Sciences is explained as thinking of the nature of knowledge, the process of producing new things with present data (Ayas, Çepni, Johnson and Turgut, 1997), it can also be explained as understanding and examining already known and seen parts of the events and an effort to guess the unobservable events (Çepni, 2005). In science education which starts with these general goals, there are some targets such as knowing and understanding the scientific information, studying and discovering, imaging and improving, being affected and appreciating and practicing (Çepni, 2005). Therefore, training activities and different teaching methods to provide students with these goals are needed. Today, some different training activities, as an alternative to traditional teaching, have been put into practice in order to provide these goals. The easiest way to teach knowledge and processes to students by removing the memorization is to adopt an education of which the students are on the centre in the process of teaching and to teach science lesson which relates with daily life, is far from unnecessary memorized knowledge, focuses on problem solving and has more practice. It also helps to have an attitude towards sciences (Kıyıcı, 2008). Problem-based learning connected to constructivist education has been becoming more and more important due to the fact that it is an approach centered on problems. In sciences, it is crucial to study, examine, deal with problems and practice. Thus, it is necessary to follow acid-base subject with a different teaching method in which the students themselves can be active.
In this study, it is aimed to examine the effect of problem-based learning in acid-base subject to academic success.
The samples of this study are first grade 95 students at Erzincan University in the Faculty of Education Department of Science Teaching. One of the classes has been randomly selected and has formed the experiment group (47 students) and the other one constitute as the control group (48 students). In the experiment group, problem-based learning has been used in acid-base subject and within the control group traditional method has been applied. A 30- question- test covering the whole subject has been prepared with the help of the literature studies related to acid-base subject and already asked questions of Student Placement Examination (SPE), Student Selection Examination (SSE) for the data of this study and academic success test in acid-base subject (ASTABS) of which the first 24 questions are multiple-choice and the rest 6 questions are open-ended and related to concepts that have been prepared. Multiple-choice questions have been mostly selected from daily life and prepared as similar to problem situations. The reliability quotient (Cronbach's Alpha) of the test has been found as 0,705. The analysis of students' answers to the achievement test has been carried out with SPSS 17 Program. The points acquired from pre-test and post-test for the given variables have been compared with independent group T-test.
The pre-test result between the groups is (t(93) = -.371; p<0,05). According to this result, there is no significant difference between the experiment and control groups' average points of ASTABS. While the experiment group pre-service teachers' average pre-test point of ASTABS is X=38.62, the control group pre-service teachers' is X=39.77. The results of post-test between the groups are (t(93)=3,178; p<0,05).
According to this result, there is no significant difference between the experiment and control groups' average post-test points of ABTABS. While the experiment group pre-service teachers' average post-test point of ASTABS is X=51,77, the control group pre-service teachers' is X=41,96. Conclusion: The experiment group pre-service teachers'-in which problem-based learning (PBL) method has been used- average pre-test points of ASTABS is close to the control group preservice teachers'- in which traditional teaching methods have been used- average points from the same test (Table 1). Before the application, there is no significant difference between these groups and this situation is suitable for defining the efficiency of applied approach. The difference, between the posttest points acquired after the experimental process of the experiment group students to whom PBL approach has been applied and the control group students to whom traditional teaching approaches have been applied, has increased. After the application, a significant difference between the two groups' success has been discovered. These obtained results have shown that the classes to whom problem-based teaching method has been applied learn how to learn and they increase their academic success (Sungur and Tekkaya, 2006), and in the light of previous studies related to improving problem-solving skills, it can be concluded that problem-based teaching method is more effective than traditional teaching methods.
The effect of problem-based learning method in teaching acid-base subject on science teachers' academic success
