Speed of sound in water
Sound is one of the components of our life, anda person hears it everywhere. In order to examine this phenomenon in more detail, it is first necessary to understand the concept itself. For this it is necessary to turn to the encyclopedia, where it is written that "sound is elastic waves propagating in some elastic medium and creating mechanical oscillations in it." In a more simple language, these are audible fluctuations in some environment. From what it is, and the basic characteristics of sound depend. First of all - the speed of propagation, for example, the speed of sound in water differs from other media.
Any sound analog has certainproperties (physical characteristics) and qualities (reflection of these signs in human sensations). For example, duration-duration, frequency-height, composition-timbre and so on.
The speed of sound in water is much higher than,say, in the air. Consequently, it spreads faster and is much more audible. This happens because of the high molecular density of the aquatic environment. It is 800 times denser than air and steel. Hence it follows that the propagation of sound largely depends on the medium. Let us turn to specific figures. So, the speed of sound in the water is 1430 m / s, in the air - 331.5 m / s.
Low-frequency sound, for example, noise, whichproduces a working ship engine, always heard a little earlier than the ship appears in the visibility zone. Its speed depends on several things. If the water temperature rises, then, naturally, the speed of sound in the water rises. The same thing happens with increasing salinity of water and pressure, which increases with increasing depth of the water space. A special role in speed can have such a phenomenon as thermoclines. These are places in which layers of water meet at different temperatures.
Also in such places a different density of water (due todifference in the temperature regime). And when waves of sound pass through such heterogeneous layers, they lose most of their strength. Faced with the thermocline, the sound wave is partially and sometimes completely reflected (the degree of reflection depends on the angle at which the sound falls), after which, on the other side of this place, a shadow zone is formed. If we consider the example where the sound source is located in the water space above the thermocline, then it's already lower to hear anything at all, something will be not that difficult, but almost impossible.
Sound vibrations that are published oversurface, in the water itself is never audible. And vice versa occurs when the source of noise under the water layer: above it it does not sound. A bright example is modern divers. Their hearing is greatly reduced due to the fact that water acts on the eardrums, and the high speed of sound in the water reduces the quality of determining the direction from which it moves. This dulls the stereophonic ability to perceive sound.
Under a layer of water, sound waves enter thethe human ear is most through the bones of the head's cranium, and not as in the atmosphere, through the eardrums. The result of such a process becomes his perception simultaneously with both ears. The human brain is not able at this time to distinguish between the places from which signals are received and in what intensity. The result is the emergence of consciousness that sound rolls from all sides simultaneously, although this is far from being the case.
In addition to the above, sound waves in the waterspace have qualities such as absorption, divergence and dispersion. The first is when the sound power in salt water gradually comes to naught due to the friction of the aquatic environment and the salts that are in it. Divergence is manifested in the removal of sound from its source. It seems to dissolve in space as light, and as a result its intensity drops significantly. And the oscillations disappear completely due to scattering on all kinds of obstacles, inhomogeneities of the medium.