What is evaporation? How does the evaporation process occur?

The surrounding world is an interconnected organism in which all the processes and phenomena of animate and inanimate nature take place for a reason. It has been proved by scientists that even insignificant human interventions produce colossal changes. Despite this, people forget that they are also an integral part of the world around them. In this connection, changes are taking place in humanity as a whole.

All about the processes of life and the phenomena of nature begin to teach the children already at school, which is very important for their further understanding of what is happening around. As is known, the theme "Evaporation" (grade 8) is studied in the framework of the secondary school program, when students are already ready to reflect on the problems.

How evaporation occurs

Everyone knows what evaporation is. This phenomenon is the transformation of various substances into a state of vapor or gas. It is known that this process occurs at an appropriate temperature.

Usually, under natural conditions, many substances (both solid and liquid) practically do not evaporate or make it very slowly. But there are also such samples, for example, camphor and most liquids, which evaporate very quickly under normal conditions. Therefore they were called volatile. This process can be noticed with the help of a smell, since many bodies are toxic.

The evaporation of a liquid (water, alcohol) can be traced, by observing it for some time. Then the volume of this substance begins to decrease.

The basis of life on Earth

As you know, water is an integral part of the existence of the surrounding world. Without it, no being is possible, since all living beings are 75% water.

This is a special compound whose properties are exceptional. And only because of such anomalies of this phenomenon life in the form that now exists on the planet is possible.

Mankind has been interested in this miracle since ancient times. Another philosopher Aristotle in the IV century BC announced that water is the beginning of everything. In the 17th century, the Dutch mechanic, physicist, mathematician, astronomer and inventor Huygens recommended setting the water boiling and thawing coefficients for ice as the main levels of the thermometer scale. But what the evaporation of mankind learned much later. In 1783, the French naturalist and founder of modern chemistry Lavoisier reproduced the formula - H2O.

Properties of water

One of the incredible qualities of this substance is the ability of H2O to be in three different states under normal conditions:

• In the solid (ice);
• Flowing;
• Gaseous (evaporation of liquid).

In addition, water has a very high density, when compared with other substances, as well as a large heat of evaporation and latent heat of melting (the amount of heat absorbed or released).

At Н2О there is one more quality - an opportunity to vary the density from change of indicators of a thermometer. And the most striking thing is that if this quality was not there, the ice could not swim, and the seas, oceans, rivers and lakes would freeze all to the bottom. Then life on earth could not exist, because it is the reservoirs that are the first haven of microorganisms.

The cycle of H2O in nature

How does this process happen? Circulation is a continuous procedure, because everything in the world is interconnected. With the help of the cycle, conditions are created for the existence and development of life. It occurs between water bodies, land and atmosphere. For example, when a cloud collides with cold air, large drops appear, subsequently falling out in the form of precipitation. Then there is a process of evaporation, in which the sun heats the earth's plane, reservoirs, and the liquid rises upward, into the atmosphere.

Vegetation takes moisture from the soil, and the water circulation is carried out from the surface of the leaves. This procedure is called transpiration and is a physico-biological process.

The layers of the atmosphere, saturated with steam and near the ground, are then made lighter and begin to move upward. The smallest droplets of water in the atmosphere are restored approximately every eight to nine days.

Evaporation occurs due to cycling, and it is an important component in the circulation of H2O in nature. This process consists in the transformation of water from a liquid or solid state into a gaseous one and the introduction of steam that can not be seen in the air.

Evaporation and Evaporation

And what is the difference between the concepts of "volatility" and "evaporation"? First consider the first term. This is an indicator of the terrain climate, which determines how much liquid has escaped from the surface to the maximum. If we take into account that the humideness of the territory, as GN Vysotsky notes, is composed of the ratio of precipitation to volatility, this is the most important indicator of the microclimate.

There is also a certain dependence: if the evaporation is less, then the moisture is more. The described process relies on the humidity of the air, the wind speed and depends on them.

And what is evaporation? This phenomenon, in which a substance is converted from a liquid into a vapor or a gas in a certain phase. The reverse effect of this process is called condensation. If we compare these two phenomena, it is easy to determine how much water or ice resources are available for evaporation.

Evaporation process: conditions

There is always a certain amount of H2O molecules in the air. This indicator varies depending on certain conditions and is called humidity. This is a coefficient that measures the volume of water vapor in the atmosphere. Depending on this, the climate of the localities differs. Humidity is present everywhere. There are two of its types:

1. Absolute - the number of water molecules in one cubic meter of the atmosphere.
2. Relative - the percentage of vapor to air. For example, if the humidity is 100%, this means the atmosphere is completely saturated with water particles.

The higher the evaporation temperature, the more H2O molecules are contained in the air. So, if the relative humidity on a hot day is 90%, then this is an indicator that the atmosphere is extremely saturated with the smallest droplets.

Particularities

Suppose, in a room where there is high humidity, the water standing in it will not evaporate at all. Although if the air is dry, the process of saturation with steam will become continuous until it finally becomes full. When the air is suddenly cooled, the water vapor that has saturated it before will evaporate without stopping and settle in the form of dew. But in the case of heating the air, which is sufficiently moistened, the saturation process will resume.

The higher t °, the more intense the evaporation, and also the so-called vapor pressure, which saturate the space, increases. Boiling occurs when the vapor pressure is equal to the elasticity of the gas that surrounds the liquid. The boiling point varies depending on the gas pressure around and becomes larger when it rises.

Is evaporation fast?

As is known, the process of the transformation of water into steam is directly related to the existence of liquids. Therefore, it can be summarized that this phenomenon is very important for nature and industry.

During the study and experiments, the rate of evaporation was determined. In addition, some phenomena accompanying him became known. But they look very contradictory and to this day their nature is not yet clear.

Note that the rate of evaporation depends on many factors. Affect on it can:

• The size and shape of the container;
• Weather conditions of the environment;
• T ° of the liquid;
• Pressure in the atmosphere;
• Composition and origin of the water structure;
• The nature of the surface with which evaporation occurs;
• Some other reasons, for example, electrification of a liquid.

Once again about water

Evaporation is made from everywhere, where there is liquid: lakes, ponds, wet objects, covers of bodies of people and animals, leaves and stems of plants.

For example, sunflower gives its moisture in the amount of 100 liters during its short life. And the oceans of our planet release about 450,000 cubic meters of liquid per year.

The temperature of evaporation of water can be any. But, when it becomes warmer, the process of liquid transfer is accelerated. Note that during the summer heat puddles on the surface of the earth dry out much faster than in spring or autumn. And if the street is windy, then, respectively, the evaporation proceeds even more intensively than in those situations when the air is calm. This property also has snow and ice. If you hang drying clothes on the street in winter, then it first freezes, and then a few days will dry up.

The temperature of evaporation of water at 100 ° C is the most intensive factor, at which the named process achieves the highest result. At this time, boiling occurs, when the liquid intensively turns into vapor - a transparent, invisible gas.

If viewed under a microscope, then its composition includes single molecules of H2O, located far apart. But when the air cools, water vapor becomes visible, for example, as fog or dew. In the atmosphere, this process can be observed thanks to clouds that appear due to the transformation of droplets of water into visible ice crystals.

Nature statistics

So, what is evaporation, we found out. Now note the fact that it is closely related to the air temperature. Consequently, during the day, the largest amount of cubic meters of water turns into steam at about noon. In addition, this process is most intensive in the warm months. The strongest evaporation in the annual cycle is observed in the middle of summer, while the weak one falls on the winter.

Everyone is responsible for the state of the environment. To understand this judgment, it is necessary to catch a simple calculation. Imagine that a person speaks of his helplessness in relation to preventing an environmental disaster and believes that he is unable to do anything. But if we multiply some one insignificant action of an individual by 6.5 billion people on earth, it becomes clear why we should reason this way.