Accuracy of measurement, methods, tools and equipment

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The accuracy of measuring quantities is the ability to order the existence of a person and his habitat. It would be impossible to imagine a life in which all the usual and approved concepts of time, length or mass were absent. However, in addition to the fact that they need to be able to distinguish, it is equally important to learn how to determine and calculate distances and lengths, weight, speed of movement of objects, and the course of time intervals. Over a thousand-year history of existence, mankind has acquired many invaluable knowledge and has managed to systematize them into separate sciences.

Concepts and notation - basics of metrology

Metrology is a teaching that helps to understand the measurement of different quantities. It provides an opportunity to understand what measure, unity and standardization of quantities are, determines such concepts as accuracy of measurement, error, acquaints with various measuring instruments and instruments.

The measurement process is associated with the determination of data relating to a particular value through experiments, as well as the subsequent correlation of the obtained values with generally accepted standards and units. Thus, we can assume that the accuracy of the measurement directly depends on how close the data obtained as a result of the experiments to the true values of the quantity, which in principle are not subject to challenge and are an axiom.

Absolute inaccuracy

Scientists say that it is almost impossible to measure anything absolutely correctly. The fact is that there are too many factors affecting the process of determining the value independent of human actions. In this regard, metrology allows for the existence of errors that are inaccuracies obtained in the measurement process, as well as an indicator that shows deviations from the generally accepted truth and norm.

The error can be systematic or random. To exclude during the experiment the first is practically impossible, because it 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 in analytical activity.

Reduce the likelihood of error can also be by using more advanced methods and tools, minimizing the impact of external influences during the experimental determination of quantities. An elementary example of reducing errors is the use of clocks, if you measure time not in hours and minutes, but in fractions of a second, which allows you to make electronic stopwatches.

Seven times measure ...

The need to obtain absolutely accurate knowledge of the quantities is due to the high technological sophistication of the modern world. If the first sample of furniture was a roughly knotted toilet seat, the details of which were carved into an eye, then the current technologies help to create elements of the same stools with an error of up to a millimeter. Perhaps in the everyday life of a person such microscopic meanings are absolutely unimportant, but when the accuracy of measurement concerns science, medicine, production - it becomes a decisive factor for the success of the enterprise.

If you look closely, the simplest measuring instruments are in every person in the house. Elementary examples of such - roulette construction, ruler, kitchen or floor scales, bezmen, electricity, water, gas meters, different timers and watches, thermometers and thermometers. Using the example of the latter, you can once again demonstrate the methods and accuracy of the measurement. So, a typical alcoholic thermometer installed in the room to determine the air temperature in the room has a scale of ten degrees, while a mercury thermometer designed to measure the temperature of the human body is broken down into a tenth of a degree, which helps reduce the probability of error during Collection of anamnesis of the patient.

What is the length and how to measure it?

One of the most recognizable and definite quantities is the length. Probably, initially the person measured the distance with the help of steps, now the unit of distance measurement is normalized. The world standard is a metric system, where the largest value is measured in kilometers, conditionally divided by 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, it is necessary to choose a specific segment that will have a beginning and an end (points A and B), so the length is the value of the largest distance in the plane between these points. To measure the length, many instruments have been created from elementary ones, such as a centimeter and a ruler, to high-precision instrumentation with a minimum error.

Household appliances for measuring length

Long distances to an average person is unlikely to be measured, each of us approximately knows the extent of their routes, you can specify such data with the help of an automobile speedometer, a sports and tourist pedometer, or even using a smartphone, by uploading a special program into it.

At home, the instruments for measuring length are more often used for construction and repair. Roulette construction - this is what there is in the pantry of any man. It is a metal tape with a scale on one or both sides from 0 to 3, 5, 7.5, 30 meters with an additional centimeter and millimeter division. An alternative to a simple roulette can be a laser rangefinder, with which you can calculate distances of up to 250 m, in addition, you can simply measure the length even by yourself. There are also models that display the area and volume of the room on the display.

Calipers

Measurement with a caliper will give the most accurate result. This is an instrument that is used in industry and provides an opportunity to learn the linear value of parts with a size of 0.1 mm to 15 cm with a minimum error. To determine whether the scale is close to the true value, you can use such comparative methods - comparison with an already proven tool or with a finished part of a suitable size.

There are several types of this device, the principle of their action is similar, they differ in the length of the millimeter scale and the mechanism by which the measurement is actually made. The vernier calipers are the hardest to work with, but this option makes it possible to minimize systematic errors. In a device with a dial or a digital screen, measurements are made electronically and if the instrument is of a proper quality, then its results are obtained with a high degree of probability.

Complex technologies

Even more complex computing equipment is the instrumentation used in industrial plants and organizations that install power lines, lay television, telephone and Internet cables. This technique handles several functions at once. The main task is to measure the length of the cable, but in the meanwhile the device can detect errors in the work of the wire, denoting the place of power failure, which greatly minimizes the means and time required to perform repair work.

There are different classes of measuring instruments. The most elementary ones are manual installations with cable length meters, more complex variants are able to calculate not only the length of the wires, but also measure wide rolls with fabrics, paper, different kinds of cords. In addition, that their use is advisable on production lines, the introduction of such equipment in warehouses and large outlets is spreading.

How to grasp the vast

Measuring time is also a difficult and important task. In life situations, few people pay attention to the fact that a private clock can rush or fall behind for a few minutes from the generally accepted standard. However, public organizations and enterprises can not afford this freedom, and therefore compare time with indicators in state institutions, which, in turn, are guided by data obtained with the help of satellites.

It is worth noting that such a concept, as the exact time, is rather arbitrary. Time zones on which the planet is divided are objective in nature and have a direct dependence on state borders, and sometimes on the political will of the governments of different countries.