All theories of the origin of life on Earth are somehow connected with water. She is always with us, moreover, within us. The most ordinary, simple water, included in the tissues of the body, makes every new breath and heartbeat possible. It participates in all these processes due to its unique properties.
What is water: definition
From a scientific point of view, the main liquid of the planet is hydrogen oxide - a binary inorganic compound. The molecular formula of water is probably known to everyone. Each structural element of it consists of one oxygen atom and two hydrogen atoms connected by a polar covalent bond. Under normal conditions, it is in a liquid state, has no taste and smell. In small volumes, plain water without impurities is colorless.
Biological role
Water is the main solvent. It is the nature of the structure of the molecule that makes such a definition possible. The properties of water are related to its polarization: each molecule has two poles. Negative is associated with oxygen, andpositive - with hydrogen atoms. The water molecule is able to form so-called hydrogen bonds with particles of other substances, attracting oppositely charged atoms to its "+" and "-". In this case, the substance that becomes a solution must also be polarized. One molecule of it is surrounded by several particles of water. After transformation, the substance becomes more reactive. Water is used as a solvent by all cells of living organisms. This is one of those properties that define its biological role.
Three States
Water is known to us in three forms: liquid, solid and gaseous. The first of these states of aggregation, as already mentioned, is characteristic of water under normal conditions. At normal atmospheric pressure and temperatures below 0 ºС, it becomes ice. If the heating of the substance reaches 100 ºС, vapor is formed from the liquid.
It should be noted that substances similar in structure under normal conditions are in a gaseous state and have a low boiling point. The reason for the relative stability of water is in the hydrogen bonds between molecules. To go into a state of steam, you need to break them. Hydrogen bonds are strong enough that it takes a lot of energy to break them. Hence the high boiling point.
Surface tension
Due to hydrogen bonds, water has a high surface tension. In this regard, it is second only to mercury. Surface tension occurs at the boundary of two different media and requires the expenditure of a certain amountenergy. This property results in interesting effects. In weightlessness, the drop takes on a spherical shape, as the liquid tends to shrink its own surface in order to conserve energy. Similarly, water sometimes behaves on non-wettable materials. An example is a dew drop on leaves. Due to the force of surface tension, water striders and other insects can slide along the surface of the pond.
Insulator or conductor?
In life safety classes, children are often taught that water is a good conductor of electricity. However, this is not quite true. Due to the peculiarities of its structure, pure water is weakly dissociated and does not conduct current. That is, in fact, it is an insulator. However, under normal conditions, it is practically impossible to meet such pure water, since it dissolves many substances. And thanks to numerous impurities, the liquid becomes a conductor. Moreover, the ability to conduct electricity can determine how pure the water is.
Refraction and absorption
Another property of water, known to everyone from school, is the ability to refract light rays. After passing through the liquid, the light changes its direction somewhat. This effect is associated with the formation of a rainbow. Also, the refraction of light and our perception of it underlie errors in determining the depth of water bodies: it always seems smaller than it actually is.
However, the light of the visible part of the spectrum is refracted. And, for example, infrared rays of waterare absorbed. That is why the greenhouse effect occurs. To understand the hidden possibilities of water in this sense, one can refer to the characteristics of the atmosphere on Venus. According to one version, the evaporation of water led to the greenhouse effect on this planet.
Water color
Everyone who has seen the sea or any fresh body of water and compared it to liquid in a glass has noticed a certain discrepancy. The color of water in a natural or artificial reservoir never matches what is observed in the cup. In the first case, it is blue, blue, even greenish-yellow, in the second it is simply absent. So what color is the water really?
It turns out that a pure liquid is not colorless. It has a slight bluish tint. The color of the water is so pale that in small volumes it seems completely transparent. However, in natural conditions, it appears in all its glory. Moreover, numerous impurities, as in the case of conducting electricity, change the properties of water. Everyone has met at least once a green pond or brownish puddles.
The color of water and life
The color of the reservoir often depends on the microorganisms that actively multiply in it, the admixture of rocks. The greenish color of the water often indicates the presence of small algae. In the sea, areas painted in this shade, as a rule, abound with living creatures. Therefore, fishermen always pay attention to what color the water is. Clear blue waters are poor in plankton, and hence those who feed on them.
Sometimes microorganisms give the most bizarre shades. Lakes with chocolate-colored water are known. The activity of unicellularalgae and bacteria turn a body of water turquoise on the island of Flores in Indonesia.
In Switzerland, at the Sanetsch pass, there is a lake with bright pink water. A slightly paler shade has a body of water in Senegal.
Colorful miracle
An amazing sight appears before tourists in America, in the Yellowstone National Park. Morning Glory Lake is located here. Its waters have the purest blue color. The reason for this shade is all the same bacteria. Yellowstone is famous for its numerous geysers and hot springs. At the bottom of Morning Glory Lake is a narrow volcanic vent. The heat rising from there maintains the temperature of the water, as well as the development of bacteria. Once upon a time, the entire lake was crystal blue. However, over time, the mouth of the volcano became clogged, which was facilitated by tourists with their love to throw coins and other garbage. As a result, the surface temperature dropped, and other types of bacteria began to multiply here. Today, the color of the water changes with depth. At the bottom, the lake is still deep blue.
Several billion years ago, water contributed to the emergence of life on Earth. Since then, its importance has not diminished at all. Water is necessary for a number of chemical reactions that occur at the cellular level; it is part of all tissues and organs. The oceans cover approximately 71% of the planet's surface and play a huge role in maintaining the stability of such a giant system as the Earth. The physical and chemical properties of water make it possible to call it the main substance for all living things. Reservoirs, being the habitat of multicellular microorganisms, in addition, become a source of beauty and inspiration, demonstrate the enormous creative abilities of nature.
