LETTERS A Lecture Demonstration Course
bons, (27) aryl halides, (28) nitration, (29) reduction, (30) sulfonation, (31) diazotization, (32) qualitative organic analysis. To the Editor: The needs of a rather large group of students in orA number of inquiries relative to the lecture demon- ganic chemistry are served adequately by a lecture demstration work in organic chemistry, that is being offered onstration course of this type. In this group may be in the chemistry department at Purdue University, included all beginning students in organic chemistry has prompted this note. who never expect to make any practical use of their At the outset, the writer wishes to state that the lec- laboratory training, but who will always find themselves ture demonstration course, which is being offered, is confronted with problems in everyday life that compel given in response to a specific need a n d not as a suh- them to sense accurately, to think clearly, and to record stitute for regular laboratory work. Mter seven years' intelligibly, mentally or otherwise, if they would be experience in the use of lecture demonstrations in or- successful in their chosen profession. ganic chemistry, the writer is still of the opinion that A few details relative to the administration of the lecture demonstrations cannot be used as the one and course should be given. In order that the students only means of teaching laboratory technic. may be able to see the results of the experiments, and The writer firmly believes that a four-fold set of ob- in order to facilitate oral quizzing, the sections are jectives should justify the presentation of any labora- limited to from twenty to thirty students. The demtory course. The laboratory instructor should aim to onstrations are correlated, as far as possible, with the teach his students t o d o correctly, to sense accurately, to regular lectures. Test-tube reactions are stressed. think clearly, and to record results intelligibly. If these be Simple preparations and the most important type reacthe objectives underlying laboratory instruction, which tions of the various homologous series are considered. most instructors will readily concede, then i t is quite ob- Students are expected to spend two hours of outside vious that lecture demonstrations cannot serve as a sub- preparation previous to each lecture demonstration stitute for regular laboratory work. We still live in a exercise, reports on this outside work being required. world in which we learn to do by doing, experimenta- The students are required, furthermore, to submit their tion being the teacher par excellence. One cannot, notes, for correction and grading, a t the close of the therefore, expect to teach a group of students the art of lecture demonstration h o y . It would seem, therefore, laboratory technic solely by the use of lecture demon- that lectpre demonstrations of this type may serve as strations. The proper type of demonstrations, to be adequate teaching tools. sure, may be used advantageously to supplement E. F. DEGERING regular laboratory work. Punnue UNIVERSEY It is possible, however, to give a course in lecture LAPAYETTE, INDIANA demonstration organic chemistry in which one desires to train his students to sense accurately, to think clearly, and to record results intelligibly,rbut is not concerned Mu a n d t h e Micron with teaching the art of doing correctly. It is just such a need that a course in lecture demonstration organic To the Editor: chemistry is intended to fill; for these objectives may This note is to call attention to the fact that, when be attained, in the opinion of the writer, without the used in measurements, the Greek letter, mu (p), should use of regular laboratory work. The following series indicate one millionth just as the Latin, milli-, indiof studies, in which one hour is devoted to each assign- cates one thousandth. Some time ago I copied the ment, seems to meet these particular needs in or- following table, dated 1893, from Erdmann. It is in ganic chemistry: (1) Notebooks, J. CHEM.EDUC.,10, keeping with the "International Critical Tables." 4.01-12 (1933), (2) saturated hydrocarbons, (3) unsatuMeter (M) equals l o 0 Meter rated hydrocarbons, acetylene, (4) halogen compounds, Millimeter (mm.) equals Meter 10-a Meter (5) alcohols, (6) ethers, (7) aldehydes, (8) ketones, (9) Micron (mu or rr )equals Milli-micro; (m mu or mp) lo-' Meter saturated monoacids, (10) lactic, tartaric, and citric Angstrom (A) Meter acids, (11) acid anhydrides, (12) acyl halides, (13) Double mu (mu mu or pr) 10-la Meter esters, (14) soaps and salts, (15) melting-point studies, Milli-mu mu (m mu mu or m ~ p )lo-" Meter calibration of a thermometer, (16) boiling-point studies, The micron should be defined as the millionth of a calibration of a thermometer, (17) carbohydrates, (18) carbohydrates, continued, (19) amides, (20) amides, meter and not as the thousandth of a millimeter nor as a continued, (21) amines, (22) amines, continued, (23) ten thousandth of a centimeter, as in some texts, alamino acids, proteins, urea, (24) amino acids, proteins, though all are correct. Mu, the micron, is a millionth urea, continued, (25) nitnles, (26) aromatic hydrocar- of a meter and the mu mu, double mu, or pp, is a milin Organic Chemistry
