THE PHYSICS TEACHER ◆ Vol. 42, May 2004 In a recent paper in this journal1 we presented work on the creation and use of Physlet-based2 exercises to teach physical and wave optics. Since then we have developed ready-to-run exercises for introductory physics3, 4 and have developed Physletbased exercises for more advanced topics such as quantum mechanics. In this paper we describe the materials we...

One might think that Poincare symmetry is something thoroughly understood but the Very Special Relativity [1] proposed by nobelist Sheldon Glashow and Andrew Cohen suggests that this might belief might be wrong. Glashow and Cohen propose that instead of Poincare group, call it P , some subgroup of P might be physically more relevant than the whole P . To not lose four-momentum one must assume t...

We advance an universal approach to the construction of kinematics in non-inertial and, in particular, rotating reference frames. On its basis, a 10-dimensional space including three projections of velocity vector and three turn angles in geometric space as additional coordinates to time and geometric coordinates is introduced. In a specific case, the turns in 10-space describe the uniform rota...

The Special Theory of Relativity is often interpreted as forcing us to accept a conceptual revolution in our thinking about space, time, and the temporal distinction between past, present, and future. Most importantly, it is claimed that the notion of absolute simultaneity that is embodied in our pre-relativistic thinking about time must be abandoned. Thus, our natural language use of linguisti...

We consider a single free spin- 1 / 2 particle. The reduced density matrix for its spin is not covariant under Lorentz transformations. The spin entropy is not a relativistic scalar and has no invariant meaning.