The discussion centers on the discrepancy between the three classical states of matter—solid, liquid, and gas—and the five states often mentioned online, which include plasma and others like Bose-Einstein condensates. While the teacher's simplified explanation is suitable for school, it overlooks the complexities of matter under various conditions. Plasma is highlighted as a significant state, occurring in natural phenomena like lightning. The conversation emphasizes the importance of understanding quantum mechanics for a deeper grasp of matter's behavior. Ultimately, while schools may focus on three states, a broader understanding of five or more states is beneficial for comprehensive scientific knowledge.