In this study were examined the effect of argumentation applications on the “Matter and Exchange” unit achievement of secondary school fifth grade students and the changes occurred in the student at the end of this process. The re-search model consists of a quasi-experimental design with pre-test and post-test with control groups. The study was conducted with two different fifth grade students of a second-ary school in the 2016-2017 academic year. One of the classes was determined randomly before the study as the experi-mental group and the other as the control group. In the con-trol group, science lessons were carried out by using with frequently methods such as direct instruction, question-answer and display experiments. In the experiment group, lessons were conducted based on with research and inquiry argumentation activities. The application lasted total of five weeks. As data collection tool in the study, unit-based achievement test consisting of multiple choice and open ended questions and semi-structured interview questions were used. Success test were applied to the students after the completion of the applications, interviews were conducted with a total of 12 students, six from the experimental and control groups. The quantitative data were analyzed by using independent samples t-test and one way ANCOVA analysis while qualitative data were evaluated by thematic analysis. As a result, it was determined that differ significantly in favor of the experimental group students participating in the argumentation activities the multiple choice, open-ended questions and test total scores in the test. In addition, the students in the exper-imental group stated learned better at the end of the process that the information they learned was permanent, they liked science lesson and their self-confidence increased.