The surrounding world is an interconnected organism in which all processes and phenomena of animate and inanimate nature occur for a reason. Scientists have proven that even minor human interventions bring tremendous changes. Despite this, people forget that they are also an integral part of the world around them. In this regard, changes are taking place in humanity as a whole.
Everything about life processes and natural phenomena begins to be taught to children already at school, which is very important for their further understanding of what is happening around. As you know, the topic "Evaporation" (Grade 8) is studied precisely within the framework of the secondary school program, when students are already ready to reflect on problems.
How evaporation occurs
Everyone knows what evaporation is. This is the phenomenon of the transformation of substances of different consistency into a state of vapor or gas. It is known that this process occurs at the appropriate temperature.
Usually naturalconditions, many substances (both solid and liquid) practically do not evaporate or do so very slowly. But there are also such samples, for example, camphor and most liquids, which, under normal conditions, evaporate very quickly. That is why they are called flying. You can notice this process with the help of smell, since many bodies are toxic.
Evaporation of a liquid (water, alcohol) can be observed by observing it for some time. Then the decrease in the volume of this substance begins.
The basis of life on Earth
As you know, water is an integral part of the existence of the surrounding world. Without it, no existence is possible, because all living beings are 75% water.
This is a special compound whose properties are exceptional. And it is only thanks to such anomalies of this phenomenon that life is likely in the form that is now on the planet.
Humanity has been interested in this miracle since ancient times. Even the philosopher Aristotle in the 4th century BC declared that water is the beginning of everything. In the 17th century, the Dutch mechanic, physicist, mathematician, astronomer and inventor Huygens recommended setting the coefficients of boiling water and thawing ice as the main levels of the thermometer scale. But humanity learned what evaporation is 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 ordinaryconditions:
- in solid (ice);
- fluid;
- gaseous (liquid evaporation).
In addition, water has a very high density compared to other substances, as well as a high heat of vaporization and latent heat of fusion (the amount of heat absorbed or released).
H2O has one more quality - the ability to vary its density from a change in the thermometer readings. And the most amazing thing is that if this quality did not exist, the ice would not be able to swim, and the seas, oceans, rivers and lakes would freeze to the bottom. Then life on earth could not exist, because it is the reservoirs that are the first refuge of microorganisms.
H2O cycle in nature
How does this process happen? Circulation is a continuous procedure, since 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 bodies of water, land and the atmosphere. For example, when clouds collide with cold air, large drops form, which subsequently fall out in the form of precipitation. Then the evaporation process takes place, in which the sun heats the plane of the earth, water bodies, and the liquid rises up into the atmosphere.
Vegetation takes moisture from the soil, and water is circulated from the surface of the leaves. This procedure is called transpiration and is a physical and biological process.
The layers of the atmosphere, saturated with steam and located near the ground, then become lighter and begin to move upward. tiny dropletswater in the atmosphere is replenished approximately every eight to nine days.
Evaporation occurs as a result of the cycle, 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 state and the entry of invisible vapor into the air.
Evaporation and evaporation
What is the difference between the concepts of "evaporation" and "evaporation"? Let's look at the first term first. This is an indicator of the climate of the area, which determines how much liquid has evaporated from the surface to the maximum. If we take into account that the humidity of the territory, as G. N. Vysotsky notes, is the sum of the ratio of precipitation to evaporation, then this is the most important indicator of the microclimate.
There is also a certain dependence: if the evaporation rate is less, then the humidity is greater. The described process relies on air humidity, wind speed and depends on them.
What is evaporation? This is a phenomenon in which, in a certain phase, the transformation of a substance from a liquid into a vapor or gas occurs. 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 amount of water vapor in the atmosphere. Depending on this, the climate of the areas varies. Humidity is everywhere. There isits two types:
- Absolute - the number of water molecules in one cubic meter of the atmosphere.
- Relative - the percentage of vapor to air. For example, if the humidity is 100%, it 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 tiny droplets.
Particulars
Let's say that in a room with high humidity, the water standing in it will not evaporate at all. Although if the air is dry, then the steam saturation process will become continuous until it is completely filled with it. With a sudden cooling of the air, the water vapor that saturated it before will evaporate without stopping and will settle in the form of dew. But in the case of heating the air, which is sufficiently humidified, the saturation process will resume.
The higher the t°, the more intense the evaporation, and the so-called vapor pressure increases, which saturate the space. 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 pressure of the gas around and becomes higher when it rises.
Is evaporation fast
As you know, the process of turning water into steam is directly related to the existence of liquids. Therefore, it can be concluded that thisthe phenomenon is very important for nature and industry.
In the process of studying and experimenting, the evaporation rate was revealed. In addition, some phenomena accompanying it became known. But they look very contradictory and their nature is not yet clear until now.
Note that the rate of evaporation depends on many factors. It can be affected by:
- size and shape of container;
- weather conditions of the external environment;
- t° liquid;
- atmospheric pressure;
- composition and origin of the water structure;
- nature of the surface from which evaporation occurs;
- some other causes, such as electrification of the liquid.
Once again about water
Evaporation is produced from everywhere where there is a liquid: lakes, ponds, wet objects, integuments of the bodies of people and animals, leaves and stems of plants.
For example, a sunflower during its short life gives the air moisture in the amount of 100 liters. And the oceans of our planet release approximately 450,000 cubic meters of liquid per year.
Evaporation temperature of water can be any. But, when it gets warmer, the process of fluid transition accelerates. Note that during the summer heat, puddles on the surface of the earth dry out much faster than in spring or autumn. And if it is windy outside, then, accordingly, evaporation proceeds even more intensively than in situations where the air is calm. Snow and ice also have this property. If you hang your laundry outside to dry in winter, it will first freeze, and then throughdry for a few days.
The evaporation temperature of water at 100°C is the most intense 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 it consists of single H2O molecules located far from each other. 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, which appear due to the transformation of water droplets into visible ice crystals.
Nature statistics
So, what is evaporation, we found out. Now we note the fact that it is closely related to air temperature. Consequently, during the day, the largest number of cubic meters of water turns into steam at about noon. In addition, this process is most intense in the warm months. The strongest evaporation in the annual cycle occurs in the middle of summer, while the weakest falls on the winter.
Everyone is responsible for the state of the environment. To understand this proposition, it is necessary to grasp a simple calculation. Imagine that a person talks about his helplessness in relation to the prevention of an ecological catastrophe and believes that he is not capable of doing anything. But if you multiply some one insignificant action of an individual by 6.5 billion people on earth, then it becomes clear whyit's worth thinking like that.
