Without measuring tools and methods of their application, scientific and technological progress would have been impossible. In the modern world, people cannot do without them even in everyday life. Therefore, such an extensive layer of knowledge could not be systematized and formed as a full-fledged scientific field. Just for definition of this direction the concept of "metrology" is used. What are measuring instruments in terms of scientific knowledge? It can be said that this is the subject of research, but the activities of specialists in this field necessarily have a practical character.
Metrology concept
In general, metrology is often considered as a set of scientific knowledge about the means, methods and methods of measurement, which also includes the concept of their unity. To regulate the practical application of this knowledge, there is a federal metrology agency that technically manages property in the field of metrology.
As you can see, the central place in the concept of metrology is measurement. In this context, measurement means obtaining information about the subject of study - in particular, information about properties and characteristics. A prerequisite is precisely the experimental way of obtaining this knowledge using metrological tools. It should also be borne in mind that metrology, standardization and certification are closely interconnected and only in combination can provide practically valuable information. So, if metrology deals with the development of measurement methods, then standardization establishes uniform forms and rules for applying the same methods, as well as for registering the characteristics of objects in accordance with specified standards. As for certification, it aims to determine the conformity of the studied object to one or another of the parameters laid down by the standards.
Goals and objectives of metrology
Metrology has several important tasks that are in three areas - theoretical, legislative and practical. With the development of scientific knowledge, goals from different directions are mutually supplemented and adjusted, but in general, the tasks of metrology can be represented as follows:
- Formation of systems of units and measurement characteristics.
- Development of a general theoretical knowledge of measurements.
- Standardization of measurement methods.
- Approval of measurement standards standards, calibration measures and technical means.
- The study of a system of measures in the context of a historical perspective.
Unity of Measurement
The basic level of standardization is the unity of measurements. This means that the results of measurements taken are reflected in the approved format. That is, the characteristic of the measurement is expressed in the accepted form. Moreover, this applies not only to certain measurement values, but also to errors, which can be expressed taking into account the probabilities. Metrological unity exists for the possibility of comparing results that were carried out under different conditions. Moreover, in each case, the methods and means should remain the same.
If we consider the basic concepts of metrology in terms of the quality of obtaining results, then accuracy will be the main one. In a sense, it is interconnected with an error that distorts the readings. It is precisely in order to increase accuracy that serial measurements are used under various conditions, thanks to which a more complete picture of the subject of study can be made. A significant role in improving the quality of measurements is also played by preventive measures aimed at checking technical means, testing new methods, analyzing standards, etc.
Principles and methods of metrology
To achieve high quality of measurements, metrology is based on several basic principles, including the following:
- The Peltier principle, focused on the determination of absorbed energy during the flow of ionizing radiation.
- The Josephson principle, on the basis of which voltage measurements in an electrical circuit are made.
- The Doppler principle, which provides speed measurement.
- The principle of gravity.
For these and other principles, a broad base of methods has been developed with which practical research is carried out. It is important to consider that metrology is the science of measurements that are supported by applied tools. But technical means, on the other hand, are based on specific theoretical principles and methods. Among the most common methods, one can single out a direct assessment technique, measuring weight on a scale, substitution, comparison, etc.
Measuring instruments
One of the most important concepts of metrology is a means of measurement. Typically, this is a technical device that reproduces or stores a certain physical quantity. In the process of application, it examines the object, comparing the identified parameter with the reference. Measuring instruments is an extensive group of instruments with many classifications. By design and operating principle, for example, transducers, devices, sensors, devices and mechanisms are distinguished.
The measuring installation is a relatively modern type of device used by metrology. What is this installation in practice use? Unlike the simplest tools, the installation is a machine in which a whole range of functional components is provided. Each of them may be responsible for one or more measures. An example is laser goniometers. They are used by builders to determine a wide range of geometric parameters, as well as to calculate by formulas.
What is an error?
The error also takes a considerable place in the measurement process. In theory, it is considered as one of the basic concepts of metrology, in this case, reflecting the deviation of the obtained value from the true one. This deviation may be random or systematic. In the development of measuring instruments, manufacturers usually put a certain amount of error in the list of characteristics. It is thanks to fixing the possible limits of deviations in the results that we can talk about the reliability of measurements.
But not only the error determines the possible deviations. Uncertainty is another characteristic that guides metrology in this regard. What is measurement uncertainty? In contrast to the error, it practically does not operate with exact or relatively accurate values. It indicates only doubt in one or another result, but, again, does not determine the intervals of deviations with which such an attitude to the obtained value could be caused.
Types of metrology by scope
Metrology in one form or another is involved in almost all areas of human activity. In construction, the same measuring devices are used to fix deviations of structures along planes, in medicine, diagnostic tools based on the most accurate equipment are used, in engineering, specialists also use devices that allow to determine characteristics with the smallest details. Large-scale specialized projects are carried out by the Agency for Technical Regulation and Metrology, which together with this contains a bank of standards, establishes regulations, catalogs, etc. This body, to varying degrees, covers all areas of metrological research, extending the approved standards to them.
Conclusion
In metrology, there are previously established and non-changing standards, principles and measurement methods. But there are also a number of its directions, which cannot remain unchanged. Accuracy is one of the key metrology features. What is accuracy in the context of a measurement procedure? This is a quantity that is more dependent on the technical means of measurement. And just in this area, metrology is developing dynamically, leaving behind obsolete, ineffective tools. But this is only one of the most striking examples in which this sphere is regularly updated.