We describe a theory of gravity in (1 + 1) dimensions that can be thought of as a toy model of general relativity. The theory should be a useful pedagogical tool, because it is mathematically much simpler than general relativity but shares much of the same conceptual structure; in particular, it gives a simple illustration of how gravity arises…

The Stoner-Wohlfarth (SW) model is the simplest model that describes adequately the physics of fine magnetic grains, the magnetization of which can be used in digital magnetic storage (floppies, hard disks and tapes). Magnetic storage density is presently increasing steadily in almost the same way as electronic device size and circuitry are…

The energy levels of the helium atom and isoelectronic ions in two dimensions are considered. The difficulties encountered in the analytical evaluation of the perturbative and variational expressions for the ground state, promote an interesting factorization of the inter-electronic interaction, leading to simple expressions for the energy. This…

Representations of centrifugal forces are derived in a variety of rotating frames. Although the rotating angle of a point mass relative to an inertial frame is often confused with the rotating angle of a rotating frame relative to the inertial frame, they should be differentiated. (Contains 4 figures and 1 table.)

The immune system is a vital physiological component that affords animals protection from disease and is composed of innate and adaptive mechanisms that rely on cellular and dissolved components. The serum complement system is a series of dissolved proteins that protect against a variety of pathogens. The activity of complement in serum can be…

The force between two parallel current-carrying wires is investigated in the rest frames of the ions and the electrons. A straightforward Lorentz transformation shows that what appears as a purely magnetostatic force in the ion frame appears as a combined magnetostatic and electrostatic force in the electron frame. The derivation makes use of a…

Students often have great difficulties with applications of the energy principle, especially those from biology, although most introductory physics texts include a brief discussion of metabolism. We point out that many of these discussions are unsatisfactory, since they often fail to mention how biological systems are "thermal systems in…

Infinite ladder circuits are often encountered in undergraduate electrical engineering and physics curricula when dealing with series and parallel combination of impedances, as a part of filter design or wave propagation on transmission lines. The input impedance of such infinite ladder circuits is derived by assuming that the input impedance does…

A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

This study examined the English, mathematics, and natural sciences course work taken by students in their first year of college. Four-year postsecondary institutions (k = 110) provided first-year performance data for the first-time, first-year students who began college in the fall of 2006. As in previous research, composition is the most commonly…

A university and a career technical education (CTE) center joined forces to offer dual credit courses. Two institutions worked together to create and implement five different dual credit courses in the areas of physics and mathematics. This paper presents two major findings. First, results of the student's evaluations of their dual credit…

Most scientific endeavors require science process skills such as data interpretation, problem solving, experimental design, scientific writing, oral communication, collaborative work, and critical analysis of primary literature. These are the fundamental skills upon which the conceptual framework of scientific expertise is built. Unfortunately,…

This paper describes the use of weblabs--web based experiments--for cooperative learning by students working together from two different locations to conduct experiments and write reports.

We investigated curricular and pedagogical innovations in undergraduate science courses for non-science majors at a Historically Black Institution (HBI) and a Primarily White Institution (PWI). The aims were to improve students' understanding of science, increase their enthusiasm towards science by connecting their prior experience and interest to…

The authors used a case study-based approach in the introductory biology course at Spelman College. The course taught to entering freshmen was divided into three modules--ecology, evolution, and biodiversity, each designed around a case study. They noted that (1) case study teaching was dramatically more effective than the traditional lecture…