Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in "Principles of Optics" by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer…

This research, carried out in Greece on pupils aged 12-16, focuses on the transformation of their representations concerning light emission and image formation by extended light sources. The instructive process was carried out in two stages, each one having a different, distinct target set. During the first stage, the appropriate conflict…

Simple measurements of the decay time of cathodoluminescence are described. Cathodoluminescence is used in many devices, including computer monitors, oscilloscopes, radar displays and television tubes. The experimental setup is simple and easy to build. Two oscilloscopes, a function generator, and a fast photodiode are needed for the experiments.…

To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny…

The purpose of this study was to examine young children's views about shadows. Young children hear references to or are involved in many scientific experiences in their everyday lives, and shadows are a part of children's everyday experiences. Young children may have constructed their knowledge about shadows through their daily experiences.…

The LCD screen of a laptop computer provides a broad, bright, and extended source of polarized light. A number of demonstrations on the properties of polarized light from a laptop computer screens are presented here.

The present study aims to identify first year Turkish Science undergraduates' understandings and misconceptions of the concept of light and its propagation. For this purpose, an instrument composed of four open-ended questions was developed by the researchers. The diagnostic test was piloted with twenty students and modifications were made prior…

When data with and without an optically active sample are acquired simultaneously while one manually rotates the analyser, the graph of the first signal versus the second one is an ellipse whose shape shows the phase shift between the two signals; this shift is twice the optical rotation. There is no need to measure the rotation of the analyser or…

Mass spectrometry has become a routine analytical tool in the undergraduate curriculum in the form of GC-MS. While relatively few undergraduate programs have incorporated biological mass spectrometry into their programs, the importance of these techniques, as demonstrated by their recognition with the 2002 Nobel Prize, will hopefully lead to…

In pursuance of one of the goals of the new South African curriculum to integrate science with Indigenous Knowledge Systems (IKS), this study, which forms part of a larger study, is concerned with determining teachers' and learners' conceptions of a number of familiar natural phenomena. Several recent studies have indicated that: (1) learners do…

This article explores the effectiveness of a computer program--Xcentric viewing--for training eccentric reading in persons with central scotoma. The authors conducted a small study to investigate whether this program increases the reading capacities of individuals with age-related macular degeneration (AMD). Instead of a control group, they…

In this article, a comparison of student learning outcomes is made in sophomore-level physical science classes using a "traditional" pedagogical approach versus a "modern" approach. Specifically, when students were taught the electromagnetic spectrum using diagrams and examples that incorporate technological advances and electronic devices of our…

Beautiful colored interference rings can be produced by using transparent plates such as window glass. A simple model explains this effect, which was described by Newton but has almost been forgotten. (Contains 11 figures.)

Pigeons' keypecking was maintained under two- and three-component chained schedules of food presentation. The component schedules were all fixed-interval schedules of either 1- or 2-min duration. Across conditions the presence of houselight illumination within each component schedule was manipulated. For each pigeon, first-component response rates…

Photoelectrochemical cells using dye-sensitized ZnO with a Cu[superscript 2+]/Fe[superscript 2+]/Fe[superscript 3+] electrolyte can be easily made at home or in a school classroom with household chemicals and other readily available materials. The cells, which are made with wire housed within plastic drinking straws, have open-circuit voltages of…