Temperature not lower than 0. Causes of low human body temperature
Introduction
Characteristic climatic conditions, used to describe a particular area, is a complex of average daily, monthly and annual values of all meteorological quantities, as well as data on their variability. Each meteorological quantity directly influences other characteristics of the state of the atmosphere, which, in combination and interaction, create what we call “climatic conditions”. Any changes, within certain limits, in climatic conditions, even in the same climatic region, affect plant and animal world, adapting to the climatic conditions of a given area. Human activity and well-being also depend on climatic conditions. Finally, the economic and especially agricultural importance of each geographical region is directly determined by its climate.
Using certain physical-geographical and meteorological characteristics individual areas, meteorologists and climatologists tried to classify the Earth's climates. One of the criteria for classifying climates is air temperature. Precipitation data is also used as a basis for climate classification. Another indicator to highlight climatic regions serves vegetation cover. Finally, as a criterion for classifying climates, they take data on the predominance of certain air masses.
Main climate zones of the Earth
It is easier to compare different climates if you describe them in general terms. According to air temperature data in geographical zones broad generalizations can be made. Further detailing is carried out taking into account the terrain, proximity of continents or bodies of water, etc.
Tropical latitudes
The tropical climate zone is limited in the north and south by areas in which the average temperature of the coldest month is not lower than 18ºC. Within this climate zone lies equatorial belt low blood pressure, created by the Intertropical Convergence Zone.
The main feature of the tropical climate zone is heavy rains accompanied by thunderstorm activity. Predominant in equatorial zone calm high humidity air favors the existence of thick and humid tropical forests(jungle). During periods when the Intertropical Convergence Zone moves south or north, small interseasonal changes in climate conditions occur. However, significant contrasts between the amount of precipitation in different seasons, typical for higher latitudes, do not occur in the tropical climate zone.
From the data in table. 1 shows that in Indonesia the amount of precipitation is much more variable than in, for example, Zaire, although temperature fluctuations in these areas are insignificant. High and low temperatures also alternate here differently than in temperate latitudes(Table 2).
Table 1. Data for two cities located in the tropical climate zone (average monthly air temperature and monthly precipitation)
Table 2. Data for a station located in the zone monsoon climate(average monthly air temperature and monthly precipitation)
Temperate latitudes
In the climate zone of temperate latitudes, the average temperature of the most warm month is about 25ºС. Most of This climatic zone lies between the centers of formation of different air masses (warm and cold). Many areas of this zone have a dry climate, with arid and semi-arid deserts and steppes.
On western coasts The continents in the southern part of this zone have a Mediterranean climate. Temperatures here are moderate, winters are wet and dry summer due to the belt high blood pressure. On the eastern coasts of the continents, temperature fluctuations are more significant than on the western coasts, which are under the influence of continental air masses. Accordingly, the climate east coasts closer to the climate of tropical latitudes.
In the northern part of temperate latitudes, in the zone of predominant westerly transport, temperature fluctuations are even more significant, precipitation is variable, and the prevailing steppe climate determines the development of vast meadow spaces.
Polar regions
Only a few species of animals are found in the polar regions, and vegetable world represented by small and low-growing species. average temperature the warmest month is 10ºС. In these areas it happens very short summer with a clear sunny weather, although the arrival solar radiation insignificant. There is also little precipitation here, but there is permafrost.
Other factors influencing climate
The formation of climates in different regions of the Earth is strongly influenced by many factors that do not depend on latitude, for example, relief, proximity to large bodies of water, wind conditions, etc. Factors related to the terrain have their influence at any latitude.
Wind. When considering the influence of wind on climate, it is important to know where the center of this air flow formed, in a hot or cold area, wet or dry, in addition, over which areas air flow moved and changed its properties.
Continental climate. This is usually a dry climate, typical of the inland regions of continents, where precipitation is low and air humidity is low throughout the year. The amplitude of air temperature fluctuations depends on the latitude of the area. IN tropical zone Earth's continental climate is characterized by small temperature fluctuations, but in temperate latitudes its interseasonal contrasts can be large. Deserts and steppes are the most striking manifestation of a dry continental climate (Table 3).
Table 3. Data for two cities located in the polar climate zone (average monthly air temperature and monthly precipitation)
Maritime climate
In areas with a maritime climate, especially on oceanic islands, air temperature fluctuations are small, it changes very little from day to night and from summer to winter. Due to the softening influence large body of water Temperature fluctuations here lag behind changes in solar radiation much more than on the continents.
From the table 4 it can be seen that the influence of the warm North Atlantic Current is detected, for example, in a smaller amplitude of temperature fluctuations, i.e. more even temperatures in Vardø (Norway) compared to Barrow (Alaska). More strong influence The sea level in Vardø is also reflected in the amount of precipitation at this point.
Table 4. Data for two cities, one of which is located in the maritime-arctic climate zone, and the other in the continental tundra climate zone (average monthly air temperature and monthly precipitation)
Coastal climate
Coastal climate is a direct result of the influence sea currents, as well as the wind exposed to these currents. The coasts lie in transition zone between areas with maritime and continental climate. In the belt of predominant western transport to western shores The climate of the continents is maritime; in the east it is continental. In the belt of trade winds eastern shores continents are more inclined towards maritime climate, and western - to the continental.
Climate of mountains and plateaus
The influence of relief on climate is most noticeable in mountainous areas and especially on the plateaus. The air temperature, of course, decreases with increasing altitude above sea level. Precipitation in mountainous areas occurs more often at altitudes up to an average of 2,100 m; above that, seasonal precipitation amounts quickly decrease. Rising movement air along the mountain slopes reduces the amplitude of its temperature fluctuations and smoothes out its interseasonal contrasts. On the plateaus, the air mixes weakly and becomes quite stable, as a result of which the amplitude of changes in its temperature here is much greater than above the plains.
A mountain range often serves as a dividing line between climatic zones, and the efficiency of the section depends on the prevailing wind direction. If air is forced to rise along mountain slopes, its properties change greatly. This leads to air masses, formed on the windward and leeward slopes of mountains, differ greatly.
Number of days with average daily temperature air below 0°C characterizes the duration of the cold period of the year. Its highest values are observed on the islands and coast of the Arctic basin. Thus, on Earth, temperatures below 0°C are maintained for almost 11 months (310–330 days). On the mainland, winter is longest on the coast northern seas east of Novaya Zemlya (260–300 days) and in the northern part, where in the region air temperatures above 0°C are observed only 70–100 days. 10–20 days shorter cold period in the mountainous regions of northeast Siberia, in the north and on. IN Western Siberia the duration of the period with negative temperatures varies from 220 days in the lower reaches of the Ob to 170–180 days in the foothills of Altai. The shortest cold period in the Asian part of Russia is observed on the southern coasts and Primorsky Krai, where it is 120–130 days a year.
In the European part of Russia, the duration of the cold period decreases in the direction from the northeast to the southwest, and temperatures below 0°C are maintained here from 200–210 days in the northern Cis-Ural region to 60–70 days on the plains of the western Ciscaucasia. In the north-west of the European part of Russia, the period from negative values temperatures set almost a month later than in the northeastern regions, which is due to the warming influence of the Atlantic.
The influence of terrain altitude on the duration of the cold period is more or less smoothed out, although in high mountain areas North Caucasus there is an increase of 3–4 days for every 100 meters of altitude.
The duration of the cold period can vary significantly from year to year. The regions of the northeast of the Republic of Sakha (Yakutia) and Khabarovsk Territory. Here, the values of its standard deviation do not exceed 5–5.5 days, and even with a probability of 1 time in 20 years, deviations from the average values are only 10–13 days. In the rest of the Asian part of Russia, the standard deviation of the duration of periods with negative air temperatures varies from 10–15 days in Western Siberia to 7–9 days.
In the European part of Russia, the standard deviation is slightly larger. In her central regions the values of this parameter are 10-12 days, in the northern and - 15-16 days, and on the coasts of Bely and - 17-19 days.
The most unstable period with temperatures below 0°C is observed in the south of the country. Here, south of Rostov-on-Don, the standard deviation is 22–24 days, and the maximum deviations from the average values of the duration of the cold period vary from 25–35 days in the Rostov-on-Don region to 40–55 days in the western Ciscaucasia. This is the only region in Russia where deviations from the average towards a shorter cold period, possible once every 20 years, exceed deviations from a longer period with the same probability by 14–16 days.
Scientists managed to do something incredible: they were able to cool a substance below the temperature that had previously been considered absolute minimum. In most modern physics textbooks, absolute zero on the Kelvin scale, or minus 273.16 degrees Celsius, is considered the lowest of possible temperatures, since with it even the lightest element - hydrogen - completely loses its mobility, that is, figuratively speaking, it freezes.
Oddly enough, one of the ways to study negative temperatures is to infinitely heat the substance. This unusual approach, bordering on science fiction, makes it possible in theory to design engines whose efficiency will be above 100%, and sheds light on such mysterious substances as dark energy and others.
From the point of view of atomic physics, temperature is speed. The speed at which atoms move within a substance, and the faster the atoms move, the higher the temperature. Accordingly, at minus 273.16 degrees, hydrogen atoms completely stop. With this approach, no substance can be colder than this limit.
However, modern physics, in order to understand the essence of temperature, suggests looking at it differently - not as a linear indicator, but as a loop: positive temperatures are one part of the cycle, negative temperatures are another. At temperatures tending to infinitely low or infinitely high, the scale sooner or later ends up in the negative region. At positive temperatures, atoms often occupy low energy states, and at negative temperatures, high ones. In physics, a similar effect is known as the Boltzmann distribution.
At absolute zero, atoms occupy the lowest energy state, and at “infinite temperature,” atoms can occupy all energy states at once. Accordingly, at very high temperatures they occupy all high energy states, and at very low temperatures - all low ones.
“When we talk about low temperatures, we can say that we are dealing with an inverted Boltzmann distribution,” says physicist Ulrich Schneider of the University of Munich in Germany. “By this logic, a substance that reaches a temperature below absolute zero becomes hot. We believe that when reaching minus 273 degrees, the temperature does not end, but simply goes to negative values.”
As you might imagine, objects with negative temperatures behave very strangely. For example, usually the energy coming from an object with more high temperature, will always be greater than from a cooler object. However, if a substance moves to a negative scale, then the colder it is, the more energy it emits. Thus, here a colder object will always be more energetically active than a warmer one.
Another strange consequence of freezing temperatures is entropy, a measure of how ordered a substance is. When an object has a traditional temperature, it increases the entropy of the matter around and inside itself, but when the temperature goes into the negative zone, an infinitely “cold/hot” object is able to reduce the entropy inside and around itself.
German physicists say that negative temperatures are still largely a theory. But it will become practice when science learns to work with clear energy indicators of one individual atom of a substance. When researchers can work with one individual atom in the same way as with objects in the macrocosm, it will be possible to talk about whether atoms can be cooled to super-low temperatures or whether they can fly faster speed Sveta.
In the meantime, to generate negative temperatures, scientists created a system in which the atoms had a strict limit on how much energy they could possess. To do this, physicists took 100,000 atoms and cooled them to a temperature of one billionth of a Kelvin. The atoms were cooled in a vacuum chamber isolated from external environment. To precisely control atoms, researchers used a network laser beams and magnetic fields.
According to scientists, the temperature of a substance ultimately depends on how much potential energy an atom has and how much energy is generated from interactions between atoms. In addition, temperature is also closely related to pressure - the hotter an object, the more it expands and vice versa. To make sure that a gas could have a temperature below absolute zero, it was necessary to create conditions in which the atoms themselves would not have significant energy, and more energy would be generated from the repulsion of atoms than from their attraction, CyberSecurity.ru reports.
Something similar could be recreated on the nanoscale. Simon Braun from the University of Munich says that in the future, such knowledge could lead to the creation of ultra-efficient heat engines. The operation of such engines is based on the conversion of thermal energy into mechanical energy. Theoretically, with negative temperatures such motors could have an efficiency higher than 100%, although from a logical point of view this seems impossible.
The term "temperature" appeared at a time when physicists thought that warm bodies consist of more specific substance - caloric - than the same bodies, but cold. And temperature was interpreted as a value corresponding to the amount of caloric in the body. Since then, the temperature of any body has been measured in degrees. But in reality this is a measure kinetic energy moving molecules, and, based on this, it should be measured in Joules, in accordance with the System of Units C.
The concept of “absolute zero temperature” comes from the second law of thermodynamics. According to it, the process of heat transfer from a cold body to a hot one is impossible. This concept was introduced by the English physicist W. Thomson. For his achievements in physics, he was given the title of nobility “Lord” and the title “Baron Kelvin”. In 1848, W. Thomson (Kelvin) proposed using a temperature scale in which he took absolute zero temperature, corresponding to extreme cold, as the starting point, and took degrees Celsius as the division value. The Kelvin unit is 1/27316 of the temperature of the triple point of water (about 0 degrees C), i.e. temperature at which pure water is immediately found in three forms: ice, liquid water and steam temperature is the minimum possible low temperature, at which the movement of molecules stops, and it is no longer possible to extract from the substance thermal energy. Since then the scale absolute temperatures began to be called by his name.
Temperature is measured on different scales
The most commonly used temperature scale is called the Celsius scale. It is built on two points: temperature phase transition water from liquid to steam and water to ice. A. Celsius in 1742 proposed dividing the distance between reference points into 100 intervals, and taking water as zero, with the freezing point as 100 degrees. But the Swede K. Linnaeus suggested doing the opposite. Since then, water has frozen at zero degrees A. Celsius. Although it should boil exactly at Celsius. Absolute zero Celsius corresponds to minus 273.16 degrees Celsius.
There are several more temperature scales: Fahrenheit, Reaumur, Rankin, Newton, Roemer. They have different division prices. For example, the Reaumur scale is also built on the reference points of boiling and freezing of water, but it has 80 divisions. The Fahrenheit scale, which appeared in 1724, is used in everyday life only in some countries of the world, including the USA; one is the temperature of the mixture of water ice and ammonia and the other is human body. The scale is divided into one hundred divisions. Zero Celsius corresponds to 32 Conversion of degrees to Fahrenheit can be done using the formula: F = 1.8 C + 32. Reverse conversion: C = (F - 32)/1.8, where: F - degrees Fahrenheit, C - degrees Celsius. If you are too lazy to count, go to an online service for converting Celsius to Fahrenheit. In the box, enter the number of degrees Celsius, click "Calculate", select "Fahrenheit" and click "Start". The result will appear immediately.
Named after the English (more precisely Scottish) physicist William J. Rankin, who was a contemporary of Kelvin and one of the creators of technical thermodynamics. On his scale important points three: the beginning is absolute zero, the freezing point of water is 491.67 degrees Rankine and the boiling point of water is 671.67 degrees. The number of divisions between the freezing of water and its boiling for both Rankine and Fahrenheit is 180.
Most of these scales are used exclusively by physicists. And 40% of American high school students surveyed today said that they do not know what absolute zero temperature is.
Any physical body, including all objects in the Universe, has minimum indicator temperature or its limit. For any reference point temperature scale and it is customary to consider the value of absolute zero temperature. But this is only in theory. The chaotic movement of atoms and molecules, which give up their energy at this time, has not yet been stopped in practice.
This is the main reason why absolute zero temperatures cannot be reached. There are still debates about the consequences of this process. From the point of view of thermodynamics, this limit is unattainable, since the thermal movement of atoms and molecules stops completely, and a crystal lattice is formed.
Representatives quantum physics provide for the presence of minimum zero oscillations at absolute zero temperatures.
What is the value of absolute zero temperature and why it cannot be achieved
On general conference according to weights and measures, a reference point or reference point was established for the first time measuring instruments, which determine temperature indicators.
Currently, in the International System of Units, the reference point for the Celsius scale is 0°C for freezing and 100°C for boiling, the value of absolute zero temperatures is equal to −273.15°C.
Using temperature values on the Kelvin scale according to the same International system measurement units, boiling water will occur at a reference value of 99.975°C, absolute zero is equal to 0. Fahrenheit on the scale corresponds to -459.67 degrees.
But, if these data are obtained, why then is it impossible to achieve absolute zero temperatures in practice? For comparison, we can take the well-known speed of light, which is equal to the constant physical value of 1,079,252,848.8 km/h.
However, this value cannot be achieved in practice. It depends on the transmission wavelength, the conditions, and the required absorption large quantity energy particles. To obtain the value of absolute zero temperatures, a large output of energy is required and the absence of its sources to prevent it from entering atoms and molecules.
But even in conditions of complete vacuum, scientists were unable to obtain either the speed of light or absolute zero temperatures.
Why is it possible to reach approximately zero temperatures, but not absolute zero?
What will happen when science can come close to achieving the extremely low temperature of absolute zero remains only in the theory of thermodynamics and quantum physics. What is the reason why absolute zero temperatures cannot be achieved in practice.
All known attempts to cool a substance to the lowest limit due to maximum energy loss led to the fact that the heat capacity of the substance also reached a minimum value. The molecules were simply no longer able to give up the remaining energy. As a result, the cooling process stopped without reaching absolute zero.
When studying the behavior of metals under conditions close to absolute zero temperatures, scientists found that a maximum decrease in temperature should provoke a loss of resistance.
But the cessation of the movement of atoms and molecules only led to the formation of a crystal lattice, through which passing electrons transferred part of their energy to stationary atoms. Again, it was not possible to reach absolute zero.
In 2003, the temperature was only half a billionth of 1°C short of absolute zero. NASA researchers used a Na molecule to conduct experiments, which was always in a magnetic field and gave up its energy.
The closest achievement was achieved by scientists at Yale University, who in 2014 achieved a figure of 0.0025 Kelvin. The resulting compound, strontium monofluoride (SrF), lasted only 2.5 seconds. And in the end it still disintegrated into atoms.