10/12/1995 07:00:00

Chemistry Animation Project Offers First Videos For Sale

PASADENA—The California Institute of Technology's Chemistry Animation Project has completed the first six titles in a series of broadcast-quality educational chemistry videotapes and has released them for sale to teachers and to the public.

The videos illustrate many of the three-dimensional concepts that are central to the basic chemistry curriculum, but that can be difficult to visualize. The six tapes now available cover three introductory topics, "Crystals," "Atomic Orbitals," and "VSEPR" (valence-shell electron-pair repulsion theory); two intermediate topics, "Stereochemistry" and "Nucleophilic Substitution;" and an advanced topic, "The Diels-Alder Reaction."

"Our goal with the project is to revolutionize the way students at all levels can view the chemical world," explained project director and Caltech chemistry professor Nathan S. Lewis. "We want to stimulate the thoughts and curiosity of teenagers, to get them to ask questions and to learn about the topics with vigor, instead of merely obtaining numerical answers for assigned problems on a topic that they cannot understand or fully visualize."

New videos on the topics of "Hybridization and Resonance," "Periodic Trends," and "Molecular Orbitals" should be available later in the 1995–96 academic year, and other titles in the works include "Binary Crystals" and "Spectroscopy/Molecular Motions." Information on each video is available on the World Wide Web at http://bond.caltech.edu.

Videotapes are $19.95 each, with unlimited duplication privileges for an instructor's use by his or her students. To order videos or for more information, contact the Caltech Bookstore by mail at Mail Code 1-51, Pasadena, CA 91125; by phone at (800) 514-BOOK; by fax at (818) 795-3156; or by electronic mail at citbook@caltech.edu.

Details follow about each of the tapes now available.

Crystals (Introductory Level) From gold and diamond to sodium chloride, face-centered cubic crystals characterize many important substances. Within the framework of the face-centered cubic crystal lattice, this tape illustrates Miller indices, lattice vectors, and crystal surface structure. Topics covered: o The unit cell and its relationship to crystal structure o The face-centered cubic unit cell o Miller indices o Low-index cutting planes o The structure of low-index surfaces

Atomic Orbitals (Introductory Level) The sizes and shapes of atomic orbitals play a dominant role in properties of chemical bonding. Key concepts illustrated in this tape include the organization of the periodic table, the shapes of atomic orbitals, and orbital features important for chemical bonding. Topics covered: o Shapes and directions of s, p, d, and f orbitals o The orbital basis for the periodic table o Nodes in orbital shapes

VSEPR (Introductory Level) Valence-shell electron-pair repulsion theory remains one of the simplest, most powerful tools for understanding the shapes of molecules. Based only on simple Lewis dot concepts of chemical bonding, VSEPR allows for the prediction of the shapes and bond angles of a wide variety of molecules. Topics covered: o Bond angles o Steric numbers o Shapes of molecules and the nomenclature of the various molecular geometries

Stereochemistry (Intermediate Level) The three-dimensional arrangement of atoms in molecules plays a crucial role in chemical reactivity. Enantiomers, chirality, diastereomers, Newman projections, and other important aspects of stereochemistry are graphically illustrated in this tape. Topics covered: o Chirality and enantiomers o Enantiomer nomenclature: R versus S o Diastereomers o Conformational isomers o Newman projections o Anti and gauche conformers o Cis and trans (geometric) isomers

Nucleophilic Substitution (Intermediate Level) Nucleophilic substitution provides a classic example of chemical reactions capable of proceeding through multiple pathways. This project explores the stereochemical consequences of these different paths, the concept of a transition state, the possibility of a discrete reaction intermediate, and the interpretation of reaction coordinates in the context of basic nucleophilic substitution reactions. Topics covered: o SN1 and SN2 reactions o Transition states and intermediates o Inversion of configuration in the SN2 reaction o Partial retention of configuration in the SN1 reaction o Introductory kinetics of chemical reactions

Diels-Alder Reaction (Advanced Level) The synthesis of complex substances generally involves challenges in controlling the stereochemical arrangement of molecules. Aspects of stereochemically controlled synthesis, as well as orbital control of reaction products, are featured in this tape. Topics covered: o Structural changes during the Diels-Alder reaction o Orbital control of 4+2 additions o Cis versus trans additions o Relative reactivity of S-cis and S-trans isomers o Cyclization reactions o Endo versus exo additions

Contact: Jay Aller (818) 395-3631 aller@caltech.edu

Written by John Avery