why no compressed liquids?

I know that liquids cannot be compressed such as gas or solids, but is it feasible or just impossible? If science did find a way to compress liquids what kind of technological advances would this bring?

Why do you think liquids cannot be compressed?

Put some pressure on it, it’s compressed.

Though they can not be compressed as much as gases, since the Stuff is much closer together in a liquid.

Why do you think that liquid can’t be compressed? Here’s one use. It is just the degree of compression that differs from gases.

no they can’t be compressed, maybe in the sense you said but why do you think they are used in such ways as hydraulics. Because they cant be compressed.

Um, cw you’re wrong. Hydraulic fluid most certainly is compressed when pressure is put on it. However, it doesn’t compress very much.

The exact same effect of hydraulics can be accomplished with a gas (in fact, it’s called pneumatics) it just takes more energy.

As Friedo alluded, liquids (and solids) are not observed to compress very much, even under extreme pressure, because the individual molecules (or atoms, or ions, depending on the chemical makeup of the substance in question) are very nearly in contact with each other.

The outer electrons of one molecule exert a repulsive force on those of a neighboring molecule that gets too close. This prevents the molecules from “overlapping.” This is also the source of all macroscopic contact forces.

However, should the external pressure get large enough, it is theoretically possible to overcome this repulsive force and crush the atoms together until the nuclei nearly touch. This is the situation in a neutron star. Since atoms are mostly empty space, quite a high density can be achieved, on the order of 100 million tons per cubic centimeter.

BTW, the pressure necessary to achieve such a state of matter is well beyond our capabilities in the laboratory. Neutron stars result from a Type II supernova triggered by the collapse of a very massive star.

Did this answer your question? :smiley:

Listen carefully: You asked a question, and it was answered. If you wish to differ, please provide a cite for your opinion. If you had bothered to follow my first link, you would have seen the compressibility of water calculated.

Not to hijack but this is an interesting topic re the behavior of this material in a terrestial environment.

Neutron Star Material Properties on Earth?

Give the guy (or gal) a break. As an approximation, water is often said to be incompressable.

cw, maybe this will help ( http://people.hofstra.edu/faculty/J_B_Bennington/121notes/physics.html )

rsa: as an approximation [sym]p[/sym] is sometimes referred to as 3, and g simplified to 10m/s/s; but these oversimplifications don’t allow a full understanding. The question was asked, “I know that liquids cannot be compressed such as gas or solids, but is it feasible or just impossible”. The answer is that it is indeed feasible, exactly like gasses and solids, and this answer provides the greatest understanding of the nature of liquids under pressure. I even provided a table showing that the magnitude of volume change was [relatively] small for most pressures achievable in the real world. To have answered this question, “yep, liquids are noncompressible,” would have been incorrect, and would have allowed the OP to persist in an obvious misconception.

I’ll stick by the accuracy of my answer, my mild irritation the very asker of the question would come back with “no they can’t be compressed” after is had been answered, and my request that such a statement be accompanied by a cite.

Waverly, no problem. I certainly didn’t mean to imply that you were wrong to give a COMPLETE answer. It’s just that the link you provided wasn’t easy for a non-expert to interpret. I looked at that table and couldn’t figure out what those compressibility values represented, although I could see that they were very small values. And I agree that cw shouldn’t dispute what you were saying without a cite (although he did qualify his statement a bit). It just seemed like the first couple of responses were a teeny bit patronizing.


Fair enough, rsa. I may have come across more irritable than I intended.