provocative opinion Are Our Demonstration-Based Workshops Doing More Harm Than Good? Paul Kelter University of Nebraska-Lincoln, Lincoln, NE 68588-0304 A friend called me in late April and asked if he wuld be supplied with some calcium carbide. "What's up," I said, knowing full well what was up. He said that he had seen a demonstration lecture (at the 1993 National Science Teachers Association national conlerence in Kansas City, at which the presenter had comhinrd hgdmchlonc :wid wirh culcium c;~rbidrto give acetylene and that the flames that resulted were really wild. The demonstration that my friend was talking ahout IS disrussed in detail in Shakhashin 1 I,. Shakhashin desrribes the reaction this way, Remove the rover plate from the qlmder, add a few pellets of CaC,. ~ n quickly d .tep hack. Large flamer wdl erupt from thr qlmdcr, and drposits ofblack soot will form on its sides
I did not supply my friend with the calcium carbide, because a s a middle school earth science teacher, who is teaching chemistry for the first time, he is a better teacher in one piece than in several. Lee Marek, the leader of the Weird Science group, told me recently of a fellow he met who was going to demonstrate the combustion of peroxyacetone by taking what Marek described as enough to blow a crater into the floor of the demonstration hall. Marek warned the presenter about this, to which he responded, roughly, if x is flashy then 32 must be incredible. If vou look at the Shakhashiri write up on this demonstration .21.it nearly equates handling this stuff t11 handling nuclear furl. Shukhi~shiriis quite clear that peroxyacet&e is exceptionally dangerous, but somehow the message did not get across to this presenter. Leek message did. The prese&er used only a fraction of what he had brought with him without incident. In my travels around the US., I have seen an ever-increasing number of situations like those discussed above, in which a workshop or convention participant walked away from a session with an understanding that was different than that which the presenter intended. In many instances, the results of such a n orthogonal understanding could be tragic for the teacher andior the students. The issue is not merelv one of safetv. It is also deoth of content coverage. Far too many of us present demonstrations as if they are bullets in a machine gun that must be emptied by the end of the hour. Content suffers when there is no time to truly consider what the demonstration should be used for: its-scientific, technological, and social context. Although novel demonstrations are always being devised and published in, for example, a monthly column in this Journal, it is my experience that most of the demonstrations that are used by teachers are learned a t either large state and national conferences, or at occasional tetea-tetes with colleagues. I believe that as a "hands-on" approach to science education becomes (thankfullv) more k d e l y accepted, more nonchemistry teachers and teachers at the middle and elementary levels are using more haz-
ardous demonstrations and with less conceptual understanding than they ought to have. It is time that we take a step back and begin to ask some difficult questions about the wav we Dresent our demonstration-based sessions a t conferences. We also need to assess who the attendees are, and their likelv behaviors after attending ~resentations. What follows are some questions that need& be discussed within the chemical education community. What is it that we want to aowmplish when we present at a convention? Asession at a convention sponsored by ACS, NSTA, and the like will typically be from 30 minutes to 2 hours long. The audience &I be as small as one person or can fill a 306-seat auditorium. Because the time is so short and the audience count so uncertain, the hands-on, Somaticapproach that is so important when leading a long workshop is not practical. It is as also not oradical to seriouslv assess the extent of lea& a result of such a given that a thorough assessment tool can take at least as long as the time you have to present. Given the uncertainty, then, the primary goals of a short demonstration session deal with motiuation, teaching, transference, and entertainment. We want to motivate attendees, especially those who are skittish about d o h chemistry in theirhassrioms, to want to know more. We want to teach a concept or two u s h activities. We want the attendees to bring the demonstration into their classroom because there is something pedagogically useful about that demonstration. themselves. so thev take And we wait the aidieice to eniov " ~,~ ~"~~ hack to their students the message that science is fun. The goals of a workshop, which generally lasts for a few days, are broader, and deal more with the teachingpmcess. In addition to those listed above, workshops present the opportunity to model effectiw teaching strategies, and to assess the extent of learnine of the participants. Because learnine and safetv " eo hand-in-hand, and because assessment is not practical a t conference presentations. I believe that safetvis beineunnecessarily w&pmmised biwnvention d
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Whom are we presenting to? I t is my that the audiences for demonstration . emerience . sessions are remarkably varied. They contain kindergarten teachers, who have not had a chemistry class in 30 years, alongside chemical education at graduate schools. Because preassessment is not possible when preparing a presentation, we cannot know the specific educational backgrounds of the attendees. We can assume, however, that people are a t a demonstration session to learn new activities to share with their students. And in far too many cases, attendees do not have the background to fully savor the key concepts, their societal releuance, or the key safety concerns of demonstrations. Volume 71
Number 2
February 1994
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The "Elephant Toothpaste" experiment is an excellent example. 1i this experiment, thedecomposition of hydropen peroxide is accelerated by the addition of potassium iodide solid or aqueous soluti6n. A dishwashingdetergent is added to the 30%or 50%H202to capture the oxygen and give the "toothpaste effect." I have demonstrated this reaction in countless workshops. I briefly mention the usual can cause severe hums, etc..) and I safety hazards (HzOz know that many in the audience do not have the background to adequately assess other potential hazards to the activity that might be obvious to those with a richer chemistrv backaround. For example. the resultant foam is mosky watkr, oxygen, and somedishwashing detergent. Yet there is a likelihood that some hydrogen peroxide is present in the foam, and a s such, ihe fGam-should be treated with great care. The heat generated from this exothermic reaction is also cause for concern. Even though KI is a catalyst, some I2is generated, as evidenced by the purple color of the foam product. This is important chemistry, and I don't often have time to discuss i t in a brief presentation. I put it in handouts, but it has been my experience that those with poor chemistry backgrounds have neither the time nor expertise to digest the information in a handout. They will often follow the procedure lock-step, come what mav. I discuss curricular aoolications as much as possible, Lnt the discussion is all too brief. The bottom line here is that there are many who attend chemical demonstration workshops and are not prepared to learn what I have to teach. I am beginning to believe that I should not present such spectacular, yet dangerous, demonstrations in a short lecture format. The safety of t m many could be compromised if many in the audience run to try the demonstration in their classroom. What is likely to be done with the new concepts and demonstrations that are shown? If the demonstration is sensual, that is, visually appealing or loud, and if the substances involved are not especially exotic, many attendees will bring the demonstration into their classrooms. That. after all. is one goal of presenting. The essential problem,.as stated above,lis thatconvention t resent at ions ~rouideneither adeouate discussion nor nssrscment time tojiuorantep lhnt t h n s ~whoser the dernonstrntion~will u w then1 responsibly in class. The question of who is at risk is straightforward. Ultimately, it is the students, because they may be exposed to a demonstration by a teacher who, in far too many instances, is not clear enough on the chemistry to anticipate safety hazards, whether they are immediate or long-term. What are our responsibilities? Regarding the responsibility of the conference presenter
I t seems to me that as more middle and elementary level teachers are called upon to teach using the hands-on and demonstration-oriented approach, the responsibility of the conference presenter must also shift to honor the recognition that hi; or her audience may not know as much chemistry a s they ought to. Although presenters may warn teachers of hazards, print them in our handouts, and give curricular suggestions, we can no longer make the assumption that such advice will be heeded. This is not be-
110
Journal of Chemical Education
cause teachers want to consciously put their students a t risk. Rather, the teachers may not know enough to understand the risk. We must refocus our efforts toward safer demonstrations, where we spend more time discussing not only the chemistry, hut the application of the demonstration to classroom content, and, where a~plicable,the social and technological importance of the &rnonstratron. We also must be cognizant of the uses to which our handouts wlll be put. wemust do everything poss~bleto guarantee that our discussions are as clear as possible, and at a level that can be generally understood. Where there is a likelihood that the handouts w~llspread beyond those who have attended the oresentation.. oerhaos we should consider eliminating hazardous demonstrations from our printed matcrials. At the Chem Ed '91 conference in Oshkosh. hundreds of presenters contributed to the "Trading post," a place where their handouts were posted so t h a t all conferees could have access. I n view of the ever-increasing odds of demonstration misuse, I believe that such 'Dading Posts should be eliminated because they put students at increased risk of accidents, and conference presenters and organizers a t legal risk for supplying the activities.
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Regarding the responsibility of the conference attendee It's meat that so many school districts are adopting . -a hands-on approach to learning science. I have seen an upsurge in interest, especially from elementary-level teachers. in learnine demonstrations and activities. Teachers need to keep in mind, however, that the idea behind the teachine strateeies is to make the connection between the demonstration or activity and a particular content objective, not merely to motivate or use up class t i e . Further, teachers need to understand far more of the science behind the demonstration or activitv than their students do so that unpredicted student questions can be dealt with, and potential threats to safety can be anticipated.
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The Bottom Line The bottom line of all this is that we who present demonstrations at conventions need to think about whether the "business as usual motto" of presenting as many demonstrations as possible in a short session is doing more harm than good. Further, we ought to consider putting greater controls on what is in our handouts and whom they reach. If the presenter is giving a motivational talk, or presenting "just for fun," then he or she ought not to give out details of the activities during the talk or in handouts. But if the goal is to teach the activities in the session, the presenter should limit his or her presentation to 4 demonstrations per hour. Conference organizers could help by adopting a "standard demonstrator ameement form" that sets this limit on the number of dem&&rations per hour. If the related safety and content discussion cannot fill the hour, then the demonstrations are not worth presenting. Literature Cited 1. Shakhashiri, B .Z.ChemieieIaPapnst~fiiii,AH a n d b k for k c h a m ofChamktv,
Vol. 1: Univemity of Wismnsin: Madison, WI. 1983; pp 4 6 5 0 . 2. Shakhashiri, B. Z.Cha"ieo1 & m o ~ t r o l i o n s , A H o n d b ~ o,-or k lkachars 0,"chmistry. Vol. 2: Universifyof Wkmnsin: Madison, WI. 1985: pp 220-227.
