Several unit cells of the crystal lattice of zeolite A are depicted on this month's cover, on a background of zeolite-containing laundry detergent. On page 569, Lindquist and Smoot describe how to extract zeolite A from detergent and outline experiments that illustrate its properties as a water softener, desccant, ion exchange reagent, and catalyst. Figure 1 of their paper and the cover are complementary views of the same structure. The cover shows clearly the long empty channels or pores through the structure, but the figure on page 569 shows more clearly the cage structures, formed by Si-O-Si and Al-O-Al linkages, that surround these pores. The fraction of aluminum in a zeolite can be varied during its synthesis, and for each aluminum in the structure there is a corresponding sodium ion occupying one of the pores. It is the ability of zeolite A to exchange these sodium ions for calcium and other hard-water ions that is the basis for its use as a detergent builder.

Several papers this month deal with programs or courses that involve participants who are soon to become teachers, or are teachers already. On page 522 O'Haver reports on a chemistry course revised specifically to address the needs of preservice middle school teachers, although it continues to serve a broad range of non-science majors as well. Upon his retirement, and to his great surprise, Mayfield (page 523) found himself involved in a highly successful outreach program for high school chemistry teachers. Seven years later the program continued to be so successful that he was still involved. Cody and Hagerman are graduate students who participated in Preparing Future Faculty, a national cross-disciplinary program to help prepare graduate students to become tomorrow's college and university faculty members. Beginning on page 525, they describe the program and their experience in it. Phelps, LaPorte, and Mahood report on development of portfolio assessment, a project carried out by a high school teacher as part of his master's degree work in science education. In the paper that begins on page 528 they argue that this method, though time consuming, has many benefits. These include involving students in the assessment process and requiring that they provide more than just factual recall as a basis for assessment.

Most of us are constantly on the lookout for low-cost sources of substances, apparatus, or instruments that will help our students learn chemistry better. Several examples are provided in this issue in addition to zeolite A. On page 572, da Rocha, Gutz, and do Lago provide directions for making, from parts costing about $20, a conductivity meter whose quality rivals commercial instruments. Burns and Lewis (page 570) describe a different device for measuring conductance that is even less expensive and much easier to build, though less accurate in its quantitative output. Pacer uses a baby bottle and nipple to obtain kinetics data for a classroom demonstration and presents on page 543 an even less expensive version of a demonstration of the influence of acid strength on rate of dissolving of magnesium. Mouthwash is an interesting, inexpensive mixture to analyze for alcohol content and for the dyes that give it color, and on page 567 Siegrist and Anderson show how it can be done. Teggins and Mahaffy (page 566) provide a convenient way to use a wash bottle to follow the kinetics of decomposition of hydrogen peroxidea method that could easily be applied to any reaction in which a water-insoluble gas is produced. Certainly at least one of these ought to strike your fancy, and none of them will hit your budget very hard.

In addition to the baby-bottle and wash-bottle experiments already mentioned, we provide this month several papers involving rates and kinetics. Schultz (page 505) uses dice having different numbers of faces as an analogy for radioactive decay and first-order kinetics, allowing students to discover the statistical nature of radioactive decay and the concept of a half-life. Beginning on page 556, Dakouri and Bodenmüller describe an experiment in which the fading of a substituted phenolphthalein is used to illustrate the effect of ionic strength on reaction rates. Nóbrega and Rocha also provide an experiment in which varying ionic strength affects the rate, but in this case flow-injection analysis is emphasized as an analytical tool (page 560). Finally, El Seoud et al. have expanded the repertoire of the physical chemistry laboratory by developing an experiment in which a kinetic solvent isotope effect can be observed (page 562).

National trends in college general chemistry courses are reported by Taft (page 595) and Abraham et al. (page 591). Ed Walsh provides in our Book & Media Reviews section reviews of several general chemistry textbooks. This issue includes a new featurea comparative review of two textbooks that might be adopted for the same type of course. Petrucci and Harwood is compared with Whitten, Davis, and Peck on page 491. A textbook author, Ronald Gillespie, argues on page 484 that general chemistry textbooks need to be reformed. According to Gillespie's provocative commentary, courses and textbooks have stagnated, and neither has "succeeded in interesting the vast majority of students or in providing them with an understanding of chemistry". He provides five suggestions for reforming textbooks that might be followed by a pioneering author and publisher. Gillespie invites comments from readers, and we expect there will be many.