What is the name of the device for measuring atmospheric pressure. Barometer - a device for measuring atmospheric pressure. Measuring atmospheric pressure with a thermohygrometer

The force of the weight of an air column 10 km high, acting on a unit of the earth's surface, is called atmospheric pressure. In the SI system, the unit of pressure is Pascal (Pa)

However, 1 Pa is a very small pressure value, therefore, when measuring atmospheric pressure, multiple units are used: kPa = 1000 Pa and MPa = 10 6 Pa = 1000 kPa.

In addition to Pascal, non-systemic units are also used to measure atmospheric pressure - millimeters of mercury (water) column and bars, and

1 bar = 101.3 kPa = 760 mm. rt. Art.,

This is what atmospheric pressure at sea level means.

An instrument for measuring atmospheric pressure is called a barometer. The most common type is the metal aneroid barometer, the construction of which is shown in Fig. 1.2. The basis of the aneroid is a cylindrical chamber To from which air has been evacuated. The chamber is hermetically sealed with a thin corrugated (wavy) membrane M. To prevent atmospheric pressure from flattening the membrane, it T connected to a spring P attached to the body of the device. Hinged to the spring the lower end of the arrow is fixed With, which can rotate around an axis O. A scale is used to measure instrument readings. W. When atmospheric pressure changes, the membrane bends inward or outward and moves the arrow along the scale, showing the pressure value (the aneroid barometer scale is calibrated and verified according to the readings of a mercury barometer).

Rice. 1.2 - Schematic diagram of an aneroid barometer

BUT neroids are very easy to use, durable, small in size, but less accurate than mercury barometers. The appearance of the aneroid barometer is shown in fig. 1.3.

Rice. 1.3– Aneroid barometer

According to the barometric formula

(1.5)

that is, the value of atmospheric pressure depends on the height above the Earth's surface, therefore the scale of the aneroid barometer can be graduated in meters according to the pressure distribution along the height. The aneroid, which has a scale by which you can determine the height of the rise above the Earth, is called an altimeter (altimeter). They are widely used in aviation, parachuting, mountaineering.

1.4. Devices and methods for measuring air humidity

Atmospheric air always contains a certain amount of water vapor, therefore, in fact, it is a mechanical mixture of dry air and water vapor, corresponding to the laws of ideal gases. To characterize the degree of air humidity, absolute and relative humidity are used.

Absolute humidity- the amount of water vapor contained in 1 m 3 of air is measured in kg / m 3 (g / cm 3).

Relative Humidity- the ratio of the actual density (pressure) of air to the maximum possible at a given temperature:

(1.6)

Relative humidity is expressed as a percentage and is one of the main meteorological quantities. To determine the humidity of the air, psychrometric and hair hygrometers are used.

Household psychrometer serves to measure temperature and humidity. It consists of two thermometers (Fig. 1.4, a), and the reservoir of the right thermometer is wrapped in a cloth moistened with water. The left thermometer is dry and serves to measure the air temperature. Readings on the right and left thermometers simultaneously serve to calculate the relative humidity of the air.

To
the piece of cloth enveloping the thermometer ball must be clean; if dirty, it must be replaced with a new one. With constant use, the fabric should be replaced every two weeks.

There should not be any objects near the device that have a temperature different from the air temperature, which can affect the readings of the device.

Humidity is determined using psychrometric tables and graphs ( Annexes A and AT), the determination procedure is given in laboratory work 1.

Rice. 1.4– Humidity measuring instruments:a - household psychrometer; b - hair hygrometer

Hair hygrometer(Fig. 1.4, b) is also designed to measure the relative humidity of the air. The operation of the device is based on the property of a fat-free human hair to change its length with a change in the relative humidity of the surrounding air. The main purpose of a hair hygrometer is to measure humidity in frosty times, when humidity is not determined by a psychrometer. But since hygrometer readings require corrections obtained through comparison with a psychrometer, hygrometer observations are carried out throughout the year. If during the reading it turns out that the end of the arrow has gone beyond the hundredth division, then it is necessary to approximately estimate at what division the arrow would have been if the scale had been extended by 110 and write down the “extrapolated” reading. The air temperature is measured by the dry bulb of the psychrometer.

What is atmospheric pressure? What is the name of the instrument for measuring atmospheric pressure? Tell us about its structure. Name normal atmospheric pressure. How and why does pressure change when ascending mountains and descending into depressions? Why is air pressure on the earth's surface constantly changing?

1) =20 mm. rt. Art. 2) 20 × 10.5 = 210 meters Answer: 210 meters

1) =45 mmHg Art. 2) 45 × 10.5 \u003d 427.5 m height Answer: 427.5 m.

Long before science gave a precise definition of the concept of "wind" and found an explanation for its occurrence, man learned to use the power of the wind. Sailing ships sailed on the sea. The wind, filling the sails, made it possible to cross the oceans and make geographical discoveries. For example, the great traveler Christopher Columbus crossed the Atlantic Ocean on sailing caravels and discovered a new continent - America.

Velocity The distance that air travels per unit of time. Expressed in m / s Instrument - anemometer Force The pressure exerted by air on an area of ​​​​1 square. m, located perpendicular to the movement of air. Expressed in points Direction The direction is determined by the side of the horizon from which the wind is blowing. Wind direction is expressed in points. The main points are north, south, east and west. The device is a wind vane.

The strongest winds on Earth, 104 m/s, were recorded on Mount Washington (Appalachian mountain range) (USA). The windiest place on Earth is Cape Denison (Antarctica), 300 days a year the winds reach 89 m/s.

Wind strength (points) Wind speed m/s (km/h) Designation Wind action 0.0.0-0.5 (0) CalmSmoke rises vertically. 1.0.6-1.7 (4) Quiet Light air movement 2.1.8-3.3 (9) Light Leaves rustle, the face feels the wind 3.3.4-5.4 (16) Weak Leaves and thin branches sway 4.5.5-7, 9 Moderate Tree tops bend, dust rises 5.8.0-10.7 Fresh Branches and thin trunks sway 6.10.8-13.8 Strong Thick branches sway, wires hum 7.13.9-17.1 Strong Trunks sway, it is difficult to go against the wind 8.17.2-20.7 Very strong Break small branches, very difficult to walk 9.20.8-24.4 Storm Thick branches break, buildings damaged 10.24.5-28.4 Strong storm Trees break, large damage 11.28.5-32.6 Violent storm Large destruction 12.Over 32.7 Hurricane Devastating destruction

Name of the windDistribution areas Direction Trade windsTropicsN.-E.,S.-E. Winds zap. transferModerate latitudesZ., S.-Z. MonsoonsEast coast of Eurasia and North. America In summer - from the ocean to the mainland, in winter - from the mainland to the ocean. Stock windsAntarcticaFrom the center of the mainland to the periphery BreezeSea coastsDuring the day - from the sea to land, at night - from land to the sea FenMountain systems. Especially the Alps, the Pamirs, the Caucasus From the mountains to the valleys

What is wind? What are the reasons for the formation of wind What is the windiest place on Earth. What winds do you know? How do they blow? What are the instruments that measure the strength, speed and direction of the wind? What is the importance of wind in nature and human life? Paragraph 39 p Plot the wind rose for February according to your observations.

In hygiene research, two types are used. barometers:

- liquid barometers;

- metal barometers - aneroid.

The principle of operation of various modifications of liquid barometers is based on the fact that Atmosphere pressure balances a certain height of a liquid column in a tube sealed at one end (upper). The lower the specific gravity of the liquid, the higher the column of the latter, balanced by the pressure of the atmosphere.

They are most widely used, since the high specific gravity of liquid mercury makes it possible to make the device more compact, which is explained by balancing the pressure of the atmosphere with a lower column of mercury in the tube.

Three systems of mercury barometers are used:

- cup;

- siphon;

- siphon-cup.

These systems of mercury barometers are shown schematically in Figure 35.

In some modifications, there are two scales - in mm Hg. Art. and mb. Tenths of mm Hg. Art. or mb are counted on a movable scale - vernier. To do this, you need to set the zero division of the vernier scale with a screw in line with the top of the meniscus of the mercury column, count the number of whole divisions of millimeters of mercury on the barometer scale and the number of tenths of a millimeter of mercury to the first mark vernier scales, coinciding with the division of the main scale.

Example. The zero division of the vernier scale is between 760 and 761 mm Hg. Art. main scale. Therefore, the number of integer divisions is 760 mm Hg. Art. To this figure it is necessary to add the number of tenths of a millimeter of mercury, counted on the vernier scale. The first division of the main scale coincides with the 4th division of the vernier scale. The barometric pressure is 760 + 0.4 = 760.4 mm Hg. Art.

As a rule, a thermometer is built into cup barometers (mercury or alcohol, depending on the expected range of air temperature during research), since in order to obtain the final result, it is necessary to bring the pressure to standard conditions of temperature (0 ° C) and barometric pressure (760 mm Hg) by special calculations. st.).

AT cup expeditionary barometers before observation, first, using a special screw located at the bottom of the device, set the level of mercury in the cup to zero.

Siphon and siphon cup barometers(Figure 35). In these barometers, the atmospheric pressure is measured by the difference in the heights of the mercury column in the long (sealed) and short (open) elbows of the tube. This barometer allows you to measure pressure with an accuracy of 0.05 mmHg st. Using a screw at the bottom of the instruments, the mercury level in the short (open) elbow of the tube is brought to zero, and then the barometer readings are read.

Siphon cup inspection barometer. This device has two scales: on the left in mb and on the right in mm Hg. Art. To determine tenths of mm Hg. Art. nonius serves. The found values ​​of atmospheric pressure, as well as when working with other liquid barometers, must be reduced to 0 ° C using calculations or special tables.

At meteorological stations, not only the temperature correction is introduced into the readings of barometers, but also the so-called constant correction: the instrumental correction and the correction for gravity.

Barometers should be installed at a distance or isolated from sources of thermal radiation (solar radiation, heating devices), as well as at a distance from doors and windows.

Metal aneroid barometer(Figure 36). This device is especially convenient when conducting research in expeditionary conditions. However, this barometer must be calibrated against the more accurate mercury barometer before use.

Rice. 36. Aneroid barometer

Rice. 37. Barograph

The principle of the device and operation of the aneroid barometer is very simple. A metal pad (box) with corrugated (for greater elasticity) walls, from which air is removed to a residual pressure of 50-60 mm Hg. Art., under the influence of air pressure changes its volume and, as a result, is deformed. The deformation is transmitted through the system of levers to the arrow, which indicates the atmospheric pressure on the dial. A bent-shaped thermometer is mounted on the dial of the aneroid barometer due to the need, as mentioned above, to bring the measurement results to 0°C. Dial graduations can be in mb or mm Hg. Art. In some modifications of the aneroid barometer, there are two scales - both in mb and in mmHg. Art.

Aneroid altimeter (altimeter). In the measurement of altitude by the level of atmospheric pressure, a regularity is laid down, according to which there is a relationship between air pressure and altitude, which is very close to linear. That is, when you rise to a height, atmospheric pressure decreases proportionally.

This device is designed to measure atmospheric pressure precisely at altitude and has two scales. One of them shows the pressure in mm Hg. Art. or mb, on the other - the height in meters. On aircraft, altimeters with a dial are used, on which the flight altitude is determined on a scale.

Barograph (barometer recorder). This device is designed for continuous recording of atmospheric pressure. In hygienic practice, metal (aneroid) barographs are used (Figure 37). Under the influence of changes in atmospheric pressure, a stack of aneroid boxes connected together, as a result of deformation, affects the system of levers, and through them on a special pen with non-drying special ink. With an increase in atmospheric pressure, the aneroid boxes are compressed and the lever with the pen rises.

When the pressure decreases, the aneroid boxes expand with the help of springs placed inside them and the pen draws a line downwards. Record pressure in the form of a continuous line is drawn with a pen on a graduated in mm Hg. Art. or mb paper tape placed on a cylindrical drum rotating by means of a mechanical winding. Barographs with a weekly or daily winding are used with appropriate graduated ribbons, depending on the purpose, objectives and nature of the research. Barographs are produced with an electric drive that rotates the drum.

However, in practice, this modification of the device is less convenient, since its use in expeditionary conditions is limited. To eliminate temperature effects on the barograph readings, bimetallic compensators are inserted into them, which automatically correct (correct) the movement of the levers depending on the air temperature. Before starting work, the pen lever with a special screw is set to its original position corresponding to the time indicated on the tape and to the pressure level measured by an accurate mercury barometer.

Ink for recording barograms can be prepared according to the following recipe:

Bringing the volume of air to normal conditions (760 mm Hg, 0°C). This aspect of barometric pressure measurement is very important when measuring pollutant concentrations in the air. Ignoring this aspect can cause significant errors in the calculation of the concentrations of harmful substances, which can reach 30 percent or more.

Bringing the volume of air to normal conditions is carried out according to the formula:

(39)

Example . To measure the concentration of dust in the air, 200 liters of air were passed through a paper filter using an electric aspirator. The air temperature during its aspiration was +26 ° C, barometric pressure - 752 mm Hg. Art. It is necessary to bring the volume of air to normal conditions, that is, to 0 ° C and 760 mm Hg. Art.

We substitute the values ​​of the corresponding parameters of the example into the X formula and calculate the required air volume under normal conditions:

Thus, when calculating the concentration of dust in the air, it is necessary to take into account the volume of air exactly 180.69 l, not 200 l.

To simplify the calculation of air volume under normal conditions, you can use correction factors for temperature and pressure (table 25) or calculated ready-made values ​​​​of formula 39 and (table 26).

Barometers are used to measure atmospheric or near atmospheric pressure. These instruments show absolute air pressure. The barometer scale is limited to the measurement area from 680 to 800 mmHg Art. Barometers are used to measure pressure in open space. liquid barometers. The device (Fig. 290) is a U-shaped tube closed at one end, the sealed end of which is much longer than the open one. The tube is filled with mercury; an airless space is created above its layer in the sealed end of the tube. A column of mercury in a sealed long

Rice. 291. Diagram of a box-shaped device

barometer:

/ - a box with a wavy lid; 2 - spring * zhnna; 3 - system of levers; 4 - arrow.

In table. 11 shows the relationship between the indicated values.

PRESSURE MEASUREMENTS

In laboratory practice, devices are used to measure pressure - atmospheric and close to it)

Although all these devices differ in design, there is no fundamental difference between them; they all measure the force acting on a unit surface. This force is counteracted either by a liquid column or by a spring force.

end has such a height at which the weight of this column is balanced by the weight of a column of atmospheric air.

A movable millimeter scale is installed between both knees of the tube; with its help, you can measure the difference in height in both knees. This difference is equal to the air pressure, expressed in millimeters of mercury.

With accurate barometric measurements, the temperature of the surrounding space must also be determined simultaneously. This must be done because with a change in temperature, the density of mercury changes due to

Metal barometers are of two basic designs: box-shaped and tubular. U k o r o b h a | tyh barometers (Fig. 291) air pressure effective |

Rice. 293. Barograph.

Rice. 292. Scheme of the device of a tubular barometer:

/ - hollow tube; 2 - system of levers; 3 - arrow.

sticks to the wavy, highly elastic lid of an empty metal evacuated box.

In tubular barometers (Fig. 292), air pressure acts on a flat metal tube bent empty inside - its outer surface is larger than its inner one. Small fluctuations in air pressure are increased by means of a system of levers and indicated on a scale.

Self-recording barometers, the so-called barographs (Fig. 293), are equipped with a lever that presses on the scribe, touching the tape of the diagram -I pressure - time, mounted on a drum. The drum is driven by a clock mechanism, the winding of which can be daily or weekly.

Instruments for measuring pressure greater than atmospheric pressure

To measure pressure greater than atmospheric pressure, pressure gauges are used (also sometimes called when |

burs and for determining pressure below atmospheric - see below).

Liquid manometers are open and closed.

Open liquid manometers are used in two types: straight and inclined. Straight (Fig. 294) is a U-shaped tube open on both sides, one end of which is connected to a system with measured pressure. The tube is filled with a barrier liquid, which is water or mercury, as well as silicones. The advantage of silicones is that they do not wet the tube walls like water and are more sensitive than mercury to small pressure fluctuations.

Since the pressure in the system is higher than atmospheric pressure, the mercury column in the right knee (see Fig. 294) is higher than the mercury column in the left knee. Their difference is equal to the value h, measured on a scale.

Open manometers with an inclined knee (Fig. 295) have a higher sensitivity than straight ones: in an inclined knee, the liquid moves a greater distance than in a vertical one. Post pressure h(in mmHg Art.) in this case, calculate the multiplication of the length of the liquid column / by the sine of the angle of inclination a, i.e. h-I bin a.

In closed liquid manometers, the working medium is the gas above the barrier liquid (mercury) in the closed elbow (Fig. 29P-). When measuring increased pressure, the mercury column in the right knee rises and the gas is compressed. The length of its column is measured on a scale. The disadvantage of these pressure gauges is that their scale divisions are uneven, i.e. narrower for higher pressures.

Metal manometers. Manometers with a leaf spring are used (Fig. 297), which, unlike barometers, have only an elastic cover instead of an evacuated box. For one

Tubular writing manometers (Fig. 298) are equipped with a bent non-evacuated tube, which has an elliptical shape in section. This tube is connected to the vessel in which the pressure is to be measured.

Special pressure gauges are also common, in which the scale

Rice. 297. Diagram of the device 298. Diagram of the device
metal manometer metal tubular

with leaf spring. pressure gauge.

Le there is a red line indicating the limiting pressure that can be developed in an apparatus or vessel equipped with such a pressure gauge. With the system..

using levers and a scribe, the pressure developing in the apparatus is recorded on a special round diagram or, if a barograph is used, on a flat pressure-time diagram.

Subatmospheric Pressure Instruments

Vacuum gauges are used to measure pressure below atmospheric pressure. There are several designs of these devices, designed for certain limits of rarefaction (vacuum).

Simple mercury pressure gauges (vacuum gauges), which are used to control the process of distillation under vacuum, are LJ-shaped tubes and are designed for a pressure range from 0 to approximately 200 mmHg Art.(Fig. 299). The scale can be movable, then its zero point is set at the level of the meniscus of the mercury column in the sealed knee, or fixed. In this case, to determine the pressure, add the distances between zero and both menisci.

With such pressure gauges (vacuum gauges) it is possible to determine the pressure with an accuracy of 0.5 mmHg Art., if counted by eye, and up to 0.02 mmHg Art., if the reading is carried out using a cathetometer. The cathetometer is a horizontal spotting scope that moves vertically along a frame installed strictly vertically. Using the scale provided with the frame and the vernier, the position of the pipe can be determined with an accuracy of 0.01 mm. When reading, the tube must be installed so that the horizontal thread stretched along the diameter of the eyepiece always coincides with the upper edge of the mercury meniscus. The measurement is made several times, after which the arithmetic mean of all readings is found. The pressure will be equal to the difference between the average values ​​determined for each of the menisci of the pressure gauge (vacuum gauge).

To measure high vacuum, i.e., very low pressures, of the order of 10 ~ V mmHg Art., other devices are used. Of them often use the Mac pressure gauge? Leoda (Fig. 300) This device is soldered with the upper end of the tube £ to that part of the installation in which pressure is to be measured. To measure the pressure, slowly open the tap 3, letting outside air into the tank /.

Under the action of atmospheric pressure, mercury rises, filling the cylinder 5, which previously had a pressure equal to the pressure in the installation. It must be remembered that the mercury in the device must rise very slowly. This is important because when lifting quickly, accidents are possible due to shocks or impacts of mercury on the walls of the device. To facilitate regulation of the air intake through

Rice. 299. Simple mercury manometer

(vacuum gauge):

a- starting position; b - position prn measurement.

tap 3 its inlet should be connected with a rubber tube to the capillary. Through this capillary, air will enter the device at the required speed. You can also adjust the lifting speed with a crane. 4. When the balloon 5 will be filled with mercury, the gas previously contained in it will be compressed in a capillary 6. Therefore, measured-j my pressure can be calculated using the Boyle formula - \ Mariotte, based on the fact that the volume of compressed gas Vi ych his pressure R 1 are known, as well as the volume of gas V 0 i before compression:

P n V n = PiVi

The volume of gas before compression is equal to the sum of the cylinder capacities 5, wide tube above the mark with and capillary 6. These values ​​must be determined before the pressure gauge is soldered into the system*.

The pressure of a compressed gas is found by the difference in the levels of mercury in the capillaries 6 and 7.

To equip a conventional McLeod pressure gauge, 5 to 10 kg mercury. Therefore, it is necessary to handle the device very carefully, as there is always a danger of breaking it and spilling mercury. Safer working conditions are created when using mano-

Rice. 301. Moser gauge (vacuum gauge): a- starting position; b - position during measurement.

meter (vacuum gauge) Moser, which is filled with a much smaller amount of mercury (Fig. 301). The Moser pressure gauge works on the same principle as the McLeod pressure gauge, but requires only 80-300 G mercury. These devices usually have three measuring ranges: from 500 to 10 mmHg Art., from Yu -1 to 10 mmHg Art. and from Yu -1 to Yu -4 mmHg Art.

Using a thin section, the device is connected to the apparatus in which pressure is to be measured. When measuring, the manometer is turned counterclockwise until

* For a detailed description of the method for determining these quantities, see Gerasimov Ya. Moscow State University, 1951.

until the mercury meniscus in the outer tube reaches a certain limit level. The level of the mercury meniscus in the inner knee, equipped with a logarithmic scale, determines the pressure in the system (in mmHg Art.) Each reading is preceded by a pressure gauge (vacuum gauge) at the beginning. bring to its original position, i.e. the ball must be lowered down.

Other Ways to Measure Vacuum

In addition to those described, there are several more ways to determine high vacuum. So, the Pirani vacuum gauge is based on the dependence of the thermal conductivity of gases on pressure. Penning ionization vacuum gauges use the formation of ions in the collision of gas molecules with electrons. The molar vacuum gauge Gede is based on measuring the impact force of gas molecules. All these devices allow you to measure pressure up to 10 _v mmHg Art. Operation with these gauges is described in detail in the instructions attached to the instruments.

Similar information.

In the seventeenth century, mankind became aware and proved the fact that air has a certain weight. The assumption of its pressure on various objects was proved with the help of a special device - a barometer. It will be discussed in this article.

A device that measures air pressure

Let's start with a definition. A barometer is a device for measuring a certain amount of air pressure on objects. E. Torricelli became its inventor. In 1644, the barometer was a tube filled with mercury and a measuring scale. On the day when the barometer was tested, the level of mercury was at around 760 mm, which was the reason for considering the mark at this level as normal pressure. Such devices are still used by meteorological stations.

Two centuries after the invention of the mercury barometer, as a result of many studies, a fundamentally new liquidless type was designed by Lucien Vidi. Subsequently called the aneroid barometer. Throughout the existence of aneroids have gained great popularity among many users, because they are small in size, light and accurate. Compared to mercury barometers, aneroids are completely safe to use.

Types of barometers

Mercury - a device that measures pressure. The principle of operation is the movement of mercury relative to the applied scale.

Liquid - a device with which the level of pressure is measured by balancing the weight of a column of liquid with atmospheric pressure.

Aneroid barometer - the principle of operation and the display of indicators is based on a change in the size of a sealed metal box filled with rarefied air, under the influence of atmospheric pressure on its surface.

Electronic is a modern type of device that converts the linear indicators of a classic aneroid into an electronic signal. The signals processed by the microprocessor are displayed on the liquid crystal screen.

The aneroid barometer is the most common of the above instruments, due to its small size and lack of liquid in the mechanism. Let's consider it in more detail.

The structure of an atmospheric barometer

• Round silver-nickel plate.
• Box with ribbed bases.
• transmission mechanism.
• return spring.
• Pointing arrow.

Atmospheric barometer - principle of operation

When assembled, the aneroid is a box with various mechanisms. When a certain amount of air is pumped out of it, this creates a strong discharge of the return spring, the index arrow and the transmission mechanism between them. Under the action of pressure, the walls of the “pressure chamber” shrink or increase in size, and the pointer begins to move relative to the measuring scale in the direction of increasing or decreasing pressure, respectively. In a calm state, the arrow will be at around 760 mm.

Self-recording barometer

Used to record meteorological data regarding fluctuations in atmospheric pressure. In other words, this is an improved aneroid barometer, with the addition of a clock mechanism to the pressure chamber, an apparatus holding graduated paper and an arrow-drive that puts an ink line on the paper.

The displayed “drawing” on the instrument paper is called a barogram. During the operation of the barograph, in accordance with hourly indicators, the mechanism winds special paper on its base, on the surface of which an attached arrow with ink glides and marks the indicators of atmospheric pressure deviations.

Pressure discrepancies are recorded continuously. For meteorologists, this is the main documented fact of weather changes in the near future. Depending on the size of the drum, the duration of the recording can be from several hours to one week. The special design allows you to take readings and monitor atmospheric indicators at any time.

Barometer in the phone - what is it

Technology does not stand still, and now you can measure atmospheric pressure using a mobile device. Many users of modern gadgets, faced with a new feature, are wondering - a barometer in the phone, what is it? A modern miniature weather station allows the user of the phone to constantly check electronically the level of atmospheric pressure. By tracking the pressure indicators for a certain time, you can find out whether a cyclone or anticyclone is approaching. These indicators will be useful for people with increased sensitivity to sudden changes in pressure.

The capabilities of the mobile device do not stop there. In electronic form, it shows the height, geographical width and longitude, which, in turn, contributes to the rapid search for the device and determining the exact location of its location. Thanks to GPS satellites, the process is fast and accurate. The mobile barometer is an accurate altimeter. The accuracy of determining the location of the user is reduced to a radius of 3 meters. It is these devices that climbers use in the mountains. But they gained great popularity in the aviation industry.

Barometer built into the watch

Appeared relatively recently. Few know what this device is for, and most are wondering - a barometer in a watch, what is it?

Let's try to figure it out. The barometer in certain types of watches is presented in electronic or mechanical form. Electronic view - no different from supplying atmospheric pressure data and displaying them on the screen, like on a phone. The watch with mechanical pressure display is a perfectly accurate mini copy of the aneroid. The only difference is in the simplified scale for displaying readings. The cost of barometer watches is quite high, but, as a rule, they are shockproof and waterproof.

"Non-Standard Barometer"

Thanks to its founders, it is called Harvard. The economic barometer underlies the formation of econometrics. Predicts changes in market conditions, supply and demand dynamics, etc. The Harvard Barometer is a description of empirical patterns and extrapolations over the last months of observation. They are based on a study of the dynamics of development of various indicators of the economy.

The development forecast was displayed graphically. Each curved line plotted on the graph displayed one or another indicator. For example, curve "A" reflected changes in average exchange rates (stock market); curve "B" displayed the wholesale price index and changes in turnover (production); curve "C" - displayed the growth or fall in the price of securities in the money market. In an ideal state of the graph, the indicators "A" and "C" should coincide at the level of the maximum of the first unit and the minimum of the curve of the second unit.

Thanks to the leadership of W. Persons and W. Mitchell, the United States used this kind of device until 1925. The Harvard Mitchell Barometer is the first powerful regulator and indicator of factors in the national economy of the country. Given the popularity and effectiveness of such construction and display of facts, this method has been adopted by many countries around the globe. But the prospect of development of many countries according to this ratio of indicators in the economy did not exist for a long time, because before and after the Second World War - in percentage terms, they became irrelevant. The economies of all the countries that took part in the war were in complete decline, and in order to solve the rise "from their knees", each country applied its own methods to stabilize its own monetary currency. The old methods of raising indicators (getting out of the crisis) were not used at all, but the foundations laid by Mitchell became a precedent for the world economy.

pressure gauge

It is worth noting another device that also measures pressure, but not air, but gases and liquids - this device is called a manometer. These two devices are very interconnected. The sum of the pressure gauge and barometer readings is the absolute pressure, which has a higher indicator than atmospheric pressure.

Conclusion

In the modern world, the barometer is one of the main instruments of meteorology. Marked indicators on paper help many people to learn about upcoming changes in atmospheric pressure, and accordingly, prepare for them. This is especially true for hypertensive patients. A barometer is an optional item in the house, but as an auxiliary element or in addition to the interior, it is desirable. The modern frame of the much-needed device allows it to fit into any interior solution.