Presentations on physics special theory of relativity. Presentation on the topic "special theory of relativity"

Special Theory of Relativity PRESENTATION PREPARED BY:
SIMONOVA EKATERINA
2nd YEAR STUDENT, GROUP No. 3
FACULTY OF CONFLICTOLOGY

SPECIAL THEORY OF RELATIVITY

revolutionized our ideas about space and time,
about energy and matter, ideas to which
humanity has walked for thousands of years
stories.

Classical mechanics of Newton and Galileo

Principle of inertia:
"Bodies that do not experience
influence of forces, moving
evenly and straightly"
The principle of adding speeds:
"The speed of the body is added
from the speed of the reference frame
and the speed of body movement in
her"
The principle of relativity
Galilee:
"All the laws of mechanics
are the same
in inertial systems
countdown"

Inertial reference systems - systems
readings that are at rest
or move in a straight line uniformly
Non-inertial reference systems – systems
references that move with acceleration
In 1632, Galileo Galilei formulated
principle of relativity:
all mechanical phenomena occur in any
inertial reference systems are the same
way. All laws of mechanics are invariant with respect to
in relation to any inertial systems
countdown.

Second half of the 19th century,
J. Maxwell
formulated
basic laws
electrodynamics
Does the principle apply?
relativity, valid for
mechanical phenomena, to electromagnetic
phenomena?

Development of physical concepts in the 19th century

6
Electricity and magnetism give rise to each other
friend
The electromagnetic field spreads
like a wave
Light is an electromagnetic wave
Maxwell's equations for electromagnetic
fields are the highest form of knowledge about
electromagnetism

Two ideas about light that developed in physics in the 17th century

7
Newton (1643-1727):
“Light is a stream of particles
in the void"
Huygens (1629-1695):
"Light is a wave in the ether"

NEWTON: Reflection of light is the bouncing of particles of light from an obstacle

8

HUYGENS: Light is a wave in the ether

9
Ether is a medium in which
light spreads
Speed ​​of light on air
independent of speed
source
The point reached
the wave itself becomes
wave source

Ideas about light in the 19th century

10
Light is an electromagnetic wave
spreading in the world air
The world ether is a stationary medium,
filling all the space, for
propagation of electromagnetic waves

The split in physicists’ ideas about the nature of light by the beginning of the 20th century

11
LIGHT - WAVES
IN THE EMPTIN
Poincare Einstein
Huygens
LIGHT - FLOW
PARTICLES
LIGHT - WAVES
ETHER
Newton
Lorenz
Ritz

In a carriage moving relative to the railway track
road, a light signal is sent in the direction
movements.

regarding the person in the carriage?
What is the speed of the light signal
relative to man on earth?

13
The principle of relativity
not applicable to electromagnetic
phenomena.
H. Lorenz

Contradictions were discovered between electrodynamics and Newtonian mechanics. Possible solutions:

14
Maxwell's equations
unfair
G. Hertz

Contradictions were discovered between electrodynamics and Newtonian mechanics. Possible solutions:

15
The principle of relativity and equations
Maxwell are fair,
need to give up the classic ones
ideas about space and
time.
A. Einstein

Albert Einstein - creator of the theory of relativity

Special theory
relativity
was published
in 1905.
More complex from a point of view
mathematical point of view
apparatus general theory
relativity was
completed by Einstein
by 1916.

STO and OTO

Special theory of relativity (SRT) is a theory
describing movement, relationships between
space and time at speeds close to
speed of light.
The general theory of relativity (GTR) is a theory
which is a generalization of SRT for
gravitational fields.

Postulates of Einstein's theory of special relativity (1905)

18
Postulate 1. The principle of relativity
All natural processes proceed equally in all
inertial reference systems.
Postulate 2. Principle of constancy
speed of light
The speed of light in a vacuum is the same for everyone
inertial reference systems, it does not depend on any
source speed, nor the receiver speed
light signal.

Main conclusions from Einstein's theory of special relativity (1905)

19
1. Reducing body size
2. Time dilation
3.Relativistic law of addition
speeds
4.Law of relativistic mechanics.
Relationship between mass and energy

SRT Special theory of relativity (STR) is a theory that describes motion, the laws of mechanics and space-time relations at arbitrary speeds of motion less than the speed of light in a vacuum, including those close to the speed of light. Within the framework of special relativity, classical Newtonian mechanics is a low-velocity approximation. A generalization of STR for gravitational fields is called the general theory of relativity. Special relativity (STR) is a theory that describes motion, the laws of mechanics and space-time relations at arbitrary speeds of motion less than the speed of light in a vacuum, including those close to the speed of light. Within the framework of special relativity, classical Newtonian mechanics is a low-velocity approximation. A generalization of STR for gravitational fields is called general relativity. Deviations in the course of physical processes from the predictions of classical mechanics described by the special theory of relativity are called relativistic effects, and the speeds at which such effects become significant are called relativistic speeds. Deviations in the course of physical processes from the predictions of classical mechanics described by the special theory of relativity are called relativistic effects, and speeds described by the special theory of relativity. at which such effects become significant, relativistic speeds.

From the history of service stations. The special theory of relativity was developed at the beginning of the 20th century through the efforts of G. A. Lorentz, A. Poincaré, A. Einstein and other scientists. The experimental basis for the creation of SRT was Michelson's experiment. His results were unexpected for the classical physics of his time: the independence of the speed of light from direction (isotropy) and the orbital motion of the Earth around the Sun. An attempt to interpret this result at the beginning of the 20th century resulted in a revision of classical concepts and led to the creation of the special theory of relativity. The special theory of relativity was developed at the beginning of the 20th century through the efforts of G. A. Lorentz, A. Poincaré, A. Einstein and other scientists. The experimental basis for the creation of SRT was Michelson's experiment. His results were unexpected for the classical physics of his time: the independence of the speed of light from direction (isotropy) and the orbital motion of the Earth around the Sun. An attempt to interpret this result at the beginning of the 20th century resulted in a revision of classical concepts and led to the creation of the special theory of relativity.

When moving at near-light speeds, the laws of dynamics change. Newton's second law, relating force and acceleration, must be modified for bodies with velocities close to the speed of light. In addition, the expression for the momentum and kinetic energy of the body has a more complex dependence on speed than in the nonrelativistic case. When moving at near-light speeds, the laws of dynamics change. Newton's second law, relating force and acceleration, must be modified for bodies with velocities close to the speed of light. In addition, the expression for the momentum and kinetic energy of the body has a more complex dependence on speed than in the nonrelativistic case.

Basic concepts of SRT. The reference system represents a certain material body chosen as the beginning of this system, a method for determining the position of objects relative to the beginning of the reference system, and a method for measuring time. Usually a distinction is made between reference systems and coordinate systems. Adding a procedure for measuring time to a coordinate system “transforms” it into a reference system. The reference system is a certain material body chosen as the origin of this system, a method for determining the position of objects relative to the origin of the reference system, and a method for measuring time. Usually a distinction is made between reference systems and coordinate systems. Adding a time measurement procedure to a coordinate system “turns” it into a reference system. An inertial reference system (IRS) is a system relative to which an object, not subject to external influences, moves uniformly and rectilinearly. An inertial reference system (IRS) is a system relative to which an object, not subject to external influences, moves uniformly and rectilinearly. An event is any physical process that can be localized in space and has a very short duration. In other words, an event is completely characterized by coordinates (x, y, z) and time t. An event is any physical process that can be localized in space and has a very short duration. In other words, the event is completely characterized by coordinates (x, y, z) and time t.

Usually two inertial systems S and S are considered." The time and coordinates of some event measured relative to the S system are denoted as (t, x, y, z), and the coordinates and time of the same event measured relative to the S system are denoted as (t" , x", y", z"). It is convenient to assume that the coordinate axes of the systems are parallel to each other and the system S" moves along the x-axis of the system S with speed v. One of the problems of SRT is to search for relations connecting (t", x", y", z") and (t, x, y, z), which are called Lorentz transformations.

1 principle of relativity. All laws of nature are invariant with respect to the transition from one inertial frame of reference to another (they proceed identically in all inertial frames of reference). All laws of nature are invariant with respect to the transition from one inertial frame of reference to another (they proceed identically in all inertial frames of reference). This means that in all inertial systems the physical laws (not just mechanical ones) have the same form. Thus, the principle of relativity of classical mechanics is generalized to all processes of nature, including electromagnetic ones. This generalized principle is called Einstein's principle of relativity. This means that in all inertial systems the physical laws (not just mechanical ones) have the same form. Thus, the principle of relativity of classical mechanics is generalized to all processes of nature, including electromagnetic ones. This generalized principle is called Einstein's principle of relativity.

2 principle of relativity. The speed of light in a vacuum does not depend on the speed of movement of the light source or observer and is the same in all inertial frames of reference. The speed of light in a vacuum does not depend on the speed of movement of the light source or observer and is the same in all inertial frames of reference. The speed of light occupies a special position in the SRT. This is the maximum speed of transmission of interactions and signals from one point in space to another. The speed of light occupies a special position in the SRT. This is the maximum speed of transmission of interactions and signals from one point in space to another.

ONE HUNDRED. SRT made it possible to resolve all the problems of “pre-Einstein” physics and explain the “contradictory” results of experiments in the field of electrodynamics and optics known at that time. Subsequently, STR was supported by experimental data obtained from studying the movement of fast particles in accelerators, atomic processes, nuclear reactions, etc. SRT made it possible to resolve all the problems of “pre-Einstein” physics and explain the “contradictory” results of experiments in the field known by that time electrodynamics and optics. Subsequently, STR was supported by experimental data obtained from studying the movement of fast particles in accelerators, atomic processes, nuclear reactions, etc.

Example. At the moment of time t = 0, when the coordinate axes of two inertial systems K and K" coincide, a short-term flash of light occurred at the common origin of coordinates. During time t, the systems will shift relative to each other by a distance υt, and the spherical wave front in each system will have a radius ct, since the systems are equal and in each of them the speed of light is equal to c. From the point of view of an observer in the K system, the center of the sphere is at point O, and from the point of view of an observer in the K system it will be at point O. t = 0, when the coordinate axes of two inertial systems K and K" coincide, a short-term flash of light occurred at the common origin. During time t, the systems will shift relative to each other by a distance υt, and the spherical wave front in each system will have a radius ct, since the systems are equal and in each of them the speed of light is equal to c. From the point of view of an observer in the K system, the center of the sphere is at point O, and from the point of view of an observer in the K system, it will be at point O."

Explanation of contradictions. To replace the Galilean transformations, SRT proposed other transformation formulas when moving from one inertial system to another - the so-called Lorentz transformations, which at motion speeds close to the speed of light allow us to explain all relativistic effects, and at low speeds (υ

To view the presentation with pictures, design and slides, download its file and open it in PowerPoint on your computer.
Text content of presentation slides: MOAN.V. Brandina ISO is a reference system relative to which a free body moves rectilinearly and uniformly or is at rest. An abstraction, an ideal object, an object of science, a means of describing phenomena. None in nature. Inertial reference system An event is any physical phenomenon that occurs at a certain point in space relative to any ISO at some point in time. Abstraction, ideal concept Event Postulate - an initial position, a statement accepted without strict proof, but substantiated, for example, by experiments. Postulate A proper ISO is a reference system relative to which the body is at rest. The time of movement of the body, measured in such a system, is its own time. The mass of a body, measured in such a system, is the rest mass. Own inertial frame of reference Invariant is a quantity independent of the choice of ISO. (speed of light is an invariant, an event is an invariant) Invariant In any list of the most significant people century, this person was always present. One of the founders of modern theoretical physics, winner of the Nobel Prize in Physics in 1921. Lived in Germany (1879-1893, 1914-1933), Switzerland (1893-1914) and the USA (1933-1955). At the age of six he began playing the violin, and at the gymnasium he was not among the first students. After graduating from the Polytechnic, he received a diploma as a teacher of mathematics and physics. He worked in the Patent Office, focusing primarily on expert assessment of applications for inventions. He completed his general theory of relativity in 1915, but world fame came to him only in 1919. He was a convinced democratic socialist, humanist, pacifist and anti-fascist Plan. 1. Classical ideas about space and time. 2. The emergence of new mechanics. 3. Postulates of the theory of relativity. 4. The main consequences of the postulates of the theory of relativity. 5.Mass and energy in the special theory of relativity. 6. Application of the theory of relativity. 1. Classical ideas about space and time The principle of relativity of G. Galileo (17th century) All mechanical phenomena under equal initial conditions proceed identically in all inertial systems All ISOs are equivalent from the point of view of mechanical phenomena It is impossible to establish by any mechanical means whether the ISO is at rest or moves uniformly and rectilinearly Galileo's law on the addition of velocities ʋ= ʋˈ+ ʋₒ1. Classical ideas about space and time Isaac Newton generalized the discoveries of Galileo (2 laws) added a third law and put forward a hypothesis about mutual attraction Classical mechanics The length of bodies is the same in any ISO Time flows the same in different ISOs The mass of a body does not depend on speed and does not change when moving from one ISO to another: Space and time are absolute. I Marshak wrote: The world was shrouded in deep darkness. Let there be light! And then Newton appeared! 1. Classical ideas about space and time Continuation of the poem by S.Ya. Marshak: Satan did not wait long for revenge. Einstein came - everything became as usual. 1881 American scientists A. Michelson and E. Morley compared the speed of light in the direction of the Earth's movement and in the perpendicular direction. In both cases, the speed of light turned out to be equal to c = 3*108 m/s, which contradicted the classical rule of adding velocities. Conclusion: the speed of electromagnetic waves in a vacuum is constant and finite, regardless of the choice of ISO. The law of addition of speeds does not work?2. The emergence of new mechanics Scientific problem: Is Galileo’s principle of relativity valid? (How to reconcile the principles of mechanics and the laws of electrodynamics?) Methods of resolution The principle of relativity does not apply to electromagnetic phenomena Maxwell’s equations are incorrect Refusal of classical concepts of space and time Change them so that when moving from 1 CO to another it is not changedChange Newton's laws 3. Postulates of the theory of relativity Generalized Galileo's principle of relativity to all physical processes and combined it with the postulate of the constancy of the speed of light 1905 “On the electrodynamics of moving bodies.” Postulate I: The principle of relativity: in all inertial frames of reference, all physical phenomena (all processes of nature) proceed in the same way. This postulate is a generalization of Newton’s principle of relativity not only to the laws of mechanics, but also to the laws of the rest of physics. II postulate: The principle of the constancy of the speed of light: the speed of light in a vacuum is the limiting speed of any interaction and does not depend on the speed of the source and receiver of the light signal. Special theory relativity classical mechanics, studies the motion of macroscopic bodies at low speeds (ʋ< < c); релятивистская механика, изучает движение макроскопических тел с большими скоростями (ʋ < c); квантовая механика, изучает движение микроскопических тел с малыми скоростями (ʋ < < c); релятивистская квантовая физика, изучает движение микроскопических тел с произвольными скоростями (ʋ ? c). 1. Относительность одновременности. События, одновременные в одной инерциальной системе отсчета, не одновременны в других инерциальных системах отсчета, движущихся относительно первой. 2. Относительность длины (расстояний). Длина не является абсолютной величиной, а зависит от скорости движения тела относительно данной системы отсчёта. Уменьшение длины в направлении движения (релятивистский эффект сокращения длины)3. Относительность промежутка времениДлительность одного и того же процесса различна в различных инерциальных системах отсчета. (Релятивистский эффект замедления времени)τ =4.Основные следствия постулатов теории относительности 4. Релятивистский закон сложения скоростей. Свойство закона сложения скоростей: при любых скоростях тела и системы отсчета (не больше скорости света в вакууме), результирующая скорость не превышает с. Движение реальных тел со скоростью больше с невозможно.Для малых скоростей получаем классический закон сложения скоростей 4.Основные следствия постулатов теории относительности 5. Масса и энергия в специальной теории относительностиМасса движущегося тела возрастает при увеличении скорости его движенияm =Е = mс 2Массовая частица обладает энергиейс 2Е =В системе отсчёта, в которой тело покоится, его энергия = энергия покояЕ = m0с 2 Импульс и энергия в специальной теории относительностиЕ2 = с 2р2+ с 4 m 2Справедливо во всех ИСО - ивариантр =Релятивистская энергия – собственная энергия частицы и релятивистская кинетическая энергияЕ = m с 2 + Е к Принцип соответствияЛюбая теория должна включать предыдущую как предельный случайПри скоростях движения тела, меньших скорости света, формулы СТО переходят в классическиеВывод: теория относительности не отвергает законов классической механики, она их уточняет для скоростей, близких к скорости света В астрономии: 1. Эйнштейн утверждал, что во время прохождения света вблизи больших масс должно наблюдаться искривление лучей. Это было подтверждено в 1919 г. Во время полного солнечного затмения участники Международной экспедиции сфотографировали звездное небо во время затмения. Сравнивая эти фотографии с фотографиями того же участка неба, но без Солнца, ученые обнаружили, что звезды сместились. Это результат смещения световых лучей от звезд при прохождении их вблизи Солнца. 2. Часы идут медленнее вблизи массивных тел. 3. Доказано, что во время движения планет вокруг Солнца плоскости их орбит поворачиваются. 4. В астрономии было открыто явление удаления галактик, причем скорость удаления пропорциональна расстоянию от галактики до наблюдателя. Это открытие согласовано с выводами теории относительности о зависимости длины волны от скорости. 6.Применение теории относительности

Filimonova L.V. 12.20.06 F-11, FS-12

The principle of relativity in quantum theory

Classical mechanics is based on

mechanical principle of relativity (or Galileo's principle of relativity): the laws of dynamics are the same in all inertial frames of reference.

This principle means that the laws of dynamics invariant (i.e. unchangeable) with respect to Galileo's transformations:

It is assumed that at the initial moment the coordinate axes of both systems coincide

From Galileo's transformations follows the classicalspeed conversion law when moving from one reference system to another.

Service station basics

Def. SRT - physical theory of space and

time, taking into account the geometric relationship existing between them.

It is based on the “principle of relativity” or “postulate of relativity”, i.e. negation

ideas about an absolute stationary frame of reference associated with a stationary ether.

Poincaré: “This impossibility of demonstrating experimentally the absolute motion of the Earth represents

law of nature; we come to adopt this law, which we will call postulate of relativity, and we will accept it without reservations.”

The meaning of the “postulate of relativity”

Herman Minkowski: “The meaning of the postulate boils down to the fact that in phenomena we are given only a four-dimensional world in space and time, but that the projections of this world into space and time can be taken with some

arbitrariness, I would like to give this statement a name: postulate

absolute peace"

Differences between KM and STO

The main difference between the concepts of space and

time of the theory of relativity from the ideas of Newtonian physics is relationship between space and time.

This relationship is revealed in the formulas for transforming coordinates and time when moving from one reference system to another (Lorentz transformation).

(*) expresses new ideas about space and time: their connection into a single geometric type manifold, a manifold with a special four-dimensional pseudo-Euclidean geometry, a geometry in which time is closely related to space and cannot be considered independently of the latter.

From these same ideas flow the most important

consequences for the laws of nature, expressed in the requirement of covariance (i.e. invariability of shape) of any physical processes in relation to transformations of four-dimensional space-time coordinates.

In this case, the concept of relativity acquires only the meaning of possible multiplicity spatiotemporal images of phenomena with the absoluteness of content, i.e. laws of nature.

Spacetime

At all Every physical phenomenon occurs in space and timeand cannot be depicted in our consciousness except in space and time.

Space and time are the forms of existence of matter. No matter exists outside of space and time.

A concrete image of space and time is reference system, i.e. coordinate-time variety of numbers that make up an imaginary grid and time sequence of all possible spatial and temporal points. The same space and time can be represented by different coordinate-time grids (reference systems).

Einstein's postulates

Lorentz transformations reflecting properties space-time were derived by Einstein based on 2 postulates: the principle of relativity and the principle of constancy of the speed of light.

1. The laws according to which the states of physical systems change do not depend on which of the two coordinate systems, which are in uniform translational motion relative to each other, these state changes belong to.

2. Each ray of light moves in a “resting” coordinate system with a certain speed, regardless of whether this ray of light is emitted by a body at rest or in motion.

Einstein's postulates

SRT is based on two principles or postulates formulated by Einstein in 1905.

The principle of relativity: all the laws of nature

invariant with respect to the transition from one inertial frame of reference to another . This means that in all inertial systems the physical laws (not just mechanical ones) have the same form. Thus, the principle of relativity of classical mechanics is generalized to all processes of nature, including electromagnetic ones. This generalized principle is called

Einstein's principle of relativity.

The principle of the constancy of the speed of light: speed

light in a vacuum does not depend on the speed of movement of the light source or observer and is the same in all inertial frames of reference . The speed of light occupies a special position in the SRT. This is the maximum speed of transmission of interactions and signals from one point in space to another.

POSTULATE (from the Latin postulatum requirement), a position (judgment, statement) accepted within the framework of a class. scientific theory as true due to evidence and therefore playing the role of an axiom in this theory (along with the axioms of logic). These are, for example, the Galileo-Nevsky principle of relativity and the principle of constancy of the speed of light in relativistic mechanics. judgmentstatementstatement

Einstein's postulates Einstein's postulates In his work, Einstein, without a single new experiment, having analyzed and generalized already known experimental facts, for the first time outlined the ideas of the theory of relativity, which radically changed the usual ideas about the properties of space and time. In his work, Einstein, without a single new experiment, having analyzed and generalized already known experimental facts, for the first time outlined the ideas of the theory of relativity, which radically changed the usual ideas about the properties of space and time. Einstein's theory of relativity consists of two parts: special and general relativity. In 1905, Einstein published the basic ideas of the partial or special theory of relativity, which considers the properties of space and time that are valid under conditions when the gravity of bodies can be neglected, i.e. consider their gravitational fields "negligible. The theory of relativity, which deals with the properties of space and time in strong gravitational fields, is called the general theory of relativity. The principles of the general theory of relativity were outlined by Einstein 10 years later than the private theory, in 1915. Einstein's theory of relativity consists of two parts: partial and general theory of relativity. In 1905, Einstein published the basic ideas of the partial or special theory of relativity, which considers the properties of space and time that are valid under conditions when the gravity of bodies can be neglected, i.e. they are considered gravitational. fields are negligible. The theory of relativity, which deals with the properties of space and time in strong gravitational fields, is called general relativity. The principles of general relativity were outlined by Einstein 10 years later than the general theory of relativity, in 1915.

Einstein’s special theory of relativity was based on two postulates, i.e. statements that are accepted as true within the framework of a given scientific theory without proof (in mathematics, such statements are called axioms). Einstein’s special theory of relativity was based on two postulates, i.e. statements that are accepted as true within the framework of a given scientific theory without proof (in mathematics, such statements are called axioms). 1 Einstein's postulate or principle of relativity: all laws of nature are invariant with respect to all inertial frames of reference. All physical, chemical, biological phenomena occur equally in all inertial frames of reference. 1 Einstein's postulate or principle of relativity: all laws of nature are invariant with respect to all inertial frames of reference. All physical, chemical, biological phenomena occur equally in all inertial frames of reference. 2nd postulate or principle of the constancy of the speed of light: the speed of light in a vacuum is constant and the same in relation to any inertial frame of reference. It does not depend either on the speed of the light source or on the speed of its receiver. No material object can move faster than the speed of light in a vacuum. Moreover, pi one particle of matter, i.e. a particle with a rest mass different from zero cannot reach the speed of light in a vacuum; only field particles can move at such a speed, i.e. particles with rest mass equal to zero. 2nd postulate or principle of the constancy of the speed of light: the speed of light in a vacuum is constant and the same in relation to any inertial frame of reference. It does not depend either on the speed of the light source or on the speed of its receiver. No material object can move faster than the speed of light in a vacuum. Moreover, pi one particle of matter, i.e. a particle with a rest mass different from zero cannot reach the speed of light in a vacuum; only field particles can move at such a speed, i.e. particles with rest mass equal to zero.

You work on Analyzing Einstein's 1st postulate, we see that Einstein expanded the scope of Galileo's principle of relativity, extending it to any physical phenomena, including electromagnetic ones. Einstein's postulate 1 directly follows from the Michelson-Morley experiment, which proved the absence of an absolute frame of reference in nature. From the results of this experiment follows Einstein’s 2nd postulate about the constancy of the speed of light in a vacuum, which nevertheless comes into conflict with the 1st postulate if we extend to electromagnetic phenomena not only the Galilean principle of relativity itself, but also the Galilean rule for adding velocities, which follows from Galileo -va rules for coordinate transformation (see paragraph 10). Consequently, Galileo's transformations for coordinates and time, as well as his rule for adding velocities to electromagnetic phenomena are not applicable. Analyzing Einstein's 1st postulate, we see that Einstein expanded the scope of Galileo's principle of relativity, extending it to any physical phenomena, including electromagnetic ones. Einstein's postulate 1 directly follows from the Michelson-Morley experiment, which proved the absence of an absolute frame of reference in nature. From the results of this experiment follows Einstein’s 2nd postulate about the constancy of the speed of light in a vacuum, which nevertheless comes into conflict with the 1st postulate if we extend to electromagnetic phenomena not only the Galilean principle of relativity itself, but also the Galilean rule for adding velocities, which follows from Galileo -va rules for coordinate transformation (see paragraph 10). Consequently, Galileo's transformations for coordinates and time, as well as his rule for adding velocities, are not applicable to electromagnetic phenomena