According to the second law of thermodynamics every spontaneous change,
or process, is associated with an increase in entropy. Although the probabilistic
distributions of particles and energy give the possible direction of a process, its
occurrence is enabled by the motional energy of the particles. Even particles, however,
are subjected to constraints of motion that slow down the attainment of some possible
changes and thereby reduce their probability of occurrence, especially if alternative
pathways to increase entropy are possible and can be accessed faster. Kinetic restraints
are therefore key determinants of which processes are activated among the different
possible ones.
Keywords: Average kinetic energy, Constraints of motion, Energy redistribution,
Energy spreading, Particles collisions, Particle motion, Zeroth law.
