Though central to any pedagogical development of physics, the concept of mass is still not well understood. Properly defining mass has proven to be far more daunting than contemporary textbooks would have us believe. And yet today the origin of mass is one of the most aggressively pursued areas of research in all of physics. Much of the excitement…

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 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)

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

Presents a model for the Slinky that allows for calculations that agree with observed behavior and predictions that suggest further experimentation. Offers an opportunity for introducing nonrigid bodies within the Galilean framework. (JRH)

Describes the laws of physics that allow a motorcycle rider to control the flight of a motorcycle over obstacles in a motocross track. (JRH)

Presents a few examples of not-so-traditional problems that can be very helpful in teaching some particular concepts or approaches in physics. Problem sets include vector addition and vector components, reference frames, and choosing the right approximations. (JRH)

Described are responses of first-year college students to questions regarding acceleration. Responses regarding acceleration and possible reasons for student errors are discussed. (RH)

Describes the activities of the Physics Teachers Action Research Group in which college physics teachers work together in planning, revising, and evaluating student projects that foster greater conceptual understanding and address student misconceptions. Presents the details of a project in which students were asked to build an accelerometer. (JRH)

Discusses the reasoning behind the determination of the distance from Earth to the Moon by the Greek philosopher Aristarchus upon observing a lunar eclipse. Presents calculations for estimating Earth's distance from the Moon using simple observations made during a solar eclipse. (JRH)

Demonstrates misconceptions of the meaning of temperature based on classical kinetic energy. Discusses some misconceptions about negative temperatures and the effect of compression. (YP)

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)

Discusses the applications of the principles of mechanics to rock climbing techniques. Provides illustrations showing the applied force vectors. (YP)

Discusses interesting aspects of the Carnot cycle and other thermodynamic cycles that are generally not dealt with in elementary physics texts. Presents examples that challenge the student to think about the extraction of net work from a cycle. (JRH)

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)