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EVALUATION OF LABORATORY WORK I N GENERAL CHEMISTRY' ARNOLD J. CURRIER Pennsylvania State College, State College, Pennsylvania
INDIVIDUAL laboratory work is now regarded as a vital part of the teaching of general chemistry in colleges and universities. The student will naturally be expected to do better work if he knows that he will be given proper credit for his efforts. Evaluation of the laboratory work of the student is a complex problem especially in the larger institutions where the work is handled largely by graduate assistants with little or no experience. The objectives of the laboratory work in a given course must naturally be taken into consideration in determining what criteria are to be used in the evalua tion of the work. As a practical statement, it would seem that the main objective is to give the student experience in working with substances under guidance. I n other words, to learn chemistry by "doing chemistry." Schlesinger (1) has clearly stated other important objectives, uiz., to train the student to observe, to think and to act. To devise experiments and tests in conformity with these objectives is a challenge to the industry'and ingenuity of every teacher. It is the major purpose of this paper to consider some of the items involved in evaluating student laboratory work, particularly with regard to current practice in the colleges of New England and Pennsylvania. To obtain information on evaluation of laboratory work, a questionnaire was sent in March, 1952, to 38 members of the New England Association of Chemistry Teachers in the colleges and universities. Data were requested on the percentages of credit given to six aspects of the student's work: completeness, i n d e pendence, technique, quizzes, notebooks or reports, and "unknowns." Information was also requested on the number of courses given and the type of notebook or report used. Of the 26 (68 per cent) of the questionnaires returned, 18 did not report specific percentages, allocated to the 'Presented as part of a symposium a t the Fourteenth Summer Conference of the NEACT, University of Vermont, Burlington, Vermont, August 22, 1952. Andrew J. Scarlett, Dartmouth College and Carl P. Srainnerton, Pomfret School, also contributed to this symposium.
various items, in determining the grade for the laboratory work. In these colleges, i t is presumed that a composite laboratory grade is given which is based upon the general observation and judgment of the instructor. Several instructors indicated that the relative percentages varied from week to week. A smaller number (8) of the questionnaires reported specific percentages for most of the items listed. Data from this group are summarized in Table 1. The same questionnaire was.distributed at the first meeting of the Pennsylvania Conference of College Chemistry Teachers (PCCCT) in April, a t State College, Pennsylvania. Of the 12 institutions reported, 8 indicated specific percentages of credit allocated to most of the items as shown in Table 1. TABLE 1 Items g i v a special credit
Completeness NEACT PCCCT Independence NEACT PCCCT Technique NEACT PCCCT Quizzes NEACT PCCCT Notebook or NEACT re~ort PCCCT Unknowns NEACT PCCCT
Number o f colleges reporting percentages
4 3 4 2 5 5 5 7 5
4 5 6
Percentaue o f credit MiniMazC mum mum
10 10 17 10 10 lo
lo 12 15 10 10 5
20 15 40 15 50 33 100 80 50 33 33 30
Data concerning the number of courses given and the type of notebook or report used are presented in Table 2. Although the number of institutions reported is rather limited it should be emphasized that many of them have large enrollments. The data, therefore, present a fairly comprehensive "picture" of current practice in the areas reported. It is of interest to note the wide variation in the percentage of credit given to the various phases of laboratory work. For example,
JOURNAL OF CHEMICAL EDUCATION TABLE 2 Nurnher of courses
T y p e qf notehook
KEACT 1 course in 8 oolleges 2 courses in 10 colleges 3 courses in 6 colleges 4 courses in 2 colleges
Blank hook form in 13 colleges "Fill in" form in 13 colleges
PCCCT Blank book form in 6 colleges "Fill in" form in 6 colleges
1 course in 4 colleges 2 eoumes in 8 colleees
the percentages for quizzes (oral and written) varies from 10 to 100 per cent and the percentage for notebooks or reports varies from 10 to 50 per cent. Amplifying statements in the questionnaires show a recurring emphasis upon the value and importance of the oral and written quiz and a diminishing emphasis upon notebooks and reports. Some instructors stated that the longer "essay type" of report is of considerable value to the student, when it is done under proper conditions. One teacher reported that 100 per cent of the laboratorv erade is based noon auizzes: ". . . 10 auizzes ver semester marked on basis of 10 credits each. The quiz is on the previous week's laboratory work and is given a t the beginning of the laboratory period (approximately 20 minutes). Laboratory grade counts of the course grade." Another teacher made the following comments: "Too many students relay on fraternity files for their formal reports. The laboratory examination tends to 'square things up'. . . . My experience with 'fill in' sheets and blank page notebooks has not been satisfactory; too much is written in before the experiment is performed. Often, very little actual work is done in the laboratory and the report is turned in containing only 'textbook obse~ations.' I wish I knew some really good way to make students think and learn in the laboratory."
a
TABLE 3
% W t . 01.' lab. wade Note
Sci. eng., agr., 30 and technical A~~roximate
ance of
i o n
Oral
Written
30
18
22
per-
30
0
+
TARLE 4
Item
General lab. performance g;F;eoks) Unknowns
,4 partial answer to the problem presented in the previous quotation is proposed by another teacher in the following statement: "We do not require any outside work on reports. Students come to the laboratory, do their work, check it with the instructor, and that constitutes their final responsibility on each exercise. After trying to have written reports prepared outside, for grading, we came to the conclusion that we were wasting our time and so were the students. We try to make the principle behind the exercise the most important item, second, the method of obtaining information about that principle (i. e., techniques). While this attitude does allow the uninterested student to 'get away' with less work than a complicated system of report writing and grading would do, me are satisfied that it is best for us." Another comment by still another teacher is significant: "The close association of each student, duriog laboratory time, with the instructor who is not afraid to get foot weary, has not only much teaching opportunity, but also gives the instructor much information not found by other means. Some way of evaluating this information might be sought." To eliminate some of the common undesirable practices in laboratory work, e. g., copying of laboratory notes from other reports or from nearby students, 'Lcookbook" or unintelligent following of instructions, etc., Secrist (8) offers constructive suggestions based upon the procedure used in his laboratory. In place oi the usual laboratory report, the students take a short written quiz during the last 15 minutes of the laboratory period, covering the experimental work just completed. Some of the advantages named by Secrist are: (a) a more serious and thoughtful attitude of the student toward the laboratory work, ( b ) the tendency to leave the laboratory early is discouraged, (c) the lahoratory desks are cleaned more carefully so as to be in good condition for writing the quiz, (d) a minimum of time is required for grading the quizzes-probably less thau the time used in grading laboratory reports, (e) the grades on the tests are generally good and serve to maintain interest in the laboratory work. A more extensive survey of the evaluation problem was conducted by C. S. Adams (3) in 1942, in which a questionnaire was sent to 175 colleges and universities. Replies were received from 140 institutions in 46 states. The information thus obtained is summarized in Table 3. From the approximate averages in Table 3 it is evident that rather high percentages were allocated to quizzes (12 26, or 38 per cent) and to notebooks (33 per cent). The observation of performance also rated 26 per cent. A tentative plan for grading laboratory work a t the Pennsylvania State College is shown in Table 4. General laboratory performance covers care of desk and reagents, manipulative skill and technique, initiative, punctuality, and understanding of the work done. Kotebooks or reports are graded on a scale of 10 as follows: 9 to 10, Superior; 6 to 9, Satisfactory; below 6, Unsatisfactory.
Chem. 1 5 credits,
S credits,
33 33 33
33 33 33
%
Chem. 3
%
Chem. d 5 credit+
%
20 20
Chem. 4 J credits,
%
20 20 20 40
APRIL, 1953
From our recent discussions and from the comments of a number of instructors who reported on the questionnaire, it appears that a decreasing emphasis is placed upon the student's notebook or written report. Although we do recognize the importance of checking errors or misconceptions, the notebook, it seems, is to be regarded as the student's own project which is to serve in helping him to "crystallize" the first hand knowledge which he has acquired from his experimental work. The preparation and the relative merits of the various types of written tests for laboratory work is beyond the scope of this paper. We have experimented with objective laboratoy tests on a limited scale with good results and plan to do further work. A typical question was stated asfollows:
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oratory grade. There is a wide variation in the relative percentages assigned to these items. (2) The smaller institutions, in general, reported that a subjective and conposite rating is the basis for the laboratory grade. (3) Decreasing emphasis is placed upon the student's notebook as a basis for laboratory grades in both the larger and the smaller institutions. ACKNOWLEDGMENT
The author wishes to express appreciation to the many individuals for their cooperation in the preparation of this report. The college teachers in Kew England and Pennsylvania have added many constmctive comments in their replies to the questionnaire. The committee on laboratory work a t the first conferA suhstanee was observed to react with water, forming e. solution which turned red litmus blue and a gas which burned. Cheek ence and workshop in General Chemistry (Oklahoma below the correct conclusion from this experiment. Agricultural and Mechanical College, June, 1950), of which the author was a member, emphasized the ob( ) 1. Calcium hydroxide and acetylene mere formed. jectives stated in this paper. Grant W. Smith, D~rec( ) 2. A base and a hydrocarbon were formed. ( ) 3. Sodium hydroxide and hydrogen were formed. tor of General Chemistry, Pennsylvania State College. ( ) 4. Calcium hydroxide and hydrogen were formed. has made helpful suggestions and, last year, appointed ( ) 5. A base and a combustible gas were farmed. the following committee on evaluation of laboratory work: Herman H. Appledorn, Warren W. Miller, Engelhart (4) has contributed a very practical and extensive discussion of objective tests in chemistry Thomas Wartik, and Arnold J . Currier, Chairman. which should be very helpful to teachers who desire Some of the material of this paper has been worked out by this committee. The criticisms of the general to improve their testing procedures. chemistry staff have been most helpful. Hendricks (6) describes laboratory tests in which the student is asked to set up and perform experiments LITERATURE CITED under the direct observation of the instructor. ApH. I., "The contribution of laboratory work to parently, this type of test requires experienced instruc- (1) SCHLESINGER, general education," J. CHEM.Eonc., 12, 524-8 (1935). tors, considerable time, and small classes t,o insure (2) SECRIST, J. H.,"Laboratory quizzes in the freshman labornsatisfactory results. tory course,"ibid., 29,248 (1952). (3) ADAMS, C. S., "Importance of laboratory work in general (1) The large institutions, in general, reported that a percent,age rating of the various items (quizzes, notebooks, unknowns, etc.) is used in determining the lab-
chemistry at the college level," ibid., 19,266 (1942). (4) ENGELHART, M.D., "Evaluation of achievement in chemistm." ibid..,28.373-9 (I951 ~ - ~i~ --,(5) HEXDRICRS, B. C., "Laboratory performance tests in ehemistry," ibid., 27,309-1 1 (1950).
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