Size and scale cognition is a critical ability associated with reasoning with concepts in different disciplines of science, technology, engineering, and mathematics. As such, researchers and educators have identified the need for young learners and their educators to become scale-literate. Informed by developmental psychology literature and recent…

Reports on a low-cost and unique molecular model set capable of generating a large number of structures for teaching and learning general chemistry. An important component of the kit is an 11-hole ball that gives tetrahedral, octahedral, trigonal, trigonal bipyramidal, and square planar symmetries. (WRM)

Evaluates first-year college students' perceptions of molecular modeling. Examines the effectiveness, integration with course content, interests, benefits, advantages, and disadvantages of molecular modeling. (Author/CCM)

Describes a laboratory activity in which polystyrene spheres in two preassembled motifs must be arranged to form a tetrahedral structure. (MLH)

Compares the coulumbic point charge model for hydrogen chloride with the valence bond model. It is not possible to assign either a nonpolar or ionic canonical form of the valence bond model, while the covalent-ionic bond distribution does conform to the point charge model. (JM)

Describes a bonding theory which provides a framework for the description of a wide range of substances and provides quantitative information of remarkable accuracy with far less computational effort than that required of other approaches. Includes applications, such as calculation of bond energies of two binary hydrides (methane and diborane).…

Shows how to make close-packed models from balloons and table tennis balls to illustrate structural features of clusters and organometallic cluster-compounds (which are of great interest in the study of chemical reactions). These models provide a very inexpensive and tactile illustration of the organization of matter for concrete operational…

Provides instructions for making, inexpensively from envelopes, two polyhedra that illustrate chemical geometries. The individual steps involved, supported by detailed diagrams, are included. (JN)

Discusses a successfully implemented laboratory experiment that compares the strengths and weaknesses of mechanical and computer models. The computer models used are available from the Quantum Chemistry Program Exchange (QCPE) at a modest price. (JN)

Discusses a simple, effective way of teaching S and R configurations for chiral molecules containing asymmetric centers. The method involves converting wedge/spatial representations to Fischer projections and prioritizing groups according to the Cahn-Ingold-Prelog sequence rules. Two examples illustrating the method are included. (JN)

Describes the use of balloons to show the shape of atomic orbitals and their orientation in molecules. (MLH)

Explains a new design for a cheap manual model to illustrate a popular alternative mechanism for pseudorotation, in five-coordinate compounds. (Author/GA)

Describes the use of rubber hand-stamps to generate molecular pictures. These stamps (prepared with shapes of atoms and molecules at little cost by small, local print shops) can be used in creating pictures representing the microscopic state that can be linked to macroscopic descriptions for active conceptual exploration. (JN)

Describes plastic, skeletal molecular models that are color-coded and can illustrate both the conformation and overall shape of small molecules. They can also be converted to space-filling counterparts by the additions of color-coded polystyrene spheres. (MLH)