It has long been suspected by general relativists that physicists who do not specialize in general relativity (GR) believe that special relativity (SR) is incapable of modeling dynamics within accelerated reference frames. Consequently, many physicists may conclude that certain phenomena, such as time dilation due to acceleration, can only be…

The standard model of particle physics is the most successful theory describing the behavior of matter and energy in the subatomic realm. However, success doesn't mean it is perfect, and a recent measurement of the mass of a particle called the W boson is puzzling, as it disagrees with theoretical predictions and earlier precise measurements. If…

An atlatl or spearthrower is perhaps humanity's oldest technology for accelerating projectiles. The dynamics prior to launch of the dart projectile have been much discussed in the literature. In this article we present a simple new model of launch dynamics and show that dart flex is not an important factor in determining launch speed, but it…

We describe here a low-cost experiment for introductory physics students where they compare the physical properties of aluminum and steel by means of cantilever oscillations. This, in turn, allows the students to improve their physical intuition about these materials. Further, the students can apply their physics and mathematics knowledge and…

Science labs should promote reasoning that resembles the work that scientists do. However, this is often not the case. We present a lab in which students strive to find out which of two models best describes a physics experiment. The quantification of measurement uncertainties--another topic that is often neglected in high school…

In a 1993 book review, E. Pearlstein asks, "Why don't textbook authors begin their discussion of magnetism by talking about magnets? That's what students have experience with." A similar question can be asked, "Why don't professors have students measure the force between permanent magnets in introductory physics labs?" The…

The Next Generation Science Standards lay out a model of energy that locates energy within objects and fields, and tracks energy as it transfers between these objects and transforms between forms of energy while always being conserved. This model of energy pervades much of modern science and represents a foundational, cross-cutting concept for…

The Gaussian gun is an arrangement of magnets and ball bearings (pictured in Fig. 1) such that--when the leftmost ball is released--the rightmost ball is ejected at high speeds. The device has been described in several articles on energy education. The sudden appearance of kinetic energy offers a productive context for considering a range of…

Progress is made in science by constructing many models (possibly of different complexities), testing them against measurements, and determining which of them explain the data the best. It is my observation, however, that in many introductory physics labs we provide students with the materials and methods to verify the "correct" model of…

The debate over the mechanisms responsible for the flow rates of simple tube siphons has received much attention in the physics education and general physics literature in the past decade. Particularly with regard to the driving mechanism for water siphons, some suggested explanations emphasize contributions, or lack thereof, from the atmospheric…

It is common in science for two phenomena to appear to be very different, but in fact follow from the same basic principles. Here we consider such a case, the connection between the chain fountain and a bullet-block collision experiment. When an upward moving bullet strikes a wooden block resting on a horizontal table, the block will rise to a…

Most springs do not simply obey Hooke's law because they are constructed to have an initial tension, which must be overcome before normal elongation occurs. This property, well known to engineers, is universally neglected in elementary physics courses. In particular, the standard simple harmonic motion experiment omits any discussion of this…

At some point in the future, if mankind hopes to settle planets outside our solar system, it will be crucial to determine the range of planetary conditions under which human beings could survive and function. In this article, we apply physical considerations to determine the limitations that gravity imposes on several systems governing the human…

Models are at the heart of any physics discipline, and in recent decades physics education has shifted heavily toward teaching students how to think using models. Involving students in an investigation of a real phenomenon through measurements and the applications of models is an ideal learning experience for a physics student and is the aim of…

Kinematic models are often very useful. The back and forth throw of a ball between two ice skaters may help us appreciate the meson exchange theory of Yukawa. If the skaters throw the balls at each other, they move backward, which is equivalent to a repulsive force between them. On the other hand, if they snatch the ball from each other, the…