Using kinetics experiments from The Journal of Chemical Education

try teaching for me has been my involvement in promoting student research projects.What makes this very demanding part of my teaching so satisfying is...
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Using Kinetics Experiments from The Journal of Chemical Education as the Basis for High School Science Projects John Liebermam, Jr.' T. C. Williams High School. Alexandria, VA 22302 One of the most rewardine asnects of hieh school chemistry teaching for me has heen m i involvement in promoting student research projects. What makes this very demanding part of my teaching so satisfying is the fact that my students choose to do proiects rather than being reauired to do nrojects. No grade or extra credit is giveLforthe tens or even hundreds of hours spent outside of regular class time on theheprojerts. ~nstead,tor manv of then1 a large part of their morivatiun is the hopeof achieving recognition frrm entry ut their nroiects in the-various science comoetitions. The feeling of accomplishment derived from carefully planned and executed exneriments is another imnortant source of motivation. his-latter source of motivatibn is probably the most imnortant because thereis noauarantee that iudees willlook favorably upon even the most>arefully plannedand executed project. Selection of Topics For must of my students, the biggest obstarle to overcome in doing a projert is the selertion ofa suitable research topic. 'I'he tooir thev choose must be as safe an oossible and not require more than several hours for any one experiment at anv one time. Of course. exoense is alwavs a consideration. an; equipment needs shouid not go beyond what is ahead; available. Even a topic that meets the above criteria may pose special procedural problems that an inexperienced student will not be aware of. These procedural nrohlems can lead to a frustrating rather than a s&sfying research experience. Few of my students are able to come up with project ideas on their own that meet the above criteria. Therefore, I provide a choice of project ideas covering a wide range of topics. I would prefer that my students not he worried and confused over the selection of a topic when their time and energy could better be spent finding background material on one of these suaaested oroiects. After all, the tonics I sueeest .. are soon modked b; rhe students as they are rxpanded upon during the course of their work. The rhoive. presented have also been researched by me, and, therefore, 1can he reasonably sure that students will he able to carry out the research and obtain meaningful results. A similar technique was em-

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Present address: Thomas JeffersonHigh School for Science and Technology. 6560 Braddock Road. Alexandria. VA 22312. If several students are working on different kinetics experiments simultaneously, more than one constant-temperature bath will be needed. My students have used small Styrofoam containers equipped with commercial immersion heaters regulated by percent-time-on power controls (available from Fisher Scientific and other supply houses). We have even used Styrofoam containers filled with preheated or precooled water as constant temperature baths for kinetic exoeriments of short duration. When the surfaces of these baths are covered with expanded polystyrene "packing chips'' any temperature change over a short period of time is minimized. The construction of low-cost immersion heaters (28)and constant-temperaturedevices (29, 30)have also been described.

nloved bv Alfred Werner (the founder of coordination chemistry) who checked the theoretical and even the practical feasibility of each project assigned to his graduate students (27). Source of Toplcs Many of the project ideas that I suggest each year come from the pages of this Journal. In particular, my students have had especially good success using kinetics experiments2 annearine in this Journal as the basis for nroiects. .. . . The experiments used over the last three years are summarized in the tahle. Although some of these require instrumentation not available in most high schools, the large majority do not. These exneriments have several features that make them well suitedfor this purpose. Most involve rate experiments requiring reasonable time periods. For some requiring much longer time periods, reactions can be initiated in the morning and the reaction mixture sampled between classes or during other breaks. All involve various analytical techniques for measuring the concentrations of reactants or products periodically. For those reactions having reactants or products whose concentrations can be determined by several methods, a kinetic study also becomes a comparison of analytical techniques. Some involve relatively easy syntheses of reactants and/or nroducts that a student can nerform with adequate supervision. In some instances a deriGative or derivatives of a reactant can he used and a simnle kinetic study becomes a structure-reactivity study. ~ l l i i e l ddata that give students an opportunity to interpret their empirical observations on theoretical grounds. This interpretation will very often require an additional literature search by the student, which is an equally valuable experience. It may concern some readers that these experiments, the outcomes of which are more or less known. are treated as research projects. However, these experiments are new to mvstudents, and in their hands no outcome is certain. These &dents have no false illusions about what they are doing. They realize that they are reproducing previous work, but with the intentionof modifying andextending it in some way beyond what was presented in this Journal and in some of the original literature. For example, a similar kinetic study can be carried out employing a different analytical technique and the methods and results compared (14, 15). Extensions and modifications of other kinetics experiments are indicated in the tahle. These experiments have provided realistic, open-ended research exneriences with manv of the attendant orohlems. Upon completion of these prGects, students look back at what they have done with pride and satisfaction. Most importantly of all, they have a greater interest in chemistry than when they started.

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Time and Funding tor Projects Finding the time required to carry out these projects is almost as big an obstacle to overcome as the selection of a Volume 65 Number 12

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topic. My students work before and after school, but no class time is expended for project^.^ Students also work for extended periods on in-service and record days when I am at school and they are off. I have been able to arrange a schedule that allows me to be in the lab on these days. Of course, these opportunities are few and far between and are supplemented with some weekend work when needed. Funds to buy the materials for these projects have been easier to obtain than the time to do the projects. Although, many of the chemicals needed are not typically found in a high school storeroom, they can be purchased in small quantities for not too great a cost. Perhaps I am fortunate in teaching a t a school with a science budget large enough to allow the purchase of chemicals for projects. However, when the need has arisen, I have obtained funds from the PTA, and community service groups such as the Optimists and Lions Club. The state junior academies of science also make small grants to individual students through the American Association for the Advancement of Science.

that merely suggesting the topics is just the beginning. Most of mv students reauire a ~ e r i o dof "hand holdine" in the lab untiithey becomemore kamiliar with their p a r h d a r area. At the beginning of the work it is very much like a manyringed circus depending on how many students begin projects at the same time. The instructor must be able to go from student to student giving advice on many different problems. Visitors to my lab a t these very hectic times often suggest that I should have my head examined. But they are not around to see what finally emerges from the apparent chaos. They donot get to see the pride and satisfaction in the faces of these students as they reflect on a job well done. Thev do not eet to see these students mesentine their work liie seasoned at &ious meetings and fielding veterans. Thev do. however. see these students' names listed among the semifinalists and finalists in the various science competitions. Literature Cited

Community Support

Community support such as the funding mentioned above has been important to our project work. But the support goes far beyond funding. Parents and other members of the community follow the news of my students' successes in various science competitions just as they follow home team sports. The City Council of Alexandria, Virginia, even issued proclamations in two successive years honoring students for their work on their projects. As for myself, I was invited one year to be an honorary marshall in the city's St. Patrick's Day parade. Conclusion

I have had great success with these and other project ideas obtained from this Journal. However, I should point out At the schooi where the majority of the projects listed in the table were carried out, work could begin at 2 p.m. after the last class. Students typically worked from 2 to 5 o'clock several days a week. However, at my present school (see note I), classes are not over until 40'ciock. This makes It even more difficuitto find the necessary time. The personal sacrifice on the part of the students and instructor is even greater under these circumstances.

J . Chem.Educ. 1964.41, 4F50. 8. Cor8aro.G. J . Chrm. Educ. 1973,50,575-576. 9. Watkins, K. W.; Olson, J. A. J. Cham. Educ. 1980.57, 158-159. 10. Smith, R. N.:Bolliper, W. V.J . Chem.Educ. 1950,27,369-373. 11. Vinsixa, J.;Ferrec, N. J. Cham.Edue. 1983.60, 155-156. 12. Lemh, J. D.: Chri~fenaen,J.J.:lzait,R.M. J.Cham. Edue. 1980.57.227-229. 13. Lomharda.A. J . Chem.Educ. I982,58.887488. 14. Gssfamhide, B.; Blanc, J.; Allsmagny, Y. J . Chem. Edur. 1964,41,613-614. 15. Beiley. M. E. J . Chem. Edue 1971.48.SO9-813. 16. Jerrar.A.A.:El-Zaru. R. J . Chem.Educ. 1977,34,326-327. 17. Bunnett, J. F.;Crockford, H. D. J . Chem. Edui. 1956.33.552-558. 18. Bsri1e.R.C.: Miehiels. L . P . J. Chem.Educ. 1983,60,154. 19. AMel-Kader, M. H.;Steiner. U.J . Chem.Educ. 1983.60,160-162. 20. Mineh, M.J.;SadigShah.S. J . Cham. Educ. 1977.54.709, 21. Crumhliss.A. L.: MeCsbc,M. E.:Dills.J. A.;Herman,H. B. J . Cham. Edvr. 1976.53, 7.

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Cooper. J. N. J. Chom. Educ. 1980.57.823-824. Bry8n.A. M.;Olafson,P. G.J . Chem. Edur. 1969.46.248-249. Briee,L. K. J.Chem.Educ. 1962.39.832-633. Corsaro. C.; Smith, J. K. J . Chem. Educ. 1976,53,589-590. Msson,T.J.J. Cham.Edur. 1982.59.980-981. Ksuffman. G. B.lnorgonir Coordinofion Compounds; Heyden: London, 1981;p 27. 28. Bettino.R. J . Chem. Educ. 1984.61.563. 29. Waiah. J. M. J . Cham. Educ. 1967.44.29. 30. Schneider. R.L. J . Chem.Educ. 1978.55.671.

22. 23. 24. 25. 26. 27.

Symposium on Chemical Education A symposium consisting of a half-day session on "Quantitative Analysis" and a half-day session on "Chem-Com" will he held Saturday, March 11,1989,on the campus of Los Angeles Pierce College, Woodland Hills, California. Under the sponsorship of the Southern CaliforniaSection of the American Chemical Society, the symposium will feature an address by Clayton F. Callis, President of ACS. The registration fee is $22 per person, which includes materials, lunch, and refreshments. Paid reservations must he made no later than February 21, 1989,and should be sent to Roger Nikaido, Executive Secretary, ACS Southern California Section, Chemistry Department, University of Southern California,University Park, Los Angeles, CA 90089,(213)749-4670.

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Number 12

December 1988

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