Heat is essentially the part of the internal energy of an object due to the disordered motion of its molecules.
When two objects come in contact their molecules have a lot of collisions at the contact surface. The faster molecules are slowed by the slow molecules while they are instead accelerated. This process cause the cold body to heat and the hot body to decrease its temperature while heat passes from the hot to the cold body. The process terminates when the temperature of the two bodies is the same and uniform across the bodies volume.
This heat transfer mode is called conduction: it is the prevalent way allowing solid bodies to exchange heat when they are put in contact.
In the case of liquids and gasses, conduction exists, but another phenomenon appears, that does not exist in solids: convection.
This is due to the fact that liquids and gasses tends to mix when they are put in contact and, as far as hot and cold parts are mixed, they exchange heat much more effectively with respect to a contact happening only through a surface.
Moreover, since heating imply the increase of volume in common condition's where the pressure is constant, this also imply decrease of density (the same matter is distributed in a greater volume, thus density decreases).
This also causes hot parts of the mix to go up and cold parts of the mix to go down if gravity exists, causing further motion (called convection motions) that also favour heat exchange.
However we have to take into account that normal convection motion assumes both constant pressure and gravity. In a closed container (constant volume) on the space shuttle (no gravity) the situation can be different.
A third effect exists causing heat exchange between bodies at different temperature, that is not so efficient as convection and conduction, but is the only viable way in the case of object that are not in contact, like sun and earth.
Every body at a temperature different from the absolute zero emits electromagnetic radiation at a frequency higher and higher while the temperature is higher and higher. Bodies at room temperature emits in the infrared while the sun in the visible bandwidth (essentially in the yellow bandwidth) and so on.
If we have two bodies the hotter emits at higher frequency so that, in the radiation exchange between the bodies, it transfers more energy to the colder with respect to the energy that it receives.
As a matter of fact, the number of emitted photons for unit mass is the same and the energy of the single photon is proportional to the frequency (rigorously it is true for the same number of microscopic degrees of freedom, but unit mass is explicative). Thus higher the frequency, the higher energy. This means for example that photons from sun to earth (in the visible bandwidth) are much more energetic than photons from earth to the sun (that are in the infrared bandwidth).
Thus the net balance imply transfer of heat from the hot to the cold body, due to the electromagnetic emission.
The heat transfer stops also in this case when the temperature of the two bodies becomes the same. The equilibrium temperature depends on how much heat the bodies can accumulate for each degree of temperature, that is by their mass and by their heat accumulation capability (called heat capacity).
In the sun - earth example, if the system would be insulated, (no other heat dissipation possibility would exist beside the heat exchange between sun and earth) the earth would arrive at equilibrium to a temperature very near to the sun temperature, since the sun is much bigger than earth.
In reality this does not happen since the system is not insulated and the earth dissipates towards the open space (much colder than earth) the heat received by the sun. Thus a dynamic equilibrium is reached where the earth is at an equilibrium temperature and the heat received by the sun counterbalance exactly the heath dissipated towards the outer space.
The term for when thermal energy is transferred between two objects is called heat transfer.
When two objects are in contact, heat is best transferred by conduction, which occurs through direct contact between the molecules of the two objects. Heat is transferred as the molecules vibrate and collide with each other, increasing the energy transfer between the objects.
the objects must be in physical contact with each other, and there must be a temperature difference between them. Heat will flow from the object with a higher temperature to the one with a lower temperature until thermal equilibrium is reached.
Energy is transferred as heat between two objects at the same temperature due to thermal equilibrium. In this state, there is no temperature difference driving heat flow, so heat transfer still occurs to maintain equilibrium between the two objects.
Heat flows between two objects through a process called thermal conduction, where heat is transferred from the object at a higher temperature to the object at a lower temperature. This transfer occurs due to the temperature difference between the two objects and the physical contact between them. Heat can also be transferred between objects through radiation or convection, depending on the specific circumstances.
Radiation
The term for when thermal energy is transferred between two objects is called heat transfer.
When two objects are in contact, heat is best transferred by conduction, which occurs through direct contact between the molecules of the two objects. Heat is transferred as the molecules vibrate and collide with each other, increasing the energy transfer between the objects.
the objects must be in physical contact with each other, and there must be a temperature difference between them. Heat will flow from the object with a higher temperature to the one with a lower temperature until thermal equilibrium is reached.
Energy is transferred as heat between two objects at the same temperature due to thermal equilibrium. In this state, there is no temperature difference driving heat flow, so heat transfer still occurs to maintain equilibrium between the two objects.
i think by radiation........
Heat flows between two objects through a process called thermal conduction, where heat is transferred from the object at a higher temperature to the object at a lower temperature. This transfer occurs due to the temperature difference between the two objects and the physical contact between them. Heat can also be transferred between objects through radiation or convection, depending on the specific circumstances.
No, two objects do not have to be touching to transfer heat through conduction. Heat can also be transferred through conduction between objects that are in close proximity to each other.
When objects touch each other, heat is transferred through a process called conduction. In this process, heat energy moves from the hotter object to the cooler one as the particles of the two objects collide and transfer energy between them. The rate of heat transfer depends on the thermal conductivity of the materials and the temperature difference between the objects.
Conduction. Heat is transferred from one object to another through direct contact.
If two objects of different temperature are brought into contact, internal energy is transferred via heat. If two objects collide, kinetic energy is transferred between them.
Heat transfer between two objects occurs through three main processes: conduction, convection, and radiation. In conduction, heat is transferred through direct contact between the objects. Convection involves the transfer of heat through the movement of fluids, such as air or water. Radiation is the transfer of heat through electromagnetic waves. When heat is transferred between two objects, it causes their temperatures to change. The object with a higher temperature will transfer heat to the object with a lower temperature until they reach thermal equilibrium, where their temperatures are equal. This process continues until both objects reach the same temperature.