The role of science at school in a knowledge-based society is to allow students to utilize the information that is provided to them via observations or experiments. This allows students to think scientifically and to express themselves. We established a scenario (performance task) that used the specific knowledge and skills that students had acquired directly and then analyzed the scientific thought, judgments, and expressions of the students. Consequently, we found that it was necessary for the teacher to clarify the intentions and the purpose of the performance problem for enabling the students to utilize the necessary knowledge and skills during the activity. We knew that it was vital to set it based on the characteristic of the problem. We did what kind of thought in the problem concerned when you wanted to place a performance evaluation as an intellectual power and judgment, an evaluation of the power of expression, and how you did what you judged it and expressed with the point of view of the evaluation.