Teacher's Performance in Lesson Study through Experimental Method of the Lesson on Science Subject

The implementation of lesson study in improving the teachers' performance was conducted at Junior High School I in the Katingan state. The research was carried out on the science subject with the basic competency of describing elements, compounds, and solution. The activities of the teaching lesson study consist of Plan-Do-See stages. The Plan activities were carried out by planning the learning activities done by the modelling teacher and eight observers. They are preparing the lesson plan using experiments, arranging the learning scenarios, formulating the observation sheets for the teacher's performance using experimental method and developing the evaluation forms. The do activities were carried out by reflecting on the teacher's performance in the lesson study with the experimental method. The learning activities were observed by eight observers analyzed using qualitative descriptive. The result showed that the teacher's performance in lesson study through experimental method on the lesson were good category of the opening the lessons, explaining the materials, explaining the experiment steps, guiding the experimental activities, guiding the group presentation evaluating the learning process. The excellent category was finding in the communicating with students and observing the students' learning activities.