How Instruments Make Sound

Core Idea

All instruments make sound by causing something to vibrate. A drum skin vibrates when you hit it, a guitar string vibrates when you pluck it, and air vibrates inside a flute when you blow across it. You can often feel these vibrations if you touch the instrument gently while it is sounding.

How It's Best Learned

Place a hand on a drum while someone taps it and feel the vibration. Pluck a rubber band and watch it wobble back and forth. Hold a humming tuning fork against a table and listen to the sound get louder. Discuss: what is shaking in each instrument?

Common Misconceptions

• Thinking the sound magically appears inside the instrument; there is always something physically vibrating.
• Believing only string instruments vibrate; every instrument, including drums and wind instruments, involves vibration.
• Assuming you can always see the vibration; air vibrating inside a flute is invisible but still real.

Explainer

All instruments make sound through vibration. Vibration means something shakes back and forth very, very fast. When you hit a drum, the drum head vibrates. When you pluck a guitar string, the string vibrates. When you blow air into a flute, something inside the flute vibrates. These vibrations are so fast your eyes cannot see them, but your ears hear them as sound!

When something vibrates, it pushes the air around it. Imagine a drum vibrating up and down. As it moves up, it pushes air up. As it moves down, it pulls air down. This creates waves of air moving in every direction. These air waves travel to your ears. Your ears receive these waves and your brain interprets them as sound. The vibration of the instrument becomes the sound you hear!

Different instruments vibrate in different ways, which is why they sound different. A tiny bell vibrates quickly and creates a high, bright sound. A big bass drum vibrates more slowly and creates a deep, booming sound. A string vibrates one way, and a drum head vibrates another way. Even though they all use vibration, the type of vibration creates different sounds!

Your own voice is created by vibration too! Inside your throat are two small folds of skin called vocal cords. When you speak or sing, air passes through them and makes them vibrate. These vibrations travel up through your mouth and out into the world as your voice. You are an instrument! You can feel your vibration by putting your hand on your throat while you hum—you will feel a tickle, which is the vibration of your vocal cords.

Understanding vibration helps you understand all music. Sound is vibration. Instruments make vibrations. Your ears receive vibrations and turn them into sound that your brain understands. When you make music, you are creating vibrations. When you listen to music, you are receiving vibrations through your ears. You are connected to music through vibration! Try this: hit a pot with a spoon and watch it wiggle. That wiggling is vibration. That vibration becomes the sound you hear. That is how instruments work!