Okay, listen up, sing it with me—ta da, ta da! Today we’ll explore how ratios make music, and you nailed the pre‑unit questions. Different objects sound different because they vibrate at different frequencies—size, shape and material change the speed of vibration, and that gives each object its tone. That’s why every instrument speaks its own voice. Ratios describe the relationship between two quantities; in music those quantities are frequencies. A 2:1 ratio is called an octave — double the frequency, same note higher. You remembered Pythagoras — yes! He studied musical ratios using a monochord: one string stretched over a resonating box with a movable bridge to compare pitches. Think of it as a ruler for sound, precise and simple. Proficient answers show clear links: physical vibration → frequency → numerical ratio → musical interval. Next we’ll test, measure and play: build or use a monochord, record frequencies, and map ratios to intervals. This work matches ACARA v9 aims about using ratio reasoning in real contexts and connecting mathematics to science and the arts. Great start—bravo, encore, let’s keep counting and listening. Keep asking why, keep testing sound, keep smiling — we’ll make music that measures up, together. Bravo everyone.