Is water compressible?

[BK911]

Having a discussion with somebody at work.
One of us says it is barely compressible.
The other says it is not, that it is the air entrained in the water that compresses.
Who wins?

[wdfifteen]

Interesting question. I have heard that the sea levels would be several feet higher if water were not compressible, but I've never thought about the volume change being due to entrapped air.

[Nostril Cheese]

https://water.usgs.gov/edu/compressibility.html

[imcarthur]

Wiki says yes.

Ian

[Tobra]

So Wiki is wrong again. From a practical standpoint, no, it is not. 40 atmospheres of pressure gives less than a 2% decrease in volume. That is pretty incompressible.

[HardDrive]

For the vast majority of uses, no.

[unclebilly]

Technically, any fluid is compressible however water in the liquid phase is classified as in compressible.

I am going through the peeing match with a patent examiner right now where he is playing semantics on the definition of a compressible fluid.

[Steve Carlton]

What's interesting about water is that it expands when it freezes. If that wasn't true, life would not exist as we know it on our planet.

[Bill Douglas]

It's compressed already.

[aschen]

in practice, not a bit

In theory and philosophically, yes

[Cajundaddy]

1% compressible. Greater than zero compressibility but for most practical purposes it is as good as incompressible.

Vague enough weasel-word answer?

[greglepore]

The number one rod in my A8 said its not, just before the engine was rebuilt and i bought it at a steep discount.

[Flieger]

Everything is compressible. Well, maybe not the stuff in the center of a black hole.

It's just a question of bulk modulus. If water weren't compressible you couldn't have sound waves pass through it.

[TimT]

In the dark ages, between when slide rules were used and those early Ti calculators were starting to be seen in classrooms...

In a Fluid Dynamics course I was taught, that in any calculation,assume water is not compressible...but...of course there are different kinds of water...

No adjustments are made for compressibility of water usually...

One of us says it is barely compressible.

The other says it is not, that it is the air entrained in the water that compresses.

Who wins?

Those are different types of water.... pure de-ionized water surely has different properties than water from a stagnant pond.... or your tap....

[Flieger]

Originally Posted by TimT

In the dark ages, between when slide rules were used and those early Ti calculators were starting to be seen in classrooms...

In a Fluid Dynamics course I was taught, that in any calculation,assume water is not compressible...but...of course there are different kinds of water...

No adjustments are made for compressibility of water usually...




Those are different types of water.... pure de-ionized water surely has different properties than water from a stagnant pond.... or your tap....

Yeah, and I also did a lot of calculations where air was treated as incompressible (long as it was below Mach .3).

[GWN7]

From memory from my Fire Engineer Hydraulics course "It takes 80,000 PSI to compress water 1%. So in all basics water is not compressible"

[jyl]

Elasticity, Elastic Properties

[BK911]

Ok, so we all agree that water does compress VERY slightly.
But is the compression due to the tiny air bubbles within the water?

[GH85Carrera]

Originally Posted by Flieger

Everything is compressible. Well, maybe not the stuff in the center of a black hole.

It's just a question of bulk modulus. If water weren't compressible you couldn't have sound waves pass through it.

This.
With enough pressure diamonds are compressible.
Matter is mostly empty space.

In normal day to day life, water is not really compressible. In theory or with very special equipment it is.

[slakjaw]

I don't think water is compressible