Recently, as in every field, artificial intelligence applications have started to be used in the field of education. In particular, chatbots, one of the techniques using artificial intelligence technology, have started to contribute to teachers and students in certain areas due to their features. On the one hand, it is believed that artificial intelligence technologies such as ChatGPT are one of the greatest values produced by human hands and should be included in the learning-teaching process, on the other hand, it is believed that they may have negative effects on the education system due to factors such as plagiarism. Chatbots, in general, and ChatGPT, in particular, can be used as a supportive aid in the learning-teaching process. Among the areas where ChatGPT can help a science teacher are providing information about the subject with research, designing lesson plans, suggestions for preparing experiments, providing both visual and interactive course materials and homework topics, and evaluating and following up with students. In today's conditions, making lesson plans in science teaching is becoming more and more important for teachers. On the one hand, the change in the characteristics of students and on the other hand, the effect of technological applications on the course process reveals the fact that science teachers need continuous professional development. Science teachers who make lesson plans have to take into account many variables at the same time. In this case, all possibilities and variables are evaluated by the teacher. 

This study aimed to examine the performance of ChatGPT, an artificial intelligence application, in lesson plan design according to the 5E learning model within the scope of middle school science courses. For this purpose, lesson design was made in accordance with the objectives of different learning areas in the middle school science course. ChatGPT was made to design a lesson plan according to the 5E learning model. As a result of the interactions with the chatbot, the final version of the lesson plan was decided, and the performance of ChatGPT was analyzed using the answers it gave in this process. Case study design, one of the qualitative research methods, was preferred in this study. The 5E lesson plan document designed by ChatGPT was used as the data collection tool, and content analysis was used as the analysis type. In the light of the findings obtained, it was observed that ChatGPT suggested studies related to students' readiness in the lesson plan design, offered different types of possibilities in the steps of attracting attention to the lesson and motivating the lesson, emphasized science process skills such as experiment and observation, and suggested quite a lot of activities. Supporting the original stories in the lesson plan, designing experiments suitable for classroom and laboratory conditions, and adapting the learning outcome according to the desired teaching principles and methods are among the other findings. She suggested activities to improve cooperation and communication skills within the scope of group work. It was observed that he gave detailed feedback on the questions asked in the introduction, exploration, explanation, deepening, and evaluation stages of the lesson. In some cases, it was encountered that the content, such as movies and videos she suggested to the students, was not exactly suitable for the level of the students requested. In addition, it was understood that he did not show the expected performance in concrete suggestions such as songs and references.

As a result, ChatGPT can be used as an auxiliary tool in the design of lesson plans in accordance with the 5E learning model in the middle school science course. It is not possible to replace the science teacher yet, but the fact that it can contribute to the teacher in lesson design should not be ignored. As a result of the study, suggestions were made to science teachers about the use of ChatGPT in lesson design.