class and hy a few biology students in a n introductory class. Most student reaction t o this program was favorahle. Of the approximately 40 evaluators who completed the entire program, 12% rated it as excellent, 68% as goad, and 12%as average, with only scattered responses of below average or poor. An interesting pattern emerged in the detailed responses of these students. Many of the less experienced computer users were among those who were most impressed with the momam. Thev* tended ta find the use of the program "informative as well as recreational". Mnny commented un the game-like aspects d the early partr of the program. The more experienced users werp leas impressed by the technical details of the p ~ , n a m itself. Although they slaofelt that they toextend their study had learned some of the properties of solutions, they tended to sueeest and f a r re.... that better -erauhies . sponve times would improve the program. Other suggestions were to include dirrussiun uf *tatistical variation and more feed. back from the computer when aquestion in the self-quiz section was missed. Some of the more advanced students who had studied osmosis in other science courses did not feel sufficiently challenged by the subject content, reinforcing the observation that this program will work hest for introductory-level students. Many of the students did not care for the directed format of moving hack and forth from the screen t o a lab booklet. They found that process distracting, although they recognized the usefulness of this booklet. Sugeestions for imorovement here included moditling the program so it offered the option i r f directly entering dntn into the computer and generating the graphsun thecomputer. The best feature of the program for the students was the aspect of experimental design. Even the more sophisticated users had not seen this approach, and they liked i t verv much. Because manv of them did not know much about osmosis, the results were not predictable, and they felt they were conducting a "real experiment". Some of the students worked in groups of two in order t o complete their assignment based on the program. This seemed t o work well; their discussions with each other were directed and h e l ~ f uin l clarifvine the meanine of emerimental results. Thetime snent wi;h the'program varied from 1 . 5 4 hours with :I 3.5 h w r s bring the norm for what they were asked to arcumplish. ~~~~
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Recommendatlons for Improvement The fit hetween the program and the student lah hmklet needs t o be tightened. The option to speed up the .'timed" cycles is essential in the opinion of d l users. Explanation of the assumed allowable limit6 of statistical variation would greatly enhance student understandine. It would benefit some usera u, mrorporate the optlon of be~ngnhlementer data and graph i t uslng the computer itself. An effort could he made t o relate the chosen experiment to real situations. For example, if a large water-soluble molecule were chosen in an experiment, the student could he helped to connect this to some physical reality with the observation that the chosen
molecule is similar t o glucose, followed by a few observations about how this might he important in natural systems. Summary Although the process of osmosis is not usually given too much discussion in general chemistry, it is a very important idea for the majority of our students who use chemistry as a service course for other majors. This program would provide a way to introduce or review osmwis, diffusion, random motion, and the variables that affect membrane transport. The pedagogic strength of this program lies in its unusual approach to designing and interpreting experiments. The law cost ($45) of the program makes this choice of software a good instructional value. Lucy T. Pryde Southwestern College 900OtayLakesRoad Chula Vista, CA 92010
challenged advanced students t o vary the experimental conditions. The ease of use and student reactions convinced me of this. George 0 . Powers Old Town Hlgh School Old Town. ME 04468
E. M. E. Tltratlon Lab Roger Shelion. Educational Materials and Equipment Company. P.O. Box 2805. Danbury. CT 06813. Hardware: Aaale I i famllv components-i d~skand backup. Student Lao Booklets and Study Gu~de Level and Subject: Hngn School Chemistry Cost: $47.00. Summary Ratings: category E m of Use: Sublect Miter Content:
Peda~ogicValue: Student Reaction:
Review II Osmosis and Diffusion covers several different aspects of the use of the computer. In additinn eeneral information. .. to .. nrovidine r ~ . ~~~~" the program user experimentation and testing. 1 found the program tu he usable for my students. I have average or above average students in my chemistry classes. The program could he used whether or not the topic had been previously covered in class. I found t h e material extremely user friendly! Several students, some with and some without computer experience tried this material. Neither group had any difficulties using the program! The documentation was excellent and complete. There was a general guide as well as student lab hwklets. The bwklets provided not only a way of taking notes during the program hut also a data table to complete the experimentation part of the program. Instructions were given on the screen as well as in the booklets. The program can be used with minimal equipment. No additional hardware is needed except the computer, disk drive, and screen. The entire program runs smoothly and easily. The choices shown on the screen are always clear. One convenience is the use of the right and left arrow to go ahead or go hack t o review any screen. This program might he used in several ways: tutorial, self teaching, or remedial. I found the subject matter t o he presented in a clear and straightforward manner. We could not find any errors in the material presented. I did not test the program with students that had not been exuosed t o the mplc hefore. The program was not designed ~ a l l u wthe teacher to modify it. The s t u d e m that used the programs felt that the material was presented well and completely. They found the experiment to be very useful and helpful. Several found the experiment to he the hest part, while othersliked the explanation and quiz better. All mouos thoueht that the ouiz did a e m d l o b i n r o v e r ~ n ~ t h e m a t ~ rAll i d 'thestudents enloyed usmg the computer t o learn. In cuncluaron. I would definitely recommend this program for any teacher who teaches osmosis and diffusion! I t was general enough for any student to use but also ~
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As indicated in the student guide, the E. M. E. Titrotion Lob is an interactive orogram that combines computer-~ssistedInstruction (CAI) with a lab simulation. The major objectives of the program are fourfold. First, the program is designed to help the student master titration procedures. Second, the program will help the student understand certain concepts-molarity, pH, Kw, ion dissociation, E notation, and acid-base neutralization. Third, the program helps the student understand chemical symbols, empirical formulas, metric units, and the use of a buret. Finally, the program will help the student improve on laboratory data collection and computational skills. The Titration Lab program is designed for the average and a h & average first-year chemistry student in a beginning high school chemistry class. Because of the nature of the program, the goals are too far reaching. The student must know the concepts before entering the program. Also, the student must already be familiar with the use of chemical symhols,formulas, metric units, and the basics of titration. The best aspects of the program are the visual collections of data and improvement of comnutatioual skills. Therefore. the urogram i; very good for reviewing ibros br a rerien before nctually undrrlsking n tirration in the lnhornrory. However, thp pragram is a poor suhstitute for an actual titration experiment. The documentation for this program is excellent. The overview includes the nature of each part, what each module includes, and the goals of the general program. Next is aratianale for a simulation of a titration lab. One can concentrate on important concepts without being distracted by experimental details. Finally, there is background information on the general titration procedure and definitions of some general terms (titration, indicator changes, end point and concentration determination). In addition, a student lab booklet is available, even though the program is self contained. The hooklet summarizes part B of the program, the math
Volume 65
(Continued on page A24) Number 1
January 1988
A23
REVIEWS drill, and part C, the titration simulation and data collection. The combination of the background and booklet is a better presentation than the first two parts of the program. The main advantage of placing this material in the program is to make the program self contained. The first module of the program is mainly text, which is better done in the documentation. The use of the forward and reverse arrows to change pages is an excellent idea and allows the student to move a t his or her own reading pace. This use of the m o w is not continued in part 3, in which the author introduces the five parts of this module. Each part is put on the screen in a time delay, which initially seems like a novel idea. However, at this point the students want to push forward to the actual titration. Part one is entitled A Review of Molarity and Concentration, but the module starts with the ion product of water and the dissociation of acids and bases. Molar concentration is not defined until the sixth page. This definition, which lacks clarity, belongs at the beginning. The example given is one mole of NaF dissolved in one Liter of solution. The molar concentration is therefore 1 M.The author fails to mention the dissociation of solute into Naf and F-. each of which has a concentration of approx&ately 1M. The use of a weak acid, acetic acid, in a concentration of .05 M is a poor choice for the next example. The concentration of acetic acid molecules is given as .05 M with no mention of the partial dissociation of acetic acid. The next part of the module briefly defines pH and the E notation. Then, the module reviews the dissociation of a strong acid and the resulting ion concentrations. Finally, the reviewmodule finishes with an example of neutralization. AU of this can be done as effectively on paper as on the screen. The second module is the lab math drill. The drill starts with a drill on DHfrum different concentrations of H C ~ solutions. There are five randomly generated concentrations ranging from 10W M to lo-" M solutions. The lower concentrations create a serious problem. For example, 10-l4 M HCI solution does not produce a pH of 14. Nor does a 10-8 M HCl solution produce a water solution containing 10-8M H+. Thesolution may contain 10V M C1-, but because of the ionization of water, the [Ht] is greater than 10-8M. Finally, in this module, the program randomly generates different volumes and different concentrations of HBr to be neutralized with different concentrations of NaOH. Each time the program asks the [Ht], pH, moles of H+,moles of OH-needed to neutralize the solution, and volume of NaOH needed for the different coneentrations. Each step gives a yes or no answer and exolanation for each rieht or wrone answer. A I the ~ drill can be and is done onpaper in thestudent booklet. Mast ofthestudentndo the calculations on paper anyway. Or unfor. tunately, the students use the computers for their calculations. The final module is an actual simulated titration using a buret. A colored screen is preferred since the charm of the titration is ~
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Journal Of Chemical Education
to see the indicator change from clear to blue. Before the titration is performed the student must select the right basic reagent from a shelf and make up the right concentration. The program puts the molecular weight upon the screen of the solid chosen. The program will accept a mass with three significant figures. The program tells the student how to make the solution after accepting an answer. Then, the program proreeds to tell the student if the correct reagent waschosenand the right amount measured. If the student is wrong, the program reverts to the beginning of the module, and the student has to start over. At this point, some students cannot figure what is wrong if they rounded their value for the mass incorrectly. Also, same teachers a t the beginning Level emphasize units. The program will not accept 0.146 g. Once the standard solution of base is made, the titration is done. The initial volume of the buret is read. The standard solution is delivered to the solution of unknown acid by one-third of a milliliter per turn of t h e stopcock. When t h e end point is reached, the student must stop the titration student must refill the buon his own. The -~ ret if the end point ia uvershot and redo the titratiun. Finally, a swpwise calculation ia made to get the concentration of the acid. One assumes a one to one mole ratio of acid to base in the calculations. Student reaction to the program varied with the experience of the student. The advanced students felt t h a t the titration should be more varied. Once the experiment was completed, the good students felt they had completely mastered the program giving them little opportunity for variation. The average students felt a certain amount of frustration since they felt that to perform the titration they had to know the material before entering the program. These students felt that the first two modules were of little value because thev eould not Learn the marenal through the program. Hoth groups. thegood and average students, agreed that ~f they had dune the tltratlon in the labora tory, then the program was of little use. Also, both groups agreed that the math drills were good reviews and were helpful in doing a titration calculation. The students felt the program eould be used as a device for a beginner with little experience in titration as an entry. Beyond entry level and review, the program loses its effectiveness. Most students did not like to use the program as review. They did not like to go through the pages or get rntu a part of the program they eould not exit. Most of the students liked the actual titration but were unwilling to get to the titration part a seeond time. Very few of the students could get through all three modules in a fifty-five minute oeriod. -The author should he commended for his effort. However, wrth newer programs, wlth better graphics, or with computer interfacing systems, this program seems outdated. Also, a teacher should try to do experiments or demonstrations as much as possihle in the laboratory. Titrations are not expensive, nor do they require unusual equipment, especially if one substitutes medicine droppers for burets. Thus, the necessity of detailed procedure is removed, one rationale for a titration simulation. Moreover, the hazards are at a minimum when concentrations are held to less than 0.1 M. Thus, ex~
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cept for instructional purposes, a program seems to he a poor substitute for actual titratian. Philip H. Ogata Boulder High School 1604 Arapahw Boulder. CO 80302 Simplex-V: An Interactive Computer Program for Experimental Optlmizatlon S. N. Demlng and S. L. Morgan Statistical Programs, 9941 Rowletl. Suite 6. houston, TX 77075 Hardware: IBM PC Componenlr: 1 disk and manual Level and Subleek Advanced chemical statistics Cost: $150.00.
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Summary Ratlngs:
catww Ease of Use Sub/en hiafter Content PedaQogic Value: S M m t Reaotion:
This disk and documentation package provide a valuable tool for performing the calculations necessary to select new factor levels in optimizing experimental conditions involving simplex methodology. The user needs to be familiar with response surface methodology, experimental design, simolex ootimization.. and fundamental personal computer system operation.r in order to appreciate fully the program. For those not su well versed in these topics the documentation material provides ample help and lists additional references. A tutorial is provided toguide the user through the execution of the program SIMPLEX-V. The program is aimed a t advanced students who have had previous experience with simplex optimization and who might he enrolled in an advanced chemical statistics class. An instrumental analysis class could readily use the program as a tool to carry out an optimization. Students in such a class found the program easy to follow and encountered little difficulty in running the program. Typically, less than 15 minutes were reouired for a student to run throueh " the program for the f m t tme. T h ~ program s could also be used by students who have no priur knowledgeof smplex tu crankout new factor levels such as those used to maximize the yield of a reaction in an organiclinorganic synthesis class. Before use installation of the disk is necessary. Instructions on how to do this and how to make back-up copies are included in the documentation material. Detailed instructions for the tutorial help to guide the user easily through the program operation. A table of contents in the documentation allows the user to find easily the answers to questions that might arise. Help is also available from the software itself a t various input points. Users with a truly IBM-compatible color monitor will enjoy the ample use of colors during the program. Not only is it esthetically pleasing but also it makes the program easier to run. The program, however, can be installed for use on a monochrome display. Prompts for data input are quite clear and inputs are easy to enter. Gross errors do not ~
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