How is light measured, in what units? Units of measurement of physical quantities.

This tutorial will not be new to beginners. We have all heard from school such things as centimeter, meter, kilometer. And when it came to mass, they usually said gram, kilogram, ton.

Centimeters, meters and kilometers; grams, kilograms and tons have one common name - units physical quantities .

In this lesson, we will look at the most popular units of measurement, but we will not go deep into this topic, since units of measurement go into the field of physics. We are forced to study a part of physics, because we need it for further study of mathematics.

Length units

The following units of measure are intended for measuring length:

• millimeters
• centimeters
• decimeters
• meters
• kilometers

millimeter(mm). You can even see millimeters with your own eyes if you take the ruler that we used at school every day.

Consecutive small lines running one after another are millimeters. More precisely, the distance between these lines is equal to one millimeter (1 mm):

centimeter(cm). On the ruler, each centimeter is marked with a number. For example, our ruler, which was in the first picture, had a length of 15 centimeters. The last centimeter on this ruler is marked with the number 15.

There are 10 millimeters in one centimeter. An equal sign can be placed between one centimeter and ten millimeters, since they represent the same length.

1 cm = 10 mm

You can see for yourself if you count the number of millimeters in the previous figure. You will find that the number of millimeters (distance between lines) is 10.

The next unit of measure for length is decimeter(dm). There are ten centimeters in one decimeter. An equal sign can be placed between one decimeter and ten centimeters, since they denote the same length:

1 dm = 10 cm

You can verify this if you count the number of centimeters in the following figure:

You will find that the number of centimeters is 10.

The next unit of measurement is meter(m). There are ten decimeters in one meter. An equal sign can be put between one meter and ten decimeters, because they denote the same length:

1 m = 10 dm

Unfortunately, the meter cannot be illustrated in the figure because it is quite large. If you want to see the meter live, take a tape measure. Everyone in the house has it. On a tape measure, one meter will be designated as 100 cm.This is because there are ten decimeters in one meter, and one hundred centimeters in ten decimeters:

1 m = 10 dm = 100 cm

100 is obtained by converting one meter to centimeters. This is a separate topic, which we will consider a little later. In the meantime, let's move on to the next unit of measure for length, which is called a kilometer.

The kilometer is considered the largest unit of measure for length. There are, of course, other older units, such as megameter, gigameter, terameter, but we will not consider them, since a kilometer is enough for us to study mathematics further.

One kilometer is a thousand meters. An equal sign can be placed between one kilometer and one thousand meters, since they represent the same length:

1 km = 1000 m

Distances between cities and countries are measured in kilometers. For example, the distance from Moscow to St. Petersburg is about 714 kilometers.

International system of units SI

The international system of units SI is a certain set of generally accepted physical quantities.

The main purpose of the international system of SI units is to achieve agreements between countries.

We know that the languages ​​and traditions of the countries of the world are different. There is nothing you can do about it. But the laws of mathematics and physics work the same everywhere. If in one country “twice two will be four”, then in another country “twice two will be four”.

The main problem was that there are several units of measurement for each physical quantity. For example, we have now learned that there are millimeters, centimeters, decimeters, meters and kilometers for measuring length. If several scholars speaking different languages, will gather in one place to solve a particular problem, then such a large variety of units of measurement of length can give rise to contradictions between these scientists.

One scientist will state that in their country, length is measured in meters. The second might say that in their country, length is measured in kilometers. The third can offer its own unit of measurement.

Therefore, the international system of units SI was created. SI is an abbreviation for the French phrase. Le Système International d'Unités, SI (which translated into Russian means - the international system of units SI).

The SI contains the most popular physical quantities and each of them has its own generally accepted unit of measurement. For example, in all countries, when solving problems, it was agreed that the length would be measured in meters. Therefore, when solving problems, if the length is given in another unit of measurement (for example, in kilometers), then it must be converted to meters. We will talk about how to convert one unit of measurement to another a little later. In the meantime, let's draw our international system of units, SI.

Our figure will be a table of physical quantities. We will include each studied physical quantity in our table and indicate the unit of measurement that is accepted in all countries. Now we have studied the units of measurement of length and learned that in the SI system, meters are defined for measuring length. So our table will look like this:

Mass units

Mass is a quantity that indicates the amount of a substance in a body. In the people, body weight is called weight. Usually, when something is weighed, they say "It weighs so many kilograms" , although we are not talking about weight, but about the mass of this body.

However, mass and weight are different concepts. Weight is the force with which a body acts on a horizontal support. Weight is measured in Newtons. And mass is a quantity that shows the amount of matter in this body.

But there is nothing wrong if you call body weight weight. Even in medicine they say "Human weight" , although we are talking about the mass of a person. The main thing is to be aware that these are different concepts.

The following units are used to measure mass:

• milligrams
• grams
• kilograms
• centners
• tons

The smallest unit of measurement is milligram(mg). You will most likely never use a milligram in practice. They are used by chemists and other scientists who work with fine substances. It is enough for you to know that such a unit of measure for mass exists.

The next unit of measurement is gram(G). In grams, it is customary to measure the amount of a product when drawing up a recipe.

There are a thousand milligrams in one gram. An equal sign can be put between one gram and a thousand milligrams, because they denote the same mass:

1 g = 1000 mg

The next unit of measurement is kilogram(kg). The kilogram is a common unit of measurement. Anything is measured in it. The kilogram is included in the SI system. Let's and we will include one more physical quantity in our SI table. We will call it "mass":

One kilogram contains a thousand grams. You can put an equal sign between one kilogram and one thousand grams, because they denote the same mass:

1 kg = 1000 g

The next unit of measurement is centner(c). In centners, it is convenient to measure the mass of the crop harvested from small area or the mass of some cargo.

One centner contains one hundred kilograms. You can put an equal sign between one centner and one hundred kilograms, because they denote the same mass:

1 q = 100 kg

The next unit of measurement is ton(T). Large loads and masses are usually measured in tons. big bodies... For example, mass spaceship or a car.

There are a thousand kilograms in one ton. An equal sign can be put between one ton and a thousand kilograms, because they denote the same mass:

1 t = 1000 kg

Time units

We do not need to explain what time is. Everyone knows what time is and why it is needed. If we open a discussion on what time is and try to define it, then we will begin to delve into philosophy, and we do not need this now. Let's start with the units of time.

The following units of measure are used to measure time:

• seconds
• minutes
• day

The smallest unit of measurement is second(with). There are, of course, smaller units such as milliseconds, microseconds, nanoseconds, but we will not consider them, since on this moment it doesn't make sense.

Various indicators are measured in seconds. For example, in how many seconds an athlete will run 100 meters. The second is included in the SI international system of units for measuring time and is denoted as "s". Let's and we will include one more physical quantity in our SI table. We will call it "time":

minute(m). One minute 60 seconds. An equal sign can be placed between one minute and sixty seconds, since they represent the same time:

1 m = 60 s

The next unit of measurement is hour(h). One hour 60 minutes. An equal sign can be placed between one hour and sixty minutes, since they represent the same time:

1 h = 60 m

For example, if we studied this lesson for one hour and we are asked how much time we spent studying it, we can answer in two ways: "We studied the lesson for one hour" or so "We studied the lesson for sixty minutes" ... In both cases, we will answer correctly.

The next time unit is day... There are 24 hours a day. Between one day and twenty-four hours, you can put an equal sign, since they denote the same time:

1 day = 24 hours

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Unity of measurements implies consistency unit sizes of all quantities. This becomes obvious if we recall the possibility of measuring the same quantity by direct and indirect measurements. This consistency is achieved by creating a system of units. But, although the advantages of a system of units over a set of isolated units were realized a long time ago, the first system of units appeared only at the end of the 18th century. It was the famous metric system (meter, kilogram, second), approved on March 26, 1791. By the Constituent Assembly France. The first scientifically grounded system of units, as a set of arbitrary basic units and derived units dependent on them, was proposed by K. Gauss in 1832. He built a system of units called absolute, based on three arbitrary, independent units: millimeter, milligram and second. The development of the Gauss system was the CGS system (centimeter, gram, second), which appeared in 1881, convenient for use in electromagnetic measurements, and its various modifications.

The development of industry and trade during the era of the first industrial revolution required the unification of units on an international scale. The beginning of this process was laid on May 20, 1875 by the signing of 17 countries (including Russia, Germany, USA, France, England) of the Metric Convention, to which many countries later joined. According to this convention, international cooperation was established in the field of metrology. In Sevres, located in the suburbs of Paris, the International Bureau of Weights and Measures (BIPM) was established with the aim of conducting international metrological research and storing international standards. For the leadership of the BIPM, the International Committee for Weights and Measures (CIPM) was established, which includes advisory committees for units and a number of types of measurements. To resolve the fundamental issues of international metrological cooperation, international conferences called General Conferences on Weights and Measures (GCMW) began to be held regularly. All countries that signed the Metric Convention received prototypes of international standards for length (meter) and mass (kilogram). Periodic comparisons of these national measurement standards with international measurement standards stored in the BIPM were also organized. Thus, the metric system of units received international recognition for the first time. However, after the signing of the Metric Convention, systems of units were developed for various fields of measurement - SGS, SGSE, SGSM, MTS, ISS, MKGSS. The problem of the uniformity of measurements arises again, this time between different areas of measurements. And in 1954, the KhGKMV tentatively, and in October 1960, the XI GKMV finally adopted the International System of Units SI, which, with minor changes, is still in effect. At the next meetings of the SCPM, changes and additions were repeatedly made to it. Currently, the SI system of units is regulated by the ISO 31 standard and, in fact, is an international regulation that is mandatory for use. In our country, the ISO 31 standard is approved as state standard GOST 8.417-02.

SI unit system formed in accordance with general principle the formation of systems of units, which was proposed by K. Gauss in 1832. According to him, all physical quantities are divided into two groups: quantities taken as independent of other quantities, which are called basic quantities; all other quantities, called derivatives, which are expressed in terms of basic and already defined derivatives using physical equations. The classification of units follows from this: the units of basic quantities are the basic units of the system, and the units of derived quantities are derived units.

So, first it is formed system of quantities — a set of quantities formed in accordance with the principle when some quantities are taken as independent, while others are functions of independent quantities. The quantity included in the system of quantities, conventionally accepted as independent of other quantities of this system, is called the basic quantity. The quantity included in the system of quantities and determined through the basic and already defined derived quantities,is called the derived quantity.

The unit of the basic quantity of a given system of quantities is called the basic unit. Derived unit— it is a unit of the derived quantity of a given system of quantities, formed in accordance with the equation connecting it with the basic units or with the basic units and already defined derived units.

In this way, system of units— set of basic and derived units given system quantities.

Basic units of measure. For each measured physical quantity, a corresponding unit of measurement must be provided. So, a separate unit of measurement is needed for weight, distance, volume, speed, etc., and each such unit can be determined by choosing one or another standard. The system of units turns out to be much more convenient if in it only a few units are selected as the main ones, and the rest are determined through the main ones. So, if the unit of length is a meter, the standard of which is stored in the State Metrological Service, then the unit of area can be considered square meter, unit of volume - cubic meter, unit of speed - meter per second, etc.

The convenience of such a system of units of measurement is that the mathematical relationships between the basic and derived units of the system are simpler. In this case, the unit of speed is the unit of distance (length) per unit of time, the unit of acceleration is the unit of change in speed per unit of time, the unit of force is the unit of acceleration of the unit of mass, etc. In mathematical notation, it looks like this: v = l / t, a = v / t, F = ma = ml / t2. The presented formulas show the "dimension" of the quantities under consideration, establishing the relationship between the units. (Similar formulas allow you to determine the units for quantities such as pressure or force electric current.) Such ratios are of a general nature and are carried out regardless of in what units (meter, foot or arshin) the length is measured and what units are chosen for other quantities.

Radiation (or ionizing radiation) is a combination of different types physical fields and microparticles that have the ability to ionize substances.

Radiation is divided into several types and is measured using various scientific instruments specially designed for this purpose.

In addition, there are units of measurement exceeding which can be fatal to humans.

The most accurate and reliable ways to measure radiation

With the help of a dosimeter (radiometer), you can measure the intensity of radiation as accurately as possible, inspect a specific place or specific objects. Most often, devices for measuring the level of radiation are used in places:

1. Close to areas of radiation radiation (for example, near the Chernobyl nuclear power plant).
2. The planned construction of a residential type.
3. In unexplored, unexplored areas while hiking, traveling.
4. With the potential purchase of housing stock.

Since clearing the territory and objects located on it from radiation is impossible (plants, furniture, equipment, structures), then the only the right way protect yourself - check the level of danger in time and, if possible, stay away from sources and contaminated areas as far as possible. Therefore, in normal conditions to check the area, food, household items, you can use household dosimeters that successfully identify the hazard and its dose.

Radiation rationing

The purpose of radiation control is not just to measure its level, but also to determine whether the indicators meet the established standards. Criteria and standards for a safe level of radiation exposure are prescribed in separate laws and generally established rules. The conditions for keeping technogenic and radioactive substances are regulated for the following categories:

• Food products
• Air
• Building materials
• Computer technology
• Medical equipment.

Manufacturers of many types of food or industrial products are required by law to prescribe criteria and indicators of compliance with radiation safety in the conditions and certification documents. Relevant government services quite strictly monitor various deviations or violations in this regard.

Radiation units

It has long been proven that the background radiation is present almost everywhere, just in most places its level is recognized as safe. The level of radiation is measured in certain indicators, among which the main ones are considered to be doses - units of energy absorbed by a substance at the time of passage of ionizing radiation through it.

The main types of doses and their units of measurement can be listed in the following definitions:

1. Exposure dose- created by gamma or X-ray radiation and shows the degree of air ionization; non-systemic units of measurement - rem or "roentgen", in the international SI system it is classified as "coulomb per kg";
2. Absorbed dose- unit of measurement - gray;
3. Effective dose- defined in individually for each organ;
4. Dose equivalent- depending on the type of radiation, it is calculated based on the coefficients.

Radiation radiation can only be detected and instrumented. At the same time, there are certain doses and established norms, among which the permissible indicators, negative doses of exposure to the human body and lethal doses are strictly specified.

Radiation safety levels

For the population, certain levels of safe values ​​of absorbed radiation doses have been established, which are measured by a dosimeter.

Each territory has its own natural background radiation, but a value equal to approximately 0.5 microsievert (µSv) per hour (up to 50 micro-roentgen per hour) is considered safe for the population. Under a normal radiation background, the safest level of external exposure to the human body is considered to be up to 0.2 (µSv) microsievert per hour (value equal to 20 micro-roentgens per hour).

Most upper limit permissible radiation level - 0.5 μSv - or 50 μR / h.

Accordingly, a person can tolerate radiation, the power of which is 10 μZ / h (microsievert), and if the exposure time is reduced to a minimum, radiation of several millisieverts per hour is harmless. This is the effect of fluorography, X-rays - up to 3 mSv. A snapshot of a diseased tooth at the dentist's - 0.2 mSv. The absorbed dose of radiation has the ability to accumulate during life, but the amount should not cross the threshold of 100-700 mSv.

Light is a must for every person for good mood and mental health. Thanks to him, we get the opportunity to see objects, distinguish between their shape and structure of materials, because the artificial extension of daylight hours allows us to increase efficiency and labor productivity. When choosing lamps and lamps for yourself, do not forget that the light must be chosen correctly. Indoors for different purposes let's say a varied approach to lighting intensity. And in order to choose the right fixtures, you need to know how the light is measured.

and artificial

All health professionals unanimously declare that a natural source of light is the best for humans. It promotes the production of a number of vitamins and minerals in the body, and is also most favorable for the eyes. Every object can be seen in natural light without distortion or glare.

But unfortunately, modern world dictates its terms, and we can no longer do without artificial light sources in dark time days, otherwise the life of cities would have completely stopped. Each apartment has a lot of different lamps, quite often we do not even know what the light is measured in and what you need to pay attention to in the store when buying a variety of sconces, floor lamps and lampshades.

What is light like?

No less important than the selection of light intensity is the category or type of lighting. As we said, the most pleasant and safest light is a natural light source. It has a warm shade and is least harmful to the eyes. The closest to a similar tone were the old incandescent bulbs with a reddish tint of the luminous flux. They did not irritate the eyes and copied the sunlight falling into the windows of the apartments.

Modern lamps have many variations on the working element and the type of light. Be sure to check the type of light on the package before purchasing a new lamp. For example, warm light would be ideal for living spaces. A neutral is usually used in offices and large industrial areas. Cold light is often used in watchmaking, where its bluish tint helps to distinguish small parts... Cold shades of light are also welcome in subtropical countries, where they create a feeling of additional coolness and transparency of the air.

Based on the above, you can always choose the right type of light bulb, which will create the desired mood and level of comfort in a relaxing home atmosphere... Psychologists have proven that the type of light plays a significant role in shaping the working mood in factories. Naturally, labor productivity also depends on this.

What parameters are used to measure light intensity?

The average consumer does not even think about what the light is measured in and how important this information is. After all, light, being measured by many quantitative and qualitative parameters. They must be taken into account when planning renovations in an apartment and counting the number of bulbs needed for each room.

Light can be measured according to the following characteristics:

• intensity;
• strength;
• brightness.

Just like that, "by eye" you will not be able to determine all the necessary parameters, so you should take care of buying devices that will help you maintain your eyesight and a positive psychological attitude at any time of the day.

How is the brightness of light measured?

Brightness is a very important characteristic of a light source. It is the brightness of the lighting that allows us to see all the objects around us clearly and in contrast. Brightness enhances the spatial perception and exposure of whites and blacks. In addition, it is the brightness of the light source that determines the degree of comfort when reading. printed text, and this, as you know, directly affects the health of the eyes.

If we are talking about brightness, then remembering in which units light is measured is very easy. The most commonly used candela is used to measure the brightness of a light source. This unit denotes the brightness of one candle burning; it is from it that all measuring instruments are repelled. Sometimes experts also use other units of measurement - Lambert and Apostille.

What device can be used to measure the brightness of lighting?

Modern stores of specialized equipment are always ready to provide customers with a large variety of devices for measuring the brightness of light. Brightness and colorimeters do the job best. They are able to give you information not only on the degree of brightness in a particular room, but also to determine the color temperature of the room.

Advanced fixtures are suitable for professional studio photographers. And for household needs, an ordinary brightness meter is suitable, which does not have additional options.

In what

The power of light - According to the school physics course, it can be characterized as the energy of light, which is capable of being transferred from one point to another in a certain period of time. This energy can change direction depending on the given trajectory.

The light energy is measured in candelas. That is, having bought a brightness meter for home use, you can always measure not only the brightness, but also the intensity of the light.

Light intensity: how is it measured?

Light intensity is often referred to as illumination, and it is also important when choosing luminaires and different types lamps. Even a child can remember what the light intensity is measured in, although some nuances should be taken into account here.

If we are talking about falling on a certain surface, then it is necessary to measure it in lumens. But if you want to find out the degree of illumination of objects or surfaces, you need to talk about suites.

Such subtleties often frighten buyers who have heard somewhere that light is measured in lumens, and are perplexed about the incomprehensible units of measurement indicated on the package from the light bulb. To cope with the problem of finding out the degree of illumination in a room will help a very common device - a luxometer.

Luxometer - a device that preserves healthy vision

If you have a hard time remembering the units in which light is measured, then the luxometer will save you time and nerve cells. This device has small size and weight, most often it consists of a display and a measuring part.

You can use such an assistant at home, in educational institutions or office premises... To get the data, you just need to turn on the light source and take measurements. Within a few seconds, you will see the result on the display, which will show how safe your bulbs and lamps are for the eyes.

for apartments and other residential premises

In order to find the lighting that is comfortable for the eyes, it is not enough to know how the light is measured. You also need to have information about the illumination standards, by which it is worth navigating when planning the location lighting fixtures in the apartment.

Each room and space has its own required degree of illumination, which is measured in suites. For example, the nursery should be the lightest room in the apartment. There cannot be less than two hundred suites, otherwise the baby's health will be under great threat.

The kitchen and the rest of the rooms can be lit for one hundred and fifty suites, but the utility rooms and corridors cost fifty suites. Compliance with these standards guarantees your family a comfortable existence, excellent mood and vision, which even an eagle will envy.

If you care about your family, then you should know exactly what bulbs are installed in the lamps in your apartment. After all, every sane person dreams of returning from work to a house where cheerful children and a caring wife are waiting for him. good location spirit. And an important role in making the dream come true at last is played by well-chosen lighting.

Add up of two digits. The upper one is called the systolic value, and the lower one is called the diastolic value. Each of them is consistent with a certain norm, depending on the age category of the person. Like everyone else physical phenomenon, the force of the blood flow pressing on the muscle layer of the vessels can be measured. These indicators are recorded by means of a scale with divisions on the manometer. The markings on the dial correspond to a particular measure of calculation. In what units is blood pressure measured? To answer this question, one must turn to the history of the first blood pressure monitors.

Pressure is a physical quantity. It should be understood as a kind of force that affects a certain area of ​​a certain area at a right angle. This value is calculated according to the International System of Units in Pascals. One pascal is the effect of a perpendicularly directed force of one newton per square meter of surface. However, when using the tonometer, different units are used. What is the blood in the vessels?

Readings on the scale of a mechanical pressure gauge are limited to numerical values ​​from 20 to 300. There are 10 divisions between adjacent digits. Each of them corresponds to 2 mm Hg. Art. Millimeters of mercury are the units for. Why is this particular measure used?

The first sphygmomanometer (sphygmo means pulse) was mercury. He investigated the force of the blood pressing on the vessels with the help of a mercury column. The substance was placed inside a vertical flask, graduated with millimeter notches. Under the pressure of the air flow injected by the rubber bulb into the inelastic hollow cuff, the mercury rose to a certain level. Then the air was gradually released, and the column in the flask went down. Its position was recorded twice: when the first tones were heard, and when the last pulsations disappeared.

Modern blood pressure monitors have long been working without the use of a hazardous substance, but blood pressure is measured traditionally, in millimeters of mercury, to this day.

What do the numbers determined by the tonometer mean?

The blood pressure is represented by two digits. How to decode them? The first, or upper, indicator is called systolic. The second (lower) is diastolic.

Systolic pressure is always higher, it indicates the force with which the heart ejects blood from its chambers into the arteries. It occurs at the time of myocardial contraction and is responsible for the delivery of oxygen and nutrients to the organs.

The diastolic value is equal to the resistance force of the peripheral capillaries. It is formed when the heart is in the most relaxed state. The strength of the vascular walls, acting on the red blood cells, enables them to return to the heart muscle. The force of the capillaries pressing on the blood stream, which occurs during diastole (resting of the heart), largely depends on the functioning of the urinary system. Therefore, this effect is often called renal.

When measuring blood pressure, both parameters are very important, together they ensure normal blood circulation in the body. So that this process is not disturbed, the tonometer values ​​should always be in acceptable limits... For systolic (heart) pressure, the generally accepted norm is 120 mm Hg. Art., and for diastolic (renal) - 70 mm Hg. Art. Minor deviations in one direction or another are not recognized as pathology.

Normal pressure limits:

1. Slightly underestimated: 100 / 65-119 / 69.
2. Standard rate: 120 / 70-129 / 84.
3. Slightly overpriced: 130 / 85-139 / 89.

If the tonometer gives an even lower value (than in the first point), this indicates hypotension. With persistent high numbers (above 140/90), a diagnosis of hypertension is made.

Based on the identified pressure parameters, the disease can belong to one of three degrees:

1. 140 / 90-159 / 99 are 1st degree values.
2. 160 / 100-179 / 109 - indications of the 2nd degree.
3. Anything above 180/110 is already the 3rd degree of the disease.

The easiest of these is considered to be the first degree. With timely treatment and following all the doctor's recommendations, it is cured. The third is the greatest danger, it requires the constant intake of special pills and threatens human life.

Blood pressure indicators: dependence on age

Standard numbers are average. They are not so often found in the generally accepted form. The values ​​of the tonometer of a healthy person are constantly fluctuating, because the conditions of his life, physical well-being and mental state change. But these fluctuations are insignificant for the full functioning of the organism.

Arterial pressure readings also depend on which age group a man or woman belongs to. From the neonatal period to deep old age, arrows measuring instrument tend to show ever higher numbers.

Table: the norms of systolic and diastolic pressure, corresponding to a certain age and gender.

As you can see from the table, gender also matters. It is noted that women under 40 have lower blood pressure than men. After this age, the opposite phenomenon is observed. This difference is explained by the action of specific hormones that maintain a good state of the circulatory system of the fair sex during the childbearing period. With the onset of menopause, the hormonal background changes, the protection of blood vessels weakens.

The parameters of the measured pressure in the elderly also differ from the generally accepted norm. They are usually higher. But at the same time, people feel good with these indicators. The human body is a self-regulating system, and therefore a forced decrease in the usual values ​​can often lead to poor health. Vessels in old age are often affected by atherosclerosis, and for a full supply of blood to the organs, the pressure must be increased.

You can often hear such a combination as “ operating pressure". This is not a synonym for the norm, simply due to physiological characteristics, age, gender and health status, each person needs "their" indicators. With them, the vital activity of the body proceeds in optimal conditions, and a woman or a man feels vigorous and active. Perfect option when the "working pressure" is the same or not very different from generally accepted standards.

To determine the optimal parameters of the tonometer, depending on age characteristics and weight, you can use special calculations called the Volynsky formula:

• 109+ (0.5 * number of years) + (0.1 * weight taken in kg) - systolic value;
• 63+ (0.1 * years lived) + (0.15 * weight in kg) - diastolic parameters.

It is advisable to carry out such calculations for people from 17 to 79 years old.

People have tried to measure the pressure since ancient times. In 1773 Stephen Hales, an Englishman, attempted to study the pulsation of blood in a horse's artery. The glass test tube was connected through a metal tube directly to the vessel squeezed with a rope. When the clamp was removed, the blood entering the flask reflected the pulse fluctuations. She moved up and down. So the scientist managed to measure blood pressure in different animals. For this, peripheral veins and arteries were used, including the pulmonary.

In 1928, the French scientist Jean-Louis Marie Poiseuille was the first to use a device showing the level of pressure using a mercury column. The measurement was still straight forward. Experiments were carried out on animals.

Karl von Vierordt invented the sphygmograph in 1855. This apparatus did not require direct insertion into the vessel. It was used to measure the force that had to be applied to completely stop the movement of blood through the radial artery.

In 1856, surgeon Favre for the first time in the history of medicine carried out an invasive measurement of blood pressure in humans. He also used a mercury device.

The Italian physician S. Riva-Rocci invented the pressure meter in 1896, which became the progenitor of modern mechanical blood pressure monitors. It included a bicycle tire to tighten the upper arm. The tire was attached to a pressure gauge that used mercury to record the results. A peculiar cuff also communicated with a rubber bulb, which was supposed to fill the tire with air. When the pulse in the hand ceased to be felt, systolic pressure was recorded. After the resumption of pulsating tremors, a diastolic indicator was noted.

1905 is a significant date in the history of the creation of blood pressure monitors. NS Korotkov, a military doctor, improved the principle of operation of the Riva-Rocchi sphygmomanometer. He is the author of the discovery of the auscultatory method for measuring blood pressure. Its essence was to listen with a special device to the noise effects that occur inside the artery just below the cuff squeezing the shoulder. The appearance of the first knocks when air was blown off indicated a systolic value, the resulting silence indicated diastolic pressure.

The discovery of the existence of blood pressure in humans, as well as the discoveries of scientists in the field of its measurement, significantly advanced the development of medicine. Systolic and diastolic values ​​will help an experienced doctor understand a lot about the patient's health. That is why the first blood pressure monitors contributed to the improvement of diagnostic methods, which inevitably increased the effectiveness of therapeutic measures.

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