Using the layout described here (which could be photocopied or handwritten), students can see how the periodic table was first envisaged after finding similarities in the properties of common elements. Then, with more discoveries some gaps were filled and, when additional elements did not fit, new groups had to be included.

The motion of a bead along a path restricted to straight lines (restricted brachistochrone), sliding without friction from rest and accelerated by gravity, is considered. For two shapes of path, the geometry of the route optimized to provide the least travel time from one point to another is obtained. The bead's travel times, path lengths, and…

This paper describes a very simple, but accurate method of finding the position of the infinity focus of a telescope objective relative to the rear face of its lens cell. The method is easily undertaken in the classroom and provides an opportunity for learners to conduct an interesting and novel optical experiment which introduces thick lens…

An easy operating tool has been developed for the quick measurement of thermoelectric power. The setup is made using a tweezer which consists of two circular copper plate electrodes. These copper electrodes are fixed to two arms of the tweezer which act as hot and cold probes. The setup has the very important advantage of easy sample mounting and…

Before reading this essay, go to your kitchen and find a bottle of Italian salad dressing. Get one that has been sitting still for a while at a fixed temperature--that is, one in thermal equilibrium. You will find an oil-rich layer at the top of the bottle and a vinegar-rich layer at the bottom (see Fig. 1). But think for a moment before spreading…

In this paper we are interested in the relationship between disciplinary knowledge and its representation. We carry out a social semiotic analysis of a central tool used in astronomy--the Hertzsprung-Russell (H-R) diagram--in order to highlight its disciplinary and pedagogical affordances. The H-R diagram that we know today combines many layers of…

Benchtop NMR spectrometers are now becoming more widely employed in university teaching laboratories. These low-field instruments are increasingly used in reaction monitoring and product purity applications. NMR spectra obtained using these spectrometers (40-80 MHz) tend to suffer from significant overlap of signals when compared to those obtained…

A popular physics legend holds that scissors can cut paper with a speed faster than light. Here this counter-intuitive myth is investigated theoretically using four simple examples of scissors. For simplicity, all cases will involve a static lower scissors blade that remains horizontal just under the paper. In the first case, the upper blade will…

Science communication and science education aim to expose citizens to scientific knowledge, which is increasingly becoming a prerequisite for effective participation in modern society. We aim to present a review of science communication and science education literature, for highlighting the need for and importance of narrowing the gap between the…

Green chemistry is the name of a need, that of encompassing chemistry research and the environmental, safety, health, and societal issues that have been creating unprecedented concerns at a global level. Green chemistry is a modern concept, as the label that represents the entry of chemical sciences in the realm of integrated sustainability…

This paper mainly proposes a simple method to record scattered light rays via photography, presenting a clearer and brighter representation of the optical path. This technique is applied to the double-slit interference experiment and single-slit diffraction experiment typically conducted in general physics courses, and shows the intuitive results…

Practical hands-on experience is an effective component of science education. Lessons that involve demonstrations allow learners to explore and verify information learned from other sources (for example, reading a textbook). As a demonstration for use in a science educational setting, we developed a way to make a variable focal length lens using a…

Carefully scaffolded dynamic visualizations have potential to promote science learning for all students, including English language learners (ELLs) who are often underserved in mainstream science classrooms, but little is known about how to design effective scaffolding to support such diverse students' learning with dynamic visualizations. This…

For 26 years, it has been assumed by some that the thermodynamics of open-system biochemical reactions must be executed by performing Legendre transformations on the terms involving the species whose concentrations are being held fixed. In contrast, standard nontransformed thermodynamics applies to chemical processes. However, it has recently been…

In this study, we visualized the superposition principle of sound waves in a both-closed-end (BCE) resonance tube. The resonance tube is constructed using an acrylic tube with 2.64 cm internal diameter and 150 cm length, polystyrene beads to illustrate the positions of displacement nodes and antinodes and two identical detachable speakers as…