KINDAT and Kinetics-Introducing
Undergraduates to the Computer
The extensive role played by computers today in scientific undertakings compels us to seek a means of introducing chemistry students to the computer as early as possible in their careers and particularly within the context of a subject matter area. Although our heavily burdened three-year program will not permit any formal computer courses earlier than the second year, we have achieved rather encouraging results with a CAI-type program called KINDAT' which introduces our first year students t o the utility of a computer in organizing and reducing experimental data. The program is specifically designed to handle the data obtained by the students in a kinetic analysis of the hydrogen peroaide-iodide svstem.. an elerant "clock" r e a c t i ~ n Durine .~ the laboratorv exercise the students determine oseudo-first-order rate conrtanrs with respect to hydrogen peroxide at several acid concentrations, as well as the analogous rate eonatants with respect to the iodide ion. These latter constants are determined by the method of rnitrnl rates since the iodrde ion eoncentration remains constant during the course of a run. After completing the laboratory work, the students make use of KINDAT in analyzing their raw data. The program begins with a brief description of its three sections, corresponding t o the calculation of the two sets of pseudo-first-order rate constants as well as an evaluation of the actual second and third order ones. After instructing the student to enter his initial parameters, the program guides him through the computations with considerable attention t o detail for the first run and correspondingly less detail for the successive ones. The computer requires the student to demonstrate his understanding of the calculatianal methods by answering correctly several of the pertinent questions posed. Incorrect responses invite a second chance a t a similar question often fallowing a short exposition of the principle involved. Much to the delight of the students, the computer tabulates and graphs their experimental data, waits patiently while they "eyeball" the best line through their points and then proceeds to show them the mathematically most correct line for their data. Mast of the students were eager t o experiment with the option of discarding the more deviant points and observe their influence on the rate constants and correlation coefficients. Since none of the first year students were expected to have any prior knowledge of APL, nemonic functions such as START. RESTART. and STOP were desiened to handle the svstems commands that control the loadine and swine of " the individual wwkspacev. In addi~ion,a CA1.C feature provided a temporary exit irom the program mode for the pur. pose of exploiting the romputacional features of the cumpuler. Hy entering 51'01' at any request fur input. the student', place in the program is saved and he is signed off autumatically. At his next iersiun he is given the choke of continuing where he left off or starting anew a t any section of the program. We have allotted two 4-hr laboratory periods for the experiment. Part one of the kinetics requires a full period, while the second part, the initial rate determinations, can he easily completed in 2% hr after which the laboratory is adjourned. A meeting is convened for the remaining 90 min during the following week after the students have completed their calculations and submitted the listines to their instructors. At this time the results and imolieations of the entire experiment are rewewed in llaht of the experiences encountered at the terminals. The meeting is run as a formal reeitation during w h ~ hn has15 fur discarding experimental points, as well as the apparent non-linearny of several of the graphs toward the ends of the reactions is discussed. At this same time, we attempt to give some meaning t o the statistical parameters used in the program and develop the idea behind a least squares treatment of experimental data. During this session we also tried t o correct the natural tendency of students t o accept anything that comes out of the computer as infallible. Fortunately, one can always count on finding a few explicitly absurd examples to work with in each group. In conclusion, we have found a simple hut effective means of introducing freshmen to the utility of a computer as a tool in scientific experimentation. The tutorial format in the program de-emphasizes the computer as merely a hlackbox apparatus for processing data. The selected kinetic determinations are ideally suited to this type of treatment in that the basic algebraic relationships inherent in the calculations are not lost in using the program. On the contrary, the extensive use of the computer's graphic facilities had a far greater impact on the students than in the past when the computer was not used. The author wishes t o thank Mr. D. Speizman for his patient assistance in debugging the programs. Financial support by the Bar-Ilan University Research Committee Grant No.161-84-22-2 is gratefully acknowledged.
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The program is written in APL'PLCS hut ir easily made compatible with APL 360. 2Shurvell, H. F., J.CHEM. EDLT.,4?.577 ,19K,. Bar-Ilan University Ramat-Gan, Israel
436 / Journal of Chemical Education
M. Ben-Zion
