source of energy for the Earth - Sun.Solar energy is the basis of many of the phenomena occurring at the surface and in the atmosphere of the planet.Heating, cooling, evaporation, boiling, condensation - some examples of which thermal phenomena occurring around us.
no process in itself does not occur.Each of them has its source and mechanism of implementation.Any thermal phenomena in nature due to obtain heat from external sources.Such a source can be not only the sun - fire also successfully cope with this role.
For a further understanding of what constitutes thermal phenomena, it is necessary to define the heat.The heat - energy transfer characteristics, in other words, how much energy pays (receives) the body or the system during the interaction.Quantitatively, it can be characterized by temperature: the higher it is, the more heat (energy) has given body.
In the process of interaction of bodies with each other there is a transfer of heat from hot to cold body, t. E. The body with higher energy to the body with less energy.This process is known as thermal transfer.As an example, consider the boiling water poured into the beaker.After some time, the glass becomes hot, ie. E. There was a process of heat transfer from hot water to cold glass.
However, thermal phenomena characterized not only by heat transfer, but also a term such as thermal conductivity.What it means, it can be explained by an example.If you put the pan on the fire, its handle, though not in contact with fire, it heats up in the same way as the rest of the pan.This heating is provided by heat conduction.Heating is provided in one place, and then heats the whole body.Or not heated - it depends on whether it has a thermal conductivity.If the thermal conductivity of the body is high, the heat is easily transmitted from one section to another, if the thermal conductivity is low, the heat transfer does not occur.
Before the advent of the concept heat physicist thermal phenomena explained using the concept of "caloric".I believe that every substance has a certain substance similar to liquid perform tasks that in the modern representation solves the heat.But the idea of caloric declined after formulated the concept of heat.
can now consider in more detail the practical application of previously entered definitions.Thus, the thermal conductivity allows heat transfer between the bodies and the material inside.The high thermal conductivity characteristic of metals.For dishes, pot is good, t. To. Allows heat to preparing foods.However, materials with low thermal conductivity also finds its application.They act as a heat insulator, preventing heat loss - for example, during the construction.Through the use of materials with low thermal conductivity are provided with comfortable living conditions in the houses.
However, the above methods are not limited to heat transfer.There is also the ability to transfer heat without direct contact tel.As an example - flows of warm air from the heater or radiator heating system in the apartment.On the subject of heated (heater, radiator) comes a stream of warm air, carrying out heating of the room.Such a method of heat exchange is called convection.In this case the heat transfer is carried out the fluid flow.
If we remember that the thermal phenomena occurring in the world, linked to the radiation of the sun, then there is another way to heat - thermal radiation.It is caused by electromagnetic radiation of a heated body.This is how the sun heats the Earth.
In the material considered various thermal phenomena described by the source of their origin and the mechanisms by which they occur.The problems of practical use of thermal phenomena in everyday practice.
