6 Nanosensors: Physical, Chemical, and Biological
1.3.6 Heat
Heat or thermal energy is the energy of vibration, rotation, or translation of
the atoms or molecules of a body. It is transferred from one place to another
by three modes: (i) conduction (through successive collisions from high-
kinetic-energy molecules to neighboring low-kinetic-energy molecules), (ii)
convection (by mass movement of high-kinetic-energy molecules from a high-
temperature region to a low-temperature region), and (iii) radiation (by elec-
tromagnetic waves at the speed of light, not requiring any material medium).
Temperature is a measure of the degree of hotness or coldness of a body, that
is, the average kinetic energy of the molecules of the body. Absolute zero i