Solid – Fixed shape and volume, tightly packed molecules. (e.g. Ice)Liquid – Takes the shape of container, definite volume. (e.g. Water)Gas – No shape or volume, spreads freely. (e.g. Air)State Changes:Solid → Liquid = MeltingLiquid → Gas = EvaporationGas → Liquid = CondensationLiquid → Solid = FreezingSolid → Gas = Sublimation