computer ~erief.58 The three articles in this Computer Series proeress from an introduction to using a sprcabshcct throuih an example spreadsheet calculation of activity coeificienrs to a compurerized solution of 17 simultaneous equations for determining equilibrium pH of a rain drop. Though in the last case the authors have constructed their own program, it is worth noting that similarly complex problems can be solved using programs like TK! S ~ l v e r ' ~an, equation solver that is a science- and engineering-oriented successor to VisiCalcm. At the Project SERAPHIM Powwow Allan Smith of Drexel University demonstrated a raindrop pH calculation for which a student or researcher merely had to formulate equations such as those in Vong and Charlson's article--the computer and TK! Solver literallv did the rest! We ouebt to consider such ~owerfultools (and the more powerful on& that surely are being developed) when makine decisions about how im~ortantit is for e v e n chemistry stident to learn programming.
VisiCalcm for the Teacher Graham Sparrow Centennial College of Applied Arts and Technology P.O. Box 631. Station A Scarborough, Ontario MIK 5E9, Canada VisiCalc is the most popular software package ever marketed. and VisiCoro has essentiallv identical versions for the PC and THS-dU miciocomputers. In addition. ~ p p l e IBM , there are manv other verv similar Talc" t.. we . Droerams.'l'his means that a knowledgeof ~ i s i ~ awill l c allow you to use different machines even if thev have different oroerammine . languages and operating systems. My uses for VisiCalc include keeping all of my grades, and marking the fill-in-the-blank type of data sheet, where students report data and calculate a final result. I have found that
Figure 1. Dacumented sequence of VisiCalc'
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Eastern Michigan university.JOHN Ypsilanti. MI MOORE 48197
students quickly learn to double and triple check their calculations and data when they realize that a computer print out (complete with correctly calculated answers) will be returned with their reoorts. I t has also been my experience that my students and colleaeues are often unaware of the Dower inherent in VisiCalc. a n i the speed and ease with which people can create and modify electronic spreadsheets. I suspect this is because VisiCalc is often thought of as an accounting or businessoriented program. To be sure the rows and columns of VisiCalc were originally designed to accommodate accounting problems, but the presence of trigonometric, logarithmic (both natural and base lo), exponential, and square root capabilities implies a far wider application than just accounting. Also VisiCalc contains commands that allow for the calculation of sums, averages, maximum, or minimum values in a list, comparison of values in tables, Boolean Logic, and format definition. Another bonus with VisiCalc (or similar programs) is that a copy soecifically for your machine may already exist within you; ichoo~or roi~ege&ice. ~t may br isimple matter to get the use of VisiCalc and a micro from the appropriate secretary, and return it when you have finished. In this way your budget does not have to absorb the cost of yet another program, or microcomputer. In VisiCalc, the screen is divided into columns and rows. The intersection of a column (identified alphabetically) and row (identified numerically), defines a cell. Therefore the number of cells is the product of the number of rows and columns, and each cell is identified by a letter (or letters) and a number ie.e.. . - . A3..Q16. . . AD156. etc.) Each cell is initiallv blank. but subsequently may contain a value, a label, or a Formula that will orovideacalculakd result ibr that cell. Sinrc VisiCalc is two-dimensional in its presentation, labels c a i be added to ~
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commands to enter grades and calculate class average.
Volume 62 Number 2 February 1985
139
