edited by SUSAN H. HiXSON National Science Foundation Arlington, VA22230
Highlights
CURTIS T. SEARS, JR. Georgia State University Atlanta, GA30303
Projects supported by the NSF Division of Undergrcrducrte Educcrtion An Experimental Curriculum for Introductory Chemistry: "Research! A Freshman Experience in the Excitement of Chemistry" Stuart Licht and David Thurlow Clark University Worcester, MA 01610
There is concern that contemporary introductory chemistry courses are often not successful in motivating competent students. As an antidote, we have probed an alternate starting point for the chemistry cumculum by exploring early exposure to the excitement and rigor of scientific research as a spark to ignite students'latent scientific interests. Pilot courses that introduce aspects of original research have been offered as part of Clark's First-Year Seminar Program. The faculty member acts both as instructor and academic advisor for the class of 15 students. These laboratory-oriented programs are intended to give students a positive initial experience in scientific methodology and promote the option of a career in the natural sciences. The challenee is to Drovide a structure bv which students can s y s t e m a t i c h l y choose and k v e s t i g a t e unanswered auestions at an elementaw level while retaining the excitement and rigor of rese&h. The prototype courses are relatively nonmathematical, yet rigorous in application of the scientific method. Unlike students in "Discovery" or "Guided Inquirv" approaches to teaching science (i, 21, in which they rediscover already known facts or principles, the participants in the programs described here undertake original research. Each project in the courses is an original study, conducted unde'close faculty supervision. The research experiencemust be carefully structured for use as an educational tool at the freshman level. First, a substantial body of unresolved research problems must be dentified. Secondlv. ".the research ~roblemsmust be accessible to students in the earliest stages oftheir undergraduate education. The ideal research project will
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be of dearly defned interest and significanceto the scientific community utilize concepts and experimental techniques comprehensihle to a college freshman and capable of conveyingimportant scientific principles, and be achievablein a limited time frame.
Two courses that fulfill these requirements are described. Pilot Courses Baftery Research
In order to enable students to generate useful original data in a one-semester time frame, we organized the fundamental material in the course with a vertical emphasis on the chemistrv of the electron. rather than with the traditional horizontal arrangement covering a broad range of chemical topics. After an intense preparatory period dur-
ine the first half of the course. students conducted research with a computerized data acquisition system that ~ermittedefficient accumulation of a laree amount of data in a short period. Initial l&tures included introductions to: electrochemical energy, the method and art of creative science, the scientific literature, and environmental science. Lecture topics and readings then focused on subiects related to the battery research and included electronics, moles, chemical formulas, concentrations, ions, oxidation-reduction, balancing equations, equilibria, computers and scientific programming, the Nernst equation, Faraday's law, the Carnot cvcle. batteries. the electrochemistw of Al.. Pb.. Zn.. Ni..Cd.. and S,and sciektific writing. ~ e v e r afull i texts were extensivelv used (3-6) . . as well as a varietv of shorter articles and selected chapters. The first laboratory period was used to orient the student to the use of the literature including Infotrac and Chemical Abstracts. Following this, safety and waste disposal were presented using MSDS sheets, demonstrations, and a wet laboratory on the safe disposal of sulfides. This was followed by spreadsheet, word processor, and programming exercises on the Macintosh. Next came a session on electro~cs,Ohm's law, and data acquisition systems. Laboratory topics then focused on subjects related to the upcoming research and included electrochemical energies, reference electrodes, electrolytes, measured electrochemical potentials, electrochemical cell components, preparation of solutions and electrodes, measurement of cell current and kinetics. and the effect of concentration on cell current. A h a 1 preparatory lab consisted of electrolysis and the mole, oxidation, reduction, the farad, and the stripping and electroplating of copper. DL& the second halfof the semester the students worked in airs to conduct exoerimental investieations of a series of new batteries. The straighfomard experimental design contained an aluminum anode, a cathode, and a reference electrode immersed in a stirred solution maintained at a constant temperature (see figure). Anode, cathode. and full cell voltage were monitored usine three channels of the ~ u ~ e r s ~ o ~ e / M a c i ndata t o s hacquisition system. Students were responsible for solution preparation, measuring and encapsulating the electrodes, and analyzing each discharge run. Analysis consisted of (1) downloading - the voltage data to the s~readsheet.(2)determining cell current and cell power, (3) determining total coulombs oassed. and (4) . . com~arinecoulombs to reacted materialLto cal'culated cell efficiency in a manner described in a previous study (7). Student pairs typically discharged three to five batteries per 5-hour laboratory session. Parameters varied included temoerature. discharee load. and solution and electrode combosition.students becamk enthusiastic about comparing their results with other student teams and predic&g trends, and all student pairs volunteered to perform addi-
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challenge of overcoming unanticipated technical difficulties and assessing unexpected observations confronted the students with the reality of doing original research. They became familiar with and used a variety of experimental skills including sterile microbiological techniques, cell disruption, isolation of DNA, analysis of genomic DNA on agaraose gels, partial digestion of genomic DNA with restriction endonucleases, recovery of DNA fragments from agarose gels, ligation of genomic DNA framents to lambda phage DNA, packaging into intact phage particles, and propagation and titering of phage. More importantly, they learned that the unexpected results are fre~uentlvthe most interesting, that care and ieticuious attention to deta?l can be decisive, and that overcomingunanticipated challenges is an integral pa& of doing original research. Final Thoughts
The intimate and supportive atmosphere of Clark's First-Year Seminar program made nossible the time-intensive commitment re&red of the supervising faculty. Equally as important, the research focus of the projects helped sustain the dedication of both faculty and students alike. Maximizing the students' input into the research process was essential to the success of both research-oriented firstseminars; the students participated fully Schematic representation of experimental mnfiguration by class member Jason Homsy,' year in the design of the experiments and in the problem-sokng process- as technical difficulties arose. Students from both courses spoke enthusisatitional experiments on weekends. In all, several hundred cally about their experience and severalhave pursued redistinct battery discharges were performed and analyzed. search opportunities subsequently. One, J. A. Maurer who Preserving Genomes is currently a junior, has coauthored six presentations at scientific meetings and one article in a peer-reviewed jourThe course explores two phenomena shared among all nal (8-14). living organisms: 1)extinction, be it eventual or imminent, and 2) storage and expression of information in the form of Acknowledgment nucleic acids. In the classroom students learn about biodiSupport for this work was provided by the National Sciversity, the significance of extinction, and the role of DNA ence Foundation's Division of Undergraduate Education as genetic material in living systems. They each select a through grant # DUE-9156035. species that is rare, exotic, endangered, or otherwise interesting; then in the laboratory they attempt to isolate DNA Literature Cited fromiheir chosen organism and preserve it in.the form of 1. Pa~lich.M.J.;Abrahams, M. R. J Chem Educ 1979,58,1W-103. a genomic library. 2. Allen. J. B.; Barker, L.N.: Ramden,J. H. JChrm. Edue. 1986.63,585554. 3. Lowe, J.N. Chemlahy, Industry and the Enuimnmnf; B m : Dubuque. I4 1994. The text Last Chance to See by Douglas Adam and Mark 4. Skwg, D.;West,0. M.;HoUIIII, F. J ~ ~ . F ~ ~ m n t d o i o i f A ~ f CheMalry, y t i i i l 6th Canvardine is used to introduce extinction of a species and ed.; Saundem: New York, 1992. 5. Kaoare, H. M. Writi~thPLhm10ryNoteboak;Amerieri ChemiealSodety: Washits impact on ecosystems and human societies. Field trips ington,DC, 1985. to local science museums and wildlife sanctuaries promote 6. TheACSStyleGuidp,AM~nuollwAuthonondE&tOtos;Dodd. J.S.,Ed.:Amerieri Chemied Society: Wmh..ston, DC,1986. further discussions of biological diversity and the role of 7. k h t , S.; Marsh, C. JEktmchrm. Soe 1881139, JAW. individual species in maintaining balance within local eco8. Maurer, J. A.;l\lmhrll, M.M.;Albrecht,A.: Wynn,C.;hdae,C.P'Syntbesisand systems. Storage and expression of genetic information in Magnetic Properties of Two Molemlar Ferrimagnets.' Presented at the 24th Northead Regional Meeting ofthe American Chemical Saoety, June 1994. living systems and gene cloning are studied using the text 9. Tumbull, M . M.: Maurer.J.A.; Stsckploe. P. S.;Alhreeht,A.;WyM,C.; Landee, C.P Understanding DNA a n d Gene Cloning: A Guide for the 'Synthesis and Magnetic Roperties of New Molecular Fnmmagletr."Re-ted at the 24th Northeast Reglond Meeting of the American Chemieal Sodety, June Curious by Karl Drlica. Specific topics include DNA struc,w,* ."". ture, replication, transcription, translation, plasmids and 10. Wynn. C. M.: Albnght. A . land-, C P . Zhang. W . Maurer J A: nmbull. M. M. phage as cloning tools, restriction endonucleases, ligation, % a p p m R o p n r c a o f l h Yol-lar F c r n m a p n r . R s w n w l ar tha Yprung of the Amencan Phywcal Sarets March 1994 transformation, selection, Southern hybridizations, expression vectors, construction of genomic libraries, DNA sequencing, and other tools of molecular biology. .,-Choosing source organisms and devising strategies for I?. L a n k . C P . Alhnyhr, A. WYM. C. M: Vuuu. G. B.;Yhaog. W . Maunr, J A . starkpole. P W , n r n h u l l . bl M 'Mawsue R o p n m of scp nolmular hkcl obtaining cell, tissue, or blood samples proved to be engagF ~ n o m a g n e u'Rerented st thc M e m g ofrhr A m m a n Phvaral S m n n March ing and challenging exercises in creativity. The idea of be,w4 ing the first person to isolate DNA from an interesting or13. Maurer, J. A: Thurlw, D. L."'Res~rvingGenome' as a Means Ib En- Under graduah in Sdentiiio Rlacanh."Rssented at the F i a National Meeting ofthe ganism and to try to preserve its genes in the form of a Council on Unde-dute Remareh, J m 1994. genomic library was highly motivating and instilled the 14. Tumbull,M.M.;Albrigh%A.;hdee.C.P;Maurer, J.A:Wynn.C.M.Md.Cryst Liq. Cryat.,in press. project with enthusiasm and an air of excitement. The 44
Journal of Chemical Education
