THE EFFECT OF GUIDED DISCOVERY LEARNING MODEL ON STUDENTS ACHIEVEMENTS AT CHARACTERISTICS OF WAVES TOPIC IN SMA N 1 MEDAN CLASS XI ACADEMIC YEAR 2014/2015

The purpose of this research was to see the effect of Guided Discovery Learning Model on Student`s Achievement at Characteristics of Waves Topic in SMA N 1 Medan Class XI Academic Year 2014/2015. The research method was quasi experimental. The populations were all 2nd grade students add semester that consist of 13 classes SMA N 1 Medan. The samples of this research conduct two classes and consist of 74 students, 37 from experiment class and 37 from control class and define by cluster random sampling. The results that were obtained: post-test mean value of the experiment class was 75.94 and 75.02 was the mean value for control class. Standard deviation for two classes was 14.94 and 12.48. Normality of the test result from the both samples was normal and homogenous In the testing of hypothesis for postest, the criteria is: H0 is accepted if tcalculate < ttable and H0 is rejected if tcalculate has another score, where ttable obtained from list of distribution t. From the calculation of test t for concept mastery using α = 0.05, obtained tcalculate = 3.78, where ttable = 1.668. So that, there was the significant effect of Guided Discovery Learning Model on Student`s Achievement at Characteristics of Waves Topic in SMA N 1 Medan Class XI Academic Year 2014/2015. Based on observation that done by observers with using observation sheet of affective and psychomotor, conclude that affective and psychomotor students in experiment class higher than control class.