Lecture Demonstrations in Chemistry: A Two-Week Summer Institute for Pre-College Teachers Art Serianz' St. Ambrose University. Davenport. IA 52803 Dennis Graham Scott Community College, Bettendorf, IA 52722 The use of lecture demonstrations as a technique to increase student interest and learning in chemistry has been strongly advocated by many chemical educators. This is reflected in the pages of the Journal of Chemical Education, which contain many essays-such as refs 1-3-discussing the philosophy and methodology of the demonstration approach, as well as by the Journal's long-running series of "Tested Demonstrations", which provide detailed demonstration procedures. In a desire to encouraee more teachers-esoeciallv at the pre-college level-to consider the use of demonstratims, the Illinois-Iowa Section of the American Chemical Society and St. Amhrose University sponsored a one-day seminar in anuary, 1985, on "Presenting Effective Chemical Demonstrations". The seminar was conducted by Marvin Lang and Donald Showalter of the University of Wisconsin a t Stevens Point. About 100 teachers from our localitv sat enthralled as a flask containing an endothermic reaction mixture froze to a wooden hoard, streams of brightly luminescent chemicals snaked their way through a long length of clear plastic tuhing, and the sounds of the exploding carbon disulfide cannon echoed through the lecture hall. Altogether, about 40 demonstrations were oerformed hv Showalter and Lane- for this very enthusiasticaudience. However, discussions with a numher of teachers during and after the program revealed that very few-we estimated about 25'-regularly used demonstrations with their classes. Reasonscited included: lackof resources suchasn variety of current literature references, chemicals, and glassware reauired to nractice and evaluate ootential demonstrations: unfamiliarity with the safe handling of commonly used materials like liauid nitroeen and white nhosnhorus: and uncertainty about how visial displays are hest presented and intearated into the curriculum of oarticular courses. ~ h e s comments e suggested tha; more excensive education of teachers in demonstration methods would he hiphlsdesirable. While published sources can provide raw information on specific procedures, and presentations by master demonstrators are very beneficial in kindling initial interest, it is the personal "hands-on" extensive exploration by each teacher of a variety of demonstrations that would seem most likely to engender knowledge, confidence, and commitment to this teachine method. T o implement this idea, a 10-day institute was organized for the summer of 1986. Plannine and instruction involved the cooperative efforts of faculG from both St. Amhrose University and Scott Community College. Major funding was provided by the Summer Institute Program sponsored by the state of Iowa; an additional grant from the IowaIllinois Section of the ACS defrayed most of the cost of textbooks to participants. The institute was offered for 3 semester-hours of graduate credit.
' Author to whom all correspondence should be sent. 356
Fifteen teachers from throughout Iowa registered, although a number of others were refused for lack of space. All participants were middle or senior high school teachers of chemistry andlor physical science. The institute's objectives were: 1. to engender an appreciation for the value of classroom demonstrations as e way to stimulate student interest and learning; 2. to examine the qualities that characterize successful demonstra-
tions;
3. to provide direct experience with organizing, preparing, and presrnting a wide variety of dernonsrration%: 4. to describe appropriate precautions necessary to present demon-
strations safely; 5. to suggest sources and costs of supplies required for demonstra-
tions. On the first day of the course, teachers were given references to about 120 demonstrations from a number of current hooks 14-10) as well as from the Journal of Chemical Education. These demonstrations were divided into six cateeories. each of which represented an area usually covered & pre: college science curricula: physical properties and physical change, types of chemical reactions, oxidation and reduction, energy changes and equilibrium, kinetics, and organic chemistry. Demonstrations were selected to include a wide variety of phenomena within each area. Tables 1 and 2 list demonstrations from two of these areas; a complete list is available upon request. Teachers were then divided into erouos of two-with one group of three-based on their h&kg;ound and subjects taueht. Each erouo selected three to four demonstrations from each of the ;ix categories. The selection process was gently guided by the staff so that every demonstration in each category was assigned to at least one group. Groups spent the morning session of the next six days preparing and practicing the demonstrations they had selected. In the afternoons, each group presented its demonstrations to the other teachers together with an evaluation of demonstration effectiveness (visibility, simphcity, liveliness, charm, cost, set-up time, and expense of supplies), safety considerations, and utility for teaching particular conceots DU& the second week of the institute, teachers presented their "best" demonstrations to summer school clnsses of general and organic chemistry that were in session at that time. This "practical testing" of demonstration methods was designed to allow teachers to apply what they had learned to "real classroom" environments and to provide a transition between the institute and teachers' own classes. Evaluation
On the last day of the institute, teachers were asked to provide written evaluations of their experience. The questions asked and teacher responses were as follows:
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