Quizzes to Encourage Preparation for Lectures WILLIAM E. MORRELL University of Illinois, Urbana, Illinois
OME instructors use the lecture method of teachmg through choice. Other sresort to it through necessity. If for afly reason relatively few qualified instructors are available to teach relatively large groups of students, recourse to the lecture method is almost inevitable. If the lecture sections are large, one advantage of this method of teaching is financial economy. On the oiher hand, the method does have disadvantages, which are sufficient to give rise to the oftrepeated definition of the lecture method as "a way of teaching whereby the material goes from the notebook of the professor into that of the student without passing through the mind of either." The instructor does the work and the student need do nothing, though he usually does take voluminous notes. One usual attempt to minimize the disadvantages of the lecture method is to split the large lecture section into smaller supplementary discussion groups. Frequently the resulting discussion is confined to the subject matter of the lecture, through choice of either the leader-ften a senior or graduate student-r the students. The "discussion" may even be a mere repetition of the lecture. The lecturer commonly feels that his lectures should be thorough and complete, and that he should organize the material for the students. The students in turn depend upon him to do so. They find that he does discuss the important topics (judging by his examinations). They find that studying the textbook is both boring and unnecessary, since it contains the same material as is presented in lectures (and attendance a t lectures is compulsory). Reading the text may even be confusing, as the book includes many extra details, which will probably not be needed for examinations. Thorough study (memorizing?) of lecture notes the night before an examination is the best way to prepare for the test, judging by common practice (in which the writer also indulged). Students finally take the attit u d e a n d the lecturer tacitly a g r e e s t h a t "if it wasn't said in lecture it isn't fair to ask i t in exams." In an attempt to overcome some of the weaknesses of the usual lecture system, the writer tried an expedient which, while no cure-all, did yield beneficial results. At the beginning of the 1944 Summer Semester a t the University of Illinois, the 100 students in his lectnre section in elementary chemistry were urged to study the textbook consistently and thoroughly during the term, and to study each assignment before going to the corresponding lecture. I t was pointed out that the lecture should then be much more understandable and
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profitable. The lecturer announced that he wohld assume that the students had studied the assignment, and he would make no effort to repeat or abstract the text, or to discuss all important topics. Rather, he would supplement the text or discuss important topics which he deemed difficult. He would practically ignore the easier material adequately discussed in the textbook.' In examinations students would be held for material assigned, whether discussed by the lecturer or not. During each lectnre a definite assignment would be made for the next lecture. To encourage the recommended study of these assignments, the students were warned to expect a quiz a t the beginning of any lecture period. The quiz would be limited to the current assignment, and would include questions specifically discussed in the assigned readings. The attempt would be made to make the questions difficult to answer merely on the basis of knowledge the student might already possess, but relatively easy if the assignment had been carefully studied. These quizzes would not take the place of the usual examinations, but they would be included in the determination of the semester's grades. Eight such quizzes were given during the semester. Two are reproduced here. All were constructed so as to require relatively little time for administration and for grading. They were mimeographed, and were graded with stencils. Subtraction for incorrect answers was not deemed worth while, the number of correct responses being accepted as the student's score. The course in which these quizzes were given was outlined for students who had had no chemistry in high school, but to the class were also assigned individuals who had taken high-school chemistry but remembered little of it, according to placement test scores. Atomic structure was to be the subject of the fourth (out of a total of 29) lecture of the semester. For it, pages 13 to 35 in the text (Hopkins, "General Chemistry for Colleges," 3rd Edition, Heath, 1942) had been assigned. At the beginning of the hour, Lecture Quiz No. 2 was given. (The average grade on it was 55 per cent.) Electrolysis was to be discussed in the 15th lecture and discussion of the chemistry of chlorine was to be started, to be continued in the succeeding lecture. For the 15th lecture, textbook pages 243 to 252 (electrolysis) and the entire chapter on chlorinepages 194 to 2 0 G had been assigned. Quiz No. 6 was given a t the beginning of the hour. (The average grade was 66 per cent.)
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1 Dr. John C. Bailar, Jr., suggested the plan of marking such topics with an asterisk in the lecture outline written on the blackhoard.
LECTURE QUIZ
Chlorine is not used for which bf the following purposes? (a) production of refrigerants, (b) of bromine, (c) purification of drinking water, (d) bleaching of wood pulp and fabrics. (e) It is used for all of the above purposes. abcde 8. At an electrode called an anode the type of reaction that occurs is (a)oxidation, (b) reduction, ( c ) oxidation and reduction, (d) neither abcd oxidation nor reduction. 9. A certain quantity of electricity, in flowing through an electrolysis cell, reduces 107.88 gramsof silver ion to silver. (Agt e- = Ag.) (Silver is atomic number 47 and has atomic weight 107.88.) The same quantity of electricity would reduce how many grams of aluminum ion to aluminum? (Alttt 38- = Al.) (Aluminum is atomic number 13and hasatomic weight 26.97.) (a) 13, (b) 26.97, (c) 107.88, (d) abcdef 8.9'3, (e) 35.96, (f) 80.91. 10. The same quantity of electricity (as in No. 9) would yield how many litersof hydrogen gas (at S.T.P.) by reducing hydrogen ion to hydrogen gas? (2H+ 2e- = H2.) (a) 1. (b) 2.016, (c) abcdef 22.4; (d) 44.8, ( e ) 11.2. (f) 107.88. 7.
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Answer each of the following questions by blackening in the list a t the right theletter which corresponds t o the one beat answer.
For purposes of comparison, Hopkins states (page 16) that a neutron, like a hydrogen atom, "may be thought of" as being "composed of a single proton and a single electron." He states further that the weights of the hydrogen atom and neutron (a) are equal, (b) differ slightly. ( c ) abc differ greatly; that the radii of the hydrogen atom and neutron abc (a) are equal. (b) differ slightly, (c) differ greatly; and that the chemical behaviors of the hydrogen atom and neutron (a) are identical, (h) differ abc slightly, ( c ) differ greatly. Two isotopes differ from each other ( a ) in chemi d properties, (b) in arrangement of valence electrons, ( c ) in their masses, (d) in none of these ahcd respects. Two isotopes d z e r from each other in that they contain different numbers of (a) neutrons, (b) abcd protons, ( c ) electrons, (d) none of these. Two isotopes differ from each other in (a) atomic number, (b) atomic weight. ( c ) both atomic number and atomic weight, (d) neither atomic numabcd ber nor atomic weight. Isotopes are (a) atoms of elements adjacent to each other in the periodic table, (b) atoms of elements in the same column in the periodic table, abc (c) atoms of the same element. If 10.000 grams of hydrogen were converted into helium, the resulting helium would weigh (a) about 9 93 grams, (b) about 40 grams. (c) about ahcd 4.003 grams, (d) 10.000 grams. Thenucleus of an atom contains (a) all. (b) most. (c) exactly half. (d) very little, (e) none of the abcde total mass of the atom. The nucleus of an atom occupies (a) practically all, (b) slightly more than half, ( c ) exactly half, (d) almost half, (e) very little of the total space abcde occupied by or enclosed within the atom.
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In each case every question could be answered on the basis of information contained in the assignment. For the most part, it was attempted to make the items straightforward and to avoid "trick" questions. In general, the effort was made to have questions concern relatively important topics and not insignificant details. However, questions were asked about smaller details than would ordinarily he included in the usual examinations in the course. Purposely included in the lecture quizzes were items which would require very careful study of the assignments, and it was hoped that relatively few of the questions could be answered on the basis of information previously possessed by the students concerned. I t should be emphasized that the principal aim of these quizzes was to encourage conLECTURE QUIZ NO. 6 sistent and careful study of assignments before the corAnswer each of the following questions by blackening in the responding lectures. list a t the right the letter which corresponds to the one besf answer. Each quiz delayed the start of the lecture from 12 to 1. Chlorine gas was first prepared by (a) Boyle in 15 minutes. This delay included the time taken by 1660, (b) Scheele in 1774, ( c ) Sir Humphry students in scattering to alternate seats. (Two verDavy in 1810, (d) Mendeleeff in 1869. (e) Nelson in 1916. a b c d e sions of each quiz could have been provided, mimeographed on two differentcolors of paper and distributed 2. As found in nature, chlorine is the neutral element (a) always, (b) usually, ( c ) occasionalternately to the students in their regular seats.) ally, (d) never. abed The writer believes that the time taken from lectures 3. The usual commercial method for the proand the time consumed in composing and grading the duction of chlorine uses which of the following quizzes was well spent. The graduate students assistas a raw material? (a) HCI, (b) AgC1, ( c ) a h c d e ing in the course agreed. Instructors and students all KNnO,, (d) NaCl, (e) none of these. 4. The usual commercial method for the producagreed that the quizzes considerably increased the tion of chlorine yields which of the following as amount of student' preparation for lectures-and that a valuable product (in addition to chlorine)? is what they were designed to do. (a) NaCI, (b) NaOH, (c) MnOn. (d) MnCb, While attendance a t lectures had previously posed no abcde (e) none of these. 5. The usual commercial method far the producparticular problem, it is of interest to note that there tion of chlorine also yields which of the followwere comparatively few absences in this section. It ing as a product? (a) Nz, (b) Hn, ( c ) NaBO,, was announced that each student's one lowest lecture abcde (d) SO8, (e) none of these. quiz score would be eliminated from consideration in 6. The usual commercial method for the producdetermining the student'; final grade. A quiz missed tion of chlorine utilizes which of the following processes? (a) distillation, (b) neutralization, would be scored zero (no provision was made for make( c ) electrolysis, (d) hydrolysis, (e) none of these.
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(Conlinued on pcge 405)
QUIZZES TO ENCOURAGE PREPARATION FOR LECTURES (Continuedfrom page 403)
up quizzes), and could be the one not counted in the final average. But the zero for a second quiz missed would be included in the final average. Of the nearly 100 students who completed the course, only one had been absent from more than one of these surprise quizzes. The students' reactions to the quizzes were indicated by the plea of a group who talked with the instructor. They said: "We find that the quizzes help. We prepare more thoroughly for lectures, and we find that that does help in learning. However, since the quizzes aren't given each time, we're inclined to 'take a chance,' and sometimes come unprepared. We should like to ask that such a quiz be given every lecture period." The writer pointed out that that would take nearly 15 minutes from each lecture. The students replied em-
phatically: "When we have studied the assignment, you can adequately cover more ground in the remaining 35 minutes of lecture than you could otherwise cover in the entire 50 minutes. We believe the quizzes have been worth while as given, but we believe they would be still more worth while if given a t the beginning of aery lecture." Whether or not the students were correct in their opinion, the writer is not prepared to judge, as we haven't tried giving a quiz at the beginning of every lecture. However, the original plan of frequently giving surprise quizzes before lectures has since been tried and adopted by other members of the elementary chemistry staff a t the University of Illinois. They too have been pleased with the results, and the use of such quizzes has become an integral part of our instruction.
