What is the transfer of thermal energy by the collisions between particles of matter?

Answer 1

In loose terms, increased energy associated with increased temperature is heat, or thermal, energy. We say heat flow from hot to cold and that is true. The simple and common mechanism for this heat to move is through the collisions between the more energetic atoms and molecules on one region with the less energetic atoms and molecules in a neighboring region. That is a simple explanation appropriate to simple materials in simple situations.

The thermal conductivity of a material is a quantitative measure of how much heat will flow through a material per unit time for a given temperature gradient.

In the simplest materials the mechanism of heat transfer may be described at the microscopic level as transfer of energy through collisions between atoms and molecules.

In a higher temperature region region the atoms and molecules have more kinetic energy than in a low temperature region. In general, when two objects collide, the higher kinetic energy object transfers energy to the lower kinetic energy object. (This is more complicated than it sounds.) Thus, as particles collide with neighboring particles and the process is repeated billions of times with billions of particles, they tend towards an average kinetic energy. For two adjacent regions, one hot and one cold, the kinetic energy moves from the hot to the cold in an average sense. This is called thermalization or thermal equilibration. Heat energy, or thermal energy, has moved from the hot region to the cold region.

Thermal energy is more than kinetic energy and also includes potential energy between atoms and molecules and may also include chemical and electronic energies. Nonetheless, it is a fundamental law of thermodynamics that two objects left in thermal contact will eventually arrive at the same temperature and that temperature will be somewhere between the initial two temperatures.

In simple materials, it is the collisions between atoms that serves to transfer the kinetic energy (some of which may become potential or another form of energy) so that the temperature of a material moves toward a uniform temperature.

The basic answer to the question is that collisions between particles allow the transfer of energy in matter.

There is a caveat. When the matter is not simple, such as in a conducting metal material, there is a strong interaction between the electronic structure and the movement of the constituent atoms. The idea of "collisions" is inadequate since there is not one atom interacting with one other atom but the motion of all atoms are interconnected through the electronic structure. Indeed, the concept of collisions at the atomic level must be employed with care since it is a concept derived from or macroscopic experience with macroscopic objects.

Answer 2

conduction

Answer 3

thermal energy