Statistical Physics Quotes

“In contrast to this macroscopic determination of pressure consider how the pressure actually comes about.”
― Franz Mandl, Statistical Physics

“This division of macroscopic physics into thermodynamics and statistical mechanics is largely of historical origin. We shall not follow this development. Instead we shall emphasize the unity of the subject, showing how the two aspects illuminate each other, and we shall use whichever is more appropriate.”
― Franz Mandl, Statistical Physics

“mechanics is to derive the properties of a macroscopic system — for example, its equation of state — from its microscopic properties.”
― Franz Mandl, Statistical Physics

“There are two aspects to statistical mechanics. One aim is to derive the thermodynamic laws of macroscopic bodies from the laws governing their atomic behaviour. This is a fascinating but very difficult field. Nowadays one has a fairly general understanding of the underlying physics but most physicists working in the field would probably agree that no real proofs exist.”
― Franz Mandl, Statistical Physics

“This line of approach originated in Maxwell’s kinetic theory of gases which led to the profound works of Boltzmann and of Gibbs.”
― Franz Mandl, Statistical Physics

“The second approach to macroscopic physics is that of statistical mechanics. This starts from the atomic constitution of matter and endeavours to derive the laws of macroscopic bodies from the atomic properties.”
― Franz Mandl, Statistical Physics

“They are not derived from a microscopic picture but avoid all atomic concepts and operate exclusively with macroscopic variables, such as pressure, volume, temperature, describing the properties of systems in terms of these. Of course, the avoidance of atomic concepts severely limits the information that thermodynamics can provide about a system.”
― Franz Mandl, Statistical Physics

“There are two approaches to the study of macroscopic physics. Historically the oldest approach, developed mainly in the first half of the 19th century by such men as Carnot, Clausius, William Thomson (the later Lord Kelvin), Robert Mayer and Joule, is that of classical thermodynamics. This is based on a small number of basic principles—the laws of thermodynamics—which are deductions from and generalizations of a large body of experiments on macroscopic systems. They are phenomenological laws, justified by their success in describing macroscopic phenomena.”
― Franz Mandl, Statistical Physics

“There are two approaches to the study of macroscopic physics. Historically the oldest approach, developed mainly in the first half of the 19th century by such men as Carnot, Clausius, William Thomson (the later Lord Kelvin), Robert Mayer and Joule, is that of classical thermodynamics.”
― Franz Mandl, Statistical Physics

“On average the piston is at rest but it will perform small irregular vibrations about its equilibrium position as a consequence of the individual molecular collisions. These small irregular movements are known as Brownian motion”
― Franz Mandl, Statistical Physics

“The pressure due to these collisions is certainly not a strictly constant time-independent quantity. On the contrary the instantaneous force acting on the piston is a rapidly fluctuating quantity.”
― Franz Mandl, Statistical Physics

“These represent averages over microscopic properties. Thus the macroscopic laws are of a statistical nature. But because of the enormous number of particles involved, the fluctuations which are an essential feature of a statistical theory turn out to be extremely small. In practice they can only be observed under very special conditions. In general they will be utterly negligible, and the statistical laws will in practice lead to statements of complete certainty.”
― Franz Mandl, Statistical Physics

“These examples illustrate that the laws of macroscopic bodies are quite different from those of mechanics or electromagnetic theory.”
― Franz Mandl, Statistical Physics

“In spite of the enormous complexity of macroscopic bodies when viewed from an atomistic viewpoint, one knows from everyday experience as well as from precision experiments that macroscopic bodies obey quite definite laws.”
― Franz Mandl, Statistical Physics