In this study, it is aimed to use scoring rubrics in assessing secondary school students' understanding in a chosen unit (Force and Motion) in science class and to make peer assessment. For this purpose, single group pretest-posttest, experimental group without control group was used. A achievement test was created regarding “Force and Motion” unit and it was administered as a pre-test without scoring rubric and post test with scoring rubric, respectively. The pre and post tests obtanied were first evaluated by the researcher and then, they were evaluated by three students who were randomly selected according to scoring rubric, and thus an opportunity was given to peer assessment. According to t-test results, it was seen that there was consistency between the evaluation results of the researcher and the evaluation results of the students. This following result has emerged that in evaluation made with scoring rubric, students’ scores are independent evaluator.