This experiment uses a radioactive technique to determine the relative leaving abilities of chloride and iodide in nucleophilic substitution reactions. (DT)

Two experiments are described which illustrate preparative as well as mechanistic features of the reactions of halogens with alkanes and alkenes. (DT)

By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

Describes a method for direct calculation of energy levels by using elementary techniques. Describes the limitations of the approach but also claims that with a minimum amount of labor a student can get greater understanding of atomic physics problems. (PS)

Suggests a first-order experiment that can be used to establish the Lorentz transformation without considering the constancy of light velocity or the full set of Maxwell's equations. Involves the use of a long solenoid to create an electric field in a moving magnetic field. (LC)

Supplies procedure, testing questions, and sample working graph for an activity in testing an operating principle of small gasoline engine. (MU)

Describes several approaches to handling the technical problems that arise in televising science experiments. The article is written in French and includes a short summary in English. (AA)

This experiment subjects bacteria in a food sample and an environmental sample to conditions of sublethal stress in order to assess the effectiveness of the agar overlay method to recover sublethally injured cells compared to direct plating onto the appropriate selective medium. (SAH)

Describes the construction and use of an inexpensive colorimeter that reliably estimates the phosphorus concentrations in water. Presents a two-step modification to an existing photometer. (SAH)

Describes a laboratory course that introduces students to chemistry using examples commonly encountered in the supermarket and on the dinner table. Acquaints students with simple chemical tasks that can be practiced at home, including the making of wine, ale, soap, cheese, and yogurt, and introduces them to the small-scale production of…