This simulation illustrates the microstructure of water in different aggregate states. |
When water is in its solid state (ice), only rotary and oscillatory motions of water molecules are possible. Translational motion over noticeable distance is impossible. Note the sharply defined crystalline structure of ice and the orientation of the structural molecules (in some of the molecules, hydrogen atoms are oriented towards the oxygen atoms of other molecules). Each water molecule is connected with four adjacent molecules. Voids formation in the ice structure results in its relatively lower density, as compared to the density of liquid water.
While in liquid state, water still exists as a single whole (keeping its volume), and molecule-to-molecule distance coincides in the order of magnitude with the size of the molecules. However, displacements of molecules from their initial positions to distances that significantly exceed this value are possible, which results in the loss of relative orientation of molecules and the liquid composition as a whole. <
Finally, in the gaseous state, the distance between water molecules is at its greatest, and molecular free paths are much larger than the molecular sizes.