Water is the juice of life... So said the famous Leonardo da Vinci. And there is no point in arguing here, because water is the basis for all life on the planet. But what is water? It is a clear liquid that has no taste or odor. Pure water is a bond between two hydrogen molecules and one oxygen molecule.
The chemical formula for water is H2O. It seems to be nothing complicated and surprising. But if you dig deeper, you begin to understand how serious the role of water is in our world and the origin of life on the planet! One of the important functions of water to sustain life on Earth is its continuous circulation in nature.
General information about water
- occupies 2/3 (about 71%) of the area of our planet. And if everyone knows that there is water in the sea, in lakes and rivers, then such interesting fact, which says that the human body is as much as 70% water, is known to a few. A person needs to drink about 3 liters of water daily for normal life. And if more than 7% of the fluid is lost, the body begins to die.
- Water is an excellent solvent due to the fact that water molecules have a very high polarity. Therefore, if water comes into contact with any substances, then they will surely dissolve in it. The exceptions are mineral compounds, as well as fats.
- Ideally purified or, as it is also called, distilled water, that is, water from which all salt impurities have been removed, does not conduct electric current. But it should be noted that, based on the previous paragraph, such water does not exist in nature under natural conditions. The water is artificially distilled.
- Water can be in three states of aggregation: "liquid" - water, "solid" - ice, "gaseous" - water vapor.
The water cycle in nature
Water does not disappear from the planet anywhere, but carries out a continuous cycle in nature. Let's give the simplest example: you water a tree from a bucket. It would seem that when the water in the bucket runs out, it simply does not exist anymore. But everything is not so simple. The water ended in the bucket, but it ended up in the ground. And now, when the tree "gets drunk", this same water that was used for irrigation will evaporate from the leaves of the tree and rise to heaven, but only in a different state. To put it more scientifically, the water cycle in nature is the constant and continuous movement of water masses, which occurs under the influence of gravity and the energy of the Sun (that is, heat).
Thanks to the water cycle on the planet, there is a continuous renewal of water masses. Renewal of water occurs in any part of the geographic shells. This process is gradual and quite lengthy. For example, it will take about 3 thousand years for the water of the World Ocean to be completely renewed. Antarctic glaciers renew their water masses in general for tens of millions of years. But pairs of clouds change the water in their composition in just one week, and the water in living organisms (including people) is completely renewed in a few hours.
Such a phenomenon as the circulation of water masses in nature consists of the evaporation of water from the surfaces of seas, lakes, rivers and dry areas of the planet. Evaporated water with the help of air flows rises, turning into steam. Due to the fact that at a height where the clouds are, the temperature is significantly lower than at the surface of the earth, vapor condensation occurs, that is, the vapor turns back into water, the water that we most often encounter - liquid. Again, water falls to the ground in the form of rain or snow.
The lion's share of the so-called "supplier" of moisture in the earth's atmosphere falls on the ocean. Thanks to the energy of the sun, the water in the ocean warms up and evaporates due to this. Remarkable is the fact that although the water in the ocean is salty, it still evaporates in the form of fresh vaporous masses. If we take the entire amount of evaporation from the surface of the earth, then the ocean will account for more than 85%. The remaining 15% evaporate already from the land, due to the "breathing" of plants and animals, as well as evaporation of water from rivers, lakes, swamps and groundwater.
This is how the water cycle occurs due to the constant movement of water masses on earth. That is, water evaporates from the surface of the ocean, then falls on land in the form of solid or liquid precipitation, seeps into the ground, meets on its way with groundwater, which one way or another will find an outlet to the World Ocean, and the ocean will again release water into the atmosphere. This cycle is endless and extremely important for all living things.
Schemes of the water cycle in nature
We present to your attention several diagrams-drawings illustrating the water cycle in nature. To display the scheme in full size, click on it with the left mouse button.
The value of water in nature
This can be said very briefly: it matters a lot! She became the primary source of life on our planet. Without air on Earth, life is possible (anaerobic organisms), but without water it is not. Water is the basis of all living things. It has been scientifically proven that even interplanetary comets have water in their composition. The Bedouins said: "Water is more precious than gold." And they were right, because a wandering traveler cannot do without water even for three days. And if water supplies run out, then death cannot be avoided. What is gold here?
Aggregate states of water in nature
Water is unique and the only substance that can exist in three different states: liquid, vapor, and ice. Not a single substance on the planet is capable of such a thing! Due to the fact that water is constantly changing its state of aggregation and its circulation occurs in nature.
Properties of water in nature
Water is unique. Here are some facts that prove it:
1. At the moment of transition of water from a liquid to a solid state, in other words, when freezing, it reduces its density, although all other substances in the world increase it by freezing. Due to this, the ice rises to the surface and is seized by an ice crust, which does not allow air to pass through, which makes it possible even at extremely low temperatures to retain heat in the water that is under the ice. Therefore, living organisms do not die. Imagine what would happen if the water behaved differently: all living organisms living in the depths of the waters of the seas, lakes and oceans would have all died in frost.
2. The value of the surface tension of water is much higher than that of any other substance, which affects the formation of raindrops. And this, of course, has a huge impact on the water cycle in nature.
3. Water has the highest boiling point of any liquid in nature. This slows down the evaporation process, which allows less loss of moisture.
Video: Water cycle in nature
The unity of the Earth's natural waters requires consideration of groundwater in its inseparable connection and interaction with all types of natural waters and with the rocks in which they are formed, accumulated and moved. Therefore, below are information about the water cycle in nature, the types of water in rocks and the main patterns of their movement; the types of underground waters and the main properties of rocks in relation to water are considered.
Water is one of the most common substances in nature. It is found in vapor, liquid and solid states in all major spheres of the Earth: in the atmosphere (vapours, clouds, snow, hail, rain), hydrosphere (oceans, seas, lakes, rivers, swamps, glaciers, snow), lithosphere (groundwater , vapors, ice, bound water), the biosphere (in all living organisms and plants).
The total volume of water in the World Ocean is 1338 million km 3, the amount of land water (with ice) is 24.5 million km 3, the atmosphere contains about 14,000 km 3 of water, and in the rocks of the earth's crust - about 400 million km 3, moreover, the so-called bound water, apparently, accounts for the bulk of them. Thus, in total on our planet (in the oceans, on the land surface and in the earth's crust) there is approximately 1.8 billion km 3 of water. At the same time, the share of fresh water does not exceed 2% (35 million km3).
All types of water are interconnected with each other. Water and its phase states are studied by various disciplines: vaporous water - by physics and meteorology, solid (ice) - by glaciology and permafrost; liquid surface - oceanology and hydrology, underground - hydrogeology.
The waters of the atmosphere, hydrosphere and lithosphere are in continuous interaction and movement. Evaporating from the surface of the oceans, seas, lakes, rivers and other bodies of water, as well as from the land surface, water in the vapor state passes into the atmosphere, from where, under favorable conditions, it again falls to the Earth's surface in the form of rain, snow, hail, making up the links of the general water cycle. on Earth, which is one of the most grandiose processes that determine the formation of the Earth's surface, metabolism and energy.
Precipitation falling on the Earth's surface partly drains through rivers into the seas and oceans (surface runoff), partly seeps (infiltrates) through the soil, providing plant moisture and groundwater recharge, and partly evaporates again into the atmosphere. Groundwater, in turn, moving along the layers of fractured and porous rocks, enters surface watercourses and reservoirs (rivers, lakes, seas, oceans), providing their underground nutrition, and thus again enters into the general water cycle in nature, starting from the evaporation of surface water.
During the cycle, water resources are constantly renewed in the atmosphere, on the Earth's surface, in the biosphere and the upper part of the lithosphere. So, the atmosphere contains on average about 14 thousand km 3 of water, mainly in the form of steam. However, due to the constant replenishment of atmospheric moisture by evaporation, 577 thousand km 3 of precipitation annually falls on the Earth's surface.
If the movement of moisture in the atmosphere and on the surface of the Earth is quite fast, then with depth the water exchange slows down significantly, however, deep groundwater also participates in the general water cycle.
The processes of water transition from one geosphere of the Earth to another, which make up the general water cycle in nature, are made up of evaporation (I), precipitation (O), surface ((? sur) and underground ((? PO dz) drains.
Distinguish big, small And inland, or local, gyres. With a large circulation, part of the water that has evaporated from the water surface of the oceans and seas is carried by the wind to land and falls there in the form of precipitation, which is then spent on surface and underground runoff, as well as on evaporation. With a small circulation, the water that has evaporated within the oceans and seas falls out here. During the intracontinental circulation, water evaporated within the continents (from the surface of lakes, swamps, rivers, from land and with the help of vegetation) falls again on the mainland.
On fig. 5.1 shows the general scheme of the water cycle in nature and its individual components.
The determining influence on the transition of water from one state to another and its movement from one sphere of the Earth to another, i.e. on the development of the processes of the water cycle in nature, have climatic factors. In the formation of individual components of the cycle, an essential role is played by geomorphological, geological-lithological, physical-geographical and other factors that largely determine surface runoff, infiltration of precipitation (i.e., their infiltration through the soil into porous and fractured rocks), evaporation , transpiration (evaporation of moisture by vegetation), underground runoff and the development of other important processes. Therefore, when studying the hydrogeological conditions of any region or deposit, it is important to take into account the climatic, geomorphological, geological-lithological, physical-geographical and other features and conditions that affect the water balance of the region under study.
All atmospheric precipitation is divided into two types: precipitation that falls on the surface from clouds (rain, hail, snow, cereals), and precipitation that forms directly on the surface of rocks due to a decrease in air temperature to the dew point (dew, hoarfrost, frost, ice) . Water balance equation in general view was proposed in 1884 by A.I. Voyeikov:
where X 0- the average annual amount of precipitation in the form of rain, snow, frost or dew; At 0 - the total stock, i.e. part of the precipitation
7 - precipitation (o - snow, b- rain); 2 - well permeable rocks; 3 - low-permeability rocks; 4 - impermeable rocks
Rice. 5.1.
5 - source; b - the direction of movement of water and water vapor that flows down the surface or underground; Z 0 - part of the precipitation, which is spent on evaporation and transpiration (minus condensation).
Precipitation. Systematic observations of atmospheric precipitation are very important for the national economy. With the help of instruments, observations have been carried out since the middle of the 19th century, as a result, certain patterns were established - the alternation of watery years (rains, floods) with low water years (droughts). Precipitation is measured by the thickness of the water layer in millimeters per year and varies widely. So, some areas of India receive 12,000-14,000 mm, and some areas of Chile - only 1 - 17 mm. The amount of precipitation varies greatly on the territory of Russia. So, on the Black Sea coast of the Caucasus, 1200-3000 mm of precipitation falls, in Moscow - 500-600 mm.
In the Non-Chernozem zone, the average annual precipitation is 400-600 mm, and groundwater is fed from 110 (upper reaches of the Volga and Western Dvina) to 20 mm (Nara river basin - southeast Ryazan region). In the European part, 480-500 mm of precipitation falls annually, 170-180 mm of it flows down, the rest goes to evaporation and is again included in the moisture cycle or remains in the soil (Fig. 5.2).
It has been established that moisture circulation in the south of Russia is carried out 4 times a year, and in general in the entire territory of the European part of Russia - 2.5 times a year (Kiryukhin, Tolstikhin, 1987).
Evaporation is the transition of a substance from a liquid or solid state to a vapor state. A year from the surface of the ocean in the tropics, a layer of water 1.5 m thick evaporates, and in polar countries - 0.5 m. Evaporation and evaporation are distinguished. Evaporation is the actual amount of evaporation from the Earth's surface, and evaporation is the maximum possible evaporation from the water surface under existing meteorological conditions. Both of these values are subject to daily and annual fluctuations: during the day and summer they are greater than at night and in winter.
Evaporation should be taken into account when solving issues of irrigation and drainage melioration. In the tundra, evaporation is 70-120 mm, and evaporation is 200-300 mm, in the steppe - 240-550 and 600-1100 mm, respectively, in the desert - 50-100 and 1500-2000 mm. Annual evaporation and evaporation in arid regions is greater than the annual amount of precipitation. The evaporation of moisture from plants is called transpiration. During the formation of 1 g of plant tissue, 300-400 g of water evaporates. During the vegetative period, grasses and cultivated plants evaporate from 1 ha 229-254 mm, wheat - 200-300 mm, coniferous trees- 102-154 mm.
Rice. 5.2.
feeding value (mm/year): 7 - 110-80; 2 - 80-70; 3 - 70-60; 4 - 60-50;
5 - 50-40; 6 - 40-30; 7 - 30-20
The main fluid of the planet
Water is the most important component of the life of any biological organism on Earth. Therefore, it is important to study, observe and monitor the quantity, quality and condition water resource planets. The main reserves of this life-giving moisture are concentrated in the oceans. And already evaporating from there, moisture nourishes the Earth, thanks to a process called the water cycle in nature. Water is a very mobile substance and easily changes from one state to another. And, thanks to this, it can easily reach the most distant corners from the source. How does this process take place?
How and why does water circulate?
Under the influence of heat radiated by the Sun, water constantly evaporates from the surface of the ocean, turning into a gaseous state. Together with the currents of warm air, the steam rises up, forming clouds. They are easily blown away by the wind from their original place of evaporation. Gradually capturing all new vapors on their way, the clouds cool down on the way up. At some point, the next stage begins - condensation. It is possible when the air comes to a state of saturation (100% humidity) with water vapor. This usually happens when there is sufficient cooling. It is known that maximum amount the vapor that can be held in the air is proportional to its temperature, therefore, at a certain moment of cooling, the cloud becomes saturated with steam, which leads to the transition of water to the next - liquid or crystalline - state. And if the cloud at that moment is still above the ocean, then the moisture returns to where it came from. Thus ended one small water cycle in nature. This process never stops. Water over the world's oceans is constantly circulating.
How water circulates over land
Not all moisture falls back into the ocean. A large amount of steam, together with the trade winds and monsoons, goes deep into the continents, falling as it moves in the form of precipitation to the Earth. Some of this moisture is retained in the upper layers of the soil, nourishing the plants, the other part flows down to streams and rivers, so that, having reached the seas and oceans, it evaporates again and enters the next water cycle in nature. A very small proportion of the precipitation will seep through the soil deep into, and, having reached the waterproof layer (clay, rocks), will flow down this slope. Some of the groundwater will find its way back to the surface, forming crystal clear water springs to later flow into rivers and evaporate again for the next cycle. And their other part, through cracks and crevices, will continue to seep into the bowels of the Earth until it reaches the layers with high temperature, where it will again turn into steam in order to spin again in the underground cycle or break out to the surface with a thermal source.
Water routes in nature
Every year, about four hundred thousand cubic kilometers of water evaporate into the air, and only one fifth of them falls on land, the area of \u200b\u200bwhich is three times smaller than the surface of the world's oceans. Water evaporates from the land surface not only by soil, but also by vegetation: every leaf on a tree and every blade of grass on Earth. Tracking all the possible travels of water is extremely difficult. But to simulate a greatly simplified version that demonstrates the water cycle in nature for children is quite realistic even in their own apartment.
An experiment demonstrating the evaporation and condensation of moisture
To demonstrate the first stage of the cycle - the evaporation of water from the surface of reservoirs under the action of sunlight - it will be enough to take a glass filled up to half with water, place it in a plastic hermetically sealed bag and attach it with adhesive tape to the window glass on a sunny day. After a while (depending on the temperature in the room and the intensity of the sunlight), you will see that the walls of the bag are fogged up, and after a while, water droplets form on them.
Demonstration model of the complete cycle of the water cycle
A more complex model can be assembled using a container partially filled with blue-tinted water (imitation of the oceans), a transparent, possibly perforated, bag filled with enough sand to rise more than half above the water (land). Close the entire structure as tightly as possible with plastic wrap and secure. Above the "land" put a small container with ice (the ice will create the cold necessary for the experiment in the upper layers of the "atmosphere"), above the "ocean" place a table lamp (the Sun), which will radiate heat. Turning it on, after a while we get on the film, over land, in a cold place, moisture condensate, which a little later will fall on land in drops. And if the bag is perforated, then you can see how moisture, seeping through the sand, flows down to the ocean.
What's left for us to do
The water cycle in the biosphere is very important process for the entire planet. Violation or loss of at least one link will lead to global and, very likely, irreparable consequences for everyone. Australian and American scientists, based on their observations of the weather, covering 50 years, came to the conclusion that the water cycle in nature due to global warming began to accelerate. And this, in turn, will lead to the fact that dry areas will become even drier, and where the climate is now rainy, even more precipitation will fall. All this proves one thing: humanity should be more serious about its activities, which are inextricably linked with nature.
Water is the most abundant substance in the biosphere. The water cycle in nature is a continuous closed process of water movement between the hydrosphere, atmosphere and lithosphere on Earth. This becomes possible due to the ability of water to change its state. On our planet, water exists in three states of aggregation - solid, liquid and gaseous.
The main water reserves are the salty waters of the seas and oceans (97%). Only 3% of the water in the total volume of the hydrosphere is fresh. And 70% fresh water is in a solid state in glaciers (2.24%). Groundwater accounts for 0.61% of fresh water, and the waters of lakes, rivers and atmospheric moisture, respectively, account for 0.016%, 0.0001% and 0.001%. Due to the continuous circulation of water the globe its total remains constant.
The water cycle is carried out due to evaporation, the movement of water vapor in the atmosphere, its condensation, precipitation and the presence of runoff. The cycle begins with the evaporation of water from the underlying surface of reservoirs. Air currents move water vapor from one area to another. Most of water evaporates from the surface of the world's oceans and, when condensed, returns as precipitation. A smaller proportion of evaporated water is carried to land by air currents. The volume of water that evaporates over land and is carried by air currents to the ocean is negligible. Thus, during evaporation, the seas and oceans lose much more water than they receive moisture during precipitation, on land - on the contrary. But the flow of river water constantly flows into the seas and oceans from the continents. This ensures the constancy of the volume of water on the planet.
In connection with the processes of moisture condensation, precipitation occurs. Part of the moisture of atmospheric precipitation evaporates, part forms temporary or permanent drains and reservoirs. A certain mass fraction of precipitation moisture seeps into the soil, forming groundwater.
In nature, there are several types of water cycles, depending on the place where the moisture evaporated and where the precipitation fell. There are large (world) and small (oceanic and continental) water cycles. With a large circulation, water vapor formed over the seas and oceans is carried by air currents to the continents, condenses there with precipitation, and moisture again enters the ocean in the form of runoff. This type of circulation is accompanied by a change in the quality of water, since during evaporation, salt water becomes fresh, and dirty water is purified.
In the process of the small oceanic cycle, water vapor formed over the ocean undergoes condensation and returns to the ocean in the form of precipitation. A small intracontinental circulation is the condensation of evaporated water over the land surface, and the subsequent precipitation over the continents. The final stage of the small continental circulation is also the World Ocean.
The speed of water transportation in different states is different, just as the time intervals of water consumption and the time of its renewal are different. The highest rate of water exchange is in living organisms (several hours). In the glaciers of the polar regions, the water cycle has been going on for thousands of years. The waters of the World Ocean are completely renewed in 2.7 thousand years.
What is the significance of the world water cycle in nature, you will learn from this article.
Importance of the water cycle in nature
How does the water cycle work?
The land and the oceans are heated by the sun's rays. As a result, water from a liquid state passes into a gaseous state, that is, steam, and rises up. The ocean supplies up to 86% of moisture to the atmosphere, and only 14% of vaporous moisture is obtained due to evaporation from the land. The water that evaporates from the surface is fresh water. It can be argued that the ocean is a colossal factory of fresh water. And without it, life on the planet would be impossible. The temperature in the atmosphere decreases with height and water vapor, having met with cold layers of air, cools down and begins to form clouds. Note that on land, water evaporates from rivers, lakes, streams and plant surfaces. Often, the evaporated water from the ocean returns to it as precipitation that falls from the clouds over the oceans and seas. Other clouds are carried by the wind to the mainland. Precipitation can fall in solid or liquid form. A particle of atmospheric precipitation falls into rivers, which, one way or another, carry their waters to the World Ocean, or to the Aral or Caspian Sea. Other water, which fell in the form of atmospheric precipitation on the ground, seeps down from the surface of the land and again flows down into the World Ocean as groundwater. Here the cycle begins again and again. In another case, the precipitation that fell into the soil through root system enters the plants. From there, it evaporates through the leaves into the atmosphere.
What is the importance of the water cycle in nature?
In nature, the water cycle is very important. It not only unites parts of the hydrosphere, but connects all the shells of the planet with each other: the hydrosphere, lithosphere, atmosphere and biosphere. During the cycle, water occurs in 3 states: solid, liquid, gaseous. She endures a large number of substances that are essential for life on the planet. The water cycle regulates river flow over time. Without it, rivers would have water only during periods of snowmelt or precipitation. This process is also important for plants, since mineral solutes and vitamins enter them from the soil with water.
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