In this work, we described an image processing procedure for the measurement of surface tension of the air-liquid interface using isothermal capillary action. The experiment, designed for an undergraduate course, is based on the analysis of a series of solutions with diverse surfactant concentrations at different ionic strengths. The objective of…

Describes some experiments showing both qualitatively and quantitatively that aerodynamic lift is a reaction force. Demonstrates reaction forces caused by the acceleration of an airstream and the deflection of an airstream. Provides pictures of demonstration apparatus and mathematical expressions. (YP)

Explains the lifting force based on Bernoulli's law and as a reaction force. Discusses the interrelation of both explanations. Considers accelerations in line with stream lines and perpendicular to stream lines. (YP)

The Moire pattern is the shimmering pattern which looks like an odd interference pattern in window screens or folds of nylon shower curtain. Illustrates some of the ways the effect may be used, including demonstration of wave interference, detection of small displacement, persistence of vision, contour measurement, beats, and optical clearness.…

Discusses an experiment which illustrates the non-mixing properties of water at normal temperature with oil because of water's strong, open-ended hydrogen bonding interactions. Examples of the mixing properties between non-interacting substances and the near-complete mixing between water and solvents with limited H-bonding capacity are also given.…

Discusses the change in pressure as a balloon expands. Describes the pressure change in a spherical soap bubble and a rubber membrane on the tube. Provides demonstrations when two balloons are connected by a tube. Lists five further reading materials. (YP)

Forty-eight new secondary science teachers participated in a study that required a listing, discussion, and application of criteria to rank three chemistry laboratory procedures. The three similar lab procedures involved synthesis of a compound from its elements. The top criteria noted by teachers focused on procedural issues (i.e., timeliness,…

Discusses some examples of Fresnel diffraction. Diffraction effects caused by round holes, round obstacles, narrow slits, narrow obstacles, and transparent obstacles are included. (HM)

Summarizes the quantitative relationships pertaining to the operation of electrochemical cells. Energy conversion efficiency, cycle efficiency, battery power, and energy/power density of two types of zinc-silver oxide cells are discussed. (YP)

Describes apparatus for Doppler demonstrations. Provides several pictures of the apparatus and ways it could be used. (YP)

Discusses the calculation of free energy in reactions between silicon dioxide and carbon. Describes several computer programs for calculating the free energy minimization and their uses in chemistry classrooms. Lists 16 references. (YP)

This material describes an activity using vinegar and baking soda to generate carbon dioxide, and writing a report using the Appleworks word processing program for grades 3 to 8 students. Time requirement, relevant process skills, vocabulary, mathematics skills, computer skills, and materials are listed. Activity procedures including class…

Discusses the use of saline solutions for demonstrations of buoyancy showing oscillations of the Cartesian diver. Describes the physical principles, preparation, and instructional uses for the demonstration. (YP)

Described are four musical instruments constructed from polyvinyl chloride (PVC) pipe. The use of computerized synthesizers to play scales and chords is discussed. Suggestions for other illustrations of acoustics are included. (CW)

Defines and discusses jerk, the time rate of change of the acceleration. Presents some cases of jerk with mathematical expressions. Provides questions and problems for classroom use. Lists seven references. (YP)