# Can water be compressed? **URL:** \ **Category:** Factual Questions\ **Created:** [May 10, 2009, 5:16pm UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957 "2009-05-10T17:16:03Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Cagey\_Drifter](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@Cagey\_Drifter](https://boards.straightdope.com/u/Cagey_Drifter)\ **Post date:** [May 10, 2009, 5:16pm UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/1 "2009-05-10T17:16:03Z")
Without changing its temperature, can water be compressed (i.e. with force)? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [May 10, 2009, 5:24pm UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/2 "2009-05-10T17:24:49Z")
Compressing anything changes its temperature; compressibility of a fluid is a function of both pressure and temperature. Water is compressible, but not by a lot. [Here](http://van.physics.illinois.edu/qa/listing.php?id=2251) is a page that discusses water compression at ocean depths. ETA: Wikipedia gives the [compressibility of pure water](http://en.wikipedia.org/wiki/Water_(molecule)#Compressibility) ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [May 10, 2009, 10:33pm UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/3 "2009-05-10T22:33:33Z")
Compressing things need not change their temperature. You can add or subtract heat energy while you push or pull to keep the temperature whatever you want at any pressre. Cagey, by how much are you interested in compressing it, and why? ---
**Author:** ![Tim\_R.Mortiss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim_r.mortiss/32/142_2.png) [@Tim\_R.Mortiss](https://boards.straightdope.com/u/Tim_R.Mortiss)\ **Post date:** [May 10, 2009, 10:51pm UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/4 "2009-05-10T22:51:41Z")
Theoretically, yes. For all practical purposes, no. ---
**Author:** ![Cagey\_Drifter](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@Cagey\_Drifter](https://boards.straightdope.com/u/Cagey_Drifter)\ **Post date:** [May 10, 2009, 10:53pm UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/5 "2009-05-10T22:53:21Z")
> [@Napier](#): > > Cagey, by how much are you interested in compressing it, and why? Just a theoretical question that arose as I was screwing on the cap to my thermos. ---
**Author:** ![Zsofia](https://avatars.discourse-cdn.com/v4/letter/z/7bcc69/32.png) [@Zsofia](https://boards.straightdope.com/u/Zsofia)\ **Post date:** [May 11, 2009, 12:08am UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/6 "2009-05-11T00:08:07Z")
The earth does it all on its own, with air and water, doesn’t it? (I suppose that’s a far cry from doing it artificially, of course.) ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [May 11, 2009, 1:32am UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/7 "2009-05-11T01:32:29Z")
Water in all the world’s oceans are measurably and compressed. It is a basic concept in physical oceanography that must be accounted for to explain observations. So, water is certainly and practically compressed. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [May 11, 2009, 2:28am UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/8 "2009-05-11T02:28:43Z")
> [@Cagey\_Drifter](#): > > Just a theoretical question that arose as I was screwing on the cap to my thermos. The cap on my thermos is plastic, and much more compressible than the water (well, coffee) I put in it. If you have no airspace, it’s the cap that will give, not the water. ---
**Author:** ![Noel\_Prosequi](https://avatars.discourse-cdn.com/v4/letter/n/b19c9b/32.png) [@Noel\_Prosequi](https://boards.straightdope.com/u/Noel_Prosequi)\ **Post date:** [May 11, 2009, 3:58am UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/9 "2009-05-11T03:58:48Z")
One of the links above led me to references to the various crystalline structures of ice, where they mentioned pressures like 128GPa. This is higher than the level at which water loses its molecular character entirely. How on earth do they generate pressures like this in a lab? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 11, 2009, 4:05am UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/10 "2009-05-11T04:05:06Z")
> [@](#): > > How on earth do they generate pressures like this in a lab? Probably only very briefly, with an extremely powerful gun. ---
**Author:** ![Omphaloskeptic](https://avatars.discourse-cdn.com/v4/letter/o/bcef8e/32.png) [@Omphaloskeptic](https://boards.straightdope.com/u/Omphaloskeptic)\ **Post date:** [May 11, 2009, 4:16am UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/11 "2009-05-11T04:16:52Z")
> [@Noel\_Prosequi](#): > > One of the links above led me to references to the various crystalline structures of ice, where they mentioned pressures like 128GPa. This is higher than the level at which water loses its molecular character entirely. How on earth do they generate pressures like this in a lab? [This](http://en.wikipedia.org/wiki/Diamond_anvil) is one way. ---
**Author:** ![Noel\_Prosequi](https://avatars.discourse-cdn.com/v4/letter/n/b19c9b/32.png) [@Noel\_Prosequi](https://boards.straightdope.com/u/Noel_Prosequi)\ **Post date:** [May 11, 2009, 5:47am UTC](https://boards.straightdope.com/t/can-water-be-compressed/495957/12 "2009-05-11T05:47:35Z")
Utterly fascinating. Ignorance fought. Thanks. I wish I had one as a kid - imagine the nipple cripples you could do with it 🙂