Investigates the conceptions and representations of light propagation, image formation, and sight typical to preinstruction learners (N=139). Findings indicate that preinstructional students display some familiarity with optical systems, light propagation, and illumination patterns and have not developed a consistent descriptive and explanatory…

Discusses the use of daylight to improve the interiors of educational facilities, offering an overview on the properties of natural light and ways and benefits of ensuring its presence indoors. (EV)

Discusses factors that determine whether or not a sunburn is possible under glass, including the spectral dependence of the skin's sensitivity to sunburn, the ground-level spectrum of solar radiation, and the wavelength dependence of the transmission for the particular piece of glass. Concludes that it is possible to get sunburned through glass.…

Elucidates some aspects of Newton's theory of light and colors, specifically as presented in his first optical paper in 1672. Analyzes Newton's main experiments intended to show that light is a mixture of rays with different refrangibilities. (SAH)

Decscribes a project to make kaleidoscopes. (CCM)

If one looks at a rain cloud with the Sun behind one's back, the sunlight and water drops may interact just right, revealing the familiar arc of red, orange, yellow, green, blue, indigo, and violet. Many of people have been pleasantly surprised to see a rainbow in the sky, but probably have not considered why they occur. Rainbows are caused by…

The interaction between light and matter is examined with the help of a photochemical experiment. This experiment is useful for the investigation of heterogeneous catalysis, semiconductor properties and adsorption phenomena.

A flashed stimulus is perceived as spatially lagging behind a moving stimulus when they are spatially aligned. When several elements are perceptually grouped into a unitary moving object, a flash presented at the leading edge of the moving stimulus suffers a larger spatial lag than a flash presented at the trailing edge (K. Watanabe. R. Nijhawan.…

The relationship between luminance (i.e., the photometric intensity of light) and its perception (i.e., sensations of lightness or brightness) has long been a puzzle. In addition to the mystery of why these perceptual qualities do not scale with luminance in any simple way, "illusions" such as simultaneous brightness contrast, Mach bands,…

In Experiment 1, pigeons were trained at a 0-s baseline delay to discriminate sequences of light flashes (illumination of the feeder) that varied in number but not time (2f/4s and 8f/4s). During training, the intertrial interval was illuminated by the houselight for Group Light, but it was dark for Group Dark. Testing conducted with dark delay…

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…

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…

The present analysis describes an analytically simple and systematic approximation procedure for modelling the free diffusive spreading of initially super-Gaussian profiles. The approach is based on a self-similar ansatz for the evolution of the diffusion profile, and the parameter functions involved in the modelling are determined by suitable…

Some simple modeling with Riemann sums can be used to develop Beer's Law, which describes the relationship between the absorbance of light and the concentration of the solution which the light is penetrating. A further application of the usefulness of Beer's Law in creating calibration curves is also presented. (Contains 3 figures.)