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…

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 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…

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…

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…

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?

In the 1930s, the teaching staff of the University of Chicago devised a clever way to deliver experimental data to their introductory students without meeting them in the laboratory. The university's curriculum included a required Introductory Course in the Physical Sciences. There were probably too many students to allow for a standard…

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…

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.

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…

Look along the shelves holding your laboratory apparatus and into the demo-prep room, and you will find apparatus by "Cenco" and "The Central Scientific Company" sharing space with your new PASCO equipment. At the 1989 AAPT meeting in San Luis Obispo I was asked to talk about Cenco in honor of one of its long-term employers and…

This note is about 1000 words in length. We have been taught that this much information is contained in a single picture. But, Fig. 1 is so rich that four separate ideas can be obtained from it! The figure appears in "The Boy's Playbook of Science" by John Henry Pepper. Pepper tells us that this shows an "assistant standing on the…

Charles Wheatstone's name was once familiar to students because they used his eponymous bridge to measure resistances. That usage seems to be disappearing--we all have access to digital ohmmeters--but the techniques that he developed for making electrical measurements can still be used with profit. Also, his work with measuring very short time…

Many of us are familiar with the demonstration of boiling water in a paper cup held over a candle or a Bunsen burner; the ignition temperature of paper is above the temperature of 100°C at which water boils under standard conditions. A more dramatic demonstration is melting tin held in a playing card. This illustration is from Tissandier's book on…