The falling temperature of the photosphere with height is responsible for the effect known as limb darkening. The Sun is not equally bright all over the disc. When we observe the Sun towards the limbs, it appears to get darker. Light from the photosphere travels through an absorptive medium. Therefore, one can see only so far into the photosphere.…

Einstein's special theory of relativity includes many non-intuitive and apparently paradoxical conclusions about space and time. One of these is time dilation, the fact that a clock moving relative to an observer runs slower than an identical clock at rest in the observer's reference frame. This is clearly exhibited in the extended mean lifetime…

The recent discovery of preserved cells and soft tissues in certain dinosaur bones seems incompatible with an age of millions of years, given the expectation that cells and soft tissues should have decayed away after millions of years. However, evidence from radiometric dating shows that dinosaur fossils are indeed millions of years old. Under…

Studying the dynamics of beams is considered an indispensable field for mechanical and civil engineering students. This paper describes, in detail, the use of smartphones in educational practical works to determine and examine the dynamic characteristics of beams subjected to free vibration. Where the smartphone is equipped with a mobile…

The Leaning Tower is a long-time staple of the demonstration room. It can be traced as far back as apparatus catalogues from the 1850s. Some years ago, while teaching himself how to use a new wood lathe, Thomas B. Greenslade, Jr. made a replica of the original design. With the top removed, the tower is stable, but once the top is added, the line…

Although it originates from the ancient Greeks, optics still arouses a lot of scientific interest, mainly due to the technological innovation associated with it. One of its most interesting applications is related to optical metrology and the characterization of materials through optical techniques. While some of these processes can be explained…

Ampère's law is presented in introductory physics as a relation between the line integral of the magnetic field around a closed loop and the net current crossing any open surface spanning that loop. By allowing the surface to pass between the plates of a charging parallel-plate capacitor, Maxwell realized that this law is incomplete and introduced…

Representational competence is a target of novel learning environments given the assumption that improved representational competence improves learning in science. There exists little evidence, however, that improving representational competence is positively correlated with learning outcomes across science disciplines. In this report, we argue…

In recent years, modern technologies have enabled the collection of exponentially larger quantities of data in the biomedical domain and elsewhere. In particular, the advent of single-cell genomics has allowed for the collection of datasets containing hundreds of thousands of cells measured in tens of thousands of dimensions. This rapid expansion…

Sometimes it takes little to keep this physicist happy on an airplane. A window seat, where the plane's shadow is visible or has disappeared into the distance, provides the opportunity to observe a variety of phenomena associated with sunlight that is reflected, refracted or scattered back towards the Sun. The term "backscattering" is…

The analysis, calculations and graphical charts presented here in this paper are based directly on a recently published paper by the first two of the above-named authors. In the present paper, it is clearly demonstrated that all of the following nine (or eleven including the centripetal acceleration and total mechanical energy) principal physical…

The acceleration of gravity in Earth's interior is determined by the density distribution in Earth. A remarkable result is that the acceleration is approximately constant all over the mantle, which amounts to about 84% of Earth's volume. This result can be explained by a simple two-layer model of Earth, showing that the constancy of the…

When learning about scientific phenomena, students are expected to "mechanistically" explain how underlying interactions produce the observable phenomenon and "conceptually" connect the observed phenomenon to canonical scientific knowledge. This paper investigates how the integration of the complementary processes of designing…

[This paper is part of the Focused Collection in Investigating and Improving Quantum Education through Research.] Instructors teaching upper-division quantum mechanics have had two primary options when it comes to textbook choice and thus curriculum sequence: starting with wave functions and the Schrödinger equation, referred to as "wave…

Previous research suggests that the use of metaphors in science education have both possibilities and challenges. In this study, we analyse the role of metaphors in meaning-making in the upper primary science classroom. We investigate the potential of metaphors about nutrient uptake occurring in classrooms in which an animation was used. To…