and have requested more extensive replacement of conventional tests. Although some glitches in the data bank surface occasionally (such as print or answer errors) the didactic benefit of enhancing general chemistry instruction with this transferable svstem amears certain. As Shown &the functional flow diagram (Fig. 1) the 5l/4inch MSDOS svstem consists of a COMPOSE disk for exam generation, a TEST disk (written by COMPOSE) for student use and the SOCRATES question bank spread over six individual disks. The SOCRATES index (called TALLY) for the 8500 items in the bank resides on COMPOSE. Before generating an exam the instructor should select from this index the appropriate question file number for each topic. Consequently, a hard copy of the TALLY file is certainly advantageous for efficient exam generation. Machiue-readable copies of the examination system may be obtained by writing to the corresponding author. Acknowledgment The authors would like to thank R. E. Seevers and Ed Williams for valuable technical advice and programming assistance throughout the development of this project. This paper was presented in part a t the 41st Northwest Regional ACS Meeting, June 16,1986.
Computerized Checking of Data in Undergraduate Laboratories D. A.
Alkens, R. A. Balley, and R. L. Strong Rensselaer Polytechnic Institute Troy. NY 12180
An aoolication of oersonal com~utersthat we have found to he v&ahle in the ;ndergraduaie laboratory is checkingof data for acceotabilitv. As we have emoloved this conce~t. the student enters the raw, measured data and receives & immediate evaluation in terms of acceptable/unacceptable-repeat. If unacceptable, there is generally enough time remaining in the laboratory period to repeat measurements as necessary while the apparatus is still set up and solutions are available. Such checking provides an impetus for improved technique and ensures that the results will be able to illustrate those principles that the experiment is intended to address. We frequently follow this checking program, which gives only yeslno answers, with other computer manipulations of the acceptable data. An example of a physical chemistry experiment to which we have applied this approach is that involving electrolytic conductivity. In this standard physical chemistry experiment (3-5). the cell constant of a conductance cell is determined by measuring the conductance of a standard KC1 solution, and the conductance of strong and weak electrolvte solutions (HCI and acetic acid) are measured over a range of concentrations. Such measurements can be made quite accuratelv. but thev can also be verv ~ o o ifr techniaues are carelesi. In our program, students "cieck their cell constant determinations by entering the cell number, KC1 concentration, and conductivity meter readings for KC1 and for the distilled water used in the solution preparation. The known cell constants for all of the cells are stored in the program, which calculates the student cell constant and compares i t with the appropriate value. Agreement within 1%is taken as acceptable. his approach has clearly resulted in an improvement in the quality of data appearing in the student's reports. In the semester preceding the use of this program, approximately 30%of the final reports received exhibited major deficiencies in the form of excessive scatter in the data or values differine from the literature value by 5% or more. Another 10%initial-
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ly reported data that clearly resulted from experimental blunders, such as mislabelling of solutions. The program eliminates all such problems. Repeated measurements have not been unreasonably burdensome, and students clearly spend more effort to get it right the first time. We are using similar programs for a vapor liquid phase diagram experiment (6-8) (checking refractive index values making up the calibration curve used for analysis), and two kinetics experiments (hydrolysis of t-butylchloride (9, 10) and neutralization of nitroethane (11,12)). The decision as to what constitutes acceptable quality results in a teaching laboratory is sub.iective. Except for the conductance experiment, where the standard is based closely on a realistic evaluation of likely sources of error and the students are second-semester iuniors with considerable laboratory experience, we have set our limits to reject the worst 5 to 1070of the results. Such a limit eliminates blunders and gross carelessness, without resulting in excessive requirements for repetition. Results from students with different levels of expkrience or with different equipment might require more or less restrictive limits. In addition, we do not insijt [hat all acceptable results be excellent: there may still be a range umhen the results are ultimately evaluat. of grades . ed for quality. A demonstration disk (IBM-PC) of these programs can be orovided if reouests are accomoanied bv a check for 55.00 to cover handlini costs, made payable to ~ e p a r t m e nof t Chemistry, Rensselaer Polytechnic Institute. Acknowledgment We wish to thank Rensselaer Polvtechnic Institute for providing support for the development of these programs under the Harlan and Lois Anderson Courseware Develonment Grant.
A Student-Generated Database for the Physical Chemistry Laboratory J. A. Wood The Polytechnic Queensgate,Huddersfield.HDl 3DH, United Kingdom
. .. Bv the time students enter ehemistrv courses.. man",~~ are quite adept at pmgramming. Students shmlld hnve o p p o r r u n i t w to use the,? skills within the chemistry rlsssnmn. One w q m dc, this is to give students pnjects that arp related t u the wntenr currently being studied. In this way, chemistry students can use their computer skills to produce software for future classes (13). This is a policy actively pursued with our undergraduate students. By the time they come to the physical chemistry laboratory sessions they have almost finished their basic programming course and it is an ideal time for them to put their newly gained expertise to use. A variety of programming and interfacing exercises have been set as part of this course, and a number of these have been developed into standard laboratory progams in later years after suitable, often minor. amendment. The one described here has proved very popular with students and combines an application of programming skills with an exercise in reference literature searching and data retrieval, the product being a useful database of phvsical . propertv - .data. At each laboratoiysession a pair of students is given the task of compiling a table of data from literature sources available in the departmental chemistry library. They convert this to aBASIC program and then transfer i t to a disk to form part of a growing collection of such tables compiled by other pairs of students, all the data being relevant to lahoratory exercises currently in use, for example, melting points of common solids, boiling points of organic solvents, densities Volume 65 Number 4
April 1986
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