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 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…

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…

Ask a physics person what the name of Robert A. Millikan brings to mind, and most would immediately think of the eponymous experiments that he did with the charge on the electron in the years 1908 to 1913. A few might remember his work, starting in 1914, with the experimental determination of Planck's constant using the photoelectric effect. Few…

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…

The object on the right-hand side of Fig. 1 is the whistling mechanism of an old-fashioned tea kettle. This started me thinking about similar devices in which a thin blade of air strikes a sharp wedge and a resonator is used to pick out specific frequencies. This note tells how I went about using the frequency spectrum application on a smartphone…

Recently the handsome little galvanometer (only 10 cm high) in Fig. 1 came into the Greenslade Collection. This is a design without a moving coil and, consequently, is very rugged. At the same time, John Daffron independently sent Tom Greenslade the picture of a similar galvanometer that he had made some years back and has been using for…

Recently I wrote about the standard Weston meter movement, that is at the heart of all modern analogue current measurements. Now I will discuss other techniques used to measure electric current that, despite being based on valid physical principles, are largely lost in technological history.

Let us now praise famous physicists, and the apparatus named after them, with apologies to the writer of Ecclesiastes. I once compiled a list of about 300 pieces of apparatus known to us as X's Apparatus. Some of the values of X are familiar, like Wheatstone and Kelvin and Faraday, but have you heard of Pickering or Rhumkorff or Barlow? In an…

This is a story about a book that I found in my collection, its author, and the boy who owned it. The book is "The Boy's Playbook of Science", first published in 1860 by John Henry Pepper (1821-1900). On the flyleaf is written "Arthur G. Webster; Christmas/75; from Mama." Arthur Gordon Webster (1863-1923) was one of the founders of the American…

I have been tinkering with ultrasonic transducers once more. In earlier notes I reported on optics-like experiments performed with ultrasonics, described a number of ultrasonic interferometers, and showed how ultrasonic transducers can be used for Fourier analysis. This time I became interested in trying the technique of using two detectors in…

Presents experiments that use Helmholtz resonators and have been designed for a sophomore-level course in oscillations and waves. Discusses the theory of the Helmholtz resonator and resonance curves. (JRH)

Describes an experiment that uses the ultrasonic transducer for demonstrating the Fourier components of waveshapes such as the square and triangular waves produced by laboratory function generators. (JRH)

Discusses a series of experiments performed by Thomas Hope in 1805 which show the temperature at which water has its maximum density. Early data cast into a modern form as well as guidelines and recent data collected from the author provide background for duplicating Hope's experiments in the classroom. (JN)