What Causes Sounds?
All sounds are made by vibrations. Lightly place your fingers on your throat, and speak. The buzz you feel is your vocal cords vibrating. Stretch a rubber band and pluck it. Notice how the rubber band vibrates. As the rubber band vibrates, you can hear a humming sound.
When an object vibrates and produces sound, it makes the surrounding air vibrate. Vibrations in the air are called sound waves. These sound waves travel outward like ripples in a pond, and when they reach your ears, they make your eardrums vibrate. This is when you hear the sound.
Sound travels through matter because it needs the vibration of molecules to propagate. Because outer space is a vacuum with no matter, it’s very quiet. The matter that transports the sound is called the medium.
The speed of sound is how fast the wave or vibrations pass through the medium or matter. The type of matter has a large impact on the speed at which the sound will travel. For example, sound travels faster in water than air. Sound travels even faster in steel.
In dry air, sound travels at 343 meters per second (768 mph). At this rate sound will travel one mile in around five seconds. Sound travels four times faster in water (1,482 meters per second) and around 13 times faster through steel (4,512 meters per second).