The problem of an oscillating magnetic dipole at the centre of a lossless dielectric spherical shell is considered. For simplicity, the free-space wavelength is taken to be much greater than the shell radii, but the relative permittivity [epsilon][subscript r] of the shell is taken as much greater than unity, so the wavelength in the shell could…

In an inhomogeneous magnetized plasma the transport of energy and particles perpendicular to the magnetic field is in general mainly caused by quasi two-dimensional turbulent fluid mixing. The physics of turbulence and structure formation is of ubiquitous importance to every magnetically confined laboratory plasma for experimental or industrial…

This article proposes a new method for measuring school desegregation in multiracial districts, and uses the new method to measure the desegregation effects of magnet schools in Los Angeles. Rather than measuring desegregation between only two groups at a time, I compute the index of interracial exposure for Blacks, Whites, Latinos, and Asians.…

Since the 1970s, school choice--the opting out of assigned neighborhood school for other schools--has studied extensively in American education. It is considered a possible means to equalize educational opportunity as well as to achieve educational excellence. The expansion of school choices is an ongoing trend, and so is the debate over school…

Since the early 1990s when the nation's first charter school was opened in Minneapolis, the scope and availability of school-based options to parents has steadily expanded. No longer can public education be characterized as a monopoly. Sponsored by the National Center on School Choice (NCSC), this handbook makes readily available the most rigorous…

This paper illustrates a series of activities designed to encourage fourth to sixth-grade students to develop their conceptions of magnets. Through scaffolding activities and facilitation from the teacher, students will be able to generate, evaluate, and refine their explanations for how magnets work. Students can gradually develop sophisticated…

The purpose of this study was to determine whether children's recall of tones, numbers, and words was supported by a common temporal sequencing mechanism; whether children's patterns of memory for tones, numbers, and nonsense words were the same despite differences in symbol systems; and whether children's recall of tones, numbers, and nonsense…

This report provides standard facts and figures about the Houston Independent School District's (HISD) finances, student populations, achievements, and more. HISD has humanized that data, as well, with vignettes and profiles that typify the remarkable programs and individuals in the district. One of the three drivers to achieve the vision of…

In this paper, we discuss a simple apparatus and accompanying class activity that we have developed to illustrate the Biot-Savart law. Since students in introductory electricity and magnetism courses often find this law a mathematical mystery, we feel that a simple experiment such as this will provide the students a better understanding of the…

The article "Torsional Oscillations with Lorentz Force" by Paul Gluck provides a glimpse into the major world of ancient physics demonstrations in the late 19th and first half of the 20th centuries. The apparatus that was described and similar pieces of apparatus are the basis for many memorable but long forgotten educational demonstrations. The…

Measured magnetic susceptibilities of paramagnetic substances must typically be corrected for their underlying diamagnetism. This correction is often accomplished by using tabulated values for the diamagnetism of atoms, ions, or whole molecules. These tabulated values can be problematic since many sources contain incomplete and conflicting data.…

Introductory calculus-based physics textbooks state that electromagnetic waves are transverse and list many of their properties, but most such textbooks do not bring forth arguments why this is so. Both physical and theoretical arguments are at a level appropriate for students of courses based on such books, and could be readily used by…

We have built a device that uses the Lorentz force on a current-carrying wire situated in a magnetic field, F = I L x B, in order to demonstrate a slowly varying alternating current by means of an optical lever. The apparatus consists of a horseshoe magnet, a length of thin enamel-coated wire (ours was 0.3 mm thick), a signal generator, a…

In the last several years, the electronics industry has released hand generator-powered flashlights, which are advertised as the end of battery-powered flashlights. This has become possible because of recent advances in capacitor, magnet, and LED technology. Nevertheless, the physics behind these flashlights is fairly simple.

Children's mental representations about physical concepts and phenomena play a vital role in the learning process. This is confirmed by the data derived from relevant researches which demonstrate that the students formulate incompatible ideas compared with the scientific ones. In this research we investigate the representations of 14-15 years old…