Feel the Buzz: How Sound is Made by Vibrations

Put your fingertips gently on your throat. Now hum — any tune you like! Can you feel something? That tiny shaking feeling under your fingers is a clue to one of the biggest secrets in science: every sound you have ever heard was made by something moving back and forth, incredibly fast.

Every sound starts with a vibration. A vibration is a very fast back-and-forth movement. When something vibrates, it bumps into the air around it. Those bumps travel through the air as invisible waves — called sound waves — all the way to your ear. Your ear picks up the waves and your brain turns them into the sounds you hear. Think about a drum. When you hit a drum, the stretched skin (called the drumhead) wobbles quickly back and forth. Press your hand gently onto the drumhead just after you hit it and you can feel it shaking. That shaking IS the vibration making the sound. When the drumhead stops vibrating, the sound stops too. The same thing happens with a guitar string. Pluck a string and watch it — you can actually see it blur as it vibrates. The faster it vibrates, the higher the sound. The slower it vibrates, the lower the sound. You can test this with your own body. Put a finger gently on your throat and speak. You feel the vibration of your vocal cords — two tiny flaps inside your throat that shake when you push air past them. Stop speaking and the vibration stops. No vibration, no sound. It really is that simple.