Table of contents

The history of thermodynamics is closely connected with a scientific school founded in Berlin by Hermann Helmholtz and Rudolf Clausius in the 1840s. Other great scientists which belonged to this school were Kronig, Kirchhoff, Planck, Nernst, Caratheodory, Einstein, Warburg, Debye, Schottky, Schrodinger, Szilard and von Neumann. Not only the foundation of the three laws of thermodynamics but also many important applications especially to chemical reactions and to radiation processes, as well as the statistical foundation of thermodynamics are closely connected with the work of these pioneers and their students.

Two projects are described that employ the REDUCE language for symbolic computation. In the first a program is produced which gives the correct 'product of powers' form of a 'target' physical quantity in terms of other relevant physical quantities and which detects dimensionless groups. The other yields programs to verify the closure under commutation of sets of operators which are relevant to the three-dimensional oscillator and to the Kepler problem, and in the second case to verify the analogous classical property (closure under Poisson brackets) of components of orbital angular momentum and of the Laplace-Lenz vector.

The rotation of the plane of polarization of light in an optical fibre whose initial and final directions are parallel is given by the Berry phase, as interpreted by Chiao and Wu (1986) and observed by Tomita and Chiao (1986). It is shown that this result follows directly from geometrical considerations, by appealing to the Gauss-Bonnet theorem in the tangent space of the fibre.

Electrons in strong magnetic fields are of interest in connection with (a) compact galactic objects and (b) conduction band behaviour in metals. The interest in case (a) is in bound electrons in atoms, and in case (b) in itinerant or delocalized electrons in metals. Besides the specific interests in these areas, some discussion is included of the way the vector potential A can be bypassed in treating the effects of the magnetic field.

The authors formulate an equivalence principle for the ANAIS experiment and show that the observed trajectory followed by a rigid sphere on the billiard table is a geodesic curve in a nonEuclidean space.

The Ehrenfests' wind-tree model is discussed and its evolution simulated on a personal computer. The distribution function and the H function are computed and compared with their theoretical counterparts. The deviation from the hypothesis of molecular chaos is defined and computed. It is shown that this quantity is small, so that the hypothesis is well justified in this model. From theory and simulation, some insight is gained into the hypothesis of molecular chaos and irreversibility in kinetic theory.

The author demonstrates a relationship between the pattern of straight interference fringes formed in Young's experiment and the circular fringes produced at infinity by a Michelson interferometer. The two patterns can both be considered to be produced by the interference of light from two coherent point sources. It is shown that the pattern given by these sources on a large sphere centred midway between them reduces to Young's fringes in the vicinity of zero path difference and to the Michelson pattern in the vicinity of maximum path difference.

During the last years the physics of low temperature plasmas has grown in importance, especially because of their various technological applications. Besides their well known employment in gas discharge lamps for light production, low temperature plasmas are widely used in advanced technologies such as, e.g., in microelectronics. High-technology applications promote the further development of applied and basic research in this field. After describing the main properties of low temperature plasmas a theoretical approach is given. Starting from the general kinetic theory of a plasma as a many-particle system it is shown that by means of several averaging procedures an appropriate macroscopic description can be found. After introducing the rate equations and explaining the relaxation processes the so called local thermodynamic equilibrium (LTE) is defined and a thermodynamic description of LTE plasmas is presented. Special attention is paid to the effects of nonideality, e.g. the plasma phase transitions. Because of its practical importance in applications and for plasma diagnostics a separate section deals with plasma radiation. After giving a short introduction to the physics of plasma-wall interaction several types of gas discharges are briefly described. Finally, the most important applications of low temperature plasmas are reviewed.

A spectroscopic study of a hollow cathode discharge is presented as a plasma diagnostic technique attainable by undergraduate students.

A calculation that can be used in an undergraduate mechanics course shows why, in the seventeenth century, there was another 'law' of planetary motion.

A new pendulum set-up is presented to be used for educational purposes. The system is made of special but simple mechanics and of a microcomputer-based interface capable of high-speed sampling of the pendulum angular position. The position detector is of the optical type and is based on spinning Polaroids.

A demonstration experiment is described, which illustrates fundamental physical processes with NMR and MRI. The terms precession, Larmor frequency, gyromagnetic ratio, 90 degrees pulse, relaxation time, and echo signal are explained with it. The experiment can be set up with the usual laboratory means, at low cost.

The passive diamagnetic levitation of pyrolytic graphite can take place in magnetic fields of approximately 1 T. This is at a field strength less than half that claimed for certain diamagnetic salts. Moreover, at these field strengths, levitation can be induced by the fields of ordinary room temperature electromagnets or high energy product permanent magnets.