Hands-on versus Computer Simulation Methods in Chemistry Donald R. Bourque Claremont High School, Claremont, CA 9171 1 Gaylen R. Carlson California State University, Fullerton, CA 92634 Many recent articles on computer-assisted instruction
Table 1. Hands-on versus Computer-Slmulatlon
(CAI) have suggested parallels between general computer awareness and student learning (1-6). I n this paper, the results of a two-part study on computer-assisted simulation in chemical education will be outlined. The study first focused on examining and comparing the cognitive effectiveness of a traditional hands-on lahoratory exercise with a computer-simulated program on the same topic. Secondly, the study sought to determine if coupling these formats into a s ~ e c i f i cseouencine would ~ r o v i d eontimum student comprehension. The effectiveness of the programs was determined by testing knowledge of the chemical concepts implicit in the lahoratory exercises. This study also examined students' attitudes concerning the computer-simulation program of instruction and the traditional hands-on lahoratory procedure. Procedure Three lahoratory experiments were designed specifically to correspond with three computer simulations developed previously by J. E. Gelder of Oklahoma State University including: (1) The acid-base titrotion-an
example of a common lahoratory procedure used to determine the concentration of an unknown. (2) The equilibrium constant o f a weak acid-used an acid-base titration to obtain themolar concentration of anunknown weak acid. The computer simulated the pH changes of three partial neutralizations to provide an equilibrium constant from which the weak acid could be identified. (3) Auogadro's number-was determined from (a) an acid-base titration toobtain the gram-molecularweightofafatty aeidand (b)by the simulation of a monomolecular layer of the fatty acid spreading across a water surface. General rhemistry claises at Claremont High School were selected for thesrudv. Thesrudents worked on the Anole ile microcomputer for the learning activities. ~ r o u p ~ & s i s t e d of 27 students from the mornina session: Group B was 24 students from the afternoon session. students were randomly assigned to each test group. Prior to the study, these students were tested using the ACS exam and were shown to perform equally well on the exam a t a 95%confidence level. Each lahoratory day, Group B completed the hands-on version of the acid-base titration whereas Group A completed thc rurresponding computer-simulation program (see [he figure). T h r inrrodurrory lecrure,demonstratic,n st'snlon -' was the same for hoth arouvs. Each student was resnonsihle for the preparation of his-or her lab notebook, which was to include a statement of purpose, the general procedure, and the construction of a table for collecting data for each activity. All students worked in pairs. For most this was their first experience using the computer as a learning tool, hut, as was expected, the computer-simulation program took less time to perform than the hands-on maninulation. Students worked through the computer-simulation program many times over within the available time. After the experimental
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Journal of Chemical Education
Topics
Mean
Group A (Hands-on) SD
Group B (Simulation) Mean SD
Acid-Base Titration
8.00
5.20
loniration Constant Avogadra's Number
5.77
2.31
3.15
1.58
9.42
1.09
9.05
1.24
1.81
n = 21. T = 3.92
n=19.T=
2.01
> t = 2.08
1.04 t = 2.08 4.20
15.38
2.80
Experiment 1 kid-Base Titration Hands-on
Experiment 1 Acid-Base Tibation Simulation
Experiment 1 Acid-Base Titration Simulation
Experiment 1 Acid-Base Titration Handan Postlab Evaluation (a) 8 questions affective domain (b) 10 questions cognitivedomain
r= cwn~utedvalue, t = nnical vaivs (0.05confidence level),
Flowchart of Acid-Base Instruction
(3) The simulation programs were not provided with a similar tutorial exercise andlor a conclusive prohlem-salving activity. (4) In the computer-simulation format all the calculations were computer programmed. Thus, students did not put forth as much effort to derive, nor to discover,the mathematical computations. The problem exercises had a direct relationship with the improvement in cognitive scores. (5) Comparative results from the derivation of Avogadro's number in the laboratory format versus the computer-simulationfarmat indicated no advantage in either learning mode. In either instructional procedure, the format was so structured that the students followed a computation in dimensional analysis without fully understanding what was happening.
The scores inTable 2 reflect the averagenumher of correct responses on the two 10-point examinations (20 points possible) shown in Figure 1. Cognitive Domain--(Part /I) The results shown in Table 2 indicated that the hands-on experiment format followed by the computer-simulation format orovided the highest cumulative scores for the two examinations. Higher cognitive scores were accumulated for experiment 1 and experiment 2. There was no apparent advantage in the performance sequence for experiment 3, the derivation of Avogadro's number. The following reasons were reported by students to explain their preferences for the hands-on experiment before attempting the computer simulation: (1) They became acquainted with the reagents and actually viewed
the reaction changes. (2) They became familiar with the manipulation of laboratory ap-
paratus. (3) They actually saw what was happening. As some students said, "You gotta do it first." (4) They gained a greater appreeition for the simulation program as they confirmed and reinforcedtheir newly acquired knowledge. For the most part, students enjoyed setting up the hands-on experiments and the operational techniques necessary to arrive a t a final determination. This method involved more time and a greater level of dexterity and endurance. The hands-on experiment had to be repeated a number of times before students could reduce their experimental errors to an acceptable level. When students had completed this procedure, including the experimental write-up, they went t o the next task. In the sequence where the computer simulation followed the hands-on experiment, students accepted this assignment as a reward. Some students actually had to be restrained from running to the computer. Most students found the computer-simulation exercise a stimulating leaming experience, although many students had no previous experience with this electronic device.
Affective Domain The following four questions were used to evaluate the students' reactions to the software and the program material. The questions compared the simulation program to the traditional laboratory instructional manual.
Question 1. Are theimtruetionobjectiues eleor?Onlythe acid-base computer simulation was rated as having a set of objectives that compared favorablyto the procedure in the laboratory manual. Question 2; Are the uisual aids in the manual ondlor the Apple II graphics insimulationuseful indescribing the experiment?Inall the topics listed, students found the Apple IIe graphics superior to the laboratory manual's descriptive display. Question3: Do you feel this isogood learningdeuice?The students' responses showed a preference for the computer-simulation software, that is, the computer's pedagogical interaction. Nevertheless. the hands-on exoerimental oroeedure provided a hicher Level in learning comprehension. Question 4: Do you feel this experiment has prepared you for further experimental studies in the laboratory?Students again had a positive response to the computer-simulation interaction with respect to the acid-base titration and Avogadro's number derivation. Students recognized no preference in either mode deriving the weak acid ionization constant. Recornrnendatlons and Discussion As is often the situation in the laboratory, students will rumvle~ea hands-on experiment and find themsdvei lingering with a vague idea ahout the nature of their work. T o prevent such problems i t is strongly recommended that the computer simulations be utilized as postlaboratory activities. I t is also recognized that CAI may be used to reinforce learning in manv that s are suited to the stu-~~~~ " a~~lication dents' needs when i t is compatible with the programs' instructional material. Evaluation of student performance should always he made following the computer's instructional program to support the learning process. Finally, the following points are included as interesting observations made during this study. A.
. .
(1) . . The Drooer use of eood com~utersoftware can add a new and cvriting dimenaim i n planning instrucrional strategic% (2) Student- utre anxious t o interact with rhe computer and anxious tcr r e t u r n 11, thr cloasm#mt o intrract on a personal level
with the instructor. (3) Unless a student's progress in CAI is monitored closely, the student's assimilation level wanes and his learning does not progress effectively. (4) Students accept the quaint positive learning reinforcement dialogue form the eomputer as pleasantries. Volume 64
Number 3
March 1967
233
(5) Students accept personal learning reinforcement from the instructor with appreciation and a sign of accomplishment. This provides the encouragement and the motivation to continue the task at hand. ( 6 ) The was the main focus for the exchanges of ideas and discussion. I t provided the best environment for the human learning experience.
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Journal of Chemical Education
Llterature Clted 1. c a v i n . ~s.; . c a v i n , ~ . ~ ; ~ a g o wJ.kJ.i ,J C h e m ~ d u c 1918,55,m. . 2. ~ohnaon,~effrey.J. cham. ~ d u 1980.57.406. c 3. Johnson,J.K.;VanWiUis,W.;Seoly,O.,Jr.;Moare,J. W. J.Chsm.Educ.. 1981.58,197. 1. Mmre. Carolyn: Smith, Stanley Avner, R. A. J . Chem Edur. 1980,57,1196. L Moare, John W.. Ed. Iterations: Computing in Aha Journal of Chemical Edveofion
1979-1980. 6. Summerlin. Lee. Tutorid Type CAI in Chamisfw Camputer-Assisted Instruction
Center. Florida State University, 1971.
