Formal Opinion: In my judgment, the class achieved exemplary understanding (Ally McBeal cadence: crisp, witty). Findings: different objects sound different because their vibrating frequencies differ; music arises when those frequencies form intentional ratios. Ratios describe relationships between two quantities; musical ratios relate two frequencies. A 2:1 ratio equals an octave. Historical note: Pythagoras explored musical ratios using the monochord. The monochord: a single string stretched over a soundbox with movable bridge to measure string length and calculate pitch. Conclusion: ACARA v9-aligned learning outcomes met; students demonstrated clear conceptual and practical grasp. I recommend continuing exploration with listening and monochord experiments.