Why are most liquids considered incompressible?

Most liquids are considered incompressible primarily because of the strong intermolecular forces present within them. These forces keep the molecules closely packed together, preventing significant changes in volume when pressure is applied. When a liquid is subjected to compression, the distance between its molecules can only be reduced slightly because they are already in close proximity.

This incompressibility is a practical assumption in many scientific calculations and applications because, under normal conditions, applying pressure to a liquid results in negligible changes in volume. Liquids maintain their density and shape more effectively than gases, which can expand significantly with changes in pressure.

The characteristics of liquids, including their behavior when subjected to external forces, hinge on this strong intermolecular attraction, which is the primary reason for their classification as incompressible.