Two curious thought experiments concerning the speed of light are presented which have been used to provoke the interest of undergraduate physics students. (Contains 2 figures.)

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…

Here, we propose a simple method for measuring the built-in potential and its temperature dependence of a photodiode by a photosaturation technique. The experimental design facilitates both current-voltage and null voltage measurements as a function of white light intensity. This method gives the built-in potential directly; as a result its…

An apparently unnoticed analogy between the torque-free motion of a rotating rigid body about a fixed point and the propagation of light in anisotropic media is stated. First, a new plane construction for visualizing this torque-free motion is proposed. This method uses an intrinsic representation alternative to angular momentum and independent of…

Single photons are used for fundamental quantum physics experiments as well as for applications. Originally being a topic of advance courses, such experiments are increasingly a subject of undergraduate courses. We provide interactive screen experiments (ISE) for supporting the work in a real laboratory, and for students who do not have access to…

The interactive nature of computer simulation allows students to develop a deeper understanding of the laws of charged particle optics. Here, the use of commercially available optical design programs is described as a tool to aid in solving charged particle optics problems. We describe simple and practical demonstrations of basic electrostatic…

Discusses the energy flux-density of two beams of light of equal energy that are intersected at a given angle. Examines an apparent contradiction to the physics law of conservation of energy known as Vavilov's paradox. (MDH)

While the new movement in the teaching of physics--the study of the physics of daily life--is the keynote of the recent text-books, yet the laboratory manuals still adhere to the old method, leaving the presentation of material from everyday life to the text-book alone. It is the authors' belief that the manual as well as the text-book should be…

In this article the effect of light quality on the size of the photosystem II (PSII) light harvesting complex (LHCII) is studied by measuring the chlorophyll fluorescence emitted by leaf sections of oat ("Avena sativa," var. Prevision) plants previously treated with either white light or with light filtered through blue, green, red or farred…

Sunlight (solar radiation) provides many beneficial contributions to mankind, including warmth and energy, vision and photoresponses, photosynthesis, and vitamin D synthesis. Along with these positive benefits attributed to solar radiation, there are also adverse effects. A particular adverse effect of current interest and concern which is…

Designed to use simple materials that can be found in almost any household, this document provides elementary teachers and students with activities and worksheets that deal with basic scientific concepts. The activities are intended to help students form and test their own hypotheses. Each topic in the booklet is addressed through a simple…

The Zimbabwe Secondary School Science Project (ZIM-SCI) developed student study guides, corresponding teaching guides, and science kits for a low-cost science course which could be taught during the first 2 years of secondary school without the aid of qualified teachers and conventional laboratories. This ZIM-SCI study guide presents activities…

This ninth grade student manual was developed to be used in conjunction with some of the experimental science activities described in the teacher's guide. It contains laboratory worksheets for: (1) measurement; (2) basic energy concepts; (3) heat energy; (4) light; (5) sound; (6) electricity; and (7) present and future energy resources. Additional…