The effects of problem solving applications on the development of science process skills, logical thinking skills and perception on problem solving ability in the science laboratory

Method

The study used a pre-test–post-test control group design. It belongs to a true experimental design. The essential ingredient of the true experimental design is that subjects are randomly assigned to treatment groups. Random assignment is a powerful technique for controlling the subject characteristic’s threat to internal validity, a major consideration in educational research (Fraenkel & Wallen, 2006). Descriptive statistics, independent t-tests and MANCOVA were employed in the data analysis. In order to determine the views of prospective teachers in the experimental group about PSASL, a fully structured interview form was used.

Participants
The study involved the participation of 98 prospective science teachers (20-21 years) studying at the Department of Science Education in Turkey, who participated in the spring term of the 2012-2013 academic year. They are third-year university students.

Instruments

Problem Solving Inventory (PSI)
PSI is utilized to assess an individual’s perception about his/her own problem solving ability, and was developed by Heppner and Petersen (1982). According to Heppner, Witty and Dixon (2004), the inventory does not assess actual problem solving abilities but rather one’s perception of one’s problem solving beliefs and style. The scale was translated by Taylan (1990) and Savaşır and Şahin (1997). PSI is a Likert-type scale with 35 statements, which are scored between 1 and 6. The inventory has three sub-scales: “Problem solving Confidence”- assesses self-perceived confidence in solving problems, “Approach Avoidance Style”- assesses whether individuals tend to approach or avoid problems and “Personal Control”- assesses elements of self-control. The Cronbach’s alpha internal consistency coefficient was calculated for the inventory as 0.90 by Savaşır and Şahin (1997). Sample items on the PSI are: “When a solution to a problem was unsuccessful, I did not examine why it didn't work” (Approach Avoidance Style sub-scale), “I make snap judgments and later regret them” (Personal Control sub-scale). The range of scores attainable on the inventory is between 32 and 192. The results from this study indicate that the PSI means, standard deviations and estimates of internal consistency from the current study samples are comparable to those revealed in previous research studies. The results of this study also suggest that the PSI seems to be generalized to Turkish undergraduate students. Thus, findings suggest that the PSI may be a useful instrument to examine problem solving appraisal with Turkish undergraduate students. Compared to previous studies, the PSI demonstrated acceptable internal consistency with the alpha coefficients ranging from .81 to .89 for PSI total.

Science Process Skills Test (SPST)
The Scientific Process Skills Test (SPST) was developed by Okey, Wise and Burns (1982) and a Turkish adaptation was made by Geban, Aşkar and Özkan (1992). The test contains 36 multiple choice questions with four alternatives. The questions of the test aim to asses recognition of variables in a problem (12) as well as construct and define hypotheses (8), make operational explanations (6), design required analysis for solving the problem (3) and draw and interpret graphs (7). After the Turkish adaptation study, the Cronbach's alpha reliability coefficient was found to be 0.81 (Geban et al., 1992). Pre-service teachers’ correct answers were coded as "1" and wrong answers were coded as "0.” For this study, the alpha value of the test was found as 0.856.

The Test of Logical Thinking (TOLT)
The Test of Logical Thinking (TOLT) was used to determine students’ reasoning ability. It was originally developed by Tobin and Copie (1981) and translated and adapted into Turkish by Geban et al. (1992). The TOLT contains 10 items designed to measure controlling variables (items 1 and 2), proportional (items 3 and 4), probabilistic (items 5 and 6), correlational (items 7 and 8) and combinational (items 9 and 10) reasoning. The 10 items of the TOLT contain two responses each - an answer as well as a reason for having selected the answer. Individuals must respond correctly to both components for the response to be considered correct. Its reliability was found as .81. The TOLT has a reported internal consistency reliability coefficient of .82 and a value of .725 for this study.

Teaching Process

In this study, problem solving applications in the science laboratory progressed in five steps and lasted nine weeks (CoHE World Bank, 1997). In order to determine the effectiveness of PSASL, researchers randomly selected 50 prospective science teachers for the experimental group to implement PSASL and 48 prospective science teachers were selected by the researchers to form the control group, which was taught within a more researcher-oriented teaching method. Approximately two weeks before the start of PSI, SPST and TOLT were administered as pre-test treatments to determine whether both the experimental and control groups were equivalent with respect to their perceptions of problem solving ability and their skills of the science process and logical thinking. Secondly, the prospective teachers in the experimental group were informed of principles and application stages of PSASL and prospective teachers in the control group were informed of a more researcher-oriented teaching method.

PSASL consisting of five steps (CoHE World Bank, 1997) was realized within nine weeks with the participation of 50 prospective science teachers. The prospective teachers in the experimental groups were asked for their opinions on what problem solving means, the importance of the problem solving process and how it is realized through a small discussion. Next, they were informed about the PSASL, the steps of these applications, and how to proceed according to these steps to introduce the application to the student teachers during the first week of the study. Then the prospective teachers in the experimental group were randomly assigned to 10 groups. According to Johnson and Johnson (1975), problem solving was a collaborative process, in which individuals gathered for acquiring the goal. According to Zhang (1998), collaborative problem solving referred to the problem solving activities that included mutual interaction among the groups. The initial phase of the application (the problem case) also proceeded in the first week. In the first session, each of the five groups was given a problem case by the researcher. For ensuring meaningful problem solving, problem cases were chosen among daily life events. According to Çuhadaroğlu, Karaduman, Önderoğlu, Karademir and Şekerel (2003), problems used in applications such as “problem-based learning,” which support the development of problem solving abilities, must be chosen from among the problems which are the most fitting to the real world, they must be open-ended and, by making suitable personifications, students must be given the opportunity to treat the problem as if it were their problem and to be willing to solve it. All problem cases were presented to all student groups of the experimental group. The sample problem cases given to PSASL groups and the problem statements created by students groups were as follows:

Problem Case: If we assume that a fizzy drink is consumed from a glass bottle without any gas release, would the amount of bubbles swallowed be billions of bubbles?
Problem Statement: Quantitative determination of the amount of carbon dioxide in fizzy drinks.
Problem Case: It is believed that vitamin C support is good for sicknesses experienced, particularly in the winter, such as the flu and common cold. Therefore, we consume fruit such as lemons and oranges more. What if you were told that parsley, strawberries and green pepper are richer in vitamin C?
Problem Statement: How could we find out which fruit/vegetable has more vitamin C?
Problem Case: One of the most essential ingredients of various fizzy drinks is phosphoric acid. This component helps to protect the ingredients and enables the acidic solution.
Problem Statement: How could we identify the existence of phosphoric acid in fizzy drinks such as coke?

Prospective teachers were informed they would determine their problems by the second week. The second week, when the second phase started (identification of the problem), groups simplified their problems and differentiated events to analyze the events that did not require analysis. They divided the problems into steps or sub problems and expressed their problems in clear language. The researchers controlled the problems determined by the groups. The third phase of the application in the third week (establishing hypothesis) involved the determination of all technical and theoretical questions they needed to solve their problems. Later, all groups shared responsibilities among their members and started to seek potential solutions to their problems. With this aim, groups made use of the library and various resources to collect information about their pre-problems. After the data collection week, the solutions suggested by the groups were collected and one among them was selected for each group to be tried. The researchers checked these solutions. Groups established their hypothesis for solving their problems and presented the solution way of their choice in the form of an experiment suggestion. In the fourth step of the application (trying the solutions), the prospective teachers were made the experiments in the science laboratory under the supervision of the researchers. During the experiment phase, the groups doing their experiments generalized the results they obtained and expressed them in their own words. In the fifth and final phase of the study (repeating), the groups that failed to obtain results according to the hypotheses they established revised their solution steps and the whole process was repeated starting from the step in which the failure occurred. During all PSASL processes, the researcher tried to make observations and provide each prospective teacher in the different groups an opportunity to participate in the process. When groups had a problem during the PSASL process, the researcher guided them with questions without giving any information. The researcher helped prospective teachers collaborate well and encouraged them to justify their thinking.

In the control group, the teaching of a variety of science topics related to everyday life followed the more researcher-oriented teaching method. For instance, with respect to problem (b), students in the control group of the PSASL process were taught within a more traditional approach through the “Determination of Vitamin C in Fruit and Vegetables” experiment directly by the researcher and the whole experiment process was conducted within a researcher-oriented teaching method. The teaching was conducted in such a way that the researcher was active and the students were passive listeners, the latter asking for explanations of the parts that they did not understand. In particular, the traditional teaching method consisted of a subject-based approach. The researcher employed such techniques as direct explanations and question-and-answer in the presentation of the topic.

Approximately two weeks after the finalization of the PSI, SPST and TOLT were administered as the post-test treatments to all groups for obtaining post-test measures after the implementation of the different teaching methods. After the PSASL, five prospective teachers were selected among the experimental group and were interviewed using the fully structured interview form about the “PSASL” and the process it involves.