turn off the tap while the dishes are soaped;
use biodegradable soap or detergents;
do not throw frying oil or leftover food into sinks or toilets;
use rainwater;
do not litter in lakes and rivers.
Grades:
|1| Unesco encourages “nature's solutions” for water management. To access, Click here.
by Rafaela Sousa
Graduated in Geography and Ma. Vanessa Sardinha.
