There is an overwhelming consensus that sustained opportunities for teachers' professional learning is critical for student success, but due to the COVID-19 pandemic, the nature, substance, and format of K-12 teachers' opportunities for professional learning necessarily shifted. District administrators, focused on maintaining the safest possible…

There has been a move toward personalized learning and alternative types of authentic assessment in K-12 education. This shift has been partly driven by increases in the available technology that can support those types of changes. This qualitative study aimed at understanding the experience of learners in a first-year physics class working with…

[This paper is part of the Focused Collection on Curriculum Development: Theory into Design.] When we examined student responses to questions about the direction of the static friction force in various situations, we both had strong ideas about how to write a tutorial to promote deeper understanding. But our ideas were quite different. In this…

In the light of own measurements on a Faraday generator, the well-known theories concerning Unipolar Induction and the Faraday paradox seem to be problematic. On the other hand, all results obtained, and all other processes described as a paradox in connection with the Faraday generator can be explained without contradiction based on the theory of…

Important changes were recently made to the International System of Units. The readers involved in chemistry and physics, either teachers or advanced students, should be aware of the new definitions of the kilogram, the mole, and more generally of the changes in International System of Units (SI, "Système International") recently…

Einstein's theory of general relativity (GR) provides the best available description of gravity. The recent detection of gravitational waves and the first picture of a black hole have provided spectacular confirmations of GR, as well as arousing substantial interest in topics related to gravitation. However, to understand present and future…

In a familiar demonstration, a hoop and a solid disk of the same diameter and mass are started from rest at the top of an inclined plane and race to the bottom. The disk reaches the bottom with a larger speed than the hoop and arrives first. Why?

A standard physics experiment for students is to measure the terminal velocity of an object in air or in glycerine. A more difficult challenge is to measure the terminal velocity in water since the depth of the water needs to be large or the object needs to be dropped in the water at a speed close to its terminal velocity. Results obtained by…

In this paper we consider the well-known experiment with the 'heavy' newspaper that breaks a stick that it is laid on. Using several appropriate control experiments we show that the currently invoked explanation using atmospheric pressure cannot be correct. We perform a theoretical analysis and propose a new explanation based on the rotational…

One may be perplexed about the voltage across an inductor, since sometimes it is -LdI/dt, but more commonly it is LdI/dt. We explain why this is so, and point out that in fact, each of them is fine to be used if under its own sign convention (listed in table 2 in the last section of this paper), and the latter, mostly used in circuit equations, is…

A previous journal article established that a hanging Slinky's restoring force is due only to the coils between the support and the Slinky's center of mass (hereafter COM). Correspondingly, it is expected the Slinky's elastic potential energy (hereafter EPE) is associated with only those coils; however, there is no confirming experimental…

According to Einstein's general theory of relativity, a clock runs more slowly if it is close to a large gravitating object. This principle was highlighted in the movie "Interstellar," in which the main character spends several hours on a planet orbiting a massive black hole, and returns to find that his young daughter has become an…

It has been noted that the static friction force poses challenges for students and, at times, even their instructors. Unlike the gravitational force, which has a precise and unambiguous magnitude (F[subscript G] = mg), the magnitude and direction of the static friction force depend on other forces at play. Friction can be understood rather well in…

The conical pendulum provides a rich source of theoretical and computational analysis and the present work presents a seamless continuation of the previous publication. The tension force F[subscript T] and centripetal force F[subscript C] are explored further in linearization analyses and the appropriate slopes are explained. A similar analysis is…

On August 16, 1960, at 7:12 a.m., United States Air Force Captain Joseph W. Kittinger Jr. looked out from his balloon gondola at a height of over 19 miles and… jumped. Kittinger's altitude and free-fall speed record lasted until Felix Baumgartner's jump from a height of nearly 24 miles on Oct. 14, 2012. Baumgartner broke several records, including…