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High reward for high blood pressure. Lesson plan in physics (grade 10) on the topic: "Basic principles of molecular kinetic theory and their experimental confirmation." Formation of basic concepts of statistical physics

American physicist Percy Williams Bridgman was born in Cambridge (Massachusetts). He was the only child of Raymond Landon Bridgman, a newspaper reporter and publicist, and Mary Ann Maria Bridgman, née Williams. Soon after his birth, the family moved to Newton, where B. grew up attending the parish church, playing chess and playing sports. A high school teacher in Newton advised him to choose science as his path.

In 1990, B. entered Harvard University, marking the beginning of his long-term collaboration with this educational institution. He chose to study chemistry, mathematics and physics, receiving a bachelor's degree with honors in 1904. The following year he was awarded a master's degree, and in 1908 he became a doctor of science with a thesis on the effect of pressure on the electrical resistance of mercury. Having started his career as a research assistant in 1908, B. became a teacher in 1910, an assistant professor in 1913, a professor in 1919, a university professor in 1950, and an honorary professor in 1954. retired.

The result of his scientific work is enormous - 260 articles and 13 books, which is not least due to his refusal of all public duties: he was never seen at faculty meetings and very rarely on a university committee. The statement “I'm not interested in your college, I want to do research,” which he made to university president Abbott Lawrence Lowell, characterizes him as a maverick, which was also reflected in his reluctance to conduct joint research or take more than the necessary number of graduate students.

In 1905, B. invented a sealed method for insulating vessels with gas under high pressure. The principle of B.'s design was that an insulating gasket, made of rubber or soft metal, was compressed under a pressure greater than the pressure inside the vessel. The sealing plug automatically seals as pressure increases and never leaks, regardless of the amount of pressure, as long as the vessel walls can withstand.

The creation of high-strength, hardened alloy steel alloys containing tungsten carbide with a cobalt additive (carbola) allowed B. to use his constantly improved apparatus to measure the compressibility, density, and melting point of hundreds of materials depending on pressure and temperature. In his works, he established that many materials under the influence of high pressure become polymorphic, their crystal structure changes, allowing a more dense packing of atoms in the crystal. His studies of pressure-induced polymorphism revealed two new forms of phosphorus and “hot ice”—ice that is stable at 180° Fahrenheit and pressures of about 20,000 atmospheres. In subsequent years, researchers used high pressure to create synthetic diamonds, cubic boron nitride crystals, and high-quality quartz crystals. B. discovered that high pressure can even affect the electronic structure of atoms, as can be seen in the example of a decrease in the atomic volume of the element cesium at 45 thousand atmospheres. His research proved that at the high pressures existing in the Earth's interior, radical changes should occur in the physical properties and crystalline structure of rocks.
Using double compression equipment, where a powerful compressor operates inside a vessel with high pressure, B. easily obtained a pressure of about 100 thousand atmospheres in small volumes. From time to time he studied the effect on matter of pressures reaching 400 thousand atmospheres.

In 1946, B. was awarded the Nobel Prize in Physics “for the invention of a device that allows the creation of ultra-high pressures, and for the discoveries made in connection with this in the physics of high pressures.” In a speech at the award ceremony A.E. Lind of the Royal Swedish Academy of Sciences congratulated B. on his “outstanding research work in the field of high pressure physics.” He said: “By means of your original instrument, coupled with brilliant experimental technique, you have greatly enriched our knowledge of the properties of matter at high pressures.”

During the First World War, B., working in New London (Connecticut), created a sound detection system for anti-submarine warfare. During World War II, he worked on the problem of the compressibility of uranium and plutonium, thereby contributing to the creation of the first atomic bomb.

In 1912, B. married Olivia Ware, daughter of Edmund Ware, founder of Atlanta University. They had a son and daughter. Living with his family in Cambridge and at his summer home in Randolph, New Hampshire, Peter, as he was known since his student days, devoted much time to gardening, mountaineering, photography, chess, playing handball, and loved reading detective stories and playing the piano.

At the age of 79, 7 years after his retirement, B. learned that he had cancer and that he had several months to live. Quickly losing the ability to walk and not finding a doctor who would make it easier for him to die, B. committed suicide on August 20, 1961. He left a note that said: “It is not very decent on the part of society to force a person to do such things himself. This is probably the last day I could do it myself. P.U.B."

B. was a member of the National Academy of Sciences and the American Philosophical Society. American Academy of Arts and Sciences. American Association for the Advancement of Science and the American Physical Society. He was a foreign member of the Royal Society of London. National Academy of Sciences of Mexico and Indian Academy of Sciences. Among his many awards were the Rumford Medal of the American Academy of Arts and Sciences (1917), the Elliot Cresson Medal of the Franklin Institute (1932), the Comstock Prize of the National Academy of Sciences (1933), and the Science Award of the American Research Corporation (1937). He held honorary degrees from Brooklyn Polytechnic Institute, Harvard University, Princeton University, Yale University, and Stevens Institute of Technology.

Topic 1. Fundamentals of molecular kinetic theory

Basic provisions of the ICT

1. All substances consist of particles with spaces between them.

2. Particles in any substance move continuously and chaotically.

3. Particles interact with each other.

Some experimental substantiations of these provisions

Indirect evidence:

1. compressibility of bodies during deformation (gases are especially well compressed, and the distances between their particles decrease);

2. fragmentation of a substance (the limit of fragmentation in molecular physics is a molecule or an atom);

3. expansion and contraction of bodies with temperature changes (changes in the distance between molecules);

4. evaporation of liquids (transition of individual liquid molecules into a gaseous state);

5. diffusion– mutual penetration of contacting substances due to the chaotic movement of molecules: spontaneous mixing of substances occurs most quickly in gases (minutes), more slowly in liquids (weeks), very slowly in solids (years), diffusion accelerates with increasing temperature;

6. Brownian motion - the random movement of very small particles of a solid suspended in a liquid or gas, continuous, indestructible, depending on temperature: it becomes more intense as it increases. It is explained by the fact that each Brownian particle is surrounded by chaotically moving molecules, the shocks of which lead to its random movement;

7. sticking of lead cylinders, adhesion of glass to water (occur due to the attraction of molecules);

8. resistance to tension and compression, low compressibility of solids and liquids prove that molecules interact.

Direct evidence:

1. observation of the structure of matter using an electron microscope, photographs of individual large molecules;

2. Bridgman's experiment (oil seepage through the steel walls of a vessel under pressure atm.);

3. The parameters of atoms and molecules were measured - diameter, mass, speed.

Atom sizes are on the order of or cm

The forces of interaction between molecules - These are the forces of attraction and repulsion. The cause of the forces is the electromagnetic interactions of electrons and nuclei of neighboring molecules: repulsion

+ - repulsion - +

attraction

The forces of intermolecular interaction are short-range: they act at distances comparable to the sizes of molecules or atoms. These forces depend on the distance between these particles:

1. at a distance equal to the diameter of the molecule, the forces of attraction and repulsion of molecules are equal, the resulting force of molecular interaction is zero

= ,

2. at a distance slightly larger than the diameter of the molecule, the attractive forces prevail over the repulsive forces, as a result, an attractive force acts between the molecules

Force of gravity;

3. at a distance less than the diameter of the molecule, the repulsive forces prevail over the attractive forces, as a result, a repulsive force acts between the molecules

Repulsive force;

4. at a distance much greater than the size of the molecules, the forces of attraction and repulsion cease to act

5. when the molecules come closer, when the repulsive force grows faster, the resulting force of interaction between molecules, manifesting itself in the form of a repulsive force, becomes infinitely large.

Basic concepts of MKT

1.Absolute mass of the molecule ( )

The absolute mass of a molecule or simply the mass of a molecule of a substance is very small, for example (O) .

2.Relative molecular weight ( ) – the ratio of the mass of a molecule of a given substance to carbon atom mass : = ;

= ( - atomic mass unit).

Knowing the chemical formula of a substance, you can find the relative molecular mass as the sum of the relative masses of the atoms that make up the molecule. The relative atomic masses of substances are taken from the periodic table. For example, () = 16 ·2 =32; () =1 2 + 16 =18.

3.Amount of substance ( – the ratio of the number of molecules of a given substance to Avogadro's constant number : ; – Avogadro's constant shows how many molecules are contained in one mole of any substance, = .

Mole– amount of substance contained in 12g of carbon.

4. Molar mass of the substance ( ) – mass of one mole of substance : The molar mass can be found knowing that = kg/mol. For example, = kg/mol; O) = 18 kg/mol.

5. Mass of substance ( : N;

6.Number of molecules or atoms( : ;

Aggregate states of matter (phases of matter)

solid liquid gas plasma

Phase transition– the transition of a substance from one state of aggregation to another.

For example, when heated, a solid can be converted into a liquid state, a liquid into a gaseous state, and a gas into a plasma state. Plasma– is a partially or fully ionized gas, i.e. an electrically neutral system consisting of neutral atoms and charged particles (ions, electrons, etc.)

In molecular physics, three phases of the state of matter are studied: gas, liquid and solid. Basic properties of gases: 1. do not have a constant volume, occupy the entire available space, expanding indefinitely; 2. do not have a permanent shape, take the shape of a vessel; 3. easy to compress; 4. exert pressure on all walls of the vessel.

Basic properties of liquids: 1. maintain a constant volume; 2. do not have a permanent shape, take the shape of a vessel; 3. practically incompressible; 4. fluid.

Basic properties of solids: 1. have a constant volume; 2. maintain a constant shape; 3. have the correct geometric shape of the crystals.

The properties of substances in various states of aggregation can be explained by knowing the features of their internal structure.

State of aggregation Particle distance Particle interaction The nature of particle movement Order in the arrangement of particles
Gases Much larger particle sizes Weak attraction, repulsion only during collisions Free, forward, chaotic movement at high speeds - “vagrants” No order
Liquids Comparable to particle sizes Strong attraction and repulsion Oscillatory-translational motion, i.e. fluctuate around the equilibrium position and can jump - “nomads” The order is not strict - “proximate” order
Solids Smaller particle sizes, “tight packing” Strong attraction and repulsion (stronger than in liquid) Limited, oscillates around the equilibrium position - “sedentary” Strict order - “long-range” order (crystal lattice)

Having begun experimental work on creating high pressures in 1908, by 1933 Percy Bridgeman with the help of his instruments he reached the pressure 12 000 atmospheres (for comparison: the pressure in the barrel of a conventional gun is hundreds of atmospheres).

Having obtained record pressure values, he was able to explore and describe:

The behavior of liquids and solids under gigantic pressures (taking into account the discoveries of other scientists, there are a total of 11 types of ice, some of which were discovered by Percy Bridgman);

Changes in electrical resistance under enormous pressures, etc.

Later he created a device in which he brought the pressure to 130 000 atmospheres at 1000 degrees.

In 1940, Percy Bridgman managed to obtain synthetic crystals of sulfur pyrites.

In 1946, for the complex of research carried out, he was awarded the Nobel Prize in Physics, we quote: “for the invention of a device that makes it possible to create ultra-high pressures, and for the discoveries made in connection with this in high-pressure physics.”

Percy Bridgman once remarked that it would not be difficult to obtain new results in physics if all known experiments were repeated under ultra-high pressure. It should be noted that several more Nobel Prizes were received by other scientists for the study of substances under anomalous conditions...

The essence of this method is that single crystals nucleating in the lower part of the crucible with the melt serve as a seed. The crucible is lowered into the cooler zone of the furnace. The lower part of the crucible is conical. The growing speed is also several mm/hour.

Diagram of the installation for growing single crystals using the Stockaberg-Bridgeman method:1 - crucible with melt,2 - crystal,3 - oven,4 - refrigerator,5 - thermocouple,6 - heat shield.

Verneuil method

The Verneuil method is implemented by pouring small portions of a powder mixture into a tubular furnace, where this mixture melts while falling in an oxygen-hydrogen flame and feeds a drop of melt on the surface of the seed. In this case, the seed is gradually pulled down, and the drop remains at the same level along the height of the furnace.

Advantages :

    absence of fluxes and expensive crucible materials;

    no need for precise temperature control;

    the ability to control the growth of a single crystal.

Flaws :

    due to the high growth temperature, the crystals have internal stresses;

    the stoichiometry of the composition may be disrupted due to the reduction of components with hydrogen and the evaporation of volatile substances.

The growing speed is several mm/hour.


The figures show the principle of growing single crystals using the Verneuil method and installation equipment.

Zone melting method

Zone melting consists of passing a melt zone along the length of a single crystal workpiece; at the same time, impurities are concentrated in the melt zone and the crystal is cleaned, the final part of which is then removed. Heating is carried out by induction, radiation-optical or other methods.


Device diagram for zone melting:1 - seed,2 - melt,3 – polycrystalline ingot, 4 – heater(the arrow shows the directionheater movement).

Germanium Induction Zone Melting System Hydrothermal Growth

The hydrothermal crystal growing method is used to grow crystals that are difficult or impossible to grow by other methods, as it most closely mimics the processes of mineral formation in nature. It is based on the fact that at high temperatures (up to 700 °C) and pressures (up to 3000 atm), aqueous solutions of salts are capable of actively dissolving compounds that are practically insoluble under normal conditions. For hydrothermal crystal growth, special durable steel vessels are used - autoclaves that can withstand such extreme pressures and temperatures.

The most common modification of the hydrothermal method is called the positive temperature gradient recrystallization method. Its essence is as follows:

N At the bottom of the autoclave, heated from below and cooled from above, a soluble substance is placed - the charge. Above it are the seeds (plates cut in a certain direction from the crystal of the substance being grown). A temperature difference is created in the autoclave (the lower zone is hotter), which is facilitated by a diaphragm - a partition with holes that separates the upper and lower zones. The solution circulates between the charge granules, becoming saturated with the substance of the crystal being grown. At the same time, the hydrothermal solution is heated. The hot (and therefore lighter) solution enters the upper part of the autoclave, where it cools.

The solubility of the crystallized substance decreases with decreasing temperature, and excess solute is deposited on the seeds. The cold, high-density depleted solution is dropped into the lower part of the autoclave and the cycle is repeated. The process continues until the charge material is completely transferred to the seeds. As a result of these processes, the crystal grows. The growth rate ranges from fractions of a mm to several mm per day. The grown single crystals are usually of high quality and have a characteristic crystallographic cut, because grow under conditions more or less close to equilibrium.

Scheme of an autoclave for hydrothermal synthesis: 1 - solution, 2 - crystal, 3 - oven, 4 - substance for crystallization (T 1 2 ).


BRIDGEMAN
(Bridgman) Percy Williams (1882-1961) - American. physicist and philosopher, Nobel Prize laureate 1946 in physics. In the philosophy and methodology of science, B. is known for the concept of “operationalism,” formulated in the work “The Logic of Modern Physics” (1927). This doctrine is based on the idea that the meanings of scientific concepts are synonymous with the set of operations by which their content is determined. The main such operations are experimental measurement procedures. The formation of operationalism was mainly influenced by pragmatism and the way in which A. Einstein defined the basic concepts of the theory of relativity. The operational introduction of concepts allows us to give them a strict meaning and separate them from the corresponding concepts of everyday experience and metaphysics. At the same time, identifying the meaning of scientific concepts with a set of operations leads to a rejection of their understanding as correlates of reality, to a convergence of operationalism with the instrumentalist interpretation of scientific knowledge. In the spirit of these ideas, B. interpreted various episodes in the development of science, and also spoke out on more general philosophies. problems. His position reflected real methodological changes in modern natural science, but the spread of operationalism to the entire content of scientific knowledge caused criticism from many philosophers. As a result, B. himself began to admit that the meaning of scientific concepts is not limited to operational-measuring procedures, even if the understanding of operations is expanded to include, along with real ones, mental operations.

Philosophy: Encyclopedic Dictionary. - M.: Gardariki. Edited by A.A. Ivina. 2004 .


BRIDGEMAN
(Bridgman) Percy William (21.4. 1882, Cambridge, Massachusetts, - 20. 8. 1961, Randolph, New Hampshire), Amer. physicist and philosopher. Nobel Prize in Physics (1946). In his interpretation of cognition, B. is close to instrumentalism (in the interpretation of the problem of the meaning of concepts) and to solipsism (in the interpretation of experience). Absolutizing the empirical aspect of science, B. underestimated the factual. the role of abstract thinking and abstractions. He considered theoretical theories pointless. concepts that cannot be verified by experience. The idea of ​​connecting the meaning of a concept with a set of actions (operations) leading to their application, B. transferred into the methodology of science and the theory of knowledge as a general principle: to determine scientific concepts, according to B., should not be in terms etc. abstractions, and in terms of the operations of experience (operational definition of concepts). This thesis served as the basis for the whole pdealistic theory. programs for the operational construction of the language of science.
see Operationalism.
Logic of modern physics, N.?., 1927; The nature of some of our physical concepts, N.Y., 1952; Reflections of a physicist, ?. ?., 19551; Way things are, Camb., 1959.

Philosophical encyclopedic dictionary. - M.: Soviet Encyclopedia. Ch. editor: L. F. Ilyichev, P. N. Fedoseev, S. M. Kovalev, V. G. Panov. 1983 .


BRIDGEMAN
BRIDGEMAN(Bridgman) Percy Williams (b. Apr. 21, 1882, Cambridge, Massachusetts - d. Aug. 20, 1961, Randolph, New Hampshire) - Amer. physicist and theorist, since 1904 – professor at Harvard University. He is known for his work in the development of the epistemological foundations of Einstein's theory of relativity. He also holds the opinion that in physics, based on knowledge of a given cause, the future state of a system can only be approximately determined. Basic prod.: “The logic of modern physics”, 1927; "Reflections of a physicist", 1950.

Philosophical Encyclopedic Dictionary. 2010 .


BRIDGEMAN
(Bridgman), Percy William (b. April 21, 1882) - Amer. physicist and idealist philosopher. Graduated from Harvard University (1904), where prof. mathematics and natural sciences philosophy until 1954. Nobel Prize winner (1946) for research in the field of high pressure physics.
In philosophy, B. is known as the founder of operationalism, mainly. the ideas of which were first expressed by him in the work “Dimensional analysis” (1922, 2nd ed., 1931, Russian translation 1934), then developed in detail in the “Logic of modern physics” ", 1927, reprint 1954) and subsequent works. According to B., the meaning of any concept can be clarified only by analyzing a number of operations that are performed either when using this concept, or during verification, i.e., when determining the truth of a sentence that includes this concept, or when answering questions regarding it . Thus, the meaning of a concept is reduced to a corresponding series of operations; this is expressed in the formula B. “meaning is operations.” Operations are defined by B. as “directed actions” of an individual and can be either purely physical or mental (“with pencil and paper”), as well as mixed. Concepts that do not allow operational definitions, B. declares unsuitable for scientific purposes. consumption. These views are a synthesis of logical positivism, from which B. takes the idea of ​​empiricism. defining the meaning of a concept with pragmatism. B.'s operationalism inevitably leads to subjective idealism, because, ultimately, cognition comes down to the subjective experience of the individual. In the field of sociology, B. takes the position of an anarchist intellectual, praising the intellectual freedom of a lone scientist; he calls for the abandonment of “sentimental democracy”, where all members of the state enjoy the same privileges, and insists on the participation in governance of only the most “authoritative” politicians and scientists.
Op.: The nature of physical theory, 2 ed., N. Y., 1949; The intelligent individual and society, N.Y., 1938; Reflections of a physicist, 2 ed., N. Y., 1955; The nature of some of our physical concepts, N. Y., 1952. Lit.: Schaff?., Some problems of the Marxist-Leninist theory of truth, M., 1953; Bykhovsky B.E., Bridgman's operationalism, "Questions of Philosophy" 1958, No. 2; Gornstein T.N., Modern positivism and philosophical issues of physics, in the book: Modern subjective idealism, M., 1957.
V. Abramov. Moscow.

Philosophical Encyclopedia. In 5 volumes - M.: Soviet Encyclopedia. Edited by F. V. Konstantinov. 1960-1970 .


BRIDGEMAN
BRIDGMAN (Bridgman) Percy Williams (April 21, 1882 Cambridge, USA - August 20, 1961, Randolph, New Hampshire) - American physicist and philosopher of science, theorist of operationalism; winner of the Nobel Prize in Physics (1946). He graduated from Harvard University (1904), from 1908 he taught there, and from 1919 he was a professor. In 1926-35 - professor of mathematics and philosophy of nature at Hittins University, in 1950-54 - again at Harvard University. Member of the American Academy of Arts and Sciences, the American Philosophical Society, and other scientific societies.
Bridgman was an experimenter in the field of physics and high-pressure technology. His book “Dimensional Analysis” (New Haven, 1922; Russian translation: M., 1934) became widely known. He was engaged in understanding the logical structure, language and nature of physical science, as well as philosophical issues. Like the neo-positivists, Bridgman focused his attention on analyzing the conceptual structure of physics and searching for empirical foundations for theoretical constructs. In the spirit of instrumentalism, Bridgman identified the meaning of a concept with a set of operations, while defining the operationalist method as a set of step-by-step actions - practical and mental experiments - to determine meanings. He assumed that the language of science should contain statements, all concepts of which have referents. In the book “The Way Things Are” (The Way Things Are. N.Y., 1959), dedicated to general epistemological issues, Bridgman defines philosophical theories as verbal experiments that testify to the possibilities of human thinking and imagination, as well as the social need for such experiments, and not the nature of the world.
J. Dewey relied on Bridgman's operationalism to substantiate his version of instrumentalism. His theory was highly appreciated by representatives of the Vienna Circle (G. Feigl), and also influenced research in the field of sociology and psychology (primarily the behaviorism of B. F. Skinner). The ideas of intellectual freedom and responsibility developed in the book “The Intelligent Individual and Society” (N.Y., 1938) caused a wide resonance among the American intelligentsia.
Works: The Logic of Modem Physics. N.Y., 1927; The Physics of High Pressure. N.Y., 1937; The Nature of Thermodynamics. Cambr. Mass., 1941; The Nature of Some of our Physical Concepts. N.Y., 1952; Reflections of a Physics. N.Y., 1950; A Sophisticate's Primer of Relativity. L., 1962.
Lit.: Livers” A. A. Operationalist interpretation of the logic of science by Percy Bridgman.-In the book: Concepts of science in bourgeois philosophy and sociology. Second half of the XIX-XX centuries. M., 1974.
?. S. Yulina

New Philosophical Encyclopedia: In 4 vols. M.: Thought. Edited by V. S. Stepin. 2001 .

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