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…

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.

Additive colors are interesting to young students. In this paper, we show a convenient and straightforward method to demonstrate this phenomenon by projector. It produces defocus blur and reduces imaging quality for color mixing. We believe this demonstration experiment can be performed in most classrooms.

Many years ago I was running the standard laboratory experiment on thin lens optics. The source was the usual self illuminated object mounted on an optical bench, and a converging lens formed a real image on a screen. One of the students sitting near one wall of the darkened lab was having some trouble with the idea of image formation. Her face…

The finale of the weekly physics department seminar series at my college is my annual demonstration lecture. Normally, the front of the room is filled with apparatus, but in May 2008 I had only a giant kaleidoscope and a leaning tower of Pisa (Fig. 1) on display. Instead, there was a pile of overhead projector transparencies that showed examples…

Describes assembly of a moderately priced synchronized projector and cassette tape recorder using a single channel recorder with a tuned amplifier to separate voice and control tones. Construction requires familiarity with transistors and use of an oscilloscope with an audio signal generator. A picture as well as schematics is provided. (GH)

Suggestions are provided for using color television projector systems to demonstrate color mixing. With such a projector, manipulation of the three primary colors can be done by simply covering and uncovering the three separate beams. In addition, projector systems serve as good examples in studying geometrical optics. (Author/JN)

Describes a technique for the projection of triple point demonstrations using apparatus constructed out of Lucite and an overhead projector. (GS)

Describes the use of a faceted geodesic structure in place of the true spherical dome in the construction of an effective and modestly priced planetarium. Indicates that the construction can be undertaken as a student group project. (CC)

Describes construction and use of a simple home-built device, using an overhead projector, for use in demonstrations of the addition of various combinations of red, green, and blue light. Useful in connection with discussions of color, color vision, or color television. (JRH)