We all know that the bodies around us are hot or cold. A glass in which boiling water is poured is hot, but the same glass when it is empty is cold. We feel cold or warm with our hands when we touch the glass. And what exactly do we feel? To understand this, scientists introduced the concept of temperature.
Initially, when the molecular-kinetic theory was not yet created, scientists believed that a special substance, the calorific, is responsible for temperature. It is he, or rather, its quantity, that determines whether the body will be hot or cold. This is similar to an assessment of how “strong” the mixture of substance and calorific turned out. Based on this analogy, the strength of alcoholic beverages and temperature are measured in the same units - degrees.
Now temperature is considered a measure of the kinetic energy of molecules and serves, in particular, as a measure of the degree of heating of bodies. Scientists use energy units to evaluate it: in the SI unit system, it will be a joule. But they began to measure temperature long before the advent of energy theory. As already mentioned, in everyday activities a special unit of measurement is used - the degree.
Several different approaches to measuring temperature are practiced . Each of them has its own temperature scale to establish a unit of degree. They are named after the scientists who proposed a method of determination - the Fahrenheit, Reaumur, Celsius scale. The principle is that they take a certain range of temperatures and divide it by a certain number. So, according to the Celsius system, 0 degrees is equal to the freezing temperature of water, and 100 degrees to its boiling point. This range is divided by 100 and get a value of 1 degree.
Each system uses its own reference points to set the value to one degree, while the same body in each of them will have its own temperature. True, its value can be transferred from one scale to another. But scientists introduced a new concept - absolute temperature. It is again connected with the understanding of temperature as a measure of the energy of the thermal motion of molecules.
From this approach it follows that the absolute temperature is that which is measured from absolute zero, which is the temperature value at which thermal movement is completely absent, and the internal energy of the body is minimal. This method of assessing it is carried out on the so-called Kelvin scale, for which the temperature is taken to be zero, equal to minus 273.15 degrees Celsius.
Thus, the absolute temperature in everyday understanding is no different from the usual one - it just has a different starting point. Of course, no one will say that the street is plus 296.15 degrees Kelvin, when there is plus 23 degrees Celsius, although both figures will be fair. Kelvin temperature has a completely different application, not related to everyday situations.
It turns out that the absolute temperature or the temperature on the Kelvin scale is a tool that is used mainly by scientists. Apply it when considering a variety of theoretical and practical issues related to the study of properties, capabilities and phenomena occurring in the world. Ordinary people who are not related to science should be more interested in the possibility of practical use of such a thing as absolute temperature.
The introduction of the definition of absolute zero leads to many interesting phenomena. For example, when trying to achieve it, a phenomenon such as superconductivity arises. Theoretically, if the electric current conductor is cooled to zero degrees Kelvin (0 ° K), the thermal motion in the volume of the substance will stop, the electrical resistance of the conductor will tend to zero, and the current loss will be minimal. However, it is believed that in practice the absolute zero temperature is unattainable, although in laboratory conditions it was possible to get as close to this value as possible.
No less interesting is the phenomenon of superfluidity. If the absolute temperature of the gas begins to decrease, then at some of its values, for each gas of its own, there is a transition of gas into liquid. When helium turns into a liquid, it acquires the ability to penetrate through the smallest capillaries. For use in everyday life, such phenomena have not yet been applied, but they make it possible to understand many questions of quantum mechanics and fundamental science.
Such a thing as absolute temperature is used in theoretical studies and practical experiments to study the world around us. Besides him, the article considers the very concept of temperature from the point of view of molecular kinetic theory.