In this article, we will present the HEC BB bag, a simple but elegant model originally invented to help students imagine how air molecules move around in vacuum. The HEC BB bag is made by packing 20 to 30 BBs in a resealable plastic bag of several tens of square centimeters (see Fig. 1). When inflated fully via a straw, the volume of the bag is…

In high school, and also in introductory physics courses in higher levels of schooling, the law of universal gravitation of planets is introduced by postulating Johannes Kepler's three laws, and later Isaac Newton's law of the inverse of the square of the distance to the Sun. The justification of the laws is only achieved in advanced courses in…

About 30 years ago I taught a series of summer enrichment programs for high school physics teachers, using funding from the Howard Hughes Medical Institutes. I deliberately chose teachers from smaller cities and towns who were unlikely to have contact with other physics teachers. One of my more interesting teachers came from a rural area in a far…

In physics education, the topic of electromagnetic induction is an important but also challenging topic for many students. The early introduction of formulae, e.g., Faraday's law of induction, seems to hinder rather than to foster the understanding of the topic's underlying principles. In this paper, we present the basic idea for a teaching…

The family of paths of ideal projectiles shot from a point with a common value of speed and at different angles to the horizontal has several interesting properties associated with it. For example, Chapou et al. have shown that an ellipse passes through the apexes of these parabolic paths. This observation encouraged us to further explore this…

In a traditional teaching approach, a physics course begins with mechanics, and generally the braking effect due to magnetic interactions is not mentioned among the various types of friction presented (static, sliding, rolling) because students will discover magnetism only in later chapters. In our didactic experience this traditional choice is…

A classical mechanical structure with an internal degree of freedom is shown to reflect off a potential well. Such behavior is impossible for point-like or rigid classical particles. This numerical study provides insight for students studying internal energy and degrees of freedom.

We will present a problem-solving method for the dynamics of a projectile that has two perpendicular acceleration vectors through rotation of the axes. This methodology of reparameterizing the two-dimensional system simplifies the speed optimization calculus.

Transfer of structural math knowledge to physics is difficult for students. While research suggests various improvement techniques, enhancing parallelism of algebraic structures used in physics to those studied in mathematics courses seems underrepresented. This paper proposes an alternative way of introducing wave functions as a set of parametric…

Science does not belong to just one civilization, one culture, one country, or one gender; it belongs to all who want to unfold the mysteries of nature. Most scientists agree that science currently is, and indeed always has been, international and multicultural in character. Our teaching at all levels should reflect this multiculturalism as part…

Research-based assessments (RBAs) measure how well a course achieves discipline-specific outcomes. Educators can use outcomes from RBAs to guide instructional choices and to request resources to implement and sustain instructional transformations. One challenge for using RBAs, however, is a lack of comparative data, particularly given the skew in…

The refractive index (RI) is probably the single most important parameter in optical systems. Chromatic dispersion, on the other hand, indicates how the RI depends on the wavelength and is central in, e.g., optical communication systems. Chromatic dispersion also plays an important role when teaching optics due to the captivating natural…

The wave nature of light has been widely demonstrated in a double-slit experiment, which has played a special role in physics teaching. When monochromatic light passes through the double-slit sheet, the diffraction and interference fringes can be observed in the far-field regime. The interference of light causes the beams passing through the two…

So many fundamental physics problems involve rigid body rotation that mastery of the subject is essential to many science and engineering undergraduate degrees. Rigid body rotation is typically taught in introductory mechanics courses and while students are generally comfortable with the corresponding kinematic equations, torques and moments of…

Physics teachers are sometimes asked to teach an astronomy course for non-majors. One can't make that class dance and sing without the starry night, but on a brightly lit campus viewing deep sky objects may seem impossible. Hence instructors often opt for planetarium shows. However: 1) Planetariums aren't the real thing. 2) People living in large…