Described is the basic biology involved in mapping chromosomes as presented at a symposium at a recent meeting of the American Chemical Association which focused on the Human Genome Initiative. Different types of gene maps and techniques used to produce gene maps are discussed. (CW)

Presented is a technique for making various molecular models from a strip of paper. Instructions for six models including tetrahedral, trigonal bipyramid, octahedral, pentagonal bipyramid, and capped octahedron models are provided. (CW)

Describes a computer program that allows undergraduate students to undertake nomenclature tutorials in organic chemistry, where user response is evaluated based on a set of rules that determine appropriate feedback. Design of the software is described, including the use of computer graphics, and results of students' evaluations are briefly…

Determined the factor structure of tasks which require students to visualize how diagrams should be drawn to represent effects of rotating three-dimensional structures about the three Cartesian axes. Results obtained from 149 English and 231 Singapore students show that visualization about X-, Y-, and Z-axes are factorially distinct. (DH)

Discussed is the importance of valence bond theory on the quantum-mechanical theory of chemical structure and the nature of the chemical bond. Described briefly are early VB theory, development of VB theory, modern versions, solid-state applications, models, treatment in textbooks, and flaws in criticisms of valence bond theory. (KR)

The pencil-and-paper assignment "Represent water in its three states using a model" was given to pupils (n=227) from eighth to twelfth grades. The findings show that the dominant model used was the space filling type; movement of particles was indicated by a minority of pupils; size of the model changed when drawn in different states.…

The purpose of this investigation was to evaluate the effectiveness of six instructional programs with the aim of alleviating the problems encountered by students in visualizing rotation in molecular diagrams. Models were filmed rotating around the three different axes with different speeds with and without shadows. (KR)