Interaction forces between magnetic fields and current loops play a central role in the theory of magnetism. This work describes a reasonably simple and cheap experiment for demonstrating this issue: the force on a thin coil due to a nearby cylindrical magnet. The magnitude of the force as well as its attractive/repulsive character is comfortably…

A recent physics challenge shows a circuit, where a voltmeter is connected in series. Indeed, real voltmeters have finite input resistance, therefore, one may think that they can be used as resistors. In addition, voltmeters measure the voltage difference between their terminals, so it seems to be possible to calculate the current flowing through…

Conceptual inventory surveys are routinely used in education research to identify student learning needs and assess instructional practices. Students might not fully engage with these instruments because of the low stakes attached to them. This paper explores tests that can be used to estimate the percentage of students in a population who might…

In 2018, we celebrated the sesquicentennial birthday of Robert A. Millikan, a Nobel laureate in physics who worked among the greats such as Niels Bohr and Albert Einstein. His name, however, is perhaps not as widely known. He was born in 1868 in Morrison, Illinois, and moved with his family to the small town of Maquoketa, Iowa, at age nine. It was…

Additive colors are interesting to young students. In this paper, we show a convenient and straightforward method to demonstrate this phenomenon by projector. It produces defocus blur and reduces imaging quality for color mixing. We believe this demonstration experiment can be performed in most classrooms.

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…

A discussion of audio tones in the physics classroom will include mention of their frequency. The frequency of a periodic signal is a well-defined quantity that can readily be measured. A concept related to frequency is that of pitch. Pitch is a perceived quantity that cannot be measured directly and is most important when listeners characterize…

When a ball bounces obliquely on a horizontal surface, the bottom of the ball stretches horizontally and then vibrates backward. The resulting ball spin depends sensitively on the transverse vibration frequency. A simple model is presented to describe the effect, showing how the stored elastic energy can result in additional spin.

This January marked the 52nd anniversary of the Apollo 1 fire. On Jan. 27, 1967, the interior of NASA's AS-204 command module (CM), occupied by American astronauts Roger Chaffee, Virgil "Gus" Grissom, and Ed White, caught fire during a rehearsal of its scheduled Feb. 21 launch. By the time the ground crew was able to open the hatch, the…

As a boy I spent many hours skipping stones across the surface of the water on the shore of Lake Michigan. The challenge was to get as many skips or as much distance as possible. Zero skips was a bust. One or two skips was disappointing, three or four skips was mediocre, and six or more skips was exhilarating. The angle of the stone with respect…

Physics and chemistry students learn several methods to determine the density of materials. While measuring the mass of materials is usually simple, volume measurements are more complex. For simple shapes the volume may be determined by measuring its geometry; for more complex shapes students often use Archimedes' principle. However, neither of…

According to Newtonian mechanics, the gravitational fields created by bodies with spherical symmetry (such as planets) are non-uniform. This may create the impression to undergraduate physics students that uniform gravitational fields are just an approximation. This is not the case as uniform gravitational fields are created in hollows of…

Science, technology, engineering, and mathematics (STEM) graduate and doctoral programs experience consistently high attrition rates. Moreover, persistent disparities exist in gender and racial representation. Students from historically excluded backgrounds have lower retention rates than white and Asian American students. To date, little work has…

A positive physics identity is crucial for women and minorities who are underrepresented in the field of physics. Pedagogical methods that focus heavily on math rather than concepts present a deterrent to many students in physics courses. This research aimed to determine how a 'gamified' physics curriculum with immediate feedback affects students'…

Momentum is a foundational concept in physics. Although it is often taught in introductory mechanics courses, there are a limited number of studies on this topic in the literature. The results from these studies have consistently shown that students have difficulties in understanding momentum, especially the connections between net force, time,…