Experiments involving RC circuits are an integral part of introductory physics courses. Previous articles using RC circuits describe determining the charge on a Van de Graaff generator, measuring currents and voltages in a charging RC circuit using a multimeter or an Arduino, measuring the decay constants of complex RC circuits, and using the…

The early 20th century marked a number of transformational experimental and theoretical discoveries in physics. Among them is one that is often neglected in the introductory physics curriculum, which revolutionized our understanding of the molecular world. Evidence for the thermal motions of atoms was first observed by Perrin in 1909, which had…

The electric field inside a uniformly charged long cylindrical shell is a standard example discussed in introductory university physics. The field is zero inside the cylinder; outside of the cylinder, the field behaves like a long wire at the center carrying the same amount of charge per unit length, analogous to that of a uniformly charged…

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…

Of all the conceivable ideal-gas processes, almost all introductory physics textbooks as well as more advanced texts on thermodynamics emphasize only four: isochoric, isobaric, isothermal, and adiabatic (isentropic). These are processes in which a state variable--volume, pressure, temperature, or entropy--remains constant. It turns out that these…

Interactive classroom demonstrations (ICDs) are used extensively in physics, and prior studies indicate that, when conducted under certain conditions, they lead to appreciable increases in student gains and retention. The literature suggests that the ICD recipe for maximizing student gain is to (i) introduce the physical theory that will be…

Diffraction refers to a kind of optical phenomena which occurs when light approaches an element (object or aperture) whose features are in the range of the illuminating wavelength (small apertures, sharp edges). It can be explained by means of the undulatory nature of light or also geometrically by using simple ray optics. Diffraction phenomena…

The Young's two-slits experiment is arguably one of the most famous and beautiful experiments in physics. In introductory physics labs the experiment is almost exclusively carried out using a laser, and it is introduced this way in some introductory physics textbooks. In the case of laser illumination, light passes directly through the slits and…

When students are learning to use math in physics, one of the most important ideas they need to learn is that equations are not just calculational tools; they represent relationships between physical variables that change together (co-vary). How much a change in one variable or parameter is associated with a change in another depends on how they…

On April 14, 1912, the British passenger liner R.M.S. "Titanic" struck an iceberg. The ship sank in a fraction of the time designers had estimated following a worst case scenario. The purpose of this article is to examine the atmospheric refractive phenomena that might have played a significant role in obscuring the iceberg from…

Light and its spectrum are central concepts in many introductory physics, astronomy, geology, and conceptual physics courses. The Sun and its spectrum are usually primary examples, likely due to the Sun's everyday familiarity and the full spectrum it generates when dispersed. To enhance such discussions with a hands-on student activity, we've…

Why does a raindrop on a window pane show an image of the environment that is turned upside-down? And why does vision go blurry underwater, but is perfectly clear with diving goggles? Our everyday life is rich in optical phenomena. Unfortunately, these phenomena often play a subordinate role in Optics teaching, compared to ray constructions or…

Students experience current electricity every day in our wired world, yet the circuit problems that students work through in physics class can seem far removed from the common experience of switching on a light bulb. However, current electricity provides many opportunities to engage students in hands-on learning. Through circuit construction,…

The Double Asteroid Redirection Test (DART) is a National Aeronautics and Space Administration--European Space Agency collaborative mission to test the feasibility of defending Earth from a catastrophic asteroid impact by using a spacecraft to deflect the asteroid away from the planet. Launched on Nov. 23, 2021, the DART spacecraft will intercept…

Races between moving objects are an engaging way to teach dynamics to introductory physics students. One standard example consists in racing hollow and solid cylinders as they roll down an inclined plane. Another striking demonstration is a race between two marbles on side-by-side tracks that start and end together, but with one track taking a…