Researchers and practitioners alike express concerns about the conceptual difficulties associated with the concepts of momentum and kinetic energy currently taught in school physics. This article presents an in-depth analysis of the treatment given to them in 44 published textbooks written for UK secondary school certificate courses. This is set…

Discusses how to stop a spinning object (such as rotating fan blades) by humming and the perception of curious blue arcs around a light. Background information, relevant research, and activities related to these two topics are provided. (JN)

Discusses the theory behind a study of motion where a hollow plastic sphere racing against a steel sphere in two parallel sections of inclined channeling always reaches the bottom first; once on the floor, however, the steel sphere travels faster, speeding past the plastic sphere when both are about one meter from the base of the track. (JRH)

Describes four kinds of movement by a cat with or without angular momentum and tail or tail-less during free falling. Presents many pictures illustrating the movement. Supports the position that the angular momentum of the tail plays an important role in free fall. (YP)

Presents the theory behind the mechanics demonstration that involves projecting a ball vertically upward from a ballistic cart moving along an inclined plane. The measured overshoot is believed to be due, in part, to the presence of rolling friction and the inertial properties of the cart wheels. (JRH)

Presents activities to teach the concept of projectile motion to high school students using a spring-loaded dart gun, carbon paper, meterstick, ruler, white paper, tape, and a student's desk. (JRH)

A diffusional driving force, called the radial force, which is responsible for the increase with time of the scalar separation between a fixed point and a particle undergoing three-dimensional Brownian motion, is derived using Boltzmann's equation. (Author/HM)

Presents demonstrations that use a blowgun to illustrate scientific concepts relating to acceleration, projectile motion, Newton's Laws, and work and kinetic energy. (JRH)

Describes a stimulating interactive group project on measuring the lengths of solar days that directly supports concepts related to orbits, motion, and time in a physics or astronomy curriculum, and has the flexibility to extend from a few days to several weeks. Provides new measurement experiences for students and teachers and opportunities for…

Discusses how the discovery of chaos has created a new paradigm in scientific modeling and how findings are contributing to changes in thought about many different branches of science. Includes explanations and examples of how chaotic behavior can be understood. (ML)

Activities are provided for calculating speeds of celestial bodies. These focus on how fast earth rotates on its axis, how fast planets travel around the sun, and how fast the solar system is traveling with the Milky Way. (JN)

Presents a three-dimensional analysis of the relative speed before and after a two-body elastic collision, based on the concept of a Galilean invariant. (JRH)

Materials from a student-made kit are used to investigate physics phenomena while riding on various amusement park rides. A list of materials contained in the kit and procedures for their use are included. (JN)

One dilemma of constructivist modes of instruction, which involve engaging students in discussions concerning a range of possible explanations for a given phenomenon, is that such an approach may confuse students who believe that absolute scientific truth exists. Historical dialogues in which various perspectives are aired by key scientists of the…

Shows how through proper handling of the nonuniform motion of semiclassical coordinates spurious excitation terms are eliminated. An application to the problem of nuclear Coulomb excitation is presented as an example. (HM)