This lecture discusses defining and formulating a research problem. It begins by explaining the importance of scientific thinking in identifying a research problem. A research problem is defined as a difficulty a researcher experiences theoretically or practically and wants to solve. When selecting a problem, researchers must consider both external criteria like importance and internal criteria like interest. Problems can come from personal experience, literature reviews, or innovations in the field. Defining the problem clearly sets the direction and reveals the methodology. Key steps in defining a problem are using clear words and formulating it as a question. Criteria for a good research problem include novelty, logic, and clarifying relationships to past research.