A liquid can easily change its shape but a solid can not because
the density of a liquid is smaller than that of a solid
the forces between the molecules is stronger in solid than in liquids
the atoms combine to form bigger molecules in a solid
the average separation between the molecules is larger in solids
The forces between the molecules is stronger in solids than in liquids
The forces between the particles of a solid are stronger than those between the particles of a liquid, so the particles cannot move freely but can only vibrate. Thus, a solid has stable, definite shape and volume. A solid can only change its shape by force (when broken or cut), whereas a liquid can easily change its shape because of weak inter-particle forces.