The pages of "The Physics Teacher" have featured several clever designs for homemade diffraction gratings using a variety of materials--cloth, lithographic film, wire, compact discs, parts of aerosol spray cans, and pseudoliquids and pseudosolids. A different and inexpensive method I use to make low-resolution diffraction gratings takes advantage…

In electric or mixed electric-mechanic systems, the distinction between potential and kinetic energy is not as clear as in purely mechanical systems. A solution for the motion of an inductively loaded rail generator is presented. In this case, the magnetic field energy (1/2)Li[superscript 2] can be written "formally" in terms of a potential…

The history of science (HOS) has proven to be a useful pedagogical tool to help students learn about what has come to be regarded as an agreed upon set of core nature of science (NOS) tenets. The following article illustrates an example of how teachers can instrumentally use the history of research on heterozygote protection in sickle-cell anemia…

We have optimized a procedure for igniting hydrogen-filled balloons containing metal salts to obtain the brightest possible flash while minimizing the quantity of airborne combustion products. We report air quality measurements in a lecture hall immediately after the demonstration. While we recommend that this demonstration be done outdoors or in…

As well as being a founding father of modern chemistry and physics Michael Faraday was also a skilled lecturer, able to explain scientific principles and ideas simply and concisely to nonscientific audiences. However science didactics today emphasizes the use of open and student-centered methods of teaching in which students find and develop…

This laboratory project is one component of a semester-long advanced biochemistry laboratory course that uses several complementary techniques to study tRNA[superscript Phe] conformational changes induced by ligand binding. In this article we describe a set of experiments in which the thermal unfolding of tRNA[superscript Phe] is studied with…

Organic reactions in introductory organic chemistry courses are most commonly taught with a mechanism-based approach to the understanding of molecular reactivity. However, the effectiveness of the popular curved arrow representation to describe reaction mechanisms is often compromised by the overuse of shortcuts and obscure notation. The…

A carousel gives possibilities to explore physics in rotating systems and to gain first-hand experience of methods to measure rotation, without the need for an external reference. This paper discusses the Foucault pendulum, as well as the sideways deflection of horizontally and vertically moving objects in a rotating system. These experiments lay…

The Trends in International Mathematics and Science Study (TIMSS) Video Study explored instructional practices in the United States (US) in comparison with other countries that ranked higher on the 1999 TIMSS assessment, and revealed that 8th grade science teachers in the US emphasize activities over content during lessons (Roth et al.…

A novel instructional computer simulation that incorporates a dynamic analogy to represent Le Chatelier's Principle was designed to investigate the contribution of this feature to students' understanding. Two groups of 12th grade Chemistry students (n=15) interacted with the computer simulation during the study. Both groups did the same…

Teaching science through inquiry-based, student-centered instructional methods has been consistently emphasized by science education reform documents such as the National Research Council's (NRC) "National Science Education Standards" (NSES), and practically all states have adopted inquiry standards. In order for science education…

Design-based research, and particularly its theoretical status, is a subject of debate in the science education community. In the first part of this paper, a theoretical framework drawn up to develop design-based research will be presented. This framework is mainly based on epistemological analysis of physics modelling, learning and teaching…

Understanding the particulate nature of matter (PNM) is vital for participating in many areas of science. We assessed 11 students' atomic/molecular-level explanations of real-world phenomena after their participation in a modelling-based PNM unit. All 11 students offered a scientifically acceptable model regarding atomic/molecular behaviour in…

Students become deeply involved in physics classes when spectacular demonstrations take over from abstract and formal presentations. In this paper we propose a simple experimental setup in which the wave behavior of light can be made spectacularly evident along the whole path of the light beam in a practically unlimited number of configurations.…

The toy model rocket is used extensively as an example of a realistic physical system. Teachers from grade school to the university level use them. Many teachers and students write computer programs to investigate rocket physics since the problem involves nonlinear functions related to air resistance and mass loss. This paper describes a nonlinear…