Water (hydrogen oxide) is a binary inorganic compound, chemical formula H 2 O. A water molecule consists of two hydrogen atoms and one oxygen, which are connected by a covalent bond. Under normal conditions, it is a transparent liquid, colorless (in small volumes), odor and taste.

Distribution of water On Earth, approximately 96.5% of the world's water is in the oceans, 1.7% of the world's reserves are groundwater, another 1.7% in glaciers and ice caps in Antarctica and Greenland, a small portion in rivers, lakes and swamps, and 0.001% in clouds (formed from particles of ice and liquid water suspended in the air). An interesting fact is that the Earth’s mantle contains several times more water than the amount of water in the World Ocean.

Three aggregate states of water Liquid Gaseous Solid Water on Earth can take on various forms that can simultaneously coexist with each other: water vapor and clouds in the sky, sea water and icebergs, glaciers and rivers on the surface of the earth, aquifers in the ground.

High Specific Heat Capacity Water has the highest specific heat capacity. A physical quantity numerically equal to the amount of heat that must be transferred to a body weighing 1 kg in order for its temperature to change by 1 °C is called the specific heat capacity of a substance.

The main climate thermoregulator Due to its high heat capacity, water in the seas and oceans, when heated in summer, absorbs a large amount of heat. Therefore, in areas located near water bodies, it is not very hot in summer and very cold in winter. This is due to the fact that in winter the water cools and gives off a large amount of heat.

Water vapor The optical properties of water vapor play a significant role in plant life. The fact is that water vapor strongly absorbs infrared rays with a wavelength of 5.5 to 7 microns, which is important for protecting the soil from frost. An even more effective remedy for frost is dew and the formation of fog: moisture condensation is accompanied by the release of a large amount of heat, which delays further cooling of the soil.

Biological role Water plays a unique role as a substance that determines the possibility of existence and the very life of all creatures on Earth. The human body consists of 70-80% water, some plants contain up to 90% or more water. On average, the body of plants and animals contains more than 50% water

Universal solvent Water acts as a universal solvent in which the main biochemical processes of living organisms occur. Each molecule of the solute is surrounded by water molecules, and the positively charged sections of the molecule of the solute attract oxygen atoms, and the negatively charged hydrogen atoms. Since a water molecule is small in size, many water molecules can surround each solute molecule.

Water is of key importance in the creation and maintenance of life on Earth, in the chemical structure of living organisms, in the formation of climate and weather. It is the most important substance for all living beings. Water is necessary for the life of all unicellular and multicellular living beings without exception. Without water there would be no life on Earth.

Used literature and website materials: baltecopool.ru dic.academic.ru teme-mirovoy-okean-tixii/ teme-mirovoy-okean-tixii/ Water-Posters_i _.htm Water-Posters_i _.htm ru.wikipedia.orgWater Physics. 8kl. : textbook for general education institutions / A. V. Peryshkin.

The role of water in nature

WATER Water is the most common and important substance on Earth. The total water reserves on the planet are 133,800 cubic kilometers. Of this amount, 96.5% comes from the World Ocean, 17% is groundwater, 1.74% is glaciers and permanent snow. However, the total fresh water reserves account for only 2.53% of the total water reserves.

Fresh water supplies on the planet are limited, but they are constantly renewed. The rate of water renewal determines the water resources available to humans. In the patriarchal era on Earth, the water cycle, which included drains, rains, snowfalls, floods, etc., was, despite natural disasters, beneficial for humans. Rains and meltwater irrigated the land, brought substances beneficial to plants, and revived the very environment of nature.

With the development of civilization, when chemical fertilizers, detergents, internal combustion engines appeared, when human activity became nature-transforming, when man separated himself from nature and stood above it, human waste began to pollute everything, and primarily reservoirs. In ancient times, when man lived in harmony with nature, any fresh water, with the exception of swamp water, was potable. There was sea water and just water, without any additional definitions. It was believed that water was a mineral that a person should consume naturally.

Now a person is talking about a separate type of water - drinking water. In addition, there are waters of rivers and lakes where people can and cannot swim. There is wastewater, there is acid rain, there are emissions from industrial waste reservoirs, from which all living things in the water die. Today, the water cycle in nature is tightly connected with the technogenic environment.

In the primary water shell of the globe there was much less water than now (no more than 10% of the total amount of water in reservoirs and rivers at present). An additional amount of water appeared subsequently as a result of the release of water that was part of the earth's interior. According to experts, the Earth's mantle contains 10-12 times more water than the World Ocean. With an average depth of 4 km, the oceans cover about 71% of the planet's surface and contain 97.6% of the world's known free water reserves. Rivers and lakes contain 0.3% of the world's free water.

Glaciers are also large reservoirs of moisture; they contain up to 2.1% of the world's water reserves. If all the glaciers melted, the water level on Earth would rise by 64 m and about 1/8 of the land surface would be flooded with water. During the era of glaciation in Europe, Canada and Siberia, the thickness of the ice cover in mountainous areas reached 2 km. Currently, due to the warming of the Earth's climate, the boundaries of glaciers are gradually retreating. This causes water levels in the oceans to slowly rise.

Of great importance in the life of nature is the fact that the highest density of water is observed at a temperature of 4°C. When fresh water bodies cool in winter, as the temperature of the surface layers decreases, more dense masses of water sink down, and warmer and less dense masses rise from below in their place. This happens until the water in the deep layers reaches a temperature of 4°C. In this case, convection stops, since there will be heavier water below. Further cooling of water occurs only from the surface, which explains the formation of ice in the surface layer of reservoirs. Thanks to this, life does not stop under the ice.

Sea water freezes at a temperature of -1.91°C. With a further decrease in temperature to - 8.2°C, precipitation of sodium sulfate begins, and only at a temperature of - 23°C does sodium chloride precipitate from the solution. Since part of the brine leaves the ice during crystallization, its salinity is less than the salinity of sea water. Multi-year sea ice becomes so desalinated that it can be used to produce drinking water. The temperature of maximum density of sea water is below freezing point. This is the cause of quite intense convection, covering a significant thickness of sea water and making freezing difficult. The heat capacity of sea water ranks third after the heat capacity of hydrogen and liquid ammonia.

Snowflakes, as a rule, come in the form of six- and twelve-rayed stars, hexagonal plates, hexagonal prisms. As the air temperature decreases, the size of the crystals formed decreases and the variety of their shapes increases. The characteristics of crystal growth in air are associated with the presence of water vapor in it.

Today, all people know the fact that water is the source of life on Earth.