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Things Computers Do Well
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John W. Moore
University of Wisconsin-Madison, Madison, WI 53706-1396 |
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This issue is out of print. |
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Both this issue and the most recent issue in Series B (IBM compatibles) contain programs that help students carry out calculations and make graphs. George Lisensky's Grafit (1) and Robert Rittenhouse's Notebook (2) provide a means by which large numbers of students, many of whom have little or no computer expertise, can carry out data analysis without spending significant time learning the ropes of a spreadsheet but nevertheless making use of many of the convenient calculational features spreadsheets provide. Grafit and Notebook are ideal for use by beginning students because the way these programs calculate is patterned after the way a pocket calculator works. A column of numbers can be entered (or generated by the program) and then operated on in the same way that a single number entered into a calculator can be operated on: by raising to a power, taking a logarithm, using as an exponential, etc. Two-column operations such as multiply, divide, add, or subtract can also be performed; again the method used is analogous to using a pocket calculator and therefore easy for a student to learn. More importantly, both of these programs go well beyond simple arithmetic. Both allow for plotting of data, either as a histogram or as an X-Y graph. Grafit even permits a three-dimensional graph of three variables. Also, both programs include linear least squares routines that can be used to obtain slope and intercept of data that are expected to be linear. This feature also encourages students to consider how nearly linear (how "good") their data are, and in some cases to repeat experiments to improve the quality of their data. That such analyses can be made numerically was something I did not learn until the summer following my senior undergraduate year, but computers make it a standard tool for essentially all college chemistry students and many high school students as well. In real laboratories chemists no longer plot graphs on preprinted paper nor carry out statistical analyses by means of laborious calculations. Spreadsheets with graphing functions analyze data and generate graphs that are often transferred to electronic as well as paper notebooks. Students are being enabled to work in much the same way by software authors such as Lisensky and Rittenhouse. Just as calculators freed instructors to require more complicated single calculations, column calculators like Notebook and Grafit free us to ask students to collect and analyze much larger, much more realistic data sets. In a kinetics experiment being done at the University of Wisconsin-Madison, students use a computer to collect between 150 and 200 concentration/time data pairs for a reaction under six sets of conditions. Then they use a column calculator to check the order of the reaction, calculate rate constants, and analyze the temperature dependence. Many other experiments, whether computer-interfaced or not, are being done that generate large data sets; analysis of such realistically large data sets is convenient as long as adequate computing power is available. The proof of the utility of such programs is that students who have used them in general chemistry return to the computer room the following year to analyze their data from analytical chemistry laboratories. The other program in this issue, Animation of an Atom-Molecule Chemical Reaction, also makes very effective use of things the computer does well. It provides the freedom to vary any parameter related to the collision of a bromine molecule with an argon atom, compute the trajectories of all three atoms as a function of time, and then display the result as a graphic animation. Such results provide a way of looking at a simple reaction step that has not previously been available to students and that will almost certainly provide new insights about how reactions occur. Even with a reasonably speedy Macintosh, the calculations required for each collision may take several minutes. Each animation requires computing power that would have been available to only a few chemists twenty years ago, but now a very large number of students can benefit from it. A systematic approach to setting up the parameters of each collision can yield a collection of animations that illustrate most of the insights kineticists have gained about detailed, fine-grained reaction mechanisms. And students with a Macintosh and Douglas Kutz's program can experiment with those parameters as much as they wish. The instructional advantages of such experimentation are considerable and quite obvious. In both of these types of software, programmers have made very effective use of the computer's strong points. They have created programs that constitute useful tools by which students can learn more, and more quickly and effectively. The entire purpose of JCE: Software is to stimulate and maintain creativity of the type represented in this issue. I strongly encourage as many readers as possible to think carefully about what kinds of software can be created to help students learn chemistry and to serve as useful tools for both coursework and research. JCE: Software will certainly be interested in as many submissions of this type as we can find, and even if you do not plan to create a program, your ideas about what others ought to be working on will be more than welcome. Please let me know what you think, or, even better, what you have been doing. Literature Cited |
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Last Updated: April 26, 2001 Created: December 3, 1996 |
Created by: J. L. Holmes Comments to: jceonline@chem.wisc.edu |
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| © 1997 Division of Chemical Education, Inc., American Chemical Society. All rights reserved. | |