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…

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…

In an earlier article I argued that much of what used to be called "modern physics" stems from the intersection of two earlier technologies: high vacuum and high voltage. In this article I will discuss the induction coil, invented in the 1830s, reinvented in the second half of the 19th century, and still used today to produce the high…

This article is about a famous physics course taken by thousands of students at Amherst College in the 1950s, designed and taught by its distinguished instructor, Arnold B. Arons. There are very few of us left who have taken the course. The youngest one would be, as the course was discontinued in 1968, about 72 years old!

In 1981 I published a note on "Balancers" as part of a series of illustrations drawn from 19th-century physics texts. Some months later a wonderful present arrived from a physics teacher in Japan, showing the range of our journal. This was the Horse and Rider Balancer in Fig. 1 that was just like the woodcut in my note. The little…

A good paradox has the viewer confused, but the best paradoxes lead the viewer to try to understand what is happening. One of the author's favorites is the hydrostatic paradox, in which a short and slender column of water supports a relatively enormous weight. He describes the paradox using an illustration of a student who weighs 60 points stands…

The overhead projector is perhaps passing out of use, but it is still a useful device with which to do lecture demonstrations. In my early years at Kenyon I was teaching the pre-med course, and found that the overhead projector was an ideal platform for showing the phenomena of polarized light. This note is a discussion of how I learned to use the…

Recently I took a walk through the physics demonstration room at Kenyon College, where I first started teaching in 1964. On an upper shelf was the little home-built apparatus in Fig. 1. This was used for one of two short single-concept films that I made in the 1970s. Both "The Magnus Effect" and "Optical Barrier Penetration"…

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…

In the museum wing of the Greenslade house is a clock with a two-second pendulum about one meter long. This ticks once per second, and every time it passes through dead center it completes an electrical circuit. When I came to Kenyon in 1964, this system was used to send signals to a series of telegraph relays, which ticked once per second.…

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?

Apparatus catalogues of the first half of the 20th century contain a number of clever and simple devices for measuring the index of refraction of a liquid. In some cases students can put together one of these pieces of apparatus and then make their own measurements. The Gilley board was one of the devices that caught my eye, and I would like to…

One of the memories of my freshman year at Amherst was a lecture in the required physics/calculus course in which Arnold Arons quoted Isaac Newton on standing on the shoulders of giants. Now that I have spent my physics career, I still use the same quote, but now apply it to the eponymous apparatus that has been designed by the giants in our field.

The Phantom Bouquet is a venerable lecture demonstration that does a fine job of showing how a concave spherical mirror can form a real, inverted image. In the original demonstration, a brightly illuminated artificial rose is hung by its stem in front of a concave spherical mirror. The distance from the reflecting surface to the rose is somewhat…

As I approach my 70th year in physics, let me tell my younger colleagues about my adventures with computation. When I was 14, my father gave me a slide rule because I appeared to be headed toward a career in physics. Since then, I have had experience with many other calculating devices.