[ELI5] Can one physically compress water, like with a cyclinder of water with a hydraulic press on the top, completely water tight, pressing down on it, and what would happen to the water?

Question

[ELI5] Can one physically compress water, like with a cyclinder of water with a hydraulic press on the top, completely water tight, pressing down on it, and what would happen to the water?

In: 1967

Answer 1

Yes, you can compress water a little, if you do, it gets a bit more dense. The molecules get a little closer together, and want to spread out again, a bit like stretching a rubber band, but in reverse.

Liquids in general hardly compress at all. Some liquids compress more than others. Water compresses quite a bit, compared to brake fluid, which is chosen because it hardly compresses at all. If you were to replace your car’s brake fluid with water (DON’T DO IT, IT’S NOT SAFE TO DRIVE LIKE THAT), the brake pedal would feel “Spongy” as the fluid in the lines compressed rather than transferring the energy to the brakes..