Describes a technique which enables the student to observe the relativistic behavior of electrons in a gamma ray detector and compare his results with the classical and relativistic predictions. Shows that it is possible to unambiguously determine the electron's momentum by knowing the Compton edge and photopeak energies of a gamma ray energy…

A discussion of linear collisions between two or three objects is related to a junior-level course in analytical mechanics. The theoretical discussion uses a geometrical approach that treats elastic and inelastic collisions from a unified point of view. Experiments with a linear air track are described. (Author/TS)

Describes and explains some aspects of the motion of a top, the extreme end of which is made round, spinning on surfaces provided with friction. (Author/GA)

Describes an interesting, inexpensive, and highly motivating experiment to study uniform and accelerated motion by measuring the position of a car as it crashes into a rigid wall. Data are obtained from a sequence of pictures made by a high speed camera. (Author/SLH)

Gives a perturbation analysis to recurrence effects of the spring pendulum. The recurrence depends on two conservation laws which determine the motion in an intermediate region; oscillations outside this region are unstable and must return. Gives the relation to Fermi-Pasta-Ulam problem together with the explicit solution. (Author/GA)

Describes a nineteenth century paper by Reynolds on his experiments with the tension that a column of liquid could sustain, and compares Reynolds work with some of the other related work published in French journals at that time. (GA)

Derives the precessional period of a Foucault pendulum without using small oscillation amplitudes. Shows that if the path of the pendulum passes through the origin, the periods for differing amplitudes are essentially the same. (GA)

Describes a simple demonstration that shows the change in molecular density and the reduction in pressure of air in a centrifugal field. Uses two circular disks with the same radius and rotating with the same angular velocity, in loose mutual contact, around their symmetry axis. (GA)

This simple and inexpensive experiment is an illustration of the physical concepts of interaction between light and surface tension waves, and provides a new method of measuring surface tension. (Author/GA)

Describes an apparatus and experimental procedure for quantitatively evaluating the activation energy associated with annealing color centers in glass. (MLH)

Described is an easy to assemble, and inexpensive, torsional pendulum which gives an accuracy of measurement of the modulus of rigidity, G, comparable to the accuracy obtained with the more expensive commercially available student models. (Author/GA)

Describes an apparatus which allows one to study the speed distribution, the gravitational distribution, and the mean free path of steel balls agitated into two-dimensional motion through collisions with the moving walls of their enclosure. (Author/GA)