In this chapter we studied sound waves. In this paper you will read about how the ear works, how acoustics work and how sound waves are used in real life in medicine and music. Some basic characteristics of sound waves. Sound waves are detectable to the human ear when the range is within 20 to 20, 000 Hz.

Sound waves are compressional waves also know as longitudinal waves. Sound waves require a medium to travel through. A medium is a substance or state of matter that the waves flow through. All sound waves come from vibrations. When you speak your vocal chords vibrate and send messages to the tympanic membrane or the ear drum. There is a lot more to sound waves then just sending them.

Receiving them is an interesting and complicated. First the sound waves travel through the auditory canal to the ear drum or tympanic membrane. The auditory canal resonates and amplify's the sound within a frequency range of 2, 000 Hz to 5, 500 Hz. When compressions and rare fractions reach the ear drum there is a change in pressure between the outer ear and middle ear. The eustachian tube helps keep the middle ear at atmospheric pressure. The differnece in pressure between the sound wave hitting the outer surface and normal atmospheric pressure on the inside of the ear drum cause the ear drum to vibrate.

In the ear vibrations travel through three little bones the hammer anvil and stirrup bones. The bones act as interlocking levers and they ampli phy the force of the ear drum striking the hammer. One other thing that causes amplification is the small oval window the cochlea which is smaller than the ear drum. Acoustics, the greek word "to hear" is of tem used for the general science of sound. Arcitectual acoustics depend on several things such as design, materials and insulation. Whenever planning to build an acoustical room design is extremely important.

Sound in an ordinary room due to reflections from the walls and furniture somewhat makes the room acoustically modified. For the best quality in acoustics rooms need to be designed to produce sufficient reflections for naturalness with bringing in excessive reverbaration no matter what the frequency is. Reverbaration time the amount of time required to diminish.