Why doesn't a ukulele sound like a violin? Why doesn't a clarinet sound like an oboe? (Spoiler alert: those are not the same reason.) How can a bugle play a tune without keys or valves? What's the simple arithmetic that makes two notes harmonious? Welcome to the wonderful world of sound waves, where we'll use live demonstrations, original animation, and everything from crude musical instruments to computer-synthesized keyboards to show how the study of simple pendulums just naturally leads to "Beethoven's Fifth.