Everyone faced daily with the concept of temperature.The term has become firmly established in our everyday lives: we warmed up in a microwave oven, or prepare food in the oven, are interested in the weather on the street or find out whether the cold water in the river - all closely associated with the concept.And what is the temperature, which means that the physical parameter, what it measured?On these and other questions to answer in this article.
physical quantity
Let's look at what the temperature is from the perspective of an isolated system in thermodynamic equilibrium.The term comes from Latin and means "proper mixing", "normal", "proportionality".This value characterizes the state of thermodynamic equilibrium of a macroscopic system.In the case where an isolated system is out of balance, with the passage of time there is a transition energy from a hot objects to less heated.The result is alignment (change) of the temperature throughout the system.This is the first postulate (zero beginning) thermodynamics.
temperature determines the distribution of composite particles of the levels of energy and velocity, the degree of ionization of the substances, the properties of equilibrium electromagnetic radiation of bodies full of bulk density of radiation.As for the system, which is in thermodynamic equilibrium, these parameters are equal, they are called system temperature.
plasma equilibrium
Besides bodies, there are systems in which the state is characterized by several values of the temperature, it is not equal.A good example is a plasma.It consists of electrons (light charged particles) and ions (heavy charged particles).When collisions occur fast energy transfer from electron to electron and ion-ion from.But between heterogeneous elements slow transition takes place.Plasma may be in a state in which the electrons and ions alone close to equilibrium.In this case it is possible to take the temperature of each individual particle form.However, between these parameters will vary.
Magnets
The bodies whose particles have a magnetic moment, the energy transfer is usually slow, from progressive to the magnetic degrees of freedom that are associated with the ability to change direction now.It turns out that there is a condition in which the body is characterized by fever, which does not coincide with the kinetic parameters.It corresponds to the translational motion of elementary particles.Magnetic temperature determines the portion of the internal energy.It can be both positive and negative.The alignment process energy will be transferred from the particles to the large value for particles with a smaller value of the temperature in the case if they are both positive or negative.In this situation, the opposing process will proceed in the opposite direction - a negative temperature is "higher" than positive.
And why is it necessary?
The paradox lies in the fact that the man in the street to hold a measurement process both at home and in industry, you do not even need to know what the temperature is.For it will be sufficient to realize that this degree of heating of the facility or the environment, especially since these terms we are familiar with from childhood.Indeed, much of the practical instruments for measuring this parameter actually measure different properties of substances that change the level of heating or cooling.For example, pressure, electrical resistance, amount t. D. Further indications are manually or automatically translated to the desired value.
turns to determine the temperature, there is no need to study physics.This is the way most people live on our planet.If the TV is working, there is no need to understand the transition processes of semiconductor devices, to study the origin of the electricity in the outlet or goes to a satellite dish signal.People are used to that in every region there are specialists who will be able to repair or debug the system.Babbitt did not want to strain your brain, because where better to watch a soap opera or a football on the "box", while sipping a cold beer.
And I want to know
But there are people, most often it is the students who are either the extent of their curiosity, or are forced by necessity to study physics and to determine what the temperature really is.As a result, in their search they fall into the wilds of thermodynamics and the study it is zero, first and second laws.In addition, the inquiring mind would have to understand the Carnot cycle and entropy.And at the end of its path it certainly recognizes that the determination of temperature as a parameter reversible thermal system that is not dependent on the type of the working substance not add clarity sense of this concept.Still visible part will be taken by the International System of Units (SI) some degrees.
temperature kinetic energy
more "tangible" is the approach, which is called the molecular-kinetic theory.Because it is formed a representation of that heat is regarded as a form of energy.For example, the kinetic energy of molecules and atoms, the parameter averaged over a huge number of randomly moving particles is a measure of what is called body temperature.Thus, the heated particles moving faster than cold.
Since this term is closely related to the average kinetic energy of the particle group, it would be quite natural as the temperature unit to use the joule.Nevertheless, this does not happen, due to the fact that the energy of the thermal motion of elementary particles is very small in relation to the joule.Therefore, its use inconvenient.Thermal motion is measured in units of joules obtained through a special conversion factor.
Temperature Units
To date, three main units used to display this parameter.In our country, it is taken to determine the temperature in degrees Celsius.The basis of this unit is the solidification point of water - absolute value.It is the reference point.That is, the water temperature at which ice begins to form, is zero.In this case, the water serves as an exemplary measure.This default value was adopted for convenience.The second value is the absolute temperature of the steam, that is when the water from the liquid state to the gaseous state.
following units are degrees Kelvin.The origin of this system is considered to be a point of absolute zero.Thus, one degree Kelvin equals one degree Celsius.The difference is only the beginning of reference.We find that the zero Kelvin is equal to minus 273.16 degrees Celsius.In 1954 the General Conference on Weights and Measures decided to replace the term "Kelvin" for the temperature unit to "kelvin".
Third common unit of measurement is degrees Fahrenheit.Until 1960, they were widely used in all English-speaking countries.However, even today in everyday life in the United States use this unit.The system is fundamentally different from those described above.For origin adopted freezing temperature of salt mixture, ammonia and water in the ratio of 1: 1: 1.So, on the Fahrenheit scale the freezing point of water is 32 degrees plus, and boiling - plus 212 degrees.In this system, one degree difference is equal to 1/180 of these temperatures.Thus, the range from 0 to 100 degrees Fahrenheit in the range from -18 to +38 Celsius.
absolute zero temperature
Let's see what this parameter.Absolute zero is called the limiting temperature at which the pressure of an ideal gas becomes zero at a fixed amount.This is the lowest value in nature.As predicted by Mikhail Lomonosov, "is the greatest or the last degree of cold."It follows from this chemical Avogadro's law: equal volumes of gas under the condition of the same temperature and pressure contains the same number of molecules.What follows from this?There is a minimum gas temperature at which the pressure or volume vanish.This value corresponds to the absolute zero Kelvin, or 273 degrees Celsius.
few interesting facts about the solar system
temperature on the sun's surface reaches 5700 degrees Kelvin, and the downtown core - 15 million degrees Kelvin.The planets of the solar system are very different from each other in terms of heating.For example, the core temperature of our Earth is about the same as at the surface of the sun.The hottest planet Jupiter is considered.The temperature at the center of its core to five times higher than the surface of the sun.And here is the lowest value recorded on the surface of the moon - it was only 30 degrees Kelvin.This value is even lower than the surface of Pluto.
Facts about Earth
1. The highest temperature that is recorded person was 4 billion degrees Celsius.This value is 250 times higher than the core temperature of the sun.Record delivered the New York Natural Brookhaven laboratory in the ion collider, the length of which is about 4 kilometers.
2. The temperature on the planet is not always perfect and comfortable.For example, in a city in Yakutia Verhnoyanske temperature in winter drops to minus 45 degrees Celsius.But in the Ethiopian town of Dallol reverse situation.There the average annual temperature of plus 34 degrees.
3. the most extreme conditions in which people work, recorded in the gold mines in South Africa.The miners working at a depth of three kilometers at a temperature of 65 degrees Celsius.
