The main purpose of this study is to determine the effect of the question tree technique used in the science lesson and the questions brought independently by the students on academic success. In addition, it is to get the opinions of the students about the use of question tree. Mixed method was used in the study. In the study lasting eight weeks, 61 participants participated with random sampling method. A fully structured interview form was preferred in the collection of qualitative data. Question tree questions and academic achievement test were used to collect quantitative data. The data obtained from the measurement tools were analyzed descriptively and content. In these analyzes, assistance was taken from Microsoft Excel and SPSS 17 programs. T-Test, ANCOVA, frequency and percentage and participant citations were used to interpret the data. According to the findings; It was determined that the question tree technique did not make a significant difference on the academic achievement of the experimental and control groups. The test of question tree questions did not affect academic success. It is thought that bringing the questions out of the book, freeing them not under the control of the teacher and using the low level questions are effective on this result. Students' question tree; It has been determined that they are useful and entertaining, sharing the questions with the class and solving them together, and using them in learning the subjects they cannot understand. It has been determined that the questions put on the question tree of the students have effects such as giving them information, learning new and different questions and solutions. In line with the results, suggestions are presented.