Is there any substance that can be cooled form a gas through liquid to solid or heated to go the other way? And what happens ato the proxinity and motion of the particles? I know they move more when heated but are they further apart?
Iodine It undergoes a process known as sublimation. In other words, when heated, it goes straight from solid to gas without becoming liquid.
RE: Iodine Have a read of this, especially point 4, the characteristics. http://en.wikipedia.org/wiki/Iodine
Not sure if I understand your question properly almost all substances when cooled far enough go to a solid then as you heat they go through liquid and then become a gas. There are special exceptions as mentioned by another bubble. Oh and yes they do move further apart thats why gasses are lighter - they are less dense. (Water is an exception where for some reason ice is less dense than cold water)
Used to love chemistry as a kid It helped that we had the archetypal mad scientist as a teacher though! White lab coat, thick glasses & unruly hair!
Water is a far more complex matter. Can be liquid at low temperatures amongst other anomalous properties it exhibits http://www.lsbu.ac.uk/water/explan.html
It's all about Triple points. Gets a bit complicated - all subsatnces can be solid ,liquid or gas given the correct conditions of temperature and pressure. Under normal atmospheric pressure water is virtually unque in having a solid which is slightly less dense than it's liquid at freezing point and hence ice floats. The reason for this is the open structure formed when molecules of water form a solid. This is due to a form of inter-molecular force called hydrogen-bonding. Without it, life (as we know it!) wouldn't exist - so it is pretty important.