Household water treatments (HWT) can help provide clean water to millions of people worldwide who do not have access to safe water. This article describes four common HWT used in developing countries and the pertinent chemistry involved. The intent of this article is to inform both high school and college chemical educators and chemistry students…

Dimensional analysis is a simple, clear and intuitive method for determining the functional dependence of physical quantities that are of importance to a certain process. However, in physics textbooks, very little space is usually given to this approach and it is often presented only as a diagnostic tool used to determine the validity of…

We propose a series of experiments involving balance readings of an object naturally floating or forced to be partially or fully immersed in water contained in a beaker sitting on an electronic scale balance. Students were asked to predict, observe and explain each case. The teacher facilitated the learning by asking probing questions, giving…

As an experimental project proposed to students in fourth year of university, a viscometer was developed, consisting of a small magnet levitating in a viscous fluid. The viscous force acting on the magnet is directly measured: viscosities in the range 10-10[superscript 6] mPa s are obtained. This experiment is used as an introduction to complex…

We propose an "ab initio" introduction to the well-known Minnaert pulsating bubble at graduate level. After a brief recall of the standard stuff, we begin with a detailed discussion of the radial movements of an air bubble in water. This discussion is managed from an acoustic point of view, and using the Lagrangian rather than the Eulerian…

This article presents a lab experience to study detergency from a physicochemical point of view intended for undergraduate students. By means of a simple experimental device, we analyze the influence of the surfactant concentration in both distilled water and tap water. Our method is based on the measurement of diffuse reflectances of polyester…

Many physical chemistry lab courses include an experiment in which students measure surface tension as a function of surfactant concentration. In the traditional experiment, the data are fit to the Gibbs isotherm to determine the molar area for the surfactant, and the critical micelle concentration is used to calculate the Gibbs energy of micelle…

The cryophorus dramatically demonstrates the cooling effect of evaporation. This article describes some simple and easy-to-make cryophoruses, ideal for demonstrating evaporative cooling to students at all levels. The most dramatic effects occurred with cyclohexane and benzene, with water generally freezing more slowly. (Contains 4 notes, 2 tables,…

This article describes a simple and inexpensive laboratory exercise developed to understand the effect of pressure on phase equilibrium as described by the Clausius-Clapeyron equation. The only piece of equipment required is a pressure cooker adapted with a pressure gauge and a thermometer in the lid, allowing the measurement of the pressure and…

Animations of the particulate level of matter are widely available for use in chemistry classes and are often the primary means of representing molecular behavior. These animations may also be viewed by individual students using textbook Web sites, although without reinforcement or feedback. It is not known to what extent the material in these…

A microscale laboratory experiment to investigate the formation and utility of microemulsions is described. Microemulsions are technologically important fluids that can reduce the use of toxic organic solvents. In the experiment, students prepare a microemulsion and compare the solubility of sudan III dye in the microemulsion and in dodecane. They…

The aim of this study was to elicit students' conceptions about big bubbles in boiling liquids (water, ethanol and aqueous CuSO[subscript 4] solution). The study is based on twenty-four students at different ages and grades. The clinical interviews technique was conducted to solicit students' conceptions and the interviews were analyzed to…

Whether you're a stream studies novice or a veteran aquatic monitor, "Watershed Dynamics" gives you abundant practical resources to extend your students' investigations into local water quality and land-use issues. This two-part set is ideal for teaching biological and ecological concepts and research techniques. It also shows how the interplay…

This investigation is designed to help students understand storm surges on Lake Erie. Activity A includes experiments and discussions intended to help students understand what causes storm surges on Lake Erie. Activity B considers how storm surges affect water levels and, in turn, coastal areas. The student booklet contains questions, experiments,…

This operations manual represents a continuation of operator training manuals developed for the United States Environmental Protection Agency (USEPA) in response to the technological advancements of wastewater treatment and the changing needs of the operations profession. It is intended to be used as a home-study course manual (using the concepts…