In the same way that a large solid holds its shape, the atoms inside of a solid are not allowed to move around too much. and molecules in liquids and are bouncing and floating around, free to move where they want. The molecules in a solid are stuck in a specific or arrangement of atoms. The atoms still vibrate and the fly around in their orbitals, but the entire atom will not change its position.​

Asubstance is held in an open container. its particles move past one another at random speeds but do not leave the container. heat is removed from the system, and the particles slow down. when enough heat is removed, the particles no longer have enough speed to overcome the weak attractive forces between them. when this happens, the substance enters its solid state. the process described above is known as .