This paper introduces a scientific activity named "Pythagorean Cup of Justice" for teacher candidates to discuss values by integrating moral and ethical dimensions into science education, offering crucial insights into the cup's historical significance, enhancing fluid dynamics understanding, and engaging STEM-based activity. The study group for this research consists of twenty pre-service science teachers (PSSTs) and nine middle school students who were 11 and 12-years-old. The research was conducted in four stages: (1) Experiment on developing the Justice Cup and understanding its working mechanism (PSSTs), (2) STEM activity (PSSTs), (3) in-class discussion on concepts of justice and equality (PSSTs), (4) repetition of the activity with middle school students. During the implementation process with PSSTs, Pythagoras, a scientist and philosopher, was initially introduced and then, the working principle of Justice Cup was examined through scientific research, and a question-and-answer session was conducted regarding the concepts of justice and equality. Finally, they were interviewed about how scientists can demonstrate justice and equality in their work. Two PSSTs repeated the activity with middle school students and wrote reports regarding their teaching experiences. In results, PSSTs expressed that this activity increased their motivation toward their profession and responsibility and gained experience in integrating science with different fields such as philosophy and history.