– Why is water ‘virtually’ incompressible?

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– Why is water ‘virtually’ incompressible?

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Anonymous 0 Comments

Water is compressible, but not too much.

It’s just that gases are very very very compressible.
If you have ever tried to compress a closed, empty syringe before, you are able to compress it somewhat with a little difficulty.

To get an idea for that, i want you to guess how many air molecules there are in a small cube(take 1cm sided cube for example).

A million? Seems low, a billion maybe? Even a trillion?

Nope, its around 10^16 atoms. That’s like a million trillion. Seems very large.(Incorrect)

Now guess how many atoms in one cm³ of water? Maybe like 10 or 100 times more?

Nope, its around 10^22 atoms. Basically a million times more atoms. Not too difficult to see why that might be hard to compress.

Of course, there are several other factors at play, like the energy of gas particles, the intermolecular attraction of water, attraction of the gas molecules, relation between temperature and pressure, and many more. Although i do think the significantly more amount of water molecules is the biggest reason for the less compressibility of water (or of any liquids, compared to gas).

Tldr: Water(or any liquid) has a lot more atoms than any gas. So its much harder to compress.

Edit: Whoops, use a few wrong numbers in the formulas
The number of atoms in one cm³ of air is around 10^19. That water/air molecules factor to around 1000. Should still. Still that’s a lot more atoms.

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