Since time immemorial, people have been analyzing whether it’s cold or warm, came up with means to warm themselves and their homes, improved their clothes, learned to make fire, and so on. However, only recently (on the scale of world history) did the degree of cold or heat begin to be measured and evaluated. A special term was invented - "temperature". The degree of heating of bodies began to be characterized precisely through this definition. What is the physical meaning of temperature? What is temperature at all? How to determine it, how - these and other issues will be discussed below.
What does the term "temperature" mean?
Before discussing the physical meaning of temperature, it is necessary to find out what it is. So, many have long known that you can get a burn by touching a hot object, or, conversely, frozen (for example, in the case of freezing with liquid nitrogen). And it’s not a secret to anyone that the pipes during the heating season are hotter than during the summer period (shutting down radiators). It is such an indicator as the degree of heating of an object expresses temperature. In thermodynamics, not only the physical meaning of temperature is considered, but also its more accurate definition, the measurement method.
Thermodynamics
What is "thermodynamics"? The answer is both simple and complex. This is one of the branches of science like physics. It (this section) is devoted to the study of the properties of the (most common) macro systems and methods of converting and transferring energy into them. Macrosystems are systems that, firstly, consist of a very large number of atoms and molecules, in other words, microparticles. Secondly, they are commensurate with the surrounding objects in size.
The physical meaning of temperature is in a simple sentence: temperature is a measure of the average kinetic energy. This statement follows from the basic equation of the molecular-kinetic theory of ideal gases. True, pressure is involved in this equation, but simple manipulations allow you to express pressure through temperature:
- p = nkT = 1 / 3nmv 2 ;
- (E) = (mv 2 ) / 2 = 2 / 3kT.
This equation expresses the physical meaning of temperature.
The absolute temperature. What it is?
The thermodynamic temperature is sometimes called absolute, since it is measured from absolute zero, which today (and hardly ever) is impossible to achieve. Absolute zero is the minimum possible temperature not only on Earth, but also in the whole Universe. The absolute temperature units are Kelvin.
In order to translate the usual degrees of Celsius to degrees Kelvin, all that is needed is to add 273. The physical meaning of the absolute temperature is no different from the previous description. It can even be said that the definition above is intended for absolute temperature - in this formula T is measured in degrees Kelvin.
Measurement
Not at all any physical quantity can be directly measured. Temperature, for example, refers to parameters of a thermodynamic system such as those that cannot be measured directly. They are received indirectly. For measurement, a working thermometer is required (in common people it is often called a thermometer), alcohol or mercury - it does not matter. Then it is necessary to ensure the contact of the thermometer with the analyzed object (air often acts in this capacity).
After establishing equilibrium in the system "object-thermometer", you can record the readings of the thermometer. It should be noted that not only liquid, but also other types of thermometers exist today. Of course, what can be indirect in the direct interaction of the thermometer with the analyzed sample. However, it must be remembered that the scales of thermometers are very relative.