Taking a breath of helium gas and then speaking or singing to the class is a favorite demonstration for an introductory physics course, as it usually elicits appreciative laughter, which serves to energize the class session. Students will usually report that the helium speech "raises the frequency" of the voice. A more accurate description of the…

In our initial article on teaching special relativity in the first week of an introductory physics course, we used the principle of relativity and Maxwell's theory of light to derive Einstein's second postulate (that the speed of light is the same to all observers). In this paper we study thought experiments involving a light pulse clock moving…

Recently when teaching a first-semester calculus-based physics course for engineers, I was perplexed by a particular group of students. These individuals were able to solve nearly every homework problem assigned from the end-of-chapter exercises in our textbook, and in some cases were able to do so using methods that we had not covered in class.…

We explore the consequences of a force density, [image omitted], studied by some authors, for the device designed by Lai (1980 "Am. J. Phys. 48" 658) to analyse which definition of electromagnetic momentum density, either Minkowski's or Abraham's, is consistent with mechanical torques that arise from the change in time of a magnetic field, which…

Previous studies provided evidence of the claim that the prediction of occluded action involves real-time simulation. We report two experiments that aimed to study how real-time simulation is affected by simultaneous action execution under conditions of full, partial or no overlap between observed and executed actions. This overlap was analysed by…

In this paper, we discuss the first phase of a multiphase study aimed at investigating the dynamics of students' knowledge construction in the context of unfamiliar physical phenomenon--microscopic friction. The first phase of this study involved the investigation of the variations in students' mental models of microscopic friction. Clinical…

Without applications of physics such as counter-weighted sets and backdrops, inclined planes, stage lighting instruments, and other mechanisms for "deus ex machina," dramatic productions would revert to the words only--fine for Shakespeare and Becket, but not good for audiences who are accustomed to experiencing plays with the eye as well as the…

In a recent "TPT" article, I addressed a common miscommunication about Faraday's law, namely, that introductory texts often say the law expresses a causal relationship between the magnetic fields time variation and the electric fields circulation. In that article, I demonstrated that these field behaviors share a common cause in a time-varying…

This article addresses misconceptions surrounding the Coriolis force and describes how it should be presented as a function within inertial and noninertial frames of reference. Not only does this demonstrate the nature of science as it strives to best interpret the natural world (and presents alternative explanations), but it offers a rich…

Limited weight bearing of the lower extremity is a commonly applied procedure in orthopaedic rehabilitation after reconstructive forefoot surgery, trauma surgery and joint replacement. The most frequent limitations are given as percentage of body weight (BW) and represent 10 or 50% BW. The extent of foot loading under these graduations of partial…

The challenge for a discussant of the Humphry article in this issue is that the profundity of the simple insights of the article, and the lucid arguments by which the insights are sustained, might be easily overlooked, undervalued, or misconstrued. At the risk of repeating major inferences already presented, one may note that the article…

Steel connections play important roles in the integrity of a structure, and many structural failures are attributed to connection failures. Connections are the glue that holds a structure together. The failures of the Hartford Coliseum in 1977, the Hyatt Regency Hotel in Kansas City in 1980, and the I-35W Bridge in Minneapolis in 2007 are all…

The Physics Metacognition Inventory was developed to measure physics students' metacognition for problem solving. In one of our earlier studies, an exploratory factor analysis provided evidence of preliminary construct validity, revealing six components of students' metacognition when solving physics problems including knowledge of cognition,…

The traditional Run the Football Field physics activity--in which students are timed as they move at different speeds on a football field to investigate displacement and velocity--has been updated for the 21st century. Nowadays, GPS-enabled tablets and smartphones replace the stopwatches and yard markers of the past, allowing students to collect…

This article presents an independent evaluation of the Action Research for Physics (ARP) programme, a nationwide professional development programme which trains teachers to use action research to increase student interest in physics and encourage them to take post-compulsory physics. The impact of the programme was explored from the perspective of…