Describes an undergraduate chemistry experiment in which the concentration of chloride, fluoride, or bromide ions can be quantitatively determined by titrating with mercury (II) ions. (MLH)

Describes an undergraduate organic chemistry experiment which illustrates the use of organoboranes in organic syntheses and provides for the anti-Markownikoff hydration of alkenes. (MLH)

Describes the five-step procedure in the construction of a landform model for the teaching of weathering and erosion on different geographical profiles. (GS)

Describes a circuit (utilizing simple equipment) which can be used to measure the period of a harmonic oscillator. (CP)

Provides schematics and discussion needed to construct an inexpensive device for classroom demonstrations involving beats and interference. (CP)

Describes the operation of Educational Expeditions International (EEI), a private organization which links interested amateurs with professional researchers on exploratory adventures. EEI funds scientists and their studies for which amateurs pay for the privilege of joining. (CP)

Provides a technique for the determination of the mass of a large, movable object. (CP)

Describes easily constructed "black box" activities designed to introduce students to the concept of a scientific model. Exposes students to the scientific method of research and to the multiple models which can be hypothesized for many phenomena. (CP)

Reviews Piaget's stages of development and describes types of educational activities which are appropriate for specific levels of cognitive development. (CP)

Applies the charge cloud model of atomic and molecular structure to three problems to show simplicity of calculations and interpretation of results. (CP)

Two mechanics problems which clearly show relativistic correction factors and may be suitable for introductory mechanics instruction are shown. (CP)

Describes a method to experimentally determine the longitudinal shift of a microwave beam at total internal reflection. Suggests that the activity be incorporated into an undergraduate laboratory program due to its ease in set-up and clarity of results. (CP)