Why gases are compressible but not liquids?

Question

Why gases are compressible but not liquids?

Answer 1

Actually, liquids are capable of being compressed, but not as easily. The reason has to do with space between them molecules. Comparatiely speaking, gasses have a lot of space; liquids have less space between them, and solids have very little.

Compressing the gas reduces the amount of space between the molecules...you have the same amount of molecules, but they occupy a smaller volume. You can do this to liquids as well, but, because the molecules are already much closer to together, it requires much more force to create a difference.

If you compress the gas enough, the gas can actually condense and liquify...this is one of the reasons why airbrakes have a gasket that you have to drain of condensate periodically. It accounts for some of the water that gets into some air conditioners as well (especially the old-fashioned ones or large units with the condensation plates).

I can't think of a liquid that most people compress in day-to-day life, but a good example is that the earth's core is composed off two layers: a liquid outer core, and solid inner core. The composition of each layer is the same. It is believed that the inner core is only solid because the weight pressing down from all sides compresses the inner-most liquids into a solid mass.