Type in the content of your page here.
Sound Waves
Sound is a form of energy that moves in waves. Sound waves are compressional waves. Sound is a series of compression waves that moves through air or other materials. 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. These sound waves are created by the vibration of some object, like a radio loudspeaker. sound_wave.jpgsound.gifThe waves are detected when they cause a detector to vibrate. Your eardrum vibrates from sound waves to allow you to sense them. The amount of energy flowing in the sound waves is referred to as the intensity of sound. The loudness of the sound is based on the strength of the sensation received by the eardrum and sent to the brain. The same intensity of sound may produce different degrees of loudness for different people. Intensity and loudness of a sound depend on four factors: (1) how far the distance is from the source of the sound (especially in outdoor situations), (2) the amplitude of the vibration, (3) how dense the medium is through which the sound travels, and (4) the area of the vibrating object. Sound has the standard characteristics of any waveform. Sound is a waveform that travels through matter. Although it is commonly associated in air, sound will readily travel through many materials such as water and steel. Some insulating materials absorb much of the sound waves, preventing the waves from penetrating the material. Because sound is the vibration of matter, it does not travel through a vacuum or in outer space. When you see movies or TV shows about battles in outer space, you should only be able to see an explosion but not hear it. The sounds are added for dramatic effect. The loudness of a direct sound decrease as the distance between a person and the source of the sound increases. The larger the amplitude of a sounding body, the more intense the sound. The amplitude of a sound wave is the degree of motion of air molecules within the wave. In air, the forward movement of vibrating objects pushes molecules together. This is called compression. When the vibrating object moves back in the opposite direction, the air is separated, causing the molecules to move farther apart. This is called rarefaction. Much of what we know about sound, tension, length, and thickness affect frequency of vibrating strings is accredited to the Greek philosopher Pythagoras. He discovered that if one string vibrates with twice the frequency, we hear higher frequency as one octave higher in pitch then the lower frequency (this can be demonstrated by playing the middle C on a piano, then the next C to the right).

Hearing Sound
Humans hear primarily by sound waves, watch enters the pinna and are magnified by the auditory canal. Sound waves are than directed towards the tympanic membrane. The pressure of air molecules cause the tympanic to vibrate. This causes the malleus on the other side of the membrane to move. The handle of the malleus strikes the incus causing it to vibrate witch moves the stapes in and out and vibrates the oval window. hearing-diagram-2.gif