RESIDUE of HIGH-SCHOOL KNOWLEDGE UTILIZABLE

in COLLEGE CHEMISTRY* PAUL MAURICE GLASOE

St. Olaf College, NorthCeld, Minnesota

This paper recordc a n effort made to evaluate the u p of 186 questions, gave results i n very close accord with znpuence high-school chemistry has on first-year college the performance i n the tests. Due notice i s taken of the chemistry. The experiment was conducted with two presence of a few nonyreshmen students i n both courses, sections numbering about 80 each. Twelwe tests were the two groups are compared as to native ability by the gigen during the second semester, all of the "short-answer," Minnesota college afititude test, and finally the scholastic factual type. The results are remarkably unqoorm, achimement of all the students inwolwed i s measured by showing without a single exception a decidedly better the gradepoint ratio. The conclusion i s d r a m that all achiwement on the part of the students who have had the results point to a distinct residue of knowledge carried chemistry i n high school. The final examination, made over from high-school to firstyear college chemistry.

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I T IS gratifying to note both from papers read expected that efforts would be made to get some before the Division of Chemical Education and measurement of the influence of a year of high-school from articles appearing in the JOURNAL OF CHEMI- chemistry on fust-year college work. Too often

CAL EDUCATION that high-school chemistry is being college and university teachers express the opinion taken more seriously by colleges and universities. that i t would be better not to try to teach chemistry In addition to giving a unit of entrance credit to those in high school, holding that results indicate that who enter with high-school chemistry, colleges are little or nothing is carried over from high school to organizing special classes for those who have had it. college. Of course, this is an extreme and illogical There is by no means uniformity of treatment by all statement and a grave charge against our whole institutions. The mere division of first-year college system of high-school teaching. Either high-school chemistry into two classes, one for those who have chemistry should be granted the standing of a pre- had and one for those who have not had high-school requisite, entitling the college freshman who has had chemistry, is not sufficient. In 1929, a t the St. Louis the preparation to a special first-year course, or high- meeting of the American Chemical Society, the author school chemistry should be discontinued. If high- of this paper called attention to the "Deadly Parallel- school graduates do not retain a residue of knowledge ism between Courses in High-School and First-Year on which to build their first-year college.course, it is College Chemistry,"' pointing out the pedagogical highly questionable that it pays to continue the high- error in forcing students with a year of high-school school course even for those who do not go to college. chemistry to go through a year of college chemistry, In his two-volume work "The Junior College,'' which is only an elaboration of the high-school course. Dr. L. V. Koos3 has discussed the overlapping of the In 1931 Professor Stuart R. Brinkley2 of Yale pre- two courses in question. He has gone into considerable sented a paper in which he showed that possible detail to show the parallelism and repetition that to give a course to such students that will not,be a take place when a student goes from the high-school repetition of the work done in high school, but a con- course in chemistry to the first-year college course. sistent development of the general principles of chem- An exhaustive study was made by Victor H. No114 istry based on the residue of knowledge we have a of "Laboratory Instruction in the Field of Inorganic right to expect in such students. Chemistry." The thesis covers 164 printed pages.

In view of the importance of a closer coordination In a brief four pages he makes reference to an observa- between the high-school and college courses i t was to be tion of two groups of students entering the university 'Presented beforethe Division of Chemical Education at the at the same time, one section with high-school chem- Denver meeting of the A. C. S., August 23, 1932. istry, the other without. His conclusion is that the ' P. M. GLASOE, "The deadly parallelism between high-school -

and college courses in chemistry," J. CHEM. Eouc., 6, 50&9 qL. V. Koos, "The junior college," Chap. 33. (Mar.. 1929). 4 VICTOR H. NOLL, "Laboratory instruction in the field of

2 STUART R. B R I N ~ Y , "The freshman course in chemistry inorganic chemistry," University of Minnesota Press, Minne- for students who have had secondary-school chemistry," ibid., apolis, 1930, pp. 104-7. For review, see J. CHEM. E~uc., 8, 8,28&9 (Feb., 1931). 606-7 (Mar., 1931).

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two groups "showed no significant differenc'e after two quarters of instruction in the university." After a careful study of Dr. Noll's problem we are constrained to ask if the results might not have been different had the two sections been treated differently from the start. Should not section A (with high-school chemistry) have been given to understand that they were advanced students by giving them a different textbook, different laboratory manual, and different experiments? All this in order to make the course as much as possible a continuation and not a duplication of the high- school course. In a fair test should not both sections have had exactly the same number of hours of instruc-

nized as a rehash of what they had done before. Stress was laid on problems and the development of the sub- ject on the basis of the periodic system. In entering upon such subjects as structure of the atom, theory of ionization, reversibility and equilibrium, etc., the high-school treatment of the same subjects was as- sumed as a foundation upon which to build. The students were told that they would have to review their high-school chemistry in order to be able to keep abreast of the subject as i t was given. It serves as a stimulus for them to know that they are responsible for the knowledge they should have acquired in high school. The second semester was devoted to a syste-

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Median course 11-12 21.7 11.1 6.8 12.3 7.6 12.6 12.8 12.6 22.0 30.0 29.2 36.5 Median course 21-22 .24.2 12.5 10.0 14.7 11.4 14.6 15.8 14.3 25.4 30.2 33.6 38.2 Points of diserenee 2.5 1.4 3.2 2.4 3.8 2.0 3.0 1.7 3.4 6.2 4.4 1.7 Percentage gain 21-22 over 11-12 11.5 12.6 47.0 11.4 60.0 15.8 23.4 13.5 15.5 20.6 24.0 4.6

tion per week? Would not results have been more reliable had both sections been taught by the same person and the quizzes and examinations made up and scored by the same individual? Then, again, we learn that section A was composed of chemists and chemical engineers while B was made up of a diversity of engineering students taking chemistry as a required study. Section A had everything in its favor-they had studied chemistry in high school and pursuit of chemistry was to be their life-work. This ought to make a decided difference in accomplishment. Does the test account for the complete disappearance of this advantage?

In January, 1926, Fred C. Mabee6 reported an experiment in which he tested three college first-year chemistry classes and three high schools. His findings will be referred to later in this paper.

For the past fifteen years or more I had been con- fronted by this problem. I had been satisfied from the start that there is a decided influence camed over from high-school chemistry to the first-year college course. I had as yet no definite proof or measure of the residue of knowledge carried over, but faith in the correctness of the reasoning grew to a definite con-

matic study of all the common chemical elements in much the usual way, special stress being laid on the periodic arrangement. Both courses were now running parallel.

Twelve tests were given a t fairly regular intervals; some were announced in advance, others were not. The tests were of the usual short-answer objective type; such as true-false, completion, matching, and multiple choice. They occupied one recitation period of fifty minutes each. Comparison of the data shown in the above table reveals a remarkable uniformity of results throughout. The table shows the medians of the scores of the two courses and also the percentage of superior achievement of the students in course 21-22* over those in course 11-12.

The "percentage gain" was obtained by dividing "points of difference" by the median, course 11-12.

The average semi-interquartile range for the twelve tests shows Q = 2.9 for course 11-12 and Q = 3.3 for 21-22.

For the purpose of combining the different tests, the scores were all converted to percentile rank scores. The result of thus combining all thedests is graphically shown by curves (A) and (B) of'Figure 1.

viction. - * Course 11-12 is given to those who have not had chemistry

At the beginning of the school year 1931-32 I de- in high school; course 21-22 to those who have. cided to ascertain, a t least in some degree, what the , influence of the high-school course in chemistry might .o

be. Conditions were favorable. The first-year course was all given by me. With an enrolmqt of 160-170 I could have accurate knowledge of what each student was doing. I conducted all recitations, gave all the lectures, prepared all quizzes, and scored most of them myself. The enrolment for 1931-32 was made up of 85 who had studied chemistry in high school and 79 who had not.

JL.3 a74 The first semester was used for laying the foundation ARB BASED ON A V E u ~ ~ OF ALL

for the beginners in the usual way. The advanced TE, TAKEN THE TWO GROUPS, THE RAW SCORES BEING group was given preliminary instruction sufficiently CHANCED TO PERCENTILE F ~ N K SCORES AND COMBINED

different from high-school chemistry not to be recog- Curve A-no chemistry in high schwl. - Curve B-chemistry taken in high school.

F. C. MABEE. "A test of achievement in college chemistry, Median percentile score "A" 32.3. etc.," J. CHEM. EDUC., 3, iO-6 (Jan.. 1926). Median percentile score "B" 59.3.

Without a single exception the course 21--22 sections did a better grade of work than those in course 11-12. The percentage gain of achievement ranges from 4.6% in test No. 12 to 50% in No. 5, the average being 20.8%. The variation in performance within the two groups does not differ to any marked extent as shown by the measure of variability, the semi-interquartile range. For course 11-12 this measure, Q, is 2.9 while for 21-22 it is 3.3.

The final examination naturally becomes a test of a great deal of significance. It was composed of 186 questions of the same short-answer, factual type. Two hours is the usual time given, but in this case students were allowed all the time they desired. The questions were mimeographed and a set given to each student. The differences in performance of the two groups are here indicated:

Median for course 11-12 was 64.80 Median for course 21-22 was 86.46 Percentage of higher achievement by 21-22 was 33.40 Semi-interquartile range for 11-12 11.23 Semi-jnterquartile range for 21-22 13.03

The results are graphically shown by the curves of Figure 2.

Referring again to the test reported by Mabee,= three college classes were examined. There was no uniformity as to circumstances. The college A class had not studied high-school chemistry, while classes B and C had. A was examined a t the end of 8 months of study, B a t 41/2, and C, 5 months. The results of the test compare favorably with those just given above:

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nigh-school End of Howr on Mcdion College Chcmislrg Monihr Wmk Gmde

A No 8 6 43.1 B Yes 4 . 5 9 71.8 C Yen 5 0 62.2

The advautage of B over C undoubtedly can be accounted for by the fact tbat B spent 50% more time each week on the subject.

Percentage gain of B over A Percentage gain of C over A

The objection would naturally be raised that the presence of a considerable number of upper classmen

in my study might materially influence the results; these being more mature would naturally be expected to do a better grade of work. To eliminate this factor the performance of the freshmen alone in the two groups has been compared, giving the following results:

Median for course 11-12 64.0 Median for course 21-22 89.3 Percentage higher achievement 39.5 Semi-iuterquartile range, 11-12 10.6 Semi-interquartile range, 21-22 14.5

Note that the difference in the percentage gained by the 21-22 group is even greater when the non- freshman students are omitted than when they are included.

Another possibility must be taken into consideration. The students of course 21-22 may happen to be of a suoerior made who are more interested in the subiect. use their>me to better advautage, etc. A study oi the grade-point ratio in all the students' work in college- obtained by dividing the grade points earned by the credit hours taken-tbrows an interesting light on this objection. The scholarship record measured in terms of grade-point ratio for all students taking course 11-12 was 1.17; for course 21-22 i t was 1.28.

These figures indicate that there is an advantage in favor of 21-22 amounting to 9.4% in scholarship ratio. This is to be expected, as i t is usually the better grade of student that elects chemistry in high school. But the distinctly better performance of 21-22 in chemistry, amounting to an average of 20.8% for twelve tests and 33.4% for the final examination, can hardly be explained by the slight difference shown in the grade-point ratio of the two groups in college scholarship.

-There remains the additional possibility tbat we may have a group of students in 21-22 of superior native ability. To check this point we refer to the results of the Minnesota college aptitude test. The median percentile rank for 11-12 is 28.75, while for the 21-22 group i t is 31.25. Q for 11-12 is 26.55; fos 21-22, Q is o m -0 . . '51.18.

Here we do find a slight advantage in favor of the 21-22 group amounting to 8.6% but certainly not sufEcient to account for the marked difference in their performance in chemistry, which is 20.8% for twelve tests and 33.4% in the final examination. ', -

As a further point of comparison the records of these same students in qualitative analysis during 1932- 1933 may be cited. Sixty-two students took the course. At the end of the semester six A's were given, all of which went to members of course 21-22. Thirteen B's were given and 73% of them went to members of course 21-22. This would seem to iddicate that the advantage persists.

CONCLUSIONS

There is a definite "residue of knowledge" carried over from high-school chemistry to the first-year college course. In order to retain this advantage

students presenting chemistry as an entrance credit must be treated as an advanced grade and not literally made to wait until the section without such preparation catches up. The advanced sections must be allowed to build on high-school chemistry as a foundation and not made to repeat elementary principles and experi- ments covered in the preparatory course. Such a course requires that we do away with the overlapping to which Dr. Koos3 calls attention. In this way interest in chemistry is aroused and increased rather than stifled and destroyed.

In the present study, intruding factors have been

closely checked. That the native abilities of students in course 21-22 are very much like those in course 11-12 is seen from comparison of the results of the college aptitude tests for both sections and also by the general college scholarship ratings as shown in the grade- point ratios. The definite and consistent higher achievement of the students in course 21-22 over those of course 11-12 as shown in twelve tests and the final examination leads us to the conclusion that the higher achievement is a measure of the influence carried over from high-school chemistry to the first-year college course.