Evaluation of Secondary Pupils' Chemical Problem-Solving Skills Using a Problem-Solving Model F. 0. Asieba Department of Agricultural and Science Education, University of Agricultural and Science Education, Makurdi, Nigeria
0. U. Egbugara Department of Teacher Education, University of lbadan, lbadan Generallv. i t has been observed that ouantitative chemical proble& are a major obstacle to &dents in secondary and tertiaw level courses 1 1 3 ) . Kven the West African Examination-council has repoked that secondary school students' poor performance in the subject relates to their not being systematic in solving quantitative chemistry problems (4). This condition is. however, not peculiar to Nigeria. M a w developed count& seem &have identified the same difficulties in problem-solving and general observations of students' behaviors during problem solving (5-8). Researches in this regard consequently have resulted in the development of some models for solving chemical problems (5-7). An apparent difficulty that could be associated with the application of models for problem solving would be the extent to which learners master their heuristics (the method of doingproblems). In other words, how would students be able to master and use a problem-solvingmodel? This study, therefore, addressed the issue of how a selected problem-solving model, used under different mastery learning conditions, can facilitate secondary school students problem-solving skills in chemistry. I t was hypothesized that there would be no significant difference in the development of problem-solving skills of chemistry students exposed to three mastery learning conditions and a nonmastery (control) group. The Design A pretest-posttest experimental design was adopted for the study. It consisted of four treatment p u p s . The first treatment group was taught for mastery of both the problem-solving heuristics and content. The second group was
a. Make sure you under-
the goal of the pmblem. b. Have this goal in mind as you go ahead to solve the problem. stand
Combine the separate pieces of information.
4.
a. Do this with the goal in mind. b. Carry out
Calculations. c. Write MUI clearly. '
1
1
simple
answer
pmblem involved
38
Write dawn the relevant information.
a. from memory, classnotes or texibwks. b. From information provided in the pmblem statement.
Journal of Chemical Education
Defmition of a problem Selection of appropriate information Combination of separate pieces of information Evaluation of the solution to the problem The system of heuristics was presented to the suhjects in the form of a problem-solving chart tsee the figure]. The secondphase consisted of two units of instruction in the chemical content area selected for the study. They fall under these general topics: Gas laws; and 'The mole concept in the gas phase
For the first study group (El), the first phase of instruction involved teaching students for mastery of the heuristics using the Learning for Mastery (LFM) strategy developed by Bloom (9).I t was done in three stages:
Orientation Students were first introduced to both the problem-solving chart and the list of objectives required for mastering it. For example, Graham's law of diffusion was used to present the chart using a lenure-demonstration approach. Two problems derived from it were later used to demonstrate how the chart could be used.
3.
Pmblem-Solving Chart
Treatment Procedure The first phase was a unit of instruction on problem-solving using a system of heuristics derived from the Ashmore, This system of heuristics emFrazer, and Casey model (7). phasized four major problem-solving skills:
orientation practice feedback
a. write down how you plan to do it. b. Write down the smaller
4 5. IS the omblem solved? Look at the omblem aaain to make su&. 6. Is your answer in line with the goal of the problem? 7. IS your answer in line with the information glven in the problem statement?
exposed only to the problem-solving heuristics but taught for mastery of the content. The third group was taught for mastery of the problem-solving heuristic and exposed to the content employed. The fourth group was not taught formastery of either the problem-solving heuristics or content used for the study. The study involved 193 Form Four chemistry students from four selected secondary schools in the Jos municipal of Plateau State, Nigeria. The selected schools for the study were randomly assigned to the four different conditions.
I
Practice Students were given class and home assignments on problem-solving exercises. These problems were to be solved using the problem-solvingchart. Feedback Students were instructed to turn in their class and home assignments. These were checked and corrected. A diag-
nostic test was administered for feedback and remediation purposes at the end of the unit. For study group one, the main objective of instruction in the first phase was mastery of the steps in the "ProblemSolving Chart". This was clearly emphasized. It also was ensured that a t least 80% of the students in this group mastered the heuristics in the chart. For the second phase of instruction, studentsingroup El were taueht for mastery of the wntent area. This was done using the LFM strate&. It was also ensured that 80% of the students attained mastery performance. For the second study group (Ed, the first phase was a problem-solving instruction employing the system of heuristic ('Problem-Solving Chart"). It was done in two stages: Orientation Practice Orientation Students in m o u ~Eo were first introduced to onlv the problem-solvin~chirt. kRer this, the chemistry topic iused for group El) also was used to present the chart. The instructional procedure used was similar to that of group El, but the main obiective of the problem-solving - instruction was not emphasized. Practice Students were eiven problem-solving exercises (class and home assi6ents).-~ut it was noiemphasized that students should solve these problems followine - the steps of the pmblem-solving chart. to the Students in moup EI were only casually . exposed . pmblem-solvin~ch&t;because the main objective of the problem-solving instruction was not emphasized. It was not even mandatory for students to follow or show the step in the problem-solvim chart in solving problems given to them r& assignmentsr~lso,no feedback was &en to the students concerning their learning of the problem-solving chart. Neither was it ensured that at least 80% of them actually mastered the heuristics in it. The instructional procedure and materials used for the second phase of instruction in group Ez were similar to E
