Sound - one of the components of our lives, and people can hear it everywhere.For a closer look at this phenomenon, we must first deal with the very notion.For this we must turn to the encyclopedia, which says that "the sound - it is the elastic waves propagating in a resilient environment and create mechanical vibrations in it."In more simple terms - is audible vibrations in a medium.On which it depends, and the main characteristics of the sound.In the first place - the speed of propagation, for example, the speed of sound in water is different from another medium.
Any analogue sound has certain properties (physical characteristics) and quality (reflected these traits in human feelings).For example, the length, duration, frequency-height-tone part, and so on.
speed of sound in water is much higher than, say, in the air.Consequently, it extends much farther and faster than heard.This happens because of the high molecular density aqueous medium.It is about 800 times more dense than air, and steel.It follows that the propagation of sound depends on the environment.Referring to a specific figure.Thus, the speed of sound in water is equal to 1430m / s, the air - 331,5m / s.
low-frequency sounds, such as noise, which produces marine engine running, always heard a little earlier than the ship comes in sight.Its speed depends on several things.If the water temperature is increased, naturally, it increases the speed of sound in water.The same occurs with increasing salinity and pressure which increases with increasing depth of the water space.A special role in the speed can have such a thing as the thermocline.These are places where there are layers of water of different temperatures.
also places different density of water (due to the difference in the temperature regime).When sound waves pass through such different-density layers, they lose much of their force.Faced with thermocline acoustic wave partially, and sometimes completely reflected (the reflectance depends on the angle at which the sound falls), and then on the other side of this place, a shadow area.If we consider an example where the sound source is located in a body of water above the thermocline, already below to hear anything at all it is not something that is difficult and almost impossible.
sound vibrations that are produced on the surface, in the water itself is never heard.On the contrary it occurs when the source of the noise under water layer: above him, he does not sound.A striking example - modern divers.Their ears is greatly reduced due to the fact that water acts on the eardrum, and the high speed of sound in water reduces the quality determination of the direction from which it moves.Thereby stereo dulled ability to perceive sound.
under water sound waves enter the human ear is more than just a bone skull head, not like in the atmosphere through the eardrums.The result of this process becomes his perception of both ears simultaneously.The human brain is not able to discern the time position from received signals, and to what intensity.The result is the emergence of consciousness, that sound as though rolls on all sides at once, although it is not so.
addition to the above, the sound waves in the water space have qualities such as absorption and dispersion of divergence.The first - when the power of sound in salt water gradually eroding due to friction of the water environment and are of salts.Divergence is shown in its removal from the sound source.He seemed to dissolve in the space as light and as a result its intensity decreases significantly.And the fluctuations disappear entirely due to scattering at all kinds of obstacles, heterogeneous environments.