States of the Matter

Oh, an easy one: there are 3; class dismissed. Well, may be 4, if you count plasma. Well, there may be more than 4!!
What makes a substance have solid form, or gaseous form, or liquid form, or plasma form, and what does that mean anyway?? And what about those other states?
Come and learn some surprising facts about a thing that SEEMS to be obvious, but isn't!