# Is it possible?

1. Nov 12, 2007

### aman malik

velocity of sound in dry air is 332m/s and it (linearly-i think so) increases with density.
so is it possible to formulate such a medium in which speed of sound reaches to the level of light

2. Nov 12, 2007

### Retsam

No its not possible

3. Nov 12, 2007

### rcgldr

Velocity of sound in the air is related to temperature, not density.

4. Nov 12, 2007

### Retsam

Yea and the speed of sound in a solid is actually depenadant on the material's youngs modulus by the equation :

V = sqrt(Y/P)

Where Y and P stand for the youngs modulus and the density respectively.
The youngs modulus is the ratio between the stress and strain coefficients of the material.

5. Nov 12, 2007

### pixel01

It can be the case inside a blackhole.

6. Nov 12, 2007

### wysard

But if you take the known mass of the Universe and it's known dimensions we might well be in a black hole, and it's not true here either....

OP: The answer is No. If you messed with the air in terms of temperature and solidity to make your hypothesis possible it wouldn't be air any more. Specifically to counter the density and modulus problems you would have to freeze the air to zero Kelvin. At which point it wouldn't be air, but pretty much neutronium on it's way to becoming a black hole. Then it would work per the previous poster. Then it would blow up in your face and take a good chunk of the solar system with it per Stephen Hawking.

~sigh~ So many ideas. So few solar systems worth blowing up....

7. Nov 13, 2007

### aman malik

one more thing i know now is that the velocity of sound does not linearly vary with medium. can anybody tell me how does it vary???

to jeff reid's ans it varies both with temp and density.

8. Nov 13, 2007

### stewartcs

9. Nov 13, 2007

### rcgldr

10. Nov 13, 2007

### stewartcs

Doesn't matter...

Source: http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html

Source: http://en.wikipedia.org/wiki/Speed_of_sound

I do agree with you that the overall effect of the density as it relates to the speed of sound in air is negligible. However, it technically should be considered from a theoretical stand point.

11. Nov 14, 2007

### aman malik

in a solid medium sound is tranferred br the vibrtaion of the atoms .more denser the substance more quickly the will tranfer energy from one part to another.
all the links that you have given relate velocity of sound in air, or ideal gases .but which exactly relates with density?

12. Nov 17, 2007

### thiotimoline

Take water and air for example. The speed of sound is faster in water than in air because the particles responsible for transmitting the sound energy from point to point is closer to each other. Therefore it's partially correct to say that increasing density of a material will increase the speed of sound, but difficult to attain speed of light because you have to consider the type of particles involved. Even if you use the smallest atomic particle, it still has a certain limit to be compressed in order to conduct sound energy at speed of light. Exclusion principle from Chemistry states that no two electron occupies the same quantum state, meaning there is always a difference in position. In short, the speed of sound only tends to speed of light when density increases. Similarly, increasing temperature has the same effect as the abovementioned.