What is Sound?
Every sound we hear is created by something
Sometimes we can see the vibration.
Pluck a taut elastic band and you can see
the band twanging rapidly to and fro as it hums.
Clap your hands, or stamp your feet and
you see nothing moving. Vibration is there all the same, it is not only
the band or your hands that move. You hear a sound because air moves
too. As the source of a sound vibrates to and fro, it pushes the air
molecules around them vibrating, and so the sound is transmitted through
the air to your ears in little vibrations or sound waves.
Sound is energy.
Put your index and middle finger on your
neck. Say the word "Aah"
as loud as you can. Then try it as soft as you can. You not only hear
a sound, but you can feel a movement inside your throat. When you say,
"Aah", your vocal cords vibrate. That means they move quickly
back and forth. As your vocal cords vibrate they produce sound.
Unlike light waves, sound waves do not travel through a vacuum. They
need matter to travel. That is why sound can travel through a wall.