Re: AW: Underwater latency (not completely OT) ;-)

[Doug Cox <dougcox@pdq.net>]

This can be found here: http://hypertextbook.com/facts/2000/NickyDu.shtml

Sound is a type of longitudinal, mechanical wave. They need a medium to 
propagate and will not travel through a vacuum. Sound travels at 
different speed in different media. The speed of sound is determined by 
the density and compressibility of the medium. Density is the amount of 
material in a given volume, and compressibility is the how compacted 
could a substance become for a given pressure. The denser and the lower 
the compressibility, the slower the sound waves would travel. Therefore, 
the speed of sound is about four times faster in water than in air. The 
speed of sound can also be affected by temperature. Sound waves tend to 
travel faster at higher temperatures. I have found different values for 
the speed of sound in water in different sources. They range from 1450 
to 1498 meters per second (m/s) in distilled water and 1531 m/s in sea 
water at room temperatures (20 to 25 °C).

The speed of sound in a medium can be determined by the equation...

/v/ = (/B//ρ)^1/2

Where...

    /v/ is the speed of sound,
    /B/ is the bulk modulus of elasticity, and
    ρ (rho) is the density.

The bulk modulus of elasticity, also known as the compressibility, is 
the relationship between pressure and volume. It is a measure of how 
much an increase in pressure would decrease the volume.

Nicky Du -- 2000



Jesse Lucas wrote:

> Rainer Thelonius Balthasar Straschill wrote:
>
>> If I remember my (very) basic university classes in physics, we usually
>> would test any theories we might have by bringing them to extreme values
>> and see what happens. If lower density = lower speed of sound, then we
>> would have sound travelling at infinite speed in vacuum. I don't believe
>> this is the case.
>
>
> In space there is no medium for sound to travel through. See the tag 
> line to the film "Alien."
>
>
>
>
>