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The accuracy of measuring values is the ability to streamline the existence of a person and his environment. It would be impossible to imagine a life in which there would be no familiar and approved concepts of time, length or mass for all of us. However, in addition to being able to distinguish them, it is equally important to learn how to determine and calculate distances and segments, weight, speed of movement of objects, the course of time intervals. Over the thousand-year history of existence, humanity has acquired a lot of invaluable knowledge and managed to systematize them into separate sciences.
Concepts and notation - the basics of metrology
Metrology is a teaching that helps to understand the measurement of different quantities. It makes it possible to understand what a measure is, the unity and standardization of quantities, defines such concepts as measurement accuracy, error, introduces a variety of measuring instruments and tools.
Processmeasurement is associated with the determination of data regarding a particular quantity through experiments, as well as the subsequent correlation of the obtained values \u200b\u200bwith generally accepted standards and units. Thus, we can assume that the measurement accuracy directly depends on how close the data obtained as a result of experiments are to the true values of the quantity, which in principle are not subject to dispute and are an axiom.
Totally inaccurate
Scientists say that it is almost impossible to measure anything absolutely correctly. The fact is that there are too many factors that affect the process of determining the value, independent of human actions. In this regard, metrology admits the possibility of the existence of errors, which are inaccuracies obtained in the measurement process, as well as a certain indicator that shows deviations from the generally accepted truth and norm.
Error can be systematic or random. It is practically impossible to exclude the first during the experiment, because this is such a factor that will distort the result every time, but a random error can be the result of a gross error or inaccuracy of analytical activity.
The probability of error can also be reduced by using more advanced methods and tools, minimizing the influence of external influences during the experimental determination of values. An elementary example of reducing errors can be considered the use of clocks, if time is measured not in hours and minutes, but in fractions of a second, which allowsmake electronic stopwatches.
Measure seven times…
The need to obtain absolutely accurate knowledge of quantities is due to the high manufacturability of the modern world. If the first piece of furniture was a roughly knocked together toilet seat, the details of which were cut out by eye, then current technologies help to create elements of the same stools with an error of up to a millimeter. Perhaps, in everyday life of a person, such microscopic values are absolutely unimportant, but when the accuracy of measurement concerns science, medicine, production, it becomes a decisive factor in the success of an enterprise.
If you look closely, then every person in the house has the simplest measuring instruments. Elementary examples of these are a construction tape measure, a ruler, kitchen or floor scales, a steelyard, electricity, water, gas meters, various timers and clocks, thermometers and thermometers. Using the latter as an example, one can once again demonstrate the methods and accuracy of measurement. So, a conventional alcohol thermometer, installed indoors to determine the air temperature in the room, has a ten-degree scale, while a mercury thermometer, designed to measure human body temperature, is divided into a tenth of a degree, which helps to reduce the likelihood of error during taking a patient history.
What is the length and how to measure it?
One of the most recognizable and certain quantities is the length. Probably, initially a person measured the distance with the help ofsteps, now the distance units are normalized. The world standard is a metric system, where the largest value is measured in kilometers, conventionally divided into meters, centimeters and millimeters. There are also intermediate values (decimeters, micrometers), but they are often used only in highly specialized areas.
In order to determine the length, you need to select a specific segment that will have a beginning and end (points A and B), and so the length is the value of the largest distance on the plane between these points. To measure length, many tools have been created from elementary ones, such as a centimeter and a ruler, to control and measuring equipment of a high degree of accuracy with a minimum error.
Household length measuring instruments
It is unlikely that an ordinary person will need to measure long distances, each of us approximately knows the length of our routes, you can clarify such data using a car speedometer, a sports and tourist pedometer, or even using a smartphone by downloading a special program into it.
At home, length measuring devices are more often used for construction and repair. A construction tape measure is something that any man has in his pantry. It is a metal tape with a scale from 0 to 3, 5, 7, 5, 30 meters applied to one or both of its sides with additional centimeter and millimeter divisions. An alternative to a simple tape measure can be a laser rangefinder, usingwhich you can calculate distances up to 250 m, in addition, measuring the length of it is easy to do even alone. There are also models that display the area and volume of the room.
Calipers
Measurement with a caliper will give the most accurate result. This is a device that is used in industry and provides an opportunity to find out the linear value of parts ranging in size from 0.1 mm to 15 cm with a minimum error. To find out how close the scale is to the true value, you can use such comparative methods - comparison with an already tested tool or with a finished part of a suitable size.
There are several types of this device, the principle of operation is similar, they differ in the length of the millimeter scale and the mechanism by which the actual measurement is made. Vernier calipers are the most difficult to work with, but this option makes it possible to minimize systematic errors. In a device with a dial or digital screen, measurements are made using electronics and if the instrument is of good quality, then its results are reliable with a high degree of probability.
Complex technologies
Even more sophisticated computing equipment is instrumentation used in industrial enterprises and in organizations involved in the installation of power lines, laying television, telephone and Internet cables. This technique works right away.with multiple features. The main task is to measure the length of the cable, however, along the way, the device can detect errors in the operation of the wire, indicating the place of a power outage, which significantly minimizes the funds and time required to perform repairs.
There are different classes of measuring instruments. The most elementary are manual installations with cable length meters, more complex options are able to calculate not only the length of wires, but also measure wide rolls with fabrics, paper, and various types of cords. In addition to the fact that their use is advisable on production lines, the introduction of such equipment in warehouses and large retail outlets is spreading.
How to embrace the immensity
Measuring time is also a difficult and important task. In life situations, few people pay attention to the fact that a personal watch can rush or lag several minutes behind the generally accepted standard. However, public organizations and enterprises cannot afford such liberties, and therefore compare the time with indicators in state institutions, which, in turn, are guided by data obtained using satellites.
It is worth noting that such a concept as exact time is rather arbitrary. The time zones into which the planet is divided are of an objective nature and are directly dependent on state borders, and sometimes on the political will of the governments of different countries.
