The mathematical solution to a Piagetian experiment involving topological concepts reported in a recent book is labeled as a sham. The correct solution is given and discussed. (MP)

Divides the stated aims of practical work, listed in some of the A-level syllabuses of the GCE examining boards, into four groups and discusses each: didactic aims, the development of skills, the scientific method, and affective aims. (GA)

Gives a brief description of open-circuit wind tunnels of rectangular cross-section and of how expanded polystyrene can be used to build a small one. (Author/GA)

This simple and inexpensive experiment is an illustration of the physical concepts of interaction between light and surface tension waves, and provides a new method of measuring surface tension. (Author/GA)

Discusses the following: another version of Doppler beats; alternate proof of spin-1 sin-1/2 problems; some mechanisms related to Dirac's strings; Doppler redshift in oblique approach of source and observer; undergraduate experiment on noise thermometry; use of the time evolution operator; resolution of an entropy maximization controversy;…

Investigates and explains the phenomenon associated with Rubens flame-tube demonstration, specifically the persistance of flames at regular intervals along the tube for few minutes after the gas is turned off. (GA)

A novel and efficient (34 percent overall) multi-step synthesis of the housefly sex attractant, muscalure, is described. Each of the steps involves types of reactions with which the undergraduate student would be familiar after one-and-one-half semesters of organic chemistry. (BB)

Traces the early history of an experiment, the launching of a copper or aluminum ring above the pole of an alternating current magnet at switch-on, that was conducted by Elihu Thomson in the last century and presents a simple qualitative explanation of the effect involved. (GA)

Describes the design of an experiment that is used to determine the acceleration of an accelerating system with the help of an airtrack and a pendulum. (GA)

Describes demonstrations used by the nineteenth century physicists to determine if two bodies oscillating at the same acoustic frequency were in phase. (GA)

Describes a simple method to measure the size of the Earth to an accuracy of order of magnitude 10 percent. The procedure involves finding the time interval between two sunsets, a sunset observed at sea level while lying down, and a sunset viewed at eye height after standing up. (GA)

Discusses several aspects of Fraunhofer diffraction patterns from apertures illuminated by diverging light. Develops a generalization to apertures of arbitrary shape which shows that the sizes of the pattern are related by a simple scale factor. Uses the Abbe theory of image formation by diffraction to discuss the intensity of illumination of the…

Amylose azure can be used as a chromogenic substrate for alpha-amylase in studying the effects of temperature and pH enzyme action. This is a model system which students can use to measure the energy of activation using the Arrhenius plot. (Author/BB)

Describes undergraduate chemistry curricula in which the student is asked to either build a model of one asymmetric unit in the unit cell and to indicate the positions of the symmetry-related units by putting in key atoms, or to identify on a prebuild model the asymetric and symmetry-related units. (BB)

An inexpensive DNA preparation is presented which starts with commercially available frozen packed bacterial cells. Methods for analyzing the DNA are also presented, along with physical chemical experiments which can be done using the purified DNA. (BB)