Arlene A. Russell University of California. Los Angeles S, Angeies, 90024
Bernie L. Mitchell UCLA Media CenterITelevision University of California, Los Angeles Los Angeles, CA 90024
I The Use of Videotapes in Large Lab Courses
During t h e p a s t two y e a r s t h e UCLA D e p a r t m e n t o f C h e m i s t r y in c o n j u n c t i o n with t h e T e l e v i s i o n D i v i s i o n of t h e UCLA M e d i a C e n t e r h a s d e v e l o p e d a series o f color, v i d e o t a p e d cassette p r o g r a m s t o c o m p l e m e n t i t s f r e s h m a n c h e m i s t r y l a b o r a t o r y curriculum. M a j o r funding for t h e p r o j e c t has been m a d e possible by a g r a n t from t h e Office o f I n s t r u c t i o n a l D e v e l o p m e n t on t h i s campus. T h e f i f t e e n p r o g r a m s of t h i s series cover t h e b a s i c t e c h n i a u e s a n d m a n v o f t h e e x o e r i m e n t s e n c o u n t e r e d in an i n t n d u c r u r y chrnmistry l a b o r a t o r y t h a t include-: q u a n t i t n t i v e ; ~ n ; d k .T h c tableeiees 3 b r i e f e e n r r a l d e s w i l a i o n vf each of " t h e programs. T h e series h a s b e e n d e s i g n e d not only t o s h o w t h e m a n i o u l a t i o n s i n v o l v e d in t h e e x ~ e r i m e n t atle c h n i q u e s hut also to e x p l a i n w h y t h e procedures-of t h e e x p e r i m e n t i a r e c a r r i e d o u t in s p e c i f i c ways. W h e n e v e r feasihle, r e l e v a n t a p p l i c a t i o n s of the p r o c e d u r e s and m a n i p u l a t i o n s as w e l l as historical frameworks h a v e b e e n included. T h e desire t o o b t a i n a clear i m a g e quality, e q u i v a l e n t to a n i n d i v i d u a l i n s t r u c t o r - s t u d e n t interaction, d e m a n d e d that t h e series h e s h o t u s i n g h r o a d c a s t q u a l i t y t e l e v i s i o n cameras (RCA's T K 4 4 ' s a n d H i t a c h i SK 70's). Each p r o g r a m was
Figure 1. Partial view of the UCLA video laboratory
m a s t e r e d on 2-in. q u a d videotape, w h i c h in a d d i t i o n t o a l l o w i n g for easy a n d precise e d i t i n g , p e r m i t s quality d u p l i c a tion in a w i d e v a r i e t y of f o r m a t s . A t UCLA, these p r o g r a m s a r e a v a i l a b l e t o s t u d e n t s on 314 in. videocassettes a t a c a m p u s - w i d e v i d e o l a b o r a t o r y . T h i s f a c i l i t y allows i n d i v i d u a l students t h e o p p o r t u n i t y to v i e w t h e p r o g r a m s a t t h e i r o w n convenience (Fig. 1). A d d i t i o n a l l y , d u r i n g t h e b e g i n n i n g weeks o f t h e t e r m , t h e videotapes a r e s h o w n in e a c h c h e m i s t r y l a b o r a t o r y i m m e d i a t e l y prior to t h e t i m e w h e n t h e s t u d e n t s b e g i n t h e i r e x p e r i m e n t a l work (Fig. 2). Program Descriptions for the Videotape Series "Experiments and Techniques for General Chemistry" 11 We gn ng Tne 1.ndamemal pr nc ples 01 tne E ngie-pan analyl ca oa ance are dercrnbsda ong wtn deta lsa operatong lnstrdnlons tor the Men er h15 balance (12 min). 2) Preparation af a Primary Standard Solution: A primary standard solution of p o t s s ~ i ~dichromate m is prepared. The use and precisionof volumetric glassware is considered (73 min). 3) The Vohrwtric P e t : The msnipulatims rewired to trmler an aliquot with a volumetric pipet are shown in the context of the calibration of a 10-ml pipet. 41 Acid-Base Titrations: Use of a Buret: The techniques and manipulations in using a buret are demonstrated in the context of an acid-base titration (17 min). 51 Beer's Law: A historical approachto the nature of light and colors is used as a backdroo for a discussion of the technioues of usina a cobrimeter. h e mi eclm and wearmem of data are consmered a ong w l m tne prec soon of the resLlf(t2 mml 61 heatEd Ream on Tne pr nclpler ofthermocnem#caanalysls aredemonstrated in e simple c a i w k b y experiment, intrinsic problem of experiment designs are mentioned(to mi"). 7) Emhalpiesat Salution: tempwture dependence of Me solubiiity pmduct of lead chlaide is used todemonstrate Me hlndamental relationship between enthaioies. free eneroies. and eouilibrium constants. 61 Q.a lawe Ana ys s Tne blnary og c of the analyl ca memods red wnen compar ng an "nmown aga "st a mown areoscJssea Same of m e Common manpuamns 01 qAratlve analysss are demonsnaled (1 t min). 9) Chromatography: The fundamental theory of chromatography is described and applied to a separation of a mixture on a Column, and eluting and coilecting the sample are discussed(12 mi"). 101 Transition Metal Comolexes: The orablem far the chemist in first makino a orodun and then determinino what was made -~ forms the theme of this ,~ v aeolape S.ct on foltra! on ,sdemonstrated in the experment (12 m n) 111 Rates 01 React 0"s. Tne rate of hydro ysmsoflen ary bay oromideis .sed to demonstrate same of the principles of experimental kinetics studies. 121 Potentiometric Titration of Iron: This experiment is used to demonstrate the four maja steps of any experiment, namely defining the pwpose, sening the experimental conditions, collecting the data and analyzing the results 114 mi"\. 13) Amino Acids: The acid-base reactions of amino acids are animated against an experimental titration curve of the amino acid. The procedures fwobtaining the curve, including calibration of the pH meter, are shown (16 mi"). 141 CalciumIMagnesium Analyses: The importance of there analyses are presented in terms of the problems of water hardness. The analytical procedures demonstrated use EDTA. A fluorescent indicator is used for the titration of calcium 121 mid. 151 Manganese n Sled Tne developmem of Bessemer stea ana its mpan on tne ndustr a revolLt on are olsc~rsedThe manganese in a %ampe of Bessemer steel is then preparedfar analysis by colorimetric methods (16 min) ~
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Figure 2. Students viewing a program prior to beginning experimenlai work.
Volume 56, Number 11, November 1979 I 753
An extensive longitudinal evaluation of the laboratory curriculum using the videotapes is being conducted currently by the Department of Chemistry. Initially though, one of the most striking observations of the effect of the use of the videotapes on the laboratory program has been the reduction in the time required by the students to do the experimental work. On some experiments this reduction has amounted to up to 60% of the time normallv Although the complete . reauired. . statistical data is not yet available, there aGo appears to be a marked imnrovement in the student's laboratory skills as measured h i the precision of their quantitative gnalytical results. One of the unexpected benefits that has been seen in the ~
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754 1 Journal of Chemical Education
use of the videotapes is a decrease in student anxiety in the laboratory. Having viewed the videotapes during their prelahoratory preparations, students enter the laboratory feeling confident that they know what to do. The fact that it does take them less time to do the experimental work properly and that the level of laboratory skills is increasing seems to support the validity of this student attitude. Because of these successes,a second series dealing with the techniques of the organic lahoratory is currently in pre-production. Inquiries atmut the pngram outlined here glr the videotapes (which are available fur rent or purchase^ should be directed to the first author
