Wednesday, March 24, 2010
Curious about Sound Waves???
Sound travels through the air as vibrations in air pressure. To hear sound, your ear has to do 3 basic things:
1. Direct the sound waves into the hearing part of the ear
2. Sense the fluctuations in air pressure
3. Translate these fluctuations into an electrical signal that your brain can understand
The outer part of your ear, serves to "catch" the sound waves. Your outer ear is pointed forward and it has a number of curves. This structure helps you determine the direction of a sound. If a sound is coming from behind you or above you, it will bounce off the ear in a different way than if it is coming from in front of you or below you. This sound reflection alters the pattern of the sound wave. Your brain recognizes distinctive patterns and determines whether the sound is in front of you, behind you, above you or below you.
Your brain determines the horizontal position of a sound by comparing the information coming from your two ears. If the sound is to your left, it will arrive at your left ear a little bit sooner than it arrives at your right ear. It will also be a little bit louder in your left ear than your right ear.
Since your ears face forward, you can hear sounds in front of you better than you can hear sounds behind you. Many mammals, such as dogs, have large, movable ears that let them focus on sounds from a particular direction. Human ears are not so adept at focusing on sound. They lay fairly flat against the head and don't have the necessary muscles for significant movement. But you can easily supplement your natural ears by cupping your hands behind your ears. By doing this, you create a larger surface area that can capture sound waves better.