How sounds are made: vibrations
Physics · Key Stage 1 · The School
What a vibration is
A vibration is a very fast wobble, back and forth. You often cannot see it happening, it is so fast. But you can sometimes feel it. Every single sound starts with something vibrating.
Feeling a vibration
Put your fingers gently on your throat. Say a long "aaah". You can feel a buzz. That buzz is your vocal cords vibrating. Now touch a ringing bell. You can feel it shaking. Stop it with your hand and the ringing stops at once.
Vibrations you can see
Stretch a rubber band between two fingers and pluck it. Look closely. You can actually see it blur as it vibrates. A guitar string does the same thing, just faster. The faster the vibration, the higher the sound it makes.
Making a ruler buzz
Hold a ruler flat on a desk with most of it hanging over the edge. Press one end down firmly. Now flick the free end. It vibrates up and down, fast. You hear a buzzing note. Press your finger on the ruler to stop it moving. The sound stops at exactly the same moment. No vibration, no sound. Every single time.
Vibrations all around
A drum skin vibrates when you hit it. A door vibrates a little when it slams. Even a loud speaker cone is vibrating, fast, to make music. Find something that makes a sound and try to feel or see the vibration behind it.