Describes an experiment (carried out in less than two hours) in which the merits of countercurrent extraction are immediately evident by visible colors. The experiment requires eight 125-ml separatory funnels, 250ml of 1-butanol, 250ml of 0.1-0.5 molar hydrochloric acid, and a small amount of Sheaffer's Skrip blue-black soluble ink. (JN)

Explains the physical principles which result in various colors of the sky. Topics addressed include: blueness, mystical properties of water vapor, ozone, fluctuation theory of scattering, variation of purity and brightness, and red sunsets and sunrises. (DH)

Proposes that colored compounds be classified by reference to a standard color-order system incorporating a color dictionary. Argues that the colors of new compounds could be incorporated into the characterization process and into computer storage systems. (TW)

Reasons for color in sedimentary rocks are explored. Graphs relating the color of rock and corresponding organic content and oxidation state of iron, and of the temporal evolution of a rock sample, are presented. The development of these graphs is discussed. (CW)

Tested demonstrations on (a) color development through the formation of subtractive primary dyes and (b) fluidity of gases are presented. (CP)

Presents several demonstrations in spectroscopy. (RH)

An approach which is designed to help students better understand the utility of models in understanding and doing physics, specifically in a course in light and color, is described in this paper. Explanations are given and illustrations are provided of an analogue model of waves which assist in the creation of an abstract model to deduce Snell's…

Several activities related to color are discussed. These include placing different colors on a disk which, while spinning, appears to be white. Also discusses complementary and primary colors. (JN)

Reports on the colors observed during titrations of 15 natural indicators obtained from common fruits and vegetables. These edible indicators can be used for a variety of teacher demonstrations or for simple student experiments. (JN)

Traces the development of instruments used in spectrophotometry. Discusses how spectrophotometric measurements are made. Describes the color comparator, the filter photometer, and the spectrophotometer. Outlines the evolution of optical systems, including light sources, the monochromator, the photodetector, double-beam optics, and split-beam…

Describes how color graphics are built up on microcomputer displays and how a range of colors can be produced. Discusses the logic of color formation, noting that adding/subtracting color can be conveniently demonstrated. Color generating techniques in physics (resistor color coding and continuous spectrum production) are given with program…

Describes an apparatus (called the "Rainbow Cup") used for demonstrating the colored rings produced by constructive interference in soap films. Discusses construction of the Rainbow Cup and gives hints for its use in the classroom, especially in relation to classroom humidity. (JM)

Provides background theory and an experiment relating to chemometrics. Describes the phenomenon where solutions are dichromatic or dichromic. Discusses the difficulty students have in describing such solutions that appear to be several different colors at the same time. (TW)

Designed to address the major conceptual problems associated with light and vision, appearances of surfaces, and color, this module can be used with high school students or college nonscience majors including those in elementary education. It is one in a series developed by the project "Overcoming Critical Barriers to Learning in Nonmajors'…

Discusses various types of transducers and explains the use of a photoresistor in sensing light. Describes various hardware and software combinations which can be used with photoresistors in science laboratory experiments. Presents general applications of this instrument in light-meter, solarimeter, and colorimeter experiments. (TW)