How does heat flow from a warm object to a cooler one?

Answer 1

Heat flows (moves) from object to object in any of three ways: conduction, convection, or radiation. Generally, heat will flow from the warmer object to the cooler object until both are the same temperature. This is called thermal equilibrium. Heat is still exchanged on a molecular basis, but there is no net change.

Conduction occurs when two objects are in contact: the molecules of one transfer energy, in the form of collisions, to the molecules of another.

Convection occurs within a fluid, or can use a fluid in its transfer. An object can lose heat to a fluid (e.g. air or water) which then may circulate and could pass that energy on to another object.

Radiation is the loss of heat by all heated objects, as electromagnetic waves (e.g. infrared radiation) carry heat away from it. An object in the path of this radiation may absorb this energy, and will in turn radiate some as well.

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The first law of thermodynamics states that energy can neither be created nor destroyed. If we have heat, then there was an energy source to make that heat.

In an electric iron we have a plate which heats allowing us to press our clothes. This heat is generated by passing an electric current through a resistive material. The resistance posed by the material causes the electrically charged molecules to collide more frequently causing the molecules to become excited. Once excited they continue to vibrate which increases friction between them and causes the Iron to heat up. If we then take the iron and press our clothes we are using its heat to loosen the molecular and mechanical bonds within the creases of our clothes. By doing this we are passing on some of that energy to the material being pressed whilst the remainder is lost to the environment.

If we have an area in a room at high temperature and an area at low temperature, the heat will not flow between them but the energy will transfer from hot to cold. This works on the same principle where the hot or excited air molecules collide with the cold or unexcited molecules and pass on some of that energy until the air is all at the same level of excitement. Bear in mind we have not lost any of the heat energy, merely redistributed it.

Heat is transfered by conduction, convection or radiation. At no time could you consider heat to flow.

If the heat is moving from a solid object to a solid object it is conducting, if it is moving from solid to liquid it is convecting and if it is moving from a solid or liquid into an empty space or a gas it is radiating.

In engineering and physics we sometimes talk of "heat flow" as a way of understanding the way in which heat travels through a system but it is essential to understand that heat flows in the same way as electricity and not in the way a liquid such as water does.

Answer 2

In order to have heat energy flow to the next object, the first object needs to be warmer. The energy flows until the two objects are they're same temperature [ temperature can vary; time can vary ].

Answer 3

Heat flows from a warm object to a cooler one through a process called conduction. This process involves the transfer of kinetic energy between particles in contact with each other. The heat energy is transferred from the faster-moving particles of the warmer object to the slower-moving particles of the cooler object until both reach thermal equilibrium.

Answer 4

All things, including heat follow this trend:

From a High concentration To a Low concentration.

With Heat, it would go from a hot object to a colder object.

Answer 5

because the warm one has already high pressure and it wants to attract low pressure so it turns into a cooler one; ones it atracts low pressure.