The connectedness of water molecules creates its 3 phases

It is helpful to view it as 3 states, without regard to whether it is solid or gas by appreciating the level of connectedness of the water molecules. Let's name 3 states of water in terms of level of connectedness of water molecules to each other:

• Completely separated molecules = Water vapor
• Intermittently connected molecules = liquid water
• Continuously connected molecules (Hydrogen bonded water molecules) = solid (ice, snow) water or connected water vapor (clouds)

Let's describe each of those.

These are clearly gaseous molecules. We call this water vapor. Thus, water evaporating from the ocean leaves the liquid surface of the water one molecule at a time, rising into the air.

Completely separate water molecules have covalent bonds between the oxygen and each of the 2 hydrogen atoms. The covalent bond means that hydrogen atom is connected only to one oxygen atom. When each of the hydrogen atoms are covalently bonded to the oxygen atom, it is a completely separate molecule from all the other water molecules.

When we boil water the bubbles that form are separated water molecules (plus air) that are not connected to any others. As soon as the bubble reaches the surface of the liquid, it "pops" through in its gas phase.

Liquid water, on the other hand, is a grouping of molecules that are connected as well as unconnected. Some of the hydrogen atoms are covalently bonded to oxygen and others are hydrogen-bonded. 

The covalently bonded hydrogen atoms are only connected to one oxygen atom, whereas the hydrogen-bonded ones bring two oxygen atoms together. It is the difference between a child holding one parent's arm versus two parent's arms. 

The reason liquid water is fluid is that the connectedness of water molecules is intermittent and ultra-fast. One molecule is connected to 2-3 others and then a split second later it is connected to 3 different water molecules or none at all.

This is all taking place at a femto-second scale. In the millisecond scale world that we live in, the water molecules seem connected all the time.

Now, when water molecules are connected together through hydrogen bonds (no covalent bonding at all), then you can get different types of water states: 

• connectedness of water vapor at very low temperatures = crystallize as Snow
• Connectedness of liquid water at 0º C= ice
• Connectedness of water vapor into webs of hydrogen-bonded water = mist, fog, and clouds (those states of water are a netting of hydrogen-bonded water vapor holding water droplets and air)

Note that water can go from continuously connected to intermittently connected states (ice --> water). And from continuously connected to completely separate states (Sublimation of snow). 

But to go from one type of continuously connected to another continuously connected, it has to go to another phase. For example, ice cannot transform into snow without having changed first into water vapor: Both ice and snow are hydrogen-bonded water molecules. But there is a physical difference in the connections in snow that cannot be achieved unless you start from scratch with water vapor to form snow.

Similarly, snow can form ice, but first has to transform to liquid water and then freeze.

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