Is it possible to reach temperatures below absolute zero. What is absolute zero

ABSOLUTE ZERO

ABSOLUTE ZERO, the temperature at which all components of the system have the least amount of energy allowed by the laws of QUANTUM MECHANICS; zero on the Kelvin temperature scale, or -273.15 ° C (-459.67 ° Fahrenheit). At this temperature, the entropy of the system - the amount of energy available for doing useful work - is also zero, although the total amount of energy of the system may be different from zero.

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Temperatures are the minimum temperature limit that a physical body can have. Absolute zero is the starting point for an absolute temperature scale, such as the Kelvin scale. On the Celsius scale, absolute zero corresponds to a temperature of −273 ... Wikipedia

ABSOLUTE ZERO TEMPERATURE- the origin of the thermodynamic temperature scale; located at 273.16 K (Kelvin) below (see) water, i.e. equal to 273.16 ° C (Celsius). Absolute zero is the lowest temperature in nature and almost unattainable ... Great Polytechnic Encyclopedia

This is the minimum temperature limit that a physical body can have. Absolute zero is the starting point for an absolute temperature scale, such as the Kelvin scale. On the Celsius scale, absolute zero corresponds to a temperature of −273.15 ° C. ... ... Wikipedia

Absolute zero temperature is the minimum temperature limit that a physical body can have. Absolute zero is the starting point for an absolute temperature scale, such as the Kelvin scale. On the Celsius scale, absolute zero corresponds to ... ... Wikipedia

Razg. Neglect An insignificant, insignificant person. FSRYA, 288; BTS, 24; ZS 1996, 33 ...

zero- absolute zero … Dictionary of Russian Idioms

Zero and zero n., m., use. comp. often Morphology: (no) what? zero and zero, why? zero and zero, (see) what? zero and zero, what? zero and zero, about what? about zero, zero; pl. what? zeros and zeros, (no) what? zeros and zeros, why? zeros and zeros, (I see) ... ... Dictionary of Dmitriev

Absolute zero (zero). Razg. Neglect An insignificant, insignificant person. FSRYA, 288; BTS, 24; ZS 1996, 33 To zero. 1. Jarg. they say Shuttle. iron. About severe intoxication. Yuganov, 471; Vakhitov 2003, 22. 2. Jarg. music Exactly, in full accordance with ... ... Big dictionary of Russian sayings

absolute- absolute absurdity absolute authority absolute impeccability absolute disorder absolute fiction absolute immunity absolute leader absolute minimum absolute monarch absolute morality absolute zero ... ... Dictionary of Russian Idioms

Books

• Absolute Zero, Absolute Pavel. The life of all the creations of the mad scientist of the nes race is very short. But the next experiment has a chance to exist. What lies ahead for him?...

Where do you think the coldest place in our universe is located? Today it is Earth. For example, the surface temperature of the moon is -227 degrees Celsius, and the temperature of the vacuum that surrounds us is 265 degrees below zero. However, in a laboratory on Earth, a person can achieve temperatures much lower in order to study the properties of materials in ultra-low temperatures. Materials, individual atoms, and even light subjected to extreme cooling begin to exhibit unusual properties.

The first experiment of this kind was carried out at the beginning of the 20th century by physicists who studied the electrical properties of mercury at ultralow temperatures. At -262 degrees Celsius, mercury begins to exhibit the properties of superconductivity, reducing the resistance to electric current to almost zero. Further experiments also revealed other interesting properties of cooled materials, including superfluidity, which is expressed in the "leakage" of matter through solid partitions and out of closed containers.

Science has determined the lowest achievable temperature - minus 273.15 degrees Celsius, but practically such a temperature is unattainable. In practice, temperature is an approximate measure of the energy contained in an object, so absolute zero indicates that the body does not radiate anything, and no energy can be extracted from this object. But despite this, scientists are trying to get as close as possible to absolute zero temperature, the current record was set in 2003 in the laboratory of the Massachusetts Institute of Technology. Scientists were only 810 billionths of a degree short of absolute zero. They cooled a cloud of sodium atoms held in place by a powerful magnetic field.

It would seem - what is the applied meaning of such experiments? It turns out that researchers are interested in such a concept as the Bose-Einstein condensate, which is a special state of matter - not a gas, solid or liquid, but simply a cloud of atoms with the same quantum state. This form of matter was predicted by Einstein and the Indian physicist Satyendra Bose in 1925, and was obtained only 70 years later. One of the scientists who achieved this state of matter is Wolfgang Ketterle, who received the Nobel Prize in Physics for his discovery.

One of the remarkable properties of the Bose-Einstein Condensate (BEC) is the ability to control the movement of light rays. In a vacuum, light travels at 300,000 km per second, which is the fastest speed achievable in the universe. But light can propagate more slowly if it propagates not in a vacuum, but in matter. With the help of BEC, it is possible to slow down the movement of light to low speeds, and even stop it. Due to the temperature and density of the condensate, the light emission slows down and can be "captured" and converted directly into electrical current. This current can be transferred to another BEC cloud and converted back into light radiation. This feature is in great demand for telecommunications and computing. Here I don’t understand a bit - after all, there are ALREADY devices that convert light waves into electricity and vice versa ... Apparently, the use of BEC allows this conversion to be done faster and more accurately.

One of the reasons why scientists are so eager to get an absolute zero is an attempt to understand what is happening and has happened to our Universe, what thermodynamic laws operate in it. At the same time, researchers understand that extracting all the energy to the last from the atom is practically unattainable.

The choice of the points of melting ice and boiling water as the main points of the temperature scale is completely arbitrary. The temperature scale thus obtained turned out to be inconvenient for theoretical studies.

Based on the laws of thermodynamics, Kelvin managed to build the so-called absolute temperature scale (it is currently called the thermodynamic temperature scale or the Kelvin scale), which is completely independent of either the nature of the thermometric body or the chosen thermometric parameter. However, the principle of constructing such a scale goes beyond the school curriculum. We will consider this issue using other considerations.

From formula (2), two possible ways to establish the temperature scale follow: using the change in pressure of a certain amount of gas at a constant volume, or changing the volume at a constant pressure. This scale is called ideal gas temperature scale.

The temperature defined by equation (2) is called absolute temperature. Absolute temperature Τ cannot be negative, since on the left in equality (2) there are obviously positive values ​​(more precisely, it cannot have different signs, it can be either positive or negative. It depends on the choice of the sign of the constant k. Since we agreed to consider the temperature of the triple point as positive, the absolute temperature can only be positive). Therefore, the lowest possible temperature value T= 0 is the temperature when the pressure or volume is zero.

The limiting temperature at which the pressure of an ideal gas vanishes at a fixed volume or the volume of an ideal gas tends to zero (i.e., the gas, as it were, should compress to a "point") at a constant pressure, is called absolute zero. This is the lowest temperature in nature.

From equality (3), taking into account that \(~\mathcal h W_K \mathcal i = \frac(m_0 \mathcal h \upsilon^2 \mathcal i)(2)\) , the physical meaning of absolute zero follows: absolute zero - the temperature at which the thermal translational motion of molecules should stop. Absolute zero is unreachable.

The International System of Units (SI) uses the absolute thermodynamic temperature scale. Absolute zero is taken as zero temperature on this scale. The second reference point is the temperature at which water, ice and saturated steam are in dynamic equilibrium, the so-called triple point (on the Celsius scale, the temperature of the triple point is 0.01 °C). Each unit of absolute temperature, called a Kelvin (denoted as 1 K), is equal to a degree Celsius.

By immersing the flask of a gas thermometer in melting ice and then in boiling water at normal atmospheric pressure, we found that the gas pressure in the second case is 1.3661 times greater than in the first. Taking this into account and using formula (2), it can be determined that the ice melting temperature T 0 = 273.15 K.

Indeed, we write equation (2) for the temperature T 0 ice melting and water boiling point ( T 0 + 100):

\(~\frac(p_1V)(N) = kT_0 ;\) \(~\frac(p_2V)(N) = k(T_0 + 100) .\)

Dividing the second equation by the first, we get:

\(~\frac(p_2)(p_1) = \frac(T_0 + 100)(T_0) .\)

\(~T_0 = \frac(100)(\frac(p_2)(p_1) - 1) = \frac(100)(1.3661 - 1) = 273.15 K.\)

Figure 2 schematically shows the Celsius scale and the thermodynamic scale.

Absolute zero (absolute zero) - the beginning of the absolute temperature, starting from 273.16 K below the triple point of water (the equilibrium point of three phases - ice, water and water vapor); at absolute zero, the motion of molecules stops, and they are in a state of "zero" motions. Or: the lowest temperature at which a substance contains no thermal energy.

Absolute zero Start absolute temperature reading. Corresponds to -273.16 ° С. At present, physical laboratories have managed to obtain a temperature exceeding absolute zero by only a few millionths of a degree, but according to the laws of thermodynamics, it is impossible to achieve it. At absolute zero, the system would be in a state with the lowest possible energy (in this state, atoms and molecules would make “zero” vibrations) and have zero entropy (zero disorder). The volume of an ideal gas at the point of absolute zero must be equal to zero, and to determine this point, the volume of a real helium gas is measured at consistent lowering the temperature until it liquefies at low pressure (-268.9 ° C) and extrapolates to the temperature at which the volume of gas would go to zero in the absence of liquefaction. Absolute temperature thermodynamic The scale is measured in kelvins, denoted by the symbol K. Absolute thermodynamic the scale and the Celsius scale are simply shifted relative to each other and are related by the relation K = °C + 273.16 °.

Story

The word "temperature" arose at a time when people believed that hotter bodies contained a greater amount of a special substance - caloric than less heated ones. Therefore, temperature was perceived as the strength of a mixture of body substance and caloric. For this reason, the units of measure for the strength of alcoholic beverages and temperature are called the same - degrees.

From the fact that temperature is the kinetic energy of molecules, it is clear that it is most natural to measure it in energy units (i.e. in the SI system in joules). However, temperature measurement began long before the creation of the molecular kinetic theory, so practical scales measure temperature in conventional units - degrees.

Kelvin scale

In thermodynamics, the Kelvin scale is used, in which the temperature is measured from absolute zero (the state corresponding to the minimum theoretically possible internal energy of the body), and one kelvin is equal to 1/273.16 of the distance from absolute zero to the triple point of water (the state in which ice, water and water couples are in equilibrium. The Boltzmann constant is used to convert kelvins to energy units. Derived units are also used: kilokelvin, megakelvin, millikelvin, etc.

Celsius

In everyday life, the Celsius scale is used, in which the freezing point of water is taken as 0, and the boiling point of water at atmospheric pressure is taken as 100 °. Since the freezing and boiling points of water are not well defined, the Celsius scale is currently defined in terms of the Kelvin scale: degrees Celsius equals Kelvin, absolute zero is taken to be −273.15 °C. The Celsius scale is practically very convenient, since water is very common on our planet and our life is based on it. Zero Celsius is a special point for meteorology, since the freezing of atmospheric water changes everything significantly.

Fahrenheit

In England, and especially in the USA, the Fahrenheit scale is used. This scale is divided by 100 degrees from the temperature of the coldest winter in the city where Fahrenheit lived to the temperature of the human body. Zero degrees Celsius is 32 degrees Fahrenheit, and a degree Fahrenheit is 5/9 degrees Celsius.

The current definition of the Fahrenheit scale is as follows: it is a temperature scale, 1 degree (1 °F) of which is equal to 1/180 of the difference between the boiling point of water and the melting of ice at atmospheric pressure, and the melting point of ice is +32 °F. The temperature on the Fahrenheit scale is related to the temperature on the Celsius scale (t ° С) by the ratio t ° С = 5/9 (t ° F - 32), 1 ° F = 5/9 ° С. Proposed by G. Fahrenheit in 1724.

Reaumur scale

Proposed in 1730 by R. A. Reaumur, who described the alcohol thermometer he invented.

Unit - degree Réaumur (°R), 1 °R is equal to 1/80 of the temperature interval between the reference points - the temperature of melting ice (0 °R) and boiling water (80 °R)

1°R = 1.25°C.

At present, the scale has fallen into disuse; it has been preserved for the longest time in France, in the author's homeland.

Comparison of temperature scales

Normal human body temperature is 36.6 °C ±0.7 °C, or 98.2 °F ±1.3 °F. The commonly quoted value of 98.6 °F is an exact Fahrenheit conversion of the 19th century German value of 37 °C. Since this value does not fall within the range of normal temperature according to modern concepts, it can be said that it contains excessive (incorrect) accuracy. Some values ​​in this table have been rounded.

Comparison of Fahrenheit and Celsius scales

(oF- Fahrenheit scale, o C- Celsius scale)

To convert degrees Celsius to kelvins, use the formula T=t+T0 where T is the temperature in kelvins, t is the temperature in degrees Celsius, T 0 =273.15 kelvin. A degree Celsius is equal in size to a kelvin.

Absolute temperature zero corresponds to 273.15 degrees Celsius below zero, 459.67 below zero Fahrenheit. For the Kelvin temperature scale, this temperature itself is the zero mark.

The essence of absolute zero temperature

The concept of absolute zero comes from the very essence of temperature. Any body that gives up to the external environment in the course of . In this case, the body temperature decreases, i.e. there is less energy left. Theoretically, this process can continue until the amount of energy reaches such a minimum at which the body can no longer give it away.
A distant harbinger of such an idea can already be found in M.V. Lomonosov. The great Russian scientist explained heat by "rotary" motion. Therefore, the limiting degree of cooling is a complete stop of such movement.

According to modern concepts, the absolute zero temperature is at which molecules have the lowest possible energy level. With less energy, i.e. at a lower temperature, no physical body can exist.

Theory and practice

Absolute zero temperature is a theoretical concept, it is impossible to achieve it in practice, in principle, even in the conditions of scientific laboratories with the most sophisticated equipment. But scientists manage to cool the matter to very low temperatures, which are close to absolute zero.

At such temperatures, substances acquire amazing properties that they cannot have under ordinary circumstances. Mercury, which is called "living silver" because of its close to liquid state, at this temperature becomes solid - to the point that it can hammer nails. Some metals become brittle, like glass. The rubber becomes just as hard. If a rubber object is hit with a hammer at a temperature close to absolute zero, it will break like glass.

Such a change in properties is also associated with the nature of heat. The higher the temperature of the physical body, the more intense and chaotic the molecules move. As the temperature decreases, the movement becomes less intense, and the structure becomes more ordered. So the gas becomes a liquid, and the liquid becomes a solid. The limiting level of order is the crystal structure. At ultra-low temperatures, it is acquired even by substances that in the normal state remain amorphous, for example, rubber.

Interesting phenomena occur with metals. The atoms of the crystal lattice vibrate with a smaller amplitude, the scattering of electrons decreases, therefore, the electrical resistance decreases. The metal acquires superconductivity, the practical application of which seems very tempting, although difficult to achieve.

Sources:

• Livanova A. Low temperatures, absolute zero and quantum mechanics

Body- this is one of the basic concepts in physics, which means the form of existence of matter or substance. This is a material object, which is characterized by volume and mass, sometimes also by other parameters. The physical body is clearly separated from other bodies by a boundary. There are several special types of physical bodies; their enumeration should not be understood as a classification.

In mechanics, a physical body is most often understood as a material point. This is a kind of abstraction, the main property of which is the fact that the real dimensions of the body for solving a specific problem can be neglected. In other words, a material point is a very specific body that has dimensions, shape and other similar characteristics, but they are not important in order to solve the existing problem. For example, if you need to count an object on a certain section of the path, you can completely ignore its length when solving the problem. Another type of physical bodies considered by mechanics is an absolutely rigid body. The mechanics of such a body is exactly the same as the mechanics of a material point, but additionally it has other properties. An absolutely rigid body consists of points, but neither the distance between them nor the distribution of mass change under the loads to which the body is subjected. This means that it cannot be deformed. To determine the position of an absolutely rigid body, it is enough to set the coordinate system attached to it, usually Cartesian. In most cases, the center of mass is also the center of the coordinate system. An absolutely rigid body does not exist, but for solving many problems such an abstraction is very convenient, although it is not considered in relativistic mechanics, since during movements whose speed is comparable to the speed of light, this model demonstrates internal contradictions. The opposite of a perfectly rigid body is a deformable body, which can be displaced relative to each other. There are special types of physical bodies in other branches of physics. For example, in thermodynamics, the concept of a completely black body is introduced. This is an ideal model, a physical body that absorbs absolutely all electromagnetic radiation that falls on it. At the same time, it itself may well produce electromagnetic radiation and have any color. An example of an object that is closest in properties to a completely black body is the Sun. If we take substances that are widespread beyond the Earth, then we can recall soot, which absorbs 99% of what falls on it, except for infrared, which is much worse at absorbing.

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