Name three major heat transfer mechanisms giving one example of each from day-to-day life. Also explain the physical mechanism behind these modes of heat transfer.

The major heat transfer mechanisms are:

Conduction: When a body at higher temperature comes in direct contact with a body at lower temperature flow of heat takes place from higher temperature to lower temperature due to the Kinetic energy of particles in motion and this motion continues till equilibrium is reached. Heat transfer by this method is called conduction. For example: When a hot metal comes in direct contact with a cold metal, heat is transferred by conduction. Convection: This method of heat transfer applies to fluid motion of particles. Here, the heat transfer is due to thermal energy of the fluid particles. Due to the differences in their density the liquid over hot surface expands and rises up and heat flows from high to low temperatures. For example: When earth's surface is heated by the sun, the warm air comes up and cool air comes in Radiation: Thermal radiations are generated by electromagnetic waves. These are the result of motion of random molecules in the matter which carry the energy from the emitting body and provides motion to the charge particles of EM waves. At high temperature, shorter wavelength is produced and vice-versa. For example: visible light, UV, IR, etc