Ralph K. Birdwhistell The University of West Florida Pensacola. FL 32504
I
Aids to the Lecturer
When I started teaching in the early fifties a t Michigan State University, the person I turned to for advice was Professor W. T. Lippincott. One of the first problems I faced was how to use effectively hoth lecture demonstrations and films, and his advice a t the time was to use only the simplest of demonstrations and to e x ~ l a i nin detail each film so that the students upon seeing th6.m would comprrhc~n~l their content. Over the sears sinw then. I have finallv realized the significance of his advice. That which follo& will relate hoth the experiences and the literature which has reinforced my comprehension of "Tom's" advice. After explaining to the class why we could expect NH3 (g) to be very soluble in water, I demonstrated the ammonia fountain which promptly imploded filling my hand with glass and shoes with ammonium hydroxide. The next week the students kept asking me "How could that mixture explode?" I had not explained carefully what I was trying to demonstrate and what they should expect to see. To introduce infrared sDectroscoov. I showed the excellent CHEM study film by ~ r & crawfird, e lectured on the material. and then showed the film again. The students saw the springs and masses vibrate and the instrument plot an ahsorhance but the connection between the analogy and the molecule was lost. I could not understand how they had missed this connection. In the late fifties I was involved in one of the first uses of closed circuit television to teach freshman chemistry. This technique would allow us to expase all students to the lecturer with the most experience who had a proven record and who would have the assistance to fully prepare for each lecture. His
64 / Journal of Chemical Education
would be a perfected performance. The results, hoth students' ~erformanceand their resDonses, were disappointing to say the least. On our review of the tapes we foundthe material to be well organized and complete and the resenta at ion excellent. Our expl&ations for the iackloster re&s were that 1) The programs were in black and white. 2) The camera crews many times did not focus on the principal
idea. 3) The dark viewing room improved sleeping conditions. 4) The actions of the lecturer and the students within the lecture
room were constrained by the camera's presence.
Today, I do not believe any of these factors should hear the primary responsibility for our failure. In the summer of 1970 I worked a t Reading University with the summer school portion of the chemistry course offered by the Open University. The students were all mature, highly motivated. and so~histicated.All dav and everv evenine until midnight I was assaulted by questions about the material which had been presented the previous winter on the BBC. I viewed many of the tapes to first understand the questions and secondly to review hoth the quality and content of the presentations. To summarize, the presentations were superb hoth in terms of the accuracy of the subject matter and in the care with which it was displayed. An immense effort went into the production of these tapes, and the results demonstrated this effort but the students' understanding of the material did not reflect this sophistication. I questioned them on how they prepared for and used these presentations. Their response was that they initially followed the instructions given them hut
They (the demonstrations) shcwld be important, as they respect i k n d rhnt they mere al~surl,ingnvither the idms nm thr factk irom the t e h i&m. \\'hen t h q fu~milthey wrrc*uns~~ccr.jci~~l, the science the" arc applied to, yet clear and such as may easily he underst~rd.(M.F.1 The best experiments are simple and on a large scale, and their workings are obvious to the audience. (M.F.) andkoiked as a erouu throueh the lecture material until thev could derive theresuits from the data. Two mornings I orgaI conclude from these quotations and concur that any nized a eroun of six of these students to view a sinale nroaram demonstration or i~~ustratibn should be simple, readily uitwice. b;t t i e end of the second showing I asked Gestions derstandahle, and should remain for a long period or be conabout it and several times the students had not seen or heard structed slovily with the hope or the aim of audience retenqualifying statements made during the program. Again the tion. unresolved question of why had these concepts and content Secondly, P. W. Jackson in the 1967 Horace Mann Lecture2 been missed: entitled "The Teacher and the Machine" speaks of the difTwo vears aeo after bavine seen and enioved several of the ficulties attendant to the use of the various educational lessonsfrom ''iscent of an" the full c&&e was offered on technologies, but his strongest point is that public television: I decided to make a concerted effort to take Mechanical teaching devices usually move material in one direcit. After readingthe text and the ancillary material I viewed tion at a time, at a speed over which the user hasonly limited conboth showings of each Dropram. Even with this oreuaration tml. The student has no chance to sav "Wait a minute!" or "Rednd el,l,rt I "tissnl man;,
