The incandescent bulb has been a useful tool for teaching basic electrical circuits, as brightness is related to the current or power flowing through a bulb. This has led to the development of qualitative pedagogical treatments for examining resistive combinations in simple circuits using bulbs and batteries, which were first introduced by James…

This paper presents an argumentation-based demonstration experiment to teach the light-matter interaction using an observable laser beam and vacuum pump. In the experiment, the concept of darkness was addressed using a virtual space environment created by gradually decreasing the pressure inside a quartz glass bell jar with a vacuum pump. This…

This article discusses two "magic tricks" in terms of underlying optical principles. The first trick is new and produces a "ghost" in the air, and the second is the classical real image produced with two parabolic mirrors. (Contains 2 figure and 6 photos.)

In the "The Science Study Series" book "The Physics of Television", it is stated that persistence of vision lasts for about a tenth of a second. This will be a notional figure just as 25 cm is taken to be the least distance of distinct vision. Estimates range from 1/8 to 1/16 s.

Many simple experiments can be performed in the classroom to explore the physics of vision. Students can learn of the two types of receptive cells (rods and cones), their distribution on the retina and the existence of the blind spot.

A discussion of Edwin Land's experiments with color images from black-and-white photographs. Information is presented for duplication of these experiments by the amateur photographer. (BB)

Discusses human ability to perceive repeated sensory stimuli in the visual system, and explains that its frequency fc has a critical value, under normal conditions, about 40 Hz. (GA)

Describes an experiment in which students work together in small groups, take data, and make a calculation to roughly determine the diameter of the blind spot in their eye. (WRM)

Describes an experiment enabling students to apply concept of diffraction, determine limits of their color perception, learn how to measure wavelength with a simple apparatus, observe continuous and line spectra, and associate colors with corresponding wavelengths. The homemade diffraction-grating spectrometer used is easily constructed. (JN)

Uses a projector, a prism, and two screens to demonstrate the composition of white light and detect color. (MDH)