Discusses the Internet and how it works, beginning with its origins in the U.S. military and covering such issues as clients and servers, upload and download, and the World Wide Web. (Author/PVD)

Focuses on the relationship between loudness and intensity of sounds. (Author/PVD)

Focuses on the concepts of pitch and timbre of sounds. (PVD)

Argues that by examining which concepts of a particular area of physics are fundamental and which are defined, teachers can choose concepts for investigation that progress logically and should minimize students' misconceptions and confusion. (Author)

Describes the evolution of the seven major physics syllabi used in all secondary schools in China and analyzes the shifts of these syllabi in terms of objectives, content, instructional hours and teaching methods. Suggests changes for China's future secondary-physics education, including the need for modern experimental equipment such as computers…

Presents a nonmathematical approach to help students understand that there are two types of coherence and to associate coherence as a property of the illumination at an object itself. The approach also lends itself to an introduction to the Fourier approach for analyzing imaging systems. (JN)

Examines the question "Why does light travel at speed c?", dispelling the widespread qualitative notion that the speed of light results from time delays in the interaction of electric and magnetic fields. Also presents information by which readers can work on their own qualitative insights concerning the speed of light. (JN)

Develops a teaching scheme for 11-13 year-olds based on different types of investigational practical work. Includes discussion of difficulties in investigations, four types of investigations, and deployment in the curriculum. (YP)

Discusses the use of logarithm and reciprocal graphs in the college physics classroom. Provides examples, such as electrical conductivity, reliability function in the Weibull model, and the Clausius-Clapeyron equation for latent heat of vaporation. Shows graphs with weighting of points. (YP)

Presents three case studies of physics teachers who left for business and industrial positions. Problems identified as contributing to the teacher shortage are low rates of initial training and low teacher morale. Using extra pay to solve the problem is questioned and predictions are made based on the case studies. (JM)

Shows how air flows around a sail, explaining why a dinghy is able to move toward the wind rather than be blown backwards. Also illustrates the effects of alternating the angle of a sail, using different sail shapes and using a rig consisting of two sails. (JN)

Shows that the angle of projection of a bullet is not the same as the angle of the bore of the firearm just before firing. Includes an equation that is useful when considering the firing of bullets and arrows in the air. (JN)

Describes the nature of gradient refractive index (GRIN) lenses, focusing on refraction in these materials, focal length of a thin Wood lens, and on manufacturing of such lenses. Indicates that GRIN lenses of small cross section are in limited production with applications suggested for optical communication and photocopying fields. (JN)