Roger D. Barry, Kalmer E. Stordahl, and Robert A. Carter
Northern Michigon - University Morquette, 49855
I I I
General Chemistry Slide-Audio Tape Programs Experience since
In an earlier publication an evaluation of the effectiveness of a series of slide-audio tape instructional programs designed for the first semester of a two-semester course in general chemistry was rep0rted.l As part of a continuing effort in the improvement of instruction in general chemistry, additional slide-tape programs have been developed (Table I ) for hoth the first and second semesters. The studv reoorted here was concerned with evaluating the teaching effectiveness of these materials in hoth semesters of the course during the 1971-72 school year. The first semester (CH 101) enrollment was 164 students and the second semester (CH 102) was 98 students. The general format for teaching the course was lecture, discussion, and lahoratory, supplemented by out-of-class use of the slide-tape programs. The programs were used in study carrels equipped with a slide projector and cassette audio tape playback unit. The audio tape provided instructions for changing slides, for computation pauses, for work sheet exercises, and other relevant activities. Students were informed of the availability of the slidetape programs and encouraged, but not required, to use them. A record of the amount of time (in minutes) that each student spent on each program was maintained and this time record constituted the independent variable for the evaluation.
. .
Evaluation
Students who elected to use the slide-tape programs were compared with those who did not use them on the basis of lahoratory grade, quiz grades, and course final grade. The lahoratory grade was the sum of points earned in lahoratory experiments; quizzes were scored on a scale of 0-100 and were included in the comparison only in those instances where slide-tape programs could he directly associated with quiz content. For purposes of analysis, numeric values of 0-4 were assigned to course grades of F through A, respectively. Analysis of covariance was used to compare the achievement scores of users and non-users of the programs. American College Testing Program (ACT) composite score was included as a covariate to adjust the achievement measures for differences in academic ability hetween the user and non-user groups. Mean achievement scores for those who used and did not use the slide-tape materials are given in Table 2. In all instances, students who elected to use the slide-tape programs had higher average achievement than those who did not use them, although the magnitude of the difference was not in all instances sufficiently large to be statistically significant. These findings are similar to those reported in the earlier paper. To determine whether the amount of time devoted to
'Barry, Roger D., and 49,495 (1912).
Carter, Robert A,, J. CHEM. EDUC.,
2Tables which provide more detailed statistics for this and other comparisons may be obtained by writing the senior author.
1971
Table 1. General Chemistry Slide-Audio Tape Programs Pmgram title Stoichiometry-part 1 Stoiehiometry--Part 2 Physical Properties of Solutions concentration-Part 1 Percent, Mole Fraction, Molality Concentration-Part 2 Molarit,. Concentration-Part 3 Normality Chemical Equilibrium-Part I Gases Chemical Equilibrium-Part 2 PH Chemical Equilibrium-Part 3 Weak A c i d s w e a k Base. Chemical Equilibrium-Part 4 Buffer Solutions Chemical Equilibrium-Pa* 5 Hydmlyais Chemical Equilibrium-Part 6 Solubility Eledrochemist~-Prt 1 Paraday's La-Conduction Electrachemi.try-Part 2 Voltaic CelleElectrode Potential Electrochemist-Part 3 Concentration Effects Chemical Kineties Formal Charge Valence Shell Electron Pair Repulsion Theory Writine Lewis Electmn Dot Structures
Number of slid-
Length of tape (min)
42 55
22
39
27
33
G ~ ~ ~ I~ : P ~ ~ ~ Bov1e.s Law. Charles' Law. Avoeadro's Equation of State Gases-Part 3 Diffusion and Partial Presrvre Thermodynsmiea-Part 1 Heat of Reaction Thermodynamics-Part 2 Internal Energy and Enthalpy Thermodynsmics-Part 3 Bond Energy Thermodynamics-Part 4 *me Energy and Entmpy Weighting and Determining Density Determination of the Formula of a Commund Emission Spectra Determination of Avogadm's Number Cslculation of Avogadro's Number Determination of Molecular Mass Determining Melting Points Using a Thermometer Decomposition of Potassium Chlorate Analysis of a Mixture Thermochemistry Grsvimetric Determination of Sulfate Analysis of Iron Ore
the slide-tape programs by those who used them was related to achievement, the correlation coefficient between each achievement criterion and the amount of time spent on related programs was calculated. Most of the coefficients were positive, but in only one instance (Quiz 1, Chemistry 102: r = 0.34) was the correlation coefficient large enough to he statistically significant2 The correlation between academic aptitude, as measured by ACT composite scores, and time spent in the study carrels was also ohtained. The coefficients ranged Volume 51. Number 8. August 1974 / 537
Table 2. Adjusted Mean Achievement Scores for Students Who Used and Did Not Use Related Instructional Media
Achievement criterion Lab Grade Quiz 1 Grade Quiz 2 Grade Quiz 3 Grade Final Grade
Chemistry 101 Chemistry 102 User Non-User User Non-User N Mean N Mean N Mean N Mean 103 194
54 184
114
69
45
64
117
69'
42
59
101
35.
53
26
134 2.27"
62 193
36 189
53
7O6
46
57
49
85
50
76
25 1.31 60 1.93b 39 1.37
aSignificantly different from non-user a t 0.01 level. bSignificantly different from non-user a t 0.05 level. from -0.30 to +0.01; all hut one of the nine coefficients calculated were negative. Four of the negative coefficients were statistically significant a t the 0.05 level, indicating that the more academically qualified students tended to devote less time to the materials than those of lower aptitude. About 80% of the students in hoth Chemistry 101 and 102 used a t least some of the slide-tape programs, hut very few used all of them. The relationship between academic aptitude and utilization of the programs was consistent with the correlation analysis reported above; that is, the non-users were more likely to he high than low ability students. Conclusions
From our experience with the slide-audio tape programs in general chemistry, we think that they are an effective teaching tool. On the average, students who use the materials attain a significantly higher level of achievement than those who elect not to use them. On the other hand, there seems to he little or no relationship between achievement and the amount of time the users spend on the orograms. This latter findine is consistent with a number& related studies which have found college scholarship to he essentially uncorrelated with hours of study.3 It appears that more important than time alone (beyond a reasonable minimum), are variables such as motivation to achieve and study methods. In the present evaluation, sufficient motivation to use the materials seemed to he a critical variable.
538
/
Journal
of Chemical Education
Prior to introduction of the slide-audio tape programs, the course was organized in the usual manner of large lecture sections, small group discussion, and laboratory. Since the introduction of the programs, the small discussion meeting has been eliminated and the large lecture sections increased from 2-3 meetingslwk. The third lecture meeting during the week is used for a short quiz followed by general questions and problem solving. Thus, the disadvantage of using several different discussion instructors in large courses in order to provide sufficient small group discussions has been eliminated. During this past year the lectures were altered to allow for greater reliance on the programs. Among these changes has been the introduction of more relevant applications of concepts, with the theoretical details and standard calculations being covered in the slide-audio tape programs. Also, problem sets are assigned prior to the discussion of t o ~ i c sin lecture and are collected and maded. In order to acquire the knowledge needed to solve t h e problems, students mav read the textbook or view the auumuriate slide programs; or hoth. During the past year th& approach has proven most helpful in ensuring that students prepare for a topic before it is coveted in lecture. Students in the general chemistry courses have suggested a number of topics for slide-audio tape programs and many of the additional topics covered in the later proerams were based on student reauests. Although no records have been kept, numerous students have'expressed the ooinion that the uroerams are a significant aid for the . course. Another outcome of the availability of slide-audio tape programs has been their use in other courses. During the beginning of the first semester of organic chemistry the carrel programs relating to bonding are available to students for review. Similarly, instructors in courses such as physical and inorganic chemistry often direct students to topics covered in one or more of the programs for review. No study has been carried out to verify the usefulness of the slide-audio tape programs at other institutions. The evaluations reported in this paper and the earlier study involved the same course instructor, the author of the programs. The results of the evaluations presented in this paper must be considered in this light.
Williamson, E. G., J Educ. &ch.,
26, 682 (1935).
