This study aimed to develop learning tasks and assessment criteria to improve students’ scientific views in elementary and junior high school science. To achieve this, we created learning tasks and assessment criteria that focused on the topic of an “earthquake disaster,” which is standard learning content in sixth-grade elementary science and in the first grade of junior high school science. Classes were given on the topic using these new learning tasks and assessment criteria, and the effects were verified by analyzing the results of questionnaires and assessment tests. The results indicated that the classes were an effective means for improving students’ scientific views in the first grade of junior high school, but not in the sixth grade of elementary school. Therefore, this study suggests that it is necessary to develop teaching methods based on the analysis of students’ knowledge to confirm their understanding of learning content and assessment criteria.