The "What's the "matter" With XOD" activity addresses students' misconceptions and refines their ideas about phases of matter. This activity introduces the characteristics for solids, liquids, and gases, and begins a discussion about physical and chemical changes and how matter can cycle through different phases. Depending on class size and available materials, these activities can be organized into stations for student groups to rotate through, or presented as demonstrations to the class, allowing the problem solving to occur in a class-discussion format.