PERBEDAAN KEMAMPUAN BERPIKIR KRITIS ANTARA PENDEKATAN PEMBELAJARAN OPEN ENDED DAN KONVENSIONAL SISWA SMP NEGERI 28 MEDAN

Math lessons require some aspects to support the learning process, among which is the level of students critical thinking and positive attitude of students. For it is necessary to find an alternative which can help enhance the learning activities, and provide opportunities to students more active. Open-ended learning approach is one alternative to increase the liveliness and creativity of students in learning mathematics, thus increasing students critical thinking. This was an experimental study in junior high with the subject population is the eighth grade students of SMP Negeri 28 Medan by taking 2 classes as the study sample VIII.C class as a class experiment and VIII.D as the control class. Samples were randomly selected from 7 group study class. The instrument used to collect data in this study consisted of testing students critical thinking skills on the subject of a circle, Likert scale questionnaire to determine high and low learning attitudeThose instruments have been declared eligible content validity, and reliability coefficients for 0736 and 0820 in succession to the critical thinking skills and learning attitude. Processing the data to see the difference in students critical thinking abilities between groups of students who gain learning with open-ended approach to learning and conventional learning Test begins with the test data Liliefors normality, homogeneity of data was tested with Bartlett test and the test statistic in the form of two-track Analysis of Variance (processing data with SPSS 15 and Excel) and after the test prerequisites are met followed by Scheffe test to see the difference from the sample groups in which many data are not the same for each group. Based on the analysis (ANOVA) of the research are: (1) students critical thinking skills that are taught with an open-ended approach is different from signification students taught by conventional teaching approaches. The amount of significant value obtained from ANOVA 0.000 value 5 significant level. This showed no significant differences of critical thinking skills in both teaching approaches. (2) critical thinking skills of students who have a high learning attitude different from signification students who have low learning attitude The amount of significant value obtained from ANOVA 0,001 value 5 significant level. This showed no significant differences of critical thinking skills in both types of attitude (3) there is interaction between the learning approach with student-owned learning attitude. The amount of significant value obtained from ANOVA 0000 value 5 significant level. One approach to learning that can affect students critical thinking skills into a better direction is an open-ended approach to learning. Learning attitudes held by students is one factor that supports the ability to think critically.