We reexamine the approximate formula for the path difference in the double-slit interference experiment, establish its limits of applicability from a geometric perspective and discuss its validity for the two-source interference of acoustic and surface waves.

George M. Hopkins (1842-1902) wrote a series of articles on demonstrating physical phenomena in the "Scientific American" during the last years of the 19th century. These were collected in a book, "Experimental Science," that was first published in 1890, with revisions in 1892 and 1902. It must have been well received, for the…

There is no shortage of great pedagogical tools available, but many require considerable investment of time and effort (and oftentimes money and equipment), which can be a significant barrier for already time-poor teachers. "Wonder Questions" is a pedagogical tool that is simple, flexible, and pedagogically powerful in three ways: (1) it…

In this paper, we describe the work of a teacher (Sarah) as she attempted to use culturally relevant pedagogy in her physics classroom. Culturally relevant pedagogy (CRP) is an approach to teaching developed by Gloria Ladson-Billings, with the goal of encouraging learning through drawing on students' cultural capital as a centerpiece of their…

We follow a radioactive sample from production in a reactor to its use in a biological application to model the complexities in the use of radioactive isotopes from a student's perspective. Specifically, we describe a way to use gamma ray detection outside the body to estimate the clearance rate of these radioisotopes from the body and how that…

If an empty coffee cup is spun on a horizontal surface about a vertical axis in an anti-clockwise direction, then the whole cup rotates slowly backwards, in a clockwise direction, about a vertical axis located outside the cup. Clues to this curious behaviour are presented by comparing it with other spinning objects.

How many vertical jumps does it take to jump off of a rotating merry-go-round (MGR)? The answer is hidden in the expression: "r[subscript n]" = "r[subscript 0]" (1 + ["beta superscript 2") ["superscript n/2"]. When you make a vertical jump on a train moving on a straight line at constant speed (inertial…

Gravity bends light. One can argue this by reasoning that a beam of light should travel in a curved path when viewed from within an accelerating frame of reference, and then invoking Einstein's principle of equivalence, which asserts that the effects observed in an accelerating frame of reference are indistinguishable from the effects observed in…

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.

An internet poster recently floated the idea that friction with a recently denser interstellar medium causes global warming. Despite its superficially ridiculous nature, refuting this proposition is an interesting quantitative exercise.

The standard model of particle physics is the most successful theory describing the behavior of matter and energy in the subatomic realm. However, success doesn't mean it is perfect, and a recent measurement of the mass of a particle called the W boson is puzzling, as it disagrees with theoretical predictions and earlier precise measurements. If…

The center of mass (CM) is an abstract quantity but essential as a reference point used to understand the position and movement of an object or a system of objects. Many researchers have used video recordings to analyze and understand the movement of objects in a system. In a system with colliding objects, the motion can be obtained precisely from…

The use of toys as teaching aids in physics classrooms has a rich history, and the role of play in science education is a well-established line of research. Much of what has been written on the topic has included discussions of specific toys and the implications of using those toys to teach physics. One of the toys from my childhood that seems to…

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…

Teaching upper division statistical physics can often be clouded by the theory and complex examples used. To better help students appreciate the fundamental statistical concepts and how they are connected to thermodynamic principles this paper suggests using a simple abstract model. Using Atkins' Model students can see these ideas clearly…