Robert H. Rouda
University of WisconsinStevens Point Stevens Point, Wisconsin 54481
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Student-Produted Videotapes in a Physical Chemistry Laboratory Course
The amount of apparatus is often limited in upper-level physical chemistry courses in universities with small enrollments, and the students are required to perform the experiments on a rotating schedule. This leads to the necessity of having many repetitive lectures and introductory demonstrations. When every student is performing a different experiment, this becomes an impossible task for the instructor, and the students are usuallv left to struegle through the experiments on their own: A solution & this problem is to have these introductions to the lahoratory experiments available on videotape, where they may be replayed by each student, in accordance with his personal laboratory schedule and at his convenience. The use of television as an educational aid has been around for some time (1-3), especially when the videotapes are produced hy the instructor. In our junior-level physical chemistry laboratory course here at the University of Wisconsin, these tapes are prepared by the students themselves, in consultation with the instmctor. Videorecorded microteaching has heen used for the orientation and training of graduate teaching assistants (4, 5). In our program, microteaching is brought to the undergraduate level, thereby partially integrating the roles of student and instructor, and involving the students directly in the process of their own education. Production ol Videotapes
Software After a student has chosen an experiment, he confers with the instructor as to the subject matter of his presentation. As the tapes are remade every year, the student has the benefits of the tape from the previous year, his own laboratory experience, and the suggestions of the instructor on which to base his material. This feedback process leads to ever-improving quality of the tapes. Since the students have recently been introduced to the experiment themselves for the first time, they are excellent critics of the instructional value of the old tapes. They can easily tell which points need more or less emphasis and detail, based on their own initial impressions. In our second year of making student-produced tapes, a rapid convergence is being noticed towards an optimum balanced presentation of demonstration, theory, data analysis, discussion, and references to texts for individual student reading.
126 /Journal
of Chemical Education
Each presentation contains a demonstration of the experimental apparatus, including its assembly and use. Safety precautions are stressed when appropriate. Snggestions from the students on how to avoid the most common areas of difficulty are presented; this can lead to a more efficient utilization of the students' laboratory time in the future. Variations from the laboratory text's (6) procedures are discussed and updated yearly. The students are encouraged to try out their own ideas for variations and improvements in the experimental procedure, and to discuss their results in the videotape presentation. The theoretical background relating to each experiment is also discussed. A balance must he found between the extremes of merely mentioning a reference and of a lengthy (and often boring) detailed theoretical talk. We hope to find this optimum balance in a few more of our annual iterative cycles of producing new tapes. The treatment of laboratory data is also included. The students discuss their results by means of a thorough error analysis, which is of considerable henefit to future students. Thev comnare the recision and accnracv of their results with that'expected from the experimental uncertainties of their laboratorv auvaratus and data. It is hence assured that each student wili he able to do these calculations correctly at least once during his undergraduate career. After the initial conference with the instructor, the student prepares a script for his talk (7, 8). Usually an ontline is sufficient; a student rarely has too little to say. He next prepares sketches of any graphics needed for his talk (8, 9). This usually includes titles, graphs, equations, and occasionally tables of data. The graphics are prepared by our Instructional Media Services staff, and copied onto 35 mm slides, for use on a film chain in the television studio. When the slides are ready, the student and instructor hold a final planning conference. No strict limitations on timinas are im~osed:the final tanes run from ten to fortv minutes in iength, depending i n the experiment and thk ' student. (The table lists videotapes we have produced.) Hardware Our videotapes are produced in the television studio of our university. The disadvantages of having to move the
Ftgure i Videorecordlng a leclure demonstration
Figure 2 Cornposit#on and technical d r e c t o n of a vdeotape recording
Videotapes Produced 1. 2. 3. 4. 5. 6.
diate improvement in his presentation, including both the content of his talk and the skill of his public speaking. Third, the student learns about some of the instructional media available for his future use, including the use of graphics, slides, audiotape, and videotape recording. And finally, the student becomes a better teacher-he sees that it is relatively easy to talk on what one is familiar with, hut that it is very difficult to communicate ideas to others who are unfamiliar with the subject matter. Hopefully, the student learns to slow down and lower the level of his presentation to fit his audience-a fault among too many of us. The presence of these videotapes removes the considerable burden from the instructor of rushing to demonstrate and explain everything to everyone. One now has time to help individual students, to answer their questions, to observe their laboratory technique, and to be available for personal instruction. The laboratory reports this year indicate that the students understand more than previous classes of the theories and calculations behind their labwork, especially in the treatment of experimental uncertainties. Perhaps the omission of a lecture-discussion period with a physical chemistry laboratory course is a serious oversight; the videotapes help ta fill this gap. The students have a tendency to stress only the material which was omitted the previous year. This overcorrection can be minimized by individual direction from the instructor. In this way, the instructional value of the tapes definitely improves each year. Student response indicates that, although this is not always a popular project, they consider the experience to have been verv worthwhile. Imoroved ~erformanceshv ~" the students a t their senior seminars one year later are clearly noticeahle. Finally. records of tane ~ l a v h a c k sshow that the students defiiitely are viewing the& tapes before performing the experiments, and occasionally are re-viewinn them lmor to wiring the Ishurarory ri,pnns. ' l ' h i ~work was performed under a grant from the 1 ) i r e v tor of 1nnwatir.e I'rozwms at the lln1ver41\ o f \Viir,rna~n " -Stevens Point.
Vacuum Technique; Molecular Weight by Gas Density The Oxygen Bomb Calorimeter The Peroxide Bomb Calorimeter Vapor Pressure of a Pure Liquid Liquid-VaporEquilibrium in Binary Systems Elevation of the BailinaPoint Ly
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d S?e$f.mmpy: Analysis of the High
apparatus from the laboratory to the studio are more than offset by the advantages in lighting, sound quality, technical editing facilities, and Instructional Media personnel. (Only rarely is it impossible to move the apparatus, as with a glass vacuum system. In this case, a portable camera and videorecorder are used, with considerable sacrifice in the quality of the finished tape.) Our studio uses a one inch Ampex format videotape recorder system and two floor cameras. We have found a close-up lens on one camera to he invaluable. There are numerous types of videorecorder hardware available commercially (Z), most of which should perform satisfactorily for this purpose. (See Fig. 1.) Videotape has several advantages over film for this program: Videotape is much less expensive than film if the television hardware is available. The tapes are available for instant replaying to the students. Editing and remaking of scenes may be done immediately. Close-up shots are checked on the spot, and retaped if necessary. Sound, titles, and slides are edited onto the tape during the actual production. (See Fig. 2.) A videotape playback unit and monitor must he conveniently available for the students' use. We are fortunate to have this equipment available right in our laboratory. Due to the heavy use these tapes are suhject to, it is necessary to preserve the master tapes and to make copy tapes available for continuous use. Discussion and Results The student receives many benefits from his production of these tapes: First, he becomes exceptionally familiar with one experiment-including the apparatus, experimental methods, theories, calculations, and error analysis. Second, he has an invaluable experience in communication. He has organized a live presentation himself, has had a microteaching experience in speaking, and has an opportunity to see himself perform on videotape. Through an immediate replaying and remaking of the tape (when necessary), the effect of this feedback is seen in an imme-
Literature Cited
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I l l Barnard. W. R.. Lamwski. J. d.. and OConnar, R.. d. CHEM. EOUC 15. 63 (1869L (21 Barnsrd.W. R.. d. C H E M EDUC. IS.&BL lISh8). 1:il Rarnard. W.R.. and O'connor. R...J.CHEM.EDllC. 15.745119691. 141 Gar1and.d. K.. I. C H E M E D U r 46,621 11969). i i l Mellon, E. K., andUence. d. H..J.CHEM. EDUC.lX. 674 119ill. 161 Oaniaii. F.. et.al.. " E ~ ~ e r i m e n r aPhvrtcal l Chemistrv." 7th ed.. McCraw-Hill Huok Co.. Now York. 1970. 171 Wefmore.D.E., and Millor, G.T., .Ir., J. CHEM.EDUC. 48,816 (19711, IRI American Chamical Bciety. "Hendhmk fm Sppakerr." ACS Bulletin ho. 8. Washington. D. C.. 1969. (91 B a r n s d . W .R., d. CHEM EDOC. 47.R1811.97U~.
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