Barometer, what is it? This is a device for measuring atmospheric pressure fluctuations. The aboveground layer of our planet has a thickness of tens of kilometers. The concentration of mixed gases in it is small in mass, but in such significant volumes it exerts a significant load on the surface. In fact, a person seldom feels it, as it has adaptability to the influence of this factor. Nevertheless, this value is quite realistic to measure.
The principle of operation of the simplest devices
The simplest instrument for measuring atmospheric pressure (BP) is a simple device consisting of a thin-walled glass tube and a mercury filler. One of the standard sizes of such a device: a tube 1 mm thick and a hundred centimeters long.
If you turn the container with the closed end up and the open part down, a certain amount of mercury will be removed, and a certain part will remain inside. The liquid metal content will decrease until the internal and external pressure stabilizes.
Aneroid and mercury device
Aneroid barometer, what is it? In principle, the operation of this device takes into account vibrations through a round metal body with wavy walls, from which air is pumped.
The elastic sidewalls of the duct bend with increasing pressure, and with a decrease, they bulge. By a special mechanism, the working chambers are connected with the arrow. It shows the value of atmospheric pressure on a scale graduated in millimeters of mercury.
The atmospheric pressure measuring device is a U-shaped curved glass flask with a mercury filler. Indications are determined by the difference in contents in the enlarged and small sections of the flask.
Using barographs, blood pressure variations are recorded on a tape located in the current drum-type unit. Measured values are recorded in millimeters (mmHg) or millibars (mbar).
Barograph
The following is a barograph. To the question - the barometer, what is it in this configuration, one can answer - this is a recorder for constant fixation of atmospheric pressure. Its action is based on fluctuations in blood pressure. As a result, the deformation is transmitted by the system to the device. When the readings increase, the boxes are compressed, the lever with the pen goes up, and if the pressure of the chamber decreases, the control springs become wider and the recorder draws the bottom line. The fixed pressure readings are subtracted on a special graduated paper tape, which is placed on a rotating drum.
To eliminate temperature fluctuations that affect the accuracy of the readings, bimetal capacitors are mounted in the device. Devices are installed far from heating appliances and must be protected from direct exposure to sunlight. The clockwork mechanism is designed for a day or a weekly mode.
Features of use
The barometer readings are recorded taking into account changes in climatic conditions in different regions, since air pressure is an unstable value, as we know from school natural history lessons.
In good, warm and calm weather, the wall or table barometer shows high values. Accordingly, with a decrease in data, cooling or precipitation is expected in the near future.
The device located inside the house works exactly the same as in a space not limited by fences, walls and fences. The building height slightly alters the readings of the device, since the pressure will be lower on the 9th floor and higher than at lower levels of the same building.
Height adjuster
The higher the rise, the lower the pressure of the atmospheric column. The revealed pattern is used in aircraft instruments that determine flight altitude. Such devices are called altimeters.
Of course, the results of the first, not quite perfect instruments, significantly varied from weather factors, because negative weather conditions were accompanied by a drop in pressure, respectively, the readings of the device highlighted data that was objectively more than the real mark. Correcting outgoing parameters is required to take the correct readings. The principle of operation of modern altimeters is different - they do not use atmospheric pressure to measure altitude.
How to use?
A watch with a barometer and other types of devices is a pointer device with a round or oval scale, on which there are divisions. The measurement value is taken in millimeters of mercury.
With values of 750-760 mm RT. Art. in the future a wonderful fine day is expected, which will not interfere with a walk, a trip to nature, a summer house. If the barometer indicator falls below 750, there is a possibility of a further fall, which means that one should expect inclement weather, sudden cooling and heavy rainfall.
Tracking blood pressure is vital for those who suffer from high blood pressure. During periods of critical change in this indicator, such people are prone to poor health. Information on weather changes is significant for them because of the timely taking of the medicine, preservation of their working capacity and health.
Modern instances
Now most often cup-type barometers or siphon types are used. In stationary devices that are equipped with a compensated scale, atmospheric pressure is calculated directly from the position of the mercury in the glass container.
In specimens for expeditions, before starting observations, the level of mercury in the bowl is preliminarily adjusted to the zero level using the adjusting screw. In siphon-cup devices, the BP value is measured by the difference in column heights in a long and open area. Such a device reads readings with an accuracy of five hundredths. To determine the tenths of a column, a movable metal template is used.
The numerical results of atmospheric pressure obtained are given according to a special table to zero degrees Celsius. Temperature adjustments can be very significant. Regardless of the types of barometers, they are installed away from heat sources (stoves, heaters, direct sunlight), and also away from door and window openings.
Features
The device in question can be used in a convenient and compact design. For example, a watch with a barometer has the following functionality:
- Impermeability to water, up to 50-100 meters.
- Resistance to shock and mechanical stress, which is important for fishermen, hunters and lovers of extreme relaxation.
- The barometer allows you to predict changes in atmospheric pressure and the weather in general.
- In addition, the watch can be equipped with a thermometer, a backlight, a compass and even a navigator, which greatly facilitates a stay in an unfamiliar area.
To the question "Barometer, what is it?" one can definitely answer - the device is especially important for travelers, fishermen, hunters and sailors. In addition, this thing in household use allows you to fairly accurately predict weather fluctuations, which is important for people with diseases of the cardiovascular and nervous system.