Low-efficiency solar cells for educational purposes can be simply made in school or home environments using wet-chemistry techniques and readily available chemicals of generally low toxicity. Instructions are given for making solar cells based on the heterojunctions Cu/Cu[subscript 2]O, Cu[subscript 2]O/ZnO and Cu[subscript 2]S/ZnO, together with…

This case was developed for a sophomore organic chemistry lab to illustrate how a combination of techniques is usually required in the identification of chemical compounds. It involves a murder mystery with a forensic twist: Two bodies have been recovered from two different lakes, but because of a mix-up at the morgue, the coroner is unable to…

A study combined 1D (one-dimensional) and 2D (two-dimensional) NMR spectroscopy to solve structural organic problems of three unknowns, which include 2-, 3-, and 4-heptanone. Results showed [to the first power]H NMR and [to the thirteenth power]C NMR signal assignments for 2- and 3-heptanone were more challenging than for 4-heptanone owing to the…

An alternative method that uses a simple apparatus to measure vapor pressure versus temperature in a closed system, in which the total pressure is the vapor pressure of the liquid sample, is described. The use of this apparatus gives students a more direct picture of vapor pressure than the isoteniscope method and results have generally been quite…

An experiment is developed that requires the use of the NMR spectrometer via a NOESY1D experiment to determine the diastereoselectivity in the reduction of alpha-methylbenzoin with various reducing agents. Students must synthesize racemic alpha-hydroxyketones, perform reductions under chelating and non-chelating conditions, and quantitatively…

Ozone is a powerful oxidant and disinfectant, which can be used to clean environment as well as obtain pure drinking water. A series of experiments to produce and test ozone with simple equipment and material are presented.

A study has shown that methylation of 1,8-dihydroxy-9,10-anthraquinone (1) with methyl tosylate is highly dependent upon reaction conditions. When the reaction is carried out by a simple heating of the reaction mixture without solvent it yields dimethyl product in a nearly quantitative yield and refluxing the same mixture of reactants in…

The application of Lewis concept that provides students opportunity to predict and understand reaction behavior and themes in introductory chemistry of structure-property relationships of atoms, ions, and molecules is narrated. The general sequence takes the student through atomic structural theory, electronic configuration, periodicity, chemical…

Providing a biotechnology experience for students can be challenging on several levels, and time is a real constraint for many experiments. Many DNA based methods require a gel electrophoresis step, and although some biotechnology procedures have convenient break points, gel electrophoresis does not. In addition to the time required for loading…

The purpose of this study was to reconstruct writers' reasoning process as reflected in their written texts. The codes resulting from the text analysis were related to cognitive operations, ranging from simple to more sophisticated ones. The sequence of the cognitive operations as the text unfolded represents the writer's cognitive pathway at the…

Since Robert Millikan discovered the quantization of electric charge and measured its fundamental value over 90 years ago, his oil-drop experiment has become essential in physics laboratory classes at both the high school and college level. As physics instructors, however, many of us have used the traditional setup and experienced the tedium of…

Active-learning strategies are increasingly being integrated into college-level science courses to make material more accessible to all students and to improve learning outcomes. One active-learning pedagogy, case-based learning (CBL), was developed as a way to both enhance engagement in the material and to accommodate diverse learning styles.…

The purpose of the paper is twofold: (1) To contrast the longstanding tradition of private and public courses of chemistry with the public demonstrations of physics. Whether taught in public institutions such as the Jardin du Roi or by apothecaries in their officines chemistry demonstrations were not for the entertainment of their audiences.…

In this article, the authors describe steps on how to develop a high-impact activity in which students build, test, and improve their own "coffee can" speakers to observe firsthand how loudspeakers work to convert electrical energy to sound. The activity is appropriate for students in grades three to six and lends itself best to students…

Many general physics laboratories involve the use of springs to demonstrate Hooke's law, and much ado is made about how this can be used as a model for describing the elastic characteristics of materials at the molecular or atomic level. In recent years, the proliferation of computers, and appropriate sensors, have made it possible to demonstrate…