Why do science need measurements? Why does a person need measurements - document

Absolute system for measuring physical quantities

In the last two centuries, there has been a rapid differentiation of scientific disciplines in science. In physics, in addition to Newton’s classical dynamics, electrodynamics, aerodynamics, hydrodynamics, thermodynamics, and the physics of various states of aggregation, special and general theories of relativity, quantum mechanics and much more. Narrow specialization occurred. Physicists no longer understand each other. Superstring theory, for example, is only understood by about a hundred people around the world. To professionally understand superstring theory, you need to study only superstring theory; there is simply not enough time for the rest.

But we should not forget that so many different scientific disciplines study the same physical reality - matter. Science, and especially physics, has come close to the point where further development is possible only through integration (synthesis) of various scientific directions. The considered absolute system for measuring physical quantities is the first step in this direction.

Unlike the international system of SI units, which has 7 basic and 2 additional units of measurement, the absolute system of units of measurement uses one unit - the meter (see table). The transition to the dimensions of the absolute measurement system is carried out according to the rules:

Where: L, T and M are the dimensions of length, time and mass, respectively, in the SI system.

The physical essence of transformations (1.1) and (1.2) is that (1.1) reflects the dialectical unity of space and time, and from (1.2) it follows that mass can be measured in square meters. True, />in (1.2) are not square meters of our three-dimensional space, but square meters of two-dimensional space. Two-dimensional space is obtained from three-dimensional space if three-dimensional space is accelerated to a speed close to the speed of light. According to the special theory of relativity, due to the reduction of linear dimensions in the direction of movement, the cube will turn into a plane.

The dimensions of all other physical quantities are established on the basis of the so-called “pi-theorem”, which states that any correct relationship between physical quantities, up to a constant dimensionless factor, corresponds to some physical law.

To introduce a new dimension of any physical quantity, you need:

Choose a formula containing this quantity, in which the dimensions of all other quantities are known;

Algebraically find the expression for this quantity from the formula;

Substitute the known dimensions of physical quantities into the resulting expression;

Perform the required algebraic operations on dimensions;

Accept the result obtained as the desired dimension.

The “Pi-theorem” allows not only to establish the dimensions of physical quantities, but also to derive physical laws. Let us consider, for example, the problem of gravitational instability of a medium.

It is known that as soon as the wavelength of a sound disturbance exceeds a certain critical value, elastic forces (gas pressure) are not able to return the particles of the medium to their original state. It is required to establish the relationship between physical quantities.

We have physical quantities:

/> - the length of the fragments into which a homogeneous infinitely extended medium breaks up;

/> - density of the medium;

A is the speed of sound in the medium;

G is the gravitational constant.

In the SI system, physical quantities will have the following dimensions:

/>~ L; /~ />; a~/>; G~ />

From ///>, />and /> we form a dimensionless complex:

where: />and /> are unknown exponents.

Thus:

Since P, by definition, is a dimensionless quantity, we obtain a system of equations:

The solution of the system will be:

hence,

Where we find it from:

Formula (1.3) describes the well-known Jeans criterion up to a constant dimensionless factor. In the exact formula />.

Formula (1.3) satisfies the dimensions of the absolute system of measuring physical quantities. Indeed, the physical quantities included in (1.3) have dimensions:

/>~ />; />~ />; />~ />; />~ />

Substituting the dimensions of the absolute system into (1.3), we obtain:

Analysis of the absolute system for measuring physical quantities shows that mechanical force, Planck's constant, electrical voltage and entropy have the same dimension: />. This means that the laws of mechanics, quantum mechanics, electrodynamics and thermodynamics are invariant.

For example, Newton's second law and Ohm's law for the area electrical circuit have the same formal notation:

/>~ />(1.4)

/>~ />(1.5)

At high speeds of motion, a variable dimensionless factor of the special theory of relativity is introduced into Newton’s second law (1.4):

If we introduce the same factor into Ohm’s law (1.5), we get:

According to (1.6), Ohm’s law allows for the appearance of superconductivity, since />at low temperatures can take a value close to zero. If physics had used an absolute system of measuring physical quantities from the very beginning, then the phenomenon of superconductivity would have been predicted theoretically first, and only then discovered experimentally, and not vice versa.

There is a lot of talk about the accelerated expansion of the Universe. Modern technical means cannot measure the acceleration of expansion. To solve this problem, let us use an absolute system for measuring physical quantities.

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It is quite natural to assume that the acceleration of the expansion of the Universe />depends on the distance between space objects />and on the expansion rate of the Universe />. Solving the problem using the method outlined above gives the formula:

Analysis of the physical meaning of formula (1.7) is beyond the scope of the problem under discussion. Let's just say that in the exact formula />.

The invariance of physical laws makes it possible to clarify the physical essence of many physical concepts. One of these “dark” concepts is the concept of entropy. In thermodynamics, mechanical acceleration corresponds to mass entropy density

where: S – entropy;

m is the mass of the system.

The resulting expression indicates that entropy, contrary to the existing misconception, can not only be calculated, but also measured. Let us consider, for example, a metal spiral spring, which can be considered a mechanical system of atoms in a metal crystal lattice. If you compress a spring, the crystal lattice is deformed and creates elastic forces that can always be measured. The elastic force of the spring will be the same mechanical entropy. If we divide the entropy by the mass of the spring, we obtain the mass entropy density of the spring, like a system of atoms in a crystal lattice.

A spring can also be represented as one of the elements of the gravitational system, the second element of which is our Earth. The gravitational entropy of such a system will be the force of attraction, which can be measured in several ways. Dividing the force of attraction by the mass of the spring, we obtain the gravitational entropy density. Gravitational entropy density is the acceleration of gravity.

Finally, in accordance with the dimensions of physical quantities in the absolute measurement system, the entropy of a gas is the force with which the gas presses on the walls of the vessel in which it is enclosed. Specific gas entropy is simply the pressure of the gas.

Important information about the internal structure of elementary particles can be obtained based on the invariance of the laws of electrodynamics and aero-hydrodynamics, and the invariance of the laws of thermodynamics and information theory makes it possible to fill the equations of information theory with physical content.

The absolute system of measuring physical quantities refutes the widespread misconception about the invariance of Coulomb's law and the law of universal gravitation. The dimension of mass //~/>does not coincide with the dimension of electric charge q ~/>, therefore the law of universal attraction describes the interaction of two spheres, or material points, and the Coulomb law describes the interaction of two conductors with current, or circles.

Using the absolute system of measuring physical quantities, we can purely formally derive Einstein’s famous formula:

/>~ />(1.8)

There is no insurmountable gap between special relativity and quantum theory. Planck's formula can also be obtained purely formally:

One can further demonstrate the invariance of the laws of mechanics, electrodynamics, thermodynamics and quantum mechanics, but the examples considered are sufficient to understand that all physical laws are special cases of some general laws spatiotemporal transformations. Those interested in these laws will find them in the author’s book “Theory of Multidimensional Spaces”. – M.: Com Book, 2007.

Transition from the dimensions of the international system (SI) to the dimensions of the absolute system (AS) of measurement of physical quantities

1. Basic units

Name of physical quantity

Dimension in the system

Name of physical quantity

Kilogram

Force electric current

Thermodynamic temperature

Quantity of substance

The power of light

2. Additional units

Flat angle

Solid angle

Steradian

3. Derived units

3.1 Spatiotemporal units

Square meter

Cubic meter

Speed

Continuation
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Ampere per square meter

Electric charge

Electric charge density is linear

pendant per meter

Surface electric charge density

Pendant per square meter

Magnetomotive force

Tension magnetic field

Ampere per meter

Inductance

Magnetic constant

Henry per meter

Magnetic moment of electric current

Ampere - square meter

Magnetization

Ampere per meter

Reluctance

Ampere per weber

3.5 Energy photometry

Light flow

Awareness

Radiation flux

Energy illumination and luminosity

Watt per square meter

Energy brightness

Watt per steradian square meter

Spectral density of energy luminosity:

By wavelength

By frequency

Watt per m3

Not only schoolchildren, but even adults sometimes wonder: why is physics needed? This topic is especially relevant for parents of students who at one time received an education that was far from physics and technology.

But how to help a student? In addition, teachers can assign an essay for homework in which they need to describe their thoughts about the need to study science. Of course it's better this topic entrust it to eleventh graders who have a complete understanding of the subject.

What is physics

Speaking in simple language, physics is Of course, nowadays physics is moving more and more away from it, going deeper into the technosphere. Nevertheless, the subject is closely connected not only with our planet, but also with space.

So why do we need physics? Its task is to understand how certain phenomena occur, why certain processes are formed. It is also advisable to strive to create special calculations that would help predict certain events. For example, how did Isaac Newton discover the law of universal gravitation? He studied an object falling from top to bottom and observed mechanical phenomena. Then he created formulas that really work.

What sections does physics have?

The subject has several sections that are studied generally or in depth at school:

  • Mechanics;
  • vibrations and waves;
  • thermodynamics;
  • optics;
  • electricity;
  • the quantum physics;
  • Molecular physics;
  • nuclear physics.

Each section has subsections that study in detail various processes. If you don’t just study theory, paragraphs and lectures, but learn to imagine and experiment with what is being discussed, then science will seem very interesting, and you will understand why physics is needed. Complex sciences that cannot be applied in practice, for example, atomic and nuclear physics, can be considered differently: read interesting articles from popular science magazines, watch documentaries about this area.

How does the item help in everyday life?

In the essay “Why is physics needed” it is recommended to give examples if they are relevant. For example, if you are describing why you need to study mechanics, then you should mention cases from Everyday life. An example would be an ordinary car trip: from a village to a city you need to travel along a free highway in 30 minutes. The distance is about 60 kilometers. Of course, we need to know at what speed it is best to move along the road, preferably with some time to spare.

You can also give an example of construction. Let's say when building a house you need to correctly calculate the strength. You can't choose flimsy material. A student can conduct another experiment to understand why physics is needed, for example, take a long board and place chairs at the ends. The board will be located on the backs of the furniture. Next, you should load the center of the board with bricks. The board will sag. As the distance between the chairs decreases, the deflection will be less. Accordingly, a person receives food for thought.

When preparing dinner or lunch, a housewife often faces physical phenomena: heat, electricity, mechanical work. To understand how to do the right thing, you need to understand the laws of nature. Experience often teaches you a lot. And physics is the science of experience and observation.

Professions and specialties related to physics

But why does someone who graduates from school need to study physics? Of course, those who enter a university or college majoring in the humanities have virtually no need for the subject. But in many areas science is required. Let's look at which ones:

  • geology;
  • transport;
  • electricity supply;
  • electrical engineering and instruments;
  • medicine;
  • astronomy;
  • construction and architecture;
  • heat supply;
  • gas supply;
  • water supply and so on.

For example, even a train driver needs to know this science in order to understand how a locomotive works; a builder must be able to design strong and durable buildings.

Programmers and IT specialists must also know physics in order to understand how electronics and office equipment work. In addition, they need to create realistic objects for programs and applications.

It is used almost everywhere: radiography, ultrasound, dental equipment, laser therapy.

What sciences is it related to?

Physics is very closely interconnected with mathematics, since when solving problems you need to be able to convert various formulas, carry out calculations and build graphs. You can add this idea to the essay “Why you need to study physics” if we are talking about calculations.

This science is also connected with geography in order to understand natural phenomena, be able to analyze future events, and the weather.

Biology and chemistry are also related to physics. For example, none living cell cannot exist without gravity and air. Also, living cells must move in space.

How to write an essay for a 7th grade student

Now let's talk about what a seventh grader who has partially studied some sections of physics can write. For example, you can write about the same gravity or give an example of measuring the distance he walked from one point to another in order to calculate the speed of his walking. A 7th grade student can supplement the essay “Why is physics needed” with various experiments that were carried out in class.

As you can see, creative work you can write quite interesting. In addition, it develops thinking, gives new ideas, and awakens curiosity about one of the most important sciences. Indeed, in the future, physics can help in any life circumstances: in everyday life, when choosing a profession, when applying for a job. Good work, while relaxing in nature.


Familiarize yourself with the structure and principle of operation of an aneroid barometer and teach how to use it.

To promote the development of the ability to connect natural phenomena with physical laws.

Continue to form ideas about atmospheric pressure and the connection between atmospheric pressure and altitude above sea level.

Continue to cultivate an attentive, friendly attitude towards participants in the educational process, personal responsibility for the implementation teamwork, understanding the need to take care of cleanliness atmospheric air and observe the rules of nature conservation, acquiring life skills.

Imagine a sealed cylinder filled with air, with a piston installed on top. If you start to press on the piston, the volume of air in the cylinder will begin to decrease, air molecules will begin to collide with each other and with the piston more and more intensely, and the pressure of compressed air on the piston will increase.

If the piston is now sharply released, the compressed air will sharply push it upward. This will happen because, with a constant area of ​​the piston, the force acting on the piston from the compressed air will increase. The area of ​​the piston remained unchanged, but the force exerted by the gas molecules increased, and the pressure increased accordingly.

Or another example. A man stands on the ground, stands with both feet. In this position, a person is comfortable and does not experience any discomfort. But what happens if this person decides to stand on one leg? He will bend one of his legs at the knee, and will now rest on the ground with only one foot. In this position, a person will feel a certain discomfort, because the pressure on the foot has increased, approximately 2 times. Why? Because the area through which gravity now presses a person to the ground has decreased by 2 times. Here is an example of what pressure is and how easily it can be detected in everyday life.


Pressure in physics

From the point of view of physics, pressure is a physical quantity that is numerically equal strength, acting perpendicular to the surface per unit area of ​​the given surface. Therefore, to determine the pressure at a certain point on the surface, the normal component of the force applied to the surface is divided by the area of ​​the small element of the surface, which given power works. And in order to determine the average pressure over the entire area, the normal component of the force acting on the surface must be divided by full area of this surface.

Pascal (Pa)

Pressure is measured in the SI system in pascals (Pa). This unit of measurement of pressure got its name in honor of the French mathematician, physicist and writer Blaise Pascal, the author of the fundamental law of hydrostatics - Pascal's Law, which states that the pressure exerted on a liquid or gas is transmitted to any point without changes in all directions. The pressure unit "pascal" was first introduced into circulation in France in 1961, according to the decree on units, three centuries after the death of the scientist.


One pascal is equal to the pressure caused by a force of one newton, uniformly distributed, and directed perpendicular to a surface of one square meter.

Pascals measure not only mechanical pressure (mechanical stress), but also elastic modulus, Young's modulus, bulk modulus, yield strength, proportional limit, tensile strength, shear strength, sound pressure and osmotic pressure. Traditionally, it is in pascals that the most important mechanical characteristics materials in strength.

Technical atmosphere (at), physical (atm), kilogram-force per square centimeter (kgf/cm2)

In addition to pascal, other (non-systemic) units are also used to measure pressure. One such unit is the “atmosphere” (at). The pressure of one atmosphere is approximately equal to the atmospheric pressure on the surface of the Earth at ocean level. Today, “atmosphere” refers to the technical atmosphere (at).

Technical atmosphere (at) is the pressure produced by one kilogram-force (kgf) distributed evenly over an area of ​​one square centimeter. And one kilogram-force, in turn, is equal to the force of gravity acting on a body weighing one kilogram under conditions of gravitational acceleration equal to 9.80665 m/s2. One kilogram-force is thus equal to 9.80665 newton, and 1 atmosphere turns out to be equal to exactly 98066.5 Pa. 1 at = 98066.5 Pa.

For example, the pressure in car tires is measured in atmospheres; for example, the recommended tire pressure for the GAZ-2217 passenger bus is 3 atmospheres.


There is also a “physical atmosphere” (atm), defined as the pressure of a column of mercury 760 mm high at its base, given that the density of mercury is 13595.04 kg/m3, at a temperature of 0 ° C and under conditions of gravity acceleration equal to 9, 80665 m/s2. So it turns out that 1 atm = 1.033233 atm = 101,325 Pa.

As for kilogram-force per square centimeter (kgf/cm2), this extra-systemic unit of pressure is equal to normal atmospheric pressure with good accuracy, which is sometimes convenient for assessing various effects.

Bar (bar), barium

The off-system unit "bar" is approximately equal to one atmosphere, but is more accurate - exactly 100,000 Pa. In the CGS system, 1 bar is equal to 1,000,000 dynes/cm2. Previously, the name “bar” was given to a unit now called “barium” and equal to 0.1 Pa or in the CGS system 1 barium = 1 dyne/cm2. The word "bar", "baria" and "barometer" all come from the same Greek word for "gravity".

The unit mbar (millibar), equal to 0.001 bar, is often used to measure atmospheric pressure in meteorology. And to measure pressure on planets where the atmosphere is very rarefied - μbar (microbar), equal to 0.000001 bar. On technical pressure gauges, most often the scale is graduated in bars.

Millimeter of mercury (mmHg), millimeter of water (mmHg)

The non-system unit of measurement “millimeter of mercury” is equal to 101325/760 = 133.3223684 Pa. It is designated “mmHg”, but is sometimes denoted “torr” - in honor of the Italian physicist, Galileo’s student, Evangelista Torricelli, the author of the concept of atmospheric pressure.

The unit was formed in connection with the convenient method of measuring atmospheric pressure with a barometer, in which the mercury column is in equilibrium under the influence of atmospheric pressure. Mercury has a high density of about 13600 kg/m3 and is characterized by low pressure saturated steam in conditions room temperature, which is why mercury was chosen for barometers at one time.


At sea level, the atmospheric pressure is approximately 760 mm Hg, this is the value that is now considered normal atmospheric pressure, equal to 101325 Pa or one physical atmosphere, 1 atm. That is, 1 millimeter of mercury is equal to 101325/760 pascal.

Pressure is measured in millimeters of mercury in medicine, meteorology, and aviation navigation. In medicine, blood pressure is measured in mmHg; in vacuum technology, blood pressure measuring instruments are calibrated in mmHg, along with bars. Sometimes they even simply write 25 microns, meaning microns of mercury, if we're talking about about evacuation, and pressure measurements are carried out with vacuum gauges.

In some cases, millimeters of water column are used, and then 13.59 mm water column = 1 mm Hg. Sometimes this is more appropriate and convenient. A millimeter of water column, like a millimeter of mercury, is a non-systemic unit, equal in turn to the hydrostatic pressure of 1 mm of a water column, which this column exerts on a flat base at a water column temperature of 4 ° C.

Comments

Problem arterial hypertension has become one of the most relevant in modern medicine. Big number people suffer from increase blood pressure(HELL). Heart attack, stroke, blindness, kidney failure - all these are formidable complications of hypertension, the result of improper treatment or its absence at all. There is only one way to avoid dangerous complications - maintaining a constant normal level of blood pressure with the help of modern high-quality medications.

The selection of medications is the responsibility of the doctor. The patient is required to understand the need for treatment, follow the doctor’s recommendations and, most importantly, constant self-monitoring.

Every patient suffering from hypertension should regularly measure and record their blood pressure and keep a diary of their well-being. This will help the doctor assess the effectiveness of treatment, adequately select the dose of the drug, and assess the risk possible complications and effectively prevent them.

At the same time, it is important to measure pressure and know its average daily level at home, because pressure figures obtained at a doctor’s appointment are often overestimated: the patient is worried, tired, sitting in line, forgot to take medicine and for many other reasons. And, conversely, situations may arise at home that cause a sharp increase in pressure: stress, physical exercise and other.

Therefore, every hypertensive patient should be able to measure blood pressure at home in a calm, familiar environment in order to have an idea of ​​the true level of pressure.

HOW TO CORRECTLY MEASURE PRESSURE?

When measuring blood pressure, you must adhere to some rules:

Measure blood pressure in a quiet environment with comfortable temperature, no earlier than 1 - 2 hours after eating, no earlier than 1 hour after smoking, drinking coffee. Sit comfortably against the back of a chair without crossing your legs. The arm should be bare, and the rest of the clothing should not be narrow or tight. Do not talk, this may affect the accuracy of the blood pressure measurement.

The cuff must have a length and width appropriate to the size of the hand. If the shoulder circumference exceeds 32 cm or the shoulder has a cone-shaped shape, which makes it difficult to apply the cuff correctly, a special cuff is required, because the use of a narrow or short cuff leads to a significant overestimation of blood pressure values.

Place the cuff so that its bottom edge is 2.5 cm above the edge of the cubital fossa. Do not squeeze it too tightly - your finger should fit freely between the shoulder and the cuff. Place the stethoscope where you can best hear the brachial artery pulsation just above the cubital fossa. The membrane of the stethoscope should fit snugly against the skin. But do not press too hard to avoid additional compression of the brachial artery. The stethoscope should not touch the tonometer tubes so that sounds from contact with them do not interfere with the measurement.

Place the stethoscope at the level of the subject's heart or at the level of his 4th rib. Pump air into the cuff vigorously; slow inflation increases pain and degrades the quality of sound perception. Release the air from the cuff slowly - 2 mmHg. Art. per second; The slower the air is released, the higher the quality of the measurement.

Repeated blood pressure measurement is possible 1 - 2 minutes after the air has completely escaped from the cuff. Blood pressure can fluctuate from minute to minute, so the average of two or more measurements more accurately reflects the true intra-arterial pressure. SYSTOLIC AND DIASTOLIC PRESSURE

To determine pressure parameters, it is necessary to correctly evaluate the sounds that are heard “in a stethoscope.”

Systolic pressure is determined by the nearest scale division at which the first consecutive tones become audible. In case of severe rhythm disturbances, for accuracy it is necessary to take several measurements in a row.

Diastolic pressure is determined either by a sharp decrease in the volume of tones, or by their complete cessation. Zero pressure effect, i.e. continuous up to 0 tones, can be observed in some pathological conditions (thyrotoxicosis, heart defects), pregnancy, and children. When diastolic pressure is above 90 mmHg. Art. it is necessary to continue measuring blood pressure for another 40 mmHg. Art. after the disappearance of the last tone, in order to avoid falsely elevated diastolic pressure values ​​due to the phenomena of “auscultatory failure” - temporary cessation of sounds.

Often, to obtain a more accurate result, it is necessary to measure the pressure several times in a row, and sometimes to calculate the average value, which more accurately corresponds to the true intra-arterial pressure.

HOW TO MEASURE PRESSURE?

Doctors and patients use various types of tonometers to measure blood pressure. Tonometers are distinguished according to several criteria:

According to the location of the cuff: “shoulder” tonometers are in the lead - the cuff is placed on the shoulder. This position of the cuff allows you to obtain the most accurate measurement result. Numerous studies have shown that all other positions (“cuff on the wrist”, “cuff on the finger”) can produce significant discrepancies with the true pressure. The result of measurements with a wrist device is very dependent on the position of the cuff relative to the heart at the time of measurement and, most importantly, on the measurement algorithm used in a particular device. When using finger tonometers, the result may even depend on the temperature of the finger and other parameters. Such tonometers cannot be recommended for use.

Pointer or digital - depending on the type of determination of measurement results. The digital tonometer has a small screen on which pulse, pressure and some other parameters are displayed. A dial tonometer has a dial and a needle, and the measurement result is recorded by the researcher himself.

The tonometer can be mechanical, semi-automatic or fully automatic, depending on the type of air injection device and measurement method. WHICH TONOMETER TO CHOOSE?

Each tonometer has its own characteristics, advantages and disadvantages. Therefore, if you decide to buy a tonometer, pay attention to the features of each of them.

Cuff: Should fit your arm. A standard cuff is designed for a hand with a circumference of 22 - 32 cm. If you have a large hand, you need to purchase a larger cuff. Small children's cuffs are available for measuring blood pressure in children. In special cases ( birth defects) Thigh pressure cuffs are required.
It is better if the cuff is made of nylon and equipped with a metal ring, which greatly facilitates the process of attaching the cuff to the shoulder when measuring pressure independently. The inner chamber must be made using seamless technology or have special form, which provides the cuff with strength and makes the measurement more comfortable.

Phonendoscope: Usually a phonendoscope comes with a tonometer. Pay attention to its quality. For home blood pressure measurements, it is convenient when the tonometer is equipped with a built-in phonendoscope. This is a great convenience, since in this case the phonendoscope does not need to be held in your hands. In addition, there is no need to worry about its correct location, which can be a serious problem when measuring independently and lacking sufficient experience.

Pressure gauge: a pressure gauge for a mechanical tonometer should have bright, clear divisions, sometimes they are even luminous, which is convenient when measuring in a dark room or at night. It is better if the pressure gauge is equipped with a metal case; such a pressure gauge is more durable.

It is very convenient when the pressure gauge is combined with a bulb - an air injection element. This facilitates the process of measuring pressure, allows the pressure gauge to be positioned correctly relative to the patient, and increases the accuracy of the result obtained.

Pear: as mentioned above, it is good if the bulb is combined with a pressure gauge. A high-quality bulb is equipped with a metal screw. In addition, if you are left-handed, please note that pears are adapted for use with the right or left hand.

Display: When choosing a tonometer, the size of the display matters. There are small displays where only one parameter is displayed - for example, the last blood pressure measurement. On the large display you can see the result of measuring pressure and pulse, a color pressure scale, the average pressure value from the last few measurements, an arrhythmia indicator, and a battery charge indicator.

Additional functions: the automatic blood pressure monitor can be equipped with such convenient functions as:
arrhythmia indicator - if the heart rhythm is disturbed, you will see a mark on the display or hear sound signal. The presence of arrhythmia distorts the correct determination of blood pressure, especially with a single measurement. In this case, it is recommended to measure the pressure several times and determine the average value. Special algorithms of some devices make it possible to produce precise measurements, despite rhythm disturbances;
memory for the last few measurements. Depending on the type of tonometer, it may have the function of storing the last several measurements from 1 to 90. You can view your data, find out the latest pressure numbers, create a pressure graph, calculate the average value;
automatic calculation of average pressure; sound notification;
function of accelerated pressure measurement without loss of measurement accuracy; there are family models in which separate functional buttons provide the ability for two people to use the tonometer independently, with separate memory for the last measurements;
convenient models that provide the ability to operate both from batteries and from a general electrical network. At home, this not only increases the convenience of measurement, but also reduces the cost of using the device;
There are models of tonometers equipped with a printer for printing the latest blood pressure readings from memory, as well as devices compatible with a computer.

Thus, a mechanical tonometer provides more high quality measurements in experienced hands, by a researcher with good hearing and vision, able to correctly and accurately follow all the rules for measuring blood pressure. In addition, a mechanical tonometer is significantly cheaper.

An electronic (automatic or semi-automatic) tonometer is good for home blood pressure measurement and can be recommended for people who do not have the skills to measure blood pressure by auscultation, as well as for patients with reduced hearing, vision, or reaction, because does not require the measurer to directly participate in the measurement. It is impossible not to appreciate the usefulness of such functions as automatic air inflation, accelerated measurement, memory of measurement results, calculation of average blood pressure, arrhythmia indicator and special cuffs that eliminate pain during measurement.

However, the accuracy of electronic tonometers is not always the same. Preference should be given to clinically proven devices, i.e. those that have been tested according to world-renowned protocols (BHS, AAMI, International Protocol).

Sources Magazine “CONSUMER. Expertise and Tests", 38’2004, Maria Sasonko apteka.potrebitel.ru/data/7/67/54.shtml

Topic 1

« Subject and method of physics. Measurements. Physical quantities."

The first scientific ideas arose a long time ago - apparently, at the very early stages of human history, reflected in written sources. However, physics as a science in its modern form dates back to the times of Galileo Galilei (1Galilei and his follower Isaac Newton (1made a revolution in scientific knowledge. Galileo proposed the method of experimental knowledge as the main method of research, and Newton formulated the first complete physical theories (classical mechanics, classical optics, theory of gravity).

In its historical development, physics went through 3 stages (see diagram).

The revolutionary transition from one stage to the next is associated with the destruction of old basic ideas about the world around us in connection with the new experimental results obtained.

Word physics literally translated means nature, that is, the essence, the internal basic property of the phenomenon, some hidden pattern that determines the course, the course of the phenomenon.

Physics is the science of the simplest and at the same time most common properties of bodies and phenomena. Physics is the foundation of natural science.

The connection between physics and all other sciences is presented in the diagram.

Physics (like any natural science) is based on statements about the materiality of the world and the existence of objective, stable cause-and-effect relationships between phenomena. Physics is objective, since it studies real natural phenomena, but at the same time it is subjective due to the essence of the cognition process, like reflections reality.

According to modern ideas, everything that surrounds us is a combination of a small number of so-called elementary particles, between which 4 are possible various types interactions. Elementary particles are characterized by 4 numbers (quantum charges), the values ​​of which determine what type of interaction the elementary particle in question can enter into (Table 1.1).

Charges

Interactions

mass

gravitational

electric

electromagnetic

baryonic

lepton

This formulation has two important properties:

Adequately describes our modern ideas about the world around us;

It is quite streamlined and is unlikely to conflict with new experimental facts.

Let's give a brief explanation of the unfamiliar concepts used in these statements. Why are we talking about so-called elementary particles? Elementary particles in the precise meaning of this term are primary, further indecomposable particles, of which, by assumption, all matter consists. However, most known elementary particles do not satisfy the strict definition of elementarity, since they are composite systems. According to the Zweig and Gell-Mann model, the structural units of such particles are quarks. IN free state quarks are not observed. Unusual name“quarks” was borrowed from James Joyce’s book “Finnigan’s Wake”, where the phrase “three quarks” is heard, which the hero of the novel hears in a nightmare delirium. Currently, more than 350 elementary particles are known, mostly unstable, and their number is constantly growing.

You encountered three of these interactions when you studied the phenomenon radioactive decay(see diagram below).

You have previously encountered such a manifestation of strong interaction as nuclear forces that hold protons and neutrons inside the atomic nucleus. Strong interaction causes processes that occur with the greatest intensity, compared to other processes, and leads to the strongest connection of elementary particles. Unlike gravitational and electromagnetic interactions, the strong interaction is short-range: its radius

Characteristic times of strong interaction

Brief chronology of the study of the strong interaction

1911 – atomic nucleus

1932 – proton-neutron structure

(, W. Heisenberg)

1935 – pi meson (Yukawa)

1964 – quarks (M. Gell-Mann, G. Zweig)

70s of the XX century - quantum chromodynamics

80s of the XX century - the theory of great unification

https://pandia.ru/text/78/486/images/image007_3.gif" width="47 height=21" height="21">Weak interaction is responsible for the decays of elementary particles that are stable relative to strong and electromagnetic interactions. Effective the radius of the weak interaction does not exceed. Therefore, at large distances it is significantly weaker than the electromagnetic interaction, which in turn is weaker than the strong interaction at distances less than 1 Fermi. At distances smaller, weak and electromagnetic interactions form. unified electroweak interaction. The weak interaction causes very slowly occurring processes with elementary particles, including the decays of quasi-stable elementary particles, the lifetimes of which lie in the range. Despite its small value, the weak interaction plays a very important role in nature. In particular, the process of converting a proton into a neutron, as a result of which 4 protons turn into a helium nucleus (the main source of energy release inside the Sun), is due to weak interaction.

Could a fifth interaction be discovered? There is no clear answer. However, according to modern concepts, all four types of interaction are different manifestations of one unified interaction. This statement is the essence grand unified theory.

Now let's discuss how it is formed scientific knowledge about the world around us.

Knowledge name the information based on which we can confidently plan our activities on the path to the goal, and this activity will certainly lead to success. The more complex the goal, the more knowledge is required to achieve it.

Scientific knowledge is formed as a result of the synthesis of two inherent human elements of activity: creativity and regular exploration of the surrounding space using the trial and error method (see diagram).

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A physical law is a long-lived and “deserved” physical theory. Only such ones end up in textbooks and are studied in general education courses.

If experience does not confirm the prediction, then the whole process must be started over.

A “good” physical theory must satisfy the following requirements:

1) should be based on a small number of fundamental provisions;

2) must be sufficiently general;

3) must be accurate;

4) must allow for improvement.

The value of a physical theory is determined by how accurately one can establish the limit beyond which it is unfair. An experiment cannot confirm a theory, but only refute.

The process of cognition can only proceed through the construction models, which is associated with the subjective side of this process (incompleteness of information, diversity of any phenomenon, ease of mastery with the help of specific images).

Model in science, it is not an enlarged or reduced copy of an object, but a picture of a phenomenon, freed from details that are not essential for the task at hand.

Models are divided into mechanical and mathematical.

Examples: material point, atom, absolutely solid body.

As a rule, for most concepts the process of model development proceeds through gradual complication from mechanical to mathematical.

Let's consider this process using the concept of an atom as an example. Let's list the main models.

Sharik (atom of ancient and classical physics)

Ball with hook

Thomson atom

Planetary model (Rutherford)

Bohr model

Schrödinger equation

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The model of an atom in the form of a solid indivisible ball, for all its apparent absurdity from the point of view of today’s ideas, has made it possible, for example, within the framework of the kinetic theory of gases to obtain all the basic gas laws.

The discovery of the electron in 1897 led to J. J. Thompson's creation of a model commonly called "raisin pudding" (see picture below).

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According to this model, negatively charged raisins – electrons – float in the positively charged “dough”. The model explained the electrical neutrality of the atom, the simultaneous appearance of a free electron and a positively charged ion. However, the results of Rutherford's experiment on the scattering of alpha particles fundamentally changed the understanding of the structure of the atom.

The picture below shows a diagram of the setup in Rutherford's experiment.

Within the framework of the Thompson model, it was impossible to explain the strong deviation of the trajectory of alpha particles and, therefore, the concept arose atomic nucleus. The calculations made it possible to determine the dimensions of the nucleus; they turned out to be of the order of one Fermi. Thus, the Thompson model was replaced by planetary model Rutherford (see picture below).

This is a typically mechanical model, since the atom is represented as an analogue of the solar system: around the core - the Sun - planets - electrons - move in circular trajectories. Famous Soviet poet Valery Bryusov spoke about this discovery:

Still, perhaps, every atom -

A universe with a hundred planets;

There is everything that is here, in a compressed volume,

But also what is not here.

Since its inception, the planetary model has been subject to serious criticism due to its instability. An electron moving in a closed orbit must radiate electromagnetic waves and therefore fall onto the core. Accurate calculations show that maximum time The life of an atom in Rutherford's model is no more than 20 minutes. The great Danish physicist Niels Bohr created the idea of ​​the atomic nucleus to save new model atom that bears his name. It is based on two main provisions (Bohr's postulates):

Atoms can long time is found only in certain, so-called stationary states. The energies of stationary states form a discrete spectrum. In other words, only circular orbits with radii given by the relation are possible

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Where n– an integer.

During the transition from one initial quantum state to another, a quantum of light is emitted or absorbed (see figure).

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Differential" href="/text/category/differentcial/" rel="bookmark">partial differential equation with respect to the wave function. The physical meaning is not the wave function itself, but the square of its modulus, which is proportional to the probability of finding a particle (electron) in a given point in space. In other words, during its movement, the electron is, as it were, “smeared” throughout the entire volume, forming an electron cloud, the density of which characterizes the probability of finding the electron at various points in the volume of the atom (see pictures below).

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Unfortunately, the language we use in our everyday life is unsuitable for describing the processes occurring in the depths of matter (very abstract models are used). Physicists “talk” with Nature on language of mathematics using numbers geometric shapes and lines, equations, tables, functions, etc. Such a language has amazing predictive power: using formulas, you can obtain consequences (as in mathematics), evaluate the result quantitatively and then test the validity of the prediction with experience. Physicists simply do not undertake the study of phenomena that cannot be described in the language of physics due to the uncertainty of concepts and the impossibility of defining the measurement process.

The history of the development of physics has shown that the reasonable use of mathematics has invariably led to powerful progress in the study of nature, and attempts to absolutize some mathematical apparatus as the only suitable one lead to stagnation.

Physics, like any science, can only answer the question “How?”, but not the question “Why?”.

Finally, let's look at the final part of topic No. 1 about physical quantities.

A physical concept that reflects some property of bodies and phenomena and expressed by number during the measurement process is called physical size.

Physical quantities, depending on the method of their representation, are divided into scalar, vector, tensor etc. (see Table 1.2).

Table 1.2

quantities

examples

scalar

temperature, volume, pressure

vector

speed, acceleration, tension

tensor

pressure in moving fluid

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Vector called an ordered set of numbers (see illustration above). Tensor physical quantities are written using matrices.

Also, all physical quantities can be divided into basic And derivatives from them. The basic ones include units of mass, electric charge (the main characteristics of matter that determine gravitational and electromagnetic interaction), length and time (as they reflect the fundamental properties of matter and its attributes - space and time), as well as temperature, amount of matter and light intensity. To establish derived units, physical laws are used that connect them with basic units.

Currently required for use in scientific and educational literature International system of units (SI), where the basic units are kilogram, ampere, meter, second, Kelvin, mole and Candela. The reason for replacing the Coulomb ( electric charge) per Ampere (electric current strength) is purely technical: the implementation of a standard of 1 Coulomb, in contrast to 1 Ampere, is practically impossible, and the units themselves are related by a simple relationship:

Why does a person need measurements?

Measurement is one of the most important things in modern life. But not always

it was like this. When a primitive man killed a bear in an unequal duel, he, of course, rejoiced if it turned out to be big enough. This promised a well-fed life for him and the entire tribe for for a long time. But he did not drag the bear carcass to the scales: at that time there were no scales. There was no special need for measurements when a person made a stone ax: technical specifications there was no such ax available and everything was determined by the size of a suitable stone that could be found. Everything was done by eye, as the master’s instincts suggested.

Later, people began to live in large groups. The exchange of goods began, which later turned into trade, and the first states arose. Then the need for measurements arose. The royal arctic foxes had to know the area of ​​each peasant's field. This determined how much grain he should give to the king. It was necessary to measure the harvest from each field, and when selling flax meat, wine and other liquids, the volume of goods sold. When they started building ships, it was necessary to outline the correct dimensions in advance: otherwise the ship would have sunk. And, of course, the ancient builders of pyramids, palaces and temples could not do without measurements; they still amaze us with their proportionality and beauty.

ANCIENT RUSSIAN MEASURES.

The Russian people created their own system of measures. Monuments of the 10th century speak not only about the existence of a system of measures in Kievan Rus, but also state supervision over their correctness. This supervision was entrusted to the clergy. One of the charters of Prince Vladimir Svyatoslavovich says:

“...from time immemorial it was established and entrusted to the bishops of the city and everywhere all sorts of measures and weights and weights... to observe without dirty tricks, neither to multiply nor to diminish...” (... it has long been established and entrusted to bishops to monitor the correctness of measures.. .do not allow them to be diminished or increased...). This need for supervision was caused by the needs of trade both within the country and with the countries of the West (Byzantium, Rome, and later German cities) and the East (Central Asia, Persia, India). Markets took place on the church square, in the church there were chests for storing agreements on trade transactions, the correct scales and measures were located at the churches, and goods were stored in the basements of the churches. The weighings were carried out in the presence of representatives of the clergy, who received a fee for this in favor of the church

Length measures

The oldest of them are cubit and fathom. We do not know the exact original length of either measure; a certain Englishman who traveled around Russia in 1554 testifies that a Russian cubit was equal to half an English yard. According to the “Trading Book,” compiled for Russian merchants at the turn of the 16th and 17th centuries, three cubits were equal to two arshins. The name "arshin" comes from the Persian word "arsh", which means elbow.

The first mention of fathoms is found in a chronicle of the 11th century, compiled by the Kyiv monk Nestor.

In later times, a distance measure of the verst was established, equated to 500 fathoms. In ancient monuments, a verst is called a field and is sometimes equated to 750 fathoms. This can be explained by the existence in ancient times of a shorter fathom. The verst to 500 fathoms was finally established only in the 18th century.

In the era of fragmentation, Rus' did not exist unified system measures In the 15th and 16th centuries, the unification of Russian lands around Moscow took place. With the emergence and growth of national trade and the establishment of taxes for the treasury from the entire population of the united country, the question arises of a unified system of measures for the entire state. The arshin measure, which arose during trade with eastern peoples, comes into use.

In the 18th century, the measures were refined. Peter 1 by decree established the equality of a three-arshin fathom to seven English feet. The former Russian system of length measures, supplemented by new measures, received its final form:

Mile = 7 versts (= 7.47 kilometers);

Versta = 500 fathoms (= 1.07 kilometers);

Fathom = 3 arshins = 7 feet (= 2.13 meters);

Arshin = 16 vershok = 28 inches (= 71.12 centimeters);

Foot = 12 inches (= 30.48 centimeters);

Inch = 10 lines (2.54 centimeters);

Line = 10 points (2.54 millimeters).

When they talked about a person’s height, they only indicated how many vershoks he exceeded 2 arshins. Therefore, the words “a man 12 inches tall” meant that his height was 2 arshins 12 inches, that is, 196 cm.

Measures areas

In "Russian Truth" - a legislative monument that dates back to the 11th - 13th centuries, the land measure plow is used. This was the measure of the land from which tribute was paid. There are some reasons to consider a plow equal to 8-9 hectares. As in many countries, the amount of rye needed to sow this area was often taken as a measure of area. In the 13th-15th centuries, the basic unit of area was the Kad-area; for sowing each one, approximately 24 pounds (that is, 400 kg) of rye were needed. Half of this area, called tithes became the main measure of area in pre-revolutionary Russia. It was approximately 1.1 hectares. Tithe was sometimes called box.

Another unit for measuring areas, equal to half a tithe, was called a (quarter) chet. Subsequently, the size of the tithe was brought into line not with measures of volume and mass, but with measures of length. In the “Book of Sleepy Letters”, as a guide for accounting taxes on land, a tithe is established at 80 * 30 = 2400 square fathoms.

The tax unit of land was s o x a (this is the amount of arable land that one plowman was able to cultivate).

MEASURES OF WEIGHT (MASS) and VOLUME

The oldest Russian weight unit was the hryvnia. It is mentioned in the tenth century treaties between the Kyiv princes and the Byzantine emperors. Through complex calculations, scientists learned that the hryvnia weighed 68.22 g. The hryvnia was equal to the Arabic unit of weight Rotl. Then the main units for weighing became pound and pood. A pound was equal to 6 hryvnia, and a pud was equal to 40 pounds. To weigh gold, spools were used, which amounted to 1.96 parts of a pound (hence the proverb “small spool but expensive”). The words “pound” and “pud” come from the same Latin word “pondus”, meaning heaviness. The officials who checked the scales were called “pundovschiki” or “weighmen.” In one of the stories by Maxim Gorky, in the description of the kulak barn, we read: “There are two locks on one bolt - one is heavier than the other.”

By the end of the 17th century, a system of Russian weight measures had developed in the following form:

Last = 72 pounds (= 1.18 tons);

Berkovets = 10 poods (= 1.64 c);

Pud = 40 large hryvnias (or pounds), or 80 small hryvnias, or 16 steelyards (= 16.38 kg);

The original ancient measures of liquid - a barrel and a bucket - remain unknown exactly. There is reason to believe that the bucket held 33 pounds of water, and the barrel - 10 buckets. The bucket was divided into 10 damasks.

Monetary system of the Russian people

Many nations used pieces of silver or gold of a certain weight as monetary units. In Kievan Rus such units were hryvnia silver. The Russkaya Pravda, the oldest set of Russian laws, states that for the murder or theft of a horse there is a fine of 2 hryvnia, and for an ox - 1 hryvnia. The hryvnia was divided into 20 nogat or 25 kuna, and the kuna into 2 rezans. The name “kuna” (marten) recalls the times when there was no metal money in Rus', and instead they used furs, and later leather money - quadrangular pieces of leather with stamps. Although the hryvnia as a monetary unit has long gone out of use, the word “hryvnia” has been preserved. The coin of 10 kopecks was called a dime. But this, of course, is not the same as the old hryvnia.

Minted Russian coins have been known since the time of Prince Vladimir Svyatoslavovich. During the Horde yoke, Russian princes were obliged to indicate on the issued coins the name of the khan who ruled the Golden Horde. But after the Battle of Kulikovo, which brought victory to the troops of Dmitry Donskoy over the hordes of Khan Mamai, the liberation of Russian coins from the khan’s names begins. At first, these names began to be replaced by an illegible script of oriental letters, and then completely disappeared from the coins.

In chronicles dating back to 1381, the word “money” appears for the first time. The word comes from the Hindu name for a silver coin. tank, which the Greeks called Danaka, Tatars – tenga.

The first use of the word “ruble” dates back to the 14th century. This word comes from the verb “to chop.” In the 14th century, the hryvnia began to be cut in half, and a silver ingot of half a hryvnia (= 204.76 g) was called ruble or ruble hryvnia.

In 1535, coins were issued - Novgorod coins with a drawing of a horseman with a spear in his hands, which were called penny money. The chronicle from here produces the word “kopek”.

Further supervision of measures in Russia.

With the revival of domestic and foreign trade, supervision of measures from the clergy passed to special bodies of civil power - the order of the big treasury. Under Ivan the Terrible, it was prescribed that goods should be weighed only from pood sellers.

In the 16th and 17th centuries, uniform state or customs measures were assiduously introduced. In the 18th and 19th centuries, measures were taken to improve the system of weights and measures.

The Weights and Measures Act of 1842 ended government efforts to streamline the system of weights and measures that had lasted over 100 years.

D.I. Mendeleev – metrologist.

In 1892, the brilliant Russian chemist Dmitry Ivanovich Mendeleev became the head of the Main Chamber of Weights and Measures.

Directing the work of the Main Chamber of Weights and Measures, D.I. Mendeleev completely transformed the business of measurements in Russia, established scientific research work and resolved all questions about measures that were caused by the growth of science and technology in Russia. In 1899, developed by D.I., was published. Mendeleev's new law on weights and measures.

In the first years after the revolution, the Main Chamber of Weights and Measures, continuing the traditions of Mendeleev, carried out tremendous work to prepare for the introduction of the metric system in the USSR. After some restructuring and renaming, the former Main Chamber of Weights and Measures currently exists in the form of the All-Union Scientific Research Institute of Metrology named after D.I. Mendeleev.

French measures

Initially in France, and throughout cultural Europe, used Latin measures of weight and length. But feudal fragmentation made its own adjustments. Let's say another senior had the fantasy of slightly increasing the pound. None of his subjects would object; they shouldn’t rebel over such trifles. But if you count, in general, all the quit grain, then what a benefit! The same goes for urban artisan workshops. For some it was beneficial to reduce the fathom, for others to increase it. Depending on whether they sell or buy cloth. Little by little, little by little, and now you have the Rhine pound, and the Amsterdam pound, and the Nuremberg pound, and the Parisian pound, etc., etc.

And with fathoms the situation was even worse; in the south of France alone more than a dozen different units of length rotated.

True, in the glorious city of Paris, in the fortress of Le Grand Chatel, since the time of Julius Caesar, a standard of length has been built into the fortress wall. It was an iron curved compass, the legs of which ended in two protrusions with parallel edges, between which all the fathoms in use must fit exactly. The Chatel fathom remained the official measure of length until 1776.

At first glance, the length measures looked like this:

League of the sea – 5,556 km.

Land league = 2 miles = 3.3898 km

Mile (from Latin thousand) = 1000 toises.

Tuaz (fathom) = 1.949 meters.

Foot (foot) = 1/6 toise = 12 inches = 32.484 cm.

Inch (finger) = 12 lines = 2.256 mm.

Line = 12 points = 2.256 mm.

Point = 0.188 mm.

In fact, since no one abolished feudal privileges, all this concerned the city of Paris, well, the Dauphine, as a last resort. Somewhere in the outback, a foot could easily be determined as the size of a lord’s foot, or as the average length of the feet of 16 people leaving Matins on Sunday.

Parisian pound = livre = 16 ounces = 289.41 gr.

Ounce (1/12 lb) = 30.588 g.

Gran (grain) = 0.053 gr.

But the artillery pound was still equal to 491.4144 grams, that is, it simply corresponded to the Nuremberg pound, which was used back in the 16th century by Mr. Hartmann, one of the theorists and masters of the artillery workshop. According to traditions, the size of the pound in the provinces also varied.

Measures of liquid and granular bodies were also not distinguished by harmonious monotony, because France was, after all, a country where the population mainly grew bread and wine.

Muid of wine = about 268 liters

Network - about 156 liters

Mina = 0.5 sete = about 78 liters

Mino = 0.5 mina = about 39 liters

Boisseau = about 13 liters

English measures

English measures, measures used in Great Britain, USA. Canada and other countries. Some of these measures in a number of countries differ somewhat in size, so below are mainly rounded metric equivalents of English measures, convenient for practical calculations.

Length measures

Nautical mile (UK) = 10 cables = 1.8532 km

Kabeltov (UK) = 185.3182 m

Kabeltov (USA) = 185.3249 m

Statutory mile = 8 furlongs = 5280 feet = 1609.344 m

Furlong = 10chains = 201.168 m

Chain = 4 rods = 100 links = 20.1168 m

Rod (pol, perch) = 5.5 yards = 5.0292 m

Yard = 3 feet = 0.9144 m

Foot = 3 handam = 12 inches = 0.3048 m

Hand = 4 inches = 10.16 cm

Inch = 12 lines = 72 dots = 1000 mils = 2.54 cm

Line = 6 points = 2.1167 mm

Point = 0.353 mm

Mil = 0.0254 mm

Area measures

Sq. mile = 640 acres = 2.59 km 2

Acre = 4 ores = 4046.86 m2

Rud = 40 sq. childbirth = 1011.71 m 2

Sq. gender (pol, pepper) = 30.25 sq. yards = 25.293 m2

Sq. yard = 9 sq. feet = 0.83613 m2

Sq. ft = 144 sq. inches = 929.03 cm 2

Sq. inch = 6.4516 cm 2

Measures of mass

Large ton, or long = 20 handweight = 1016.05 kg

Small ton, or short (USA, Canada, etc.) = 20 cents = 907.185 kg

Handweight = 4 quarters = 50.8 kg

Central = 100 pounds = 45.3592 kg

Quarter = 2 groans = 12.7 kg

Moan = 14 pounds = 6.35 kg

Pound = 16 ounces = 7000 grains = 453.592 g

Ounce = 16 drachms = 437.5 grains = 28.35 g

Drachma = 1.772 g

Gran = 64.8 mg

Units of volume, capacity.

Cube yard = 27 cubic meters ft = 0.7646 cu. m

Cube ft = 1728 cu in = 0.02832 cu. m

Cube inch = 16.387 cu. cm

Units of volume, capacity

for liquids.

Gallon (English) = 4 quarts = 8 pints = 4.546 liters

Quart (English) = 1.136 l

Pint (English) = 0.568 l

Units of volume, capacity

for bulk solids

Bushel (English) = 8 gallons (English) = 36.37 L

Collapse of ancient systems of measures

In the 1st-2nd AD, the Romans took possession of almost the entire world known at that time and introduced their own system of measures in all the conquered countries. But a few centuries later, Rome was conquered by the Germans and the empire created by the Romans fell apart into many small states.

After this, the collapse of the introduced system of measures began. Each king, and even duke, tried to introduce his own system of measures, and if possible, then monetary units.

The collapse of the system of measures reached its highest point in the 17th-18th centuries, when Germany was fragmented into as many states as there were days in the year, as a result of which there were 40 different feet and cubits, 30 different hundredweights, 24 different miles.

In France there were 18 units of length called leagues, etc.

This caused difficulties in trade matters, in the collection of taxes, and in the development of industry. After all, the units of measure operating simultaneously were not connected with each other, they had various divisions into smaller ones. It was difficult for a highly experienced merchant to understand this, and what can we say about an illiterate peasant. Of course, merchants and officials took advantage of this to rob the people.

In Russia, in different places, almost all measures had different meanings, so detailed tables of measures were placed in arithmetic textbooks before the revolution. In one common pre-revolutionary reference book one could find up to 100 different feet, 46 different miles, 120 different pounds, etc.

The needs of practice forced us to begin the search for a unified system of measures. At the same time, it was clear that it was necessary to abandon the establishment between units of measurement and sizes human body. And people's steps are different, their feet are not the same length, and their toes are of different widths. Therefore, it was necessary to look for new units of measurement in the surrounding nature.

The first attempts to find such units were made in ancient times in China and Egypt. The Egyptians chose the mass of 1000 grains as a unit of mass. But the grains are not the same! Therefore, the idea of ​​one of the Chinese ministers, who proposed long before our era to choose 100 red sorghum grains arranged in a row as a unit, was also unacceptable.

Scientists have put forward different ideas. Some suggested taking as the basis of measures the dimensions associated with a honeycomb, some the path covered in the first second by a freely falling body, and the famous 17th century scientist Christiaan Huygens proposed taking a third of the length of a pendulum, which swings once per second. This length is very close to twice the length of a Babylonian cubit.

Even before him, the Polish scientist Stanislav Pudlovsky proposed taking the length of the second pendulum itself as a unit of measurement.

Birth metric system of measures.

It is not surprising that when, in the eighties of the XVIII century, merchants of several French cities turned to the government with a request to establish a unified system of measures for the entire country, scientists immediately remembered Huygens’ proposal. The adoption of this proposal was prevented by the fact that the length of the seconds pendulum is different in different places globe. At the North Pole it is greater, and at the equator it is less.

At this time, a bourgeois revolution took place in France. The National Assembly was convened, which created a commission at the Academy of Sciences, composed of the largest French scientists of that time. The commission had to carry out the work of creating a new system of measures.

One of the commission members was the famous mathematician and astronomer Pierre Simon Laplace. For his scientific research it was very important to know the exact length of the earth's meridian. One of the members of the commission remembered the proposal of the astronomer Mouton to take as a unit of length a part of the meridian equal to one 21600th part of the meridian. Laplace immediately supported this proposal (and perhaps he himself suggested this idea to the other members of the commission). Only one measurement was made. For convenience, we decided to take one forty millionth of the earth's meridian as a unit of length. This proposal was submitted to the national assembly and was adopted by it.

All other units were aligned with the new unit, called meters. The unit of area was taken square meter, volume - cubic meter, masses – mass of cubic centimeter water under certain conditions.

In 1790, the National Assembly adopted a decree on the reform of the systems of measures. The report submitted to the National Assembly noted that there was nothing arbitrary in the reform project except the decimal base, and nothing local. “If the memory of these works was lost and only the results were preserved, then there would be no sign in them by which one could find out which nation conceived the plan for these works and carried them out,” the report said. Apparently, the Academy commission sought to ensure that new system The measures did not give any nation a reason to reject the system as the French one. She sought to justify the slogan: “For all times, for all peoples,” which was proclaimed later.

Already in April 17956, a law on new measures was approved, and a single standard was introduced for the entire Republic: a platinum ruler on which a meter is inscribed.

From the very beginning of work on the development of a new system, the Commission of the Paris Academy of Sciences established that the ratio of neighboring units should be equal to 10. For each quantity (length, mass, area, volume) from the basic unit of this quantity other, larger and smaller measures are formed in the same way (for with the exception of the names “micron”, “centner”, “ton”). To form the names of measures larger than the basic unit, Greek words are added to the name of the latter from the front: “deca” - “ten”, “hecto” - “hundred”, “kilo” - “thousand”, “myria” - “ten thousand” ; To form the names of measures smaller than the base unit, particles are also added in front: “deci” - “ten”, “santi” - “hundred”, “milli” - “thousand”.

Archive meter.

The Act of 1795, having established a temporary meter, indicates that the work of the commission will continue. The measuring work was completed only by the fall of 1798 and gave the final length of the meter at 3 feet 11.296 lines instead of 3 feet 11.44 lines, which was the length of the temporary meter of 1795 (the old French foot was equal to 12 inches, inch-12 lines).

The Minister of Foreign Affairs of France in those years was the outstanding diplomat Talleyrand, who had previously been involved in the reform project; he proposed convening representatives of allies with France and neutral countries to discuss the new system of measures and give it an international character. In 1795, delegates gathered for an international congress; it announced the completion of work to verify the determination of the length of the main standards. In the same year, the final prototypes of meters and kilograms were made. They were published in the Archives of the Republic for storage, which is why they received the name archival.

The temporary meter was canceled and instead of the unit of length the archival meter was recognized. It looked like a rod, the cross section of which resembled the letter X. Only 90 years later did archival standards give way to new ones, called international ones.

Reasons that prevented implementation

metric system of measures.

The population of France greeted the new measures without much enthusiasm. The reason for this attitude was partly the newest units of measures that did not correspond to centuries-old habits, as well as the new names of measures, incomprehensible to the population.

Among the people who were not enthusiastic about the new measures was Napoleon. By decree of 1812, along with the metric system, he introduced an “everyday” system of measures for use in trade.

The restoration of royal power in France in 1815 contributed to the oblivion of the metric system. The revolutionary origins of the metric system prevented its spread to other countries.

Since 1850, leading scientists have begun vigorous campaigning in favor of the metric system. One of the reasons for this was the international exhibitions that began then, which showed all the conveniences of the existing various national systems of measures. The activities of the St. Petersburg Academy of Sciences and its member Boris Semenovich Jacobi were especially fruitful in this direction. In the seventies, this activity culminated in the actual transformation of the metric system into an international one.

Metric system of measures in Russia.

In Russia, scientists from the beginning of the 19th century understood the purpose of the metric system and tried to widely introduce it into practice.

In the years from 1860 to 1870, after the energetic speeches of D.I. Mendeleev, the campaign in favor of the metric system was led by academician B.S. Jacobi, professor of mathematics A.Yu. Davidov, the author of school mathematics textbooks that were widespread in his time, and academician A.V. Gadolin. Russian manufacturers and factory owners also joined the scientists. The Russian Technical Society commissioned a special commission chaired by Academician A.V. Gadolin to develop this issue. This commission received many proposals from scientists and technical organizations, unanimously supporting proposals to switch to the metric system.

The law on weights and measures, published in 1899, developed by D.T. Mendeleev, included paragraph No. 11:

“The international method and the kilogram, their divisions, as well as other metric measures are allowed to be used in Russia, most likely with the main Russian measures, in trade and other transactions, contracts, estimates, contracts, and the like - by mutual agreement of the contracting parties, as well as in within the limits of the activities of individual government departments...with the expansion or by order of the relevant ministers...".

The final solution to the issue of the metric system in Russia was received after the Great October Socialist Revolution. In 1918, the Council of People's Commissars, chaired by V.I. Lenin, issued a resolution proposing:

“To base all measurements on the international metric system of weights and measures with decimal divisions and derivatives.

Take the meter as the basis for the unit of length, and the kilogram as the basis for the unit of weight (mass). As examples of units of the metric system, take a copy of the international meter, bearing the sign No. 28, and a copy of the international kilogram, bearing the sign No. 12, made of iridescent platinum, transferred to Russia by the First International Conference of Weights and Measures in Paris in 1889 and now stored in the Main Chamber of Measures and scales in Petrograd."

From January 1, 1927, when the transition of industry and transport to the metric system was prepared, the metric system of measures became the only system of measures and weights allowed in the USSR.

Ancient Russian measures

in proverbs and sayings.

An arshin and a caftan, and two for patches.
The beard is as long as an inch, and the words are as long as a bag.
To lie - seven miles to heaven and all through forest.
They were looking for a mosquito seven miles away, but the mosquito was on their nose.
A yard's worth of beard, but an inch's worth of intelligence.
He sees three arshins into the ground!
I won't give in an inch.
From thought to thought five thousand miles.
A hunter walks seven miles away to sip jelly.
Write (talk) about other people's sins in capital letters, and about your own in lowercase letters.
You are a span away from the truth (from service), and it is a fathom away from you.
Stretch a mile, but don’t be easy.
You can light a pound (ruble) candle for this.
It saves a pound of grain.
It's not bad that the bun is half a pound.
One grain of puda brings.
Your own spool is more expensive than someone else's.
I ate half a meal and I’m still full.
You'll find out how much it costs.
He doesn't have half a spool of brain (mind) in his head.
The bad comes in pounds, and the good comes in spools.

MEASURE COMPARISON TABLE

    Length measures

1 verst = 1.06679 kilometers
1 fathom = 2.1335808 meters
1 arshin = 0.7111936 meters
1 vershok = 0.0444496 meters
1 foot = 0.304797264 meters
1 inch = 0.025399772 meters

1 kilometer = 0.9373912 versts
1 meter = 0.4686956 fathoms
1 meter = 1.40609 arshin
1 meter = 22.4974 vershok
1 meter = 3.2808693 feet
1 meter = 39.3704320 inches

    1 fathom = 7 feet
    1 fathom = 3 arshins
    1 fathom = 48 vershok
    1 mile = 7 versts
    1 verst = 1.06679 kilometers

    Measures of volume and area

1 quadruple = 26.2384491 liters
1 quarter = 209.90759 liters
1 bucket = 12.299273 liters
1 tithe = 1.09252014 hectares

1 liter = 0.03811201 quadruplets
1 liter = 0.00952800 quarter
1 liter = 0.08130562 buckets
1 hectare = 0.91531493 tithes

    1 barrel = 40 buckets
    1 barrel = 400 damasks
    1 barrel = 4000 glasses

1 quarter = 8 quadruples
1 quarter = 64 garnz

    Weights

1 pood = 16.3811229 kilograms

1 pound = 0.409528 kilograms
1 spool = 4.2659174 grams
1 share = 44.436640 milligrams

    1 kilogram = 0.9373912 versts
    1 kilogram = 2.44183504 pounds
    1 gram = 0.23441616 spool
    1 milligram = 0.02250395 fraction

    1 pood = 40 pounds
    1 pood = 1280 lots
    1 berk = 10 poods
    1 fin = 2025 and 4/9 kilograms

    For what Main educational program

    Participation in “small conferences” on the topics: “ For what person need to be able to read?”, “My favorite book... with this requirement Mass. Comparison. Measurement(3 hours) Mass. Comparison. Measurement Concept of mass of objects. Acquaintance...



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