Describes the total internal reflection process that occurs when the internal angle of incidence is equal to or greater than the critical angle. Presents a demonstration of the effect of frustrated total internal reflection (FTIR). (YDS)

Presents resources from Alhazens' investigations on curved mirrors that investigate diffuse reflection from the moon's surface, composite mirrors, and the problem of possible points of reflection. (Author/YDS)

Proposes a ray tracing approach to thin lens analysis based on a vector form of Snell's law for paraxial rays as an alternative to the usual approach in introductory physics courses. The ray tracing approach accommodates skew rays and thus provides a complete analysis. (Author/KHR)

Health educators are in an ideal position to teach individuals about dangers from the sun's ultraviolet light and how to prevent damage to eyes. Ultraviolet light is described, eye pathology which can be caused by it is outlined, and protective eyewear is discussed. (IAH)

Explores some of the principles behind the working of fluorescent bulbs using a specially prepared fluorescent bulb with the white inner fluorescent coating applied along only half its length. Discusses the spectrum, the bulb plasma, and light production. (JRH)

Describes a modification of the traditional demonstration of Newton's rings that magnifies the scale of the interference pattern so that the demonstration can be used for the whole class or for semiquantitative measurements in any high school laboratory. (JRH)

Discusses Fermat's Principle: Light always travels the path that requires the least amount of time. Includes discussion of refraction, angle of incidence, and angle of reflection. (MKR)

Presents an explanation on subtractive and additive color processing using the colors yellow and pink as examples. (MVL)

Discusses descriptions of the way in which an optical system controls the quantity of light that reaches a point on the image plane, a basic feature of optical imaging systems such as cameras, telescopes, and microscopes. (JRH)

Discusses methods for plotting rates of photosynthesis as a function of light quantity. Presents evidence that suggests that empirically derived conversion factors, which are used to convert foot candles to photon fluence rates, should be used with extreme caution. Suggests how rate data are best plotted when any kind of light meter is not…

Presents information on the Latin School of Chicago astronomy club and their activities. Explains the effects of light pollution. (YDS)

This investigation was part of a multi-lesson unit that gave students direct experience using increasingly sophisticated tools to make more detailed observations and measurements of light. Through these lessons, students experienced a key aspect of the nature of science (McComas 2004), namely how scientists constantly refine and modify theories as…

This article reports a design experiment conducted over three successive school years, with the teacher's goal of having his Grade 4 students assume increasing levels of collective responsibility for advancing their knowledge of optics. Classroom practices conducive to sustained knowledge building were co-constructed by the teacher and students,…

New suitable approaches were investigated to visualize the photodynamic inactivation (PDI) of bacteria immobilized on agar surfaces. The PDI capacities of a cationic photosensitizer (5,10,15,20-tetra(4-N,N,N-trimethylammoniumphenyl)porphyrin) and an anionic photosensitizer (5,10,15,20-tetra(4-sulfonatophenyl)porphyrin) were analyzed on a typical…

Several papers have been published on the use of a CD as a grating for undergraduate laboratories and/or for high school and college class demonstrations. Four years ago "The Physics Teacher" had a spectacular cover picture showing emission spectrum as viewed through a CD with no coating. That picture gave the impetus to develop a system that can…