Why gases spread out and take up space?

Gases spread out and take up space due to the high kinetic energy of their particles, which causes them to move rapidly and collide with one another and the walls of their container. This motion leads to a low density and allows gases to expand to fill any available volume. Unlike solids and liquids, gas particles are far apart and not held together by strong intermolecular forces, enabling them to disperse freely. As a result, gases occupy the entire space available to them, adapting to the shape of their container.