The rain’s “lullaby” comes from a bunch of tiny vibrations. When each drop hits a surface—water, leaves, asphalt—it sends a burst of sound waves into the air. Those waves bounce around, mix, and our ears pick up a low‑frequency hum that feels soothing. Think of it like a giant, gentle percussion concert, with the drops as the drummers. That steady, almost rhythmic pattern is what makes it sound like a lullaby to us.

It’s exactly that—each raindrop is a tiny metronome that sends a burst of sound into the air. The waves spread out, overlap, and create a low‑frequency rumble that our brains interpret as a soft rhythm. Think of the city’s rooftops and puddles as a vast percussion ensemble, each drop a note in a quiet, unending lullaby that quietly keeps the world in sync.

That’s exactly what the physics of sound can help you see: each drop is a little drumbeat, and the city’s surfaces are the drums. The waves they create interfere, forming a steady pulse that feels like a tide of sound. If you ever want to break down the math of that pulse—its frequency, amplitude, and how the atmosphere shapes it—I’m ready to dissect it step by step.