I have used many ploys to start a course in introductory physics, but one of the more interesting ones was to spend 20 minutes describing some of the curves and shapes that we would encounter in our year together. The students saw parabolas, catenaries, hyperbolas, cycloids, circles, ellipses, and helices, and were shown examples, either live or…

The International Union of Pure and Applied Chemistry (IUPAC) and UNESCO have proposed that the International Year of Chemistry, 2011, should make a strong educational contribution to the goals of the UN Decade of Education for Sustainable Development. This emphasis is absolutely necessary because education for sustainability remains practically…

The paper reviews Einstein's engagement as a mediator and popularizer of science. It discusses the formative role of popular scientific literature for the young Einstein, showing that not only his broad scientific outlook but also his internationalist political views were shaped by these readings. Then, on the basis of recent detailed…

In many labs on photosynthesis, the presence of starch in leaves is used as an indirect indicator of photosynthetic activity. Students do starch tests on leaves from plants that have been kept under a variety of conditions in order to check parameters for photosynthesis. The starch test can also be used to enable students to discover differences…

The transport of water in plants is among the most difficult and challenging concepts to explain to students. It is even more difficult for students enrolled in an introductory general biology course. An easy approach is needed to demonstrate this complex concept. I describe visual and pedagogical examples that can be performed quickly and easily…

In a recent article by the authors, the suggestion was made that arrow pushing, a widely used tool in organic chemistry, could also be profitably employed in the teaching of introductory inorganic chemistry. A number of relatively simple reactions were used to illustrate this thesis, raising the question whether the same approach might rationalize…

Nearly 100 years ago de Donder introduced the term "extent of reaction", ?. We build on that work by defining the concept of reagent extrema for an arbitrary chemical reaction, aA + bB [reversible reaction] yY + zZ. The central equation is ?^[subscript i] = -n[subscript i,0]/?[subscript i]. The symbol ?^[subscript i] represents the…

Throughout the centuries, the concept of "element" has undergone a clear evolution from a strictly philosophical area to the scientific domain, although the conceptual progress has not always gone along with a terminological evolution. Some inconsistencies in the definition of element can be found in several precollege and…

A hypothesis-driven laboratory is described that introduces students to the complexities of ecosystem function. Students work with live algae, brine shrimp, and sea anemones to test hypotheses regarding the trophic interactions among species, the exchange of nutrients and gases, and the optimal ratio of producers to consumers and predators in…

To create rich learning experiences, it is important to engage students from the very beginning of a course and lay the foundation for constructing a community of active learners. The activities described here using "organism cards" connect students' previous knowledge to course goals and address key themes in biology while initiating…

Students sometimes misunderstand or misinterpret scientific content because of persistent misconceptions that need to be overcome by science education--a learning process typically called conceptual change. The acquisition of scientific content matter thus requires a transformation of the initial knowledge-state of a common-sense picture of the…

In a previous paper that focused on the transmission of periodic waves at the boundary between two media, we documented difficulties with the basic concepts of wavelength, frequency, and propagation speed, and with the relationship v=f[lambda]. In this paper, we report on student attempts to apply this relationship in problems involving two-source…

Herein, a slightly enhanced version of extended Huckel molecular orbital theory is applied to demonstrate the spontaneous distortion of 1,3,5,7-cyclooctatetraene from a perfect octagon, a consequence of the Jahn-Teller effect. The exercise is accessible to students who have been introduced to basic quantum mechanics and extended Huckel molecular…

This paper presents a comparative study of the thermal efficiencies of mechanical heat engines by using a graphical approach based on the pressure-volume ("P-V") diagram. Three types of idealized thermodynamic cycles--the Otto, the Diesel and the Brayton--are compared in pairs. Given the same temperature range within which the engines…

Catalysis with transition-metal complexes is a part of the inorganic chemistry curriculum and a challenging topic for upper-level undergraduate and graduate students. A hands-on teaching aid has been developed for use during conventional lectures to help students understand these catalytic reactions. A unique method of illustrating the…