In the comment section of my last post Patricia Griffin said...
Well, I'm back to doing what I do best...messing it up. Heh.
I made these medium sized (10 pound) jars this afternoon. Round, they are. Very Round. How now round ...er...jar. The clay was throwing so well, I had to be careful not to throw the walls so thin that they only had one side.
It's horrible to suddenly discover that jars you just spent hours making, rather than having walls that have two sides (as all good jars should), only have an outside, but no inside. Of course, jars hold exponentially more stuff without the restriction of inside walls. Without walls, even the smallest of jars could conceivable hold, say, an automobile or even a small house. But once you have both an outside AND an inside defining the jar, it is only then that you can actually say, for instance, "This is a four gallon jar."
It's a tough concept to grasp. Being a potter is tough mental work and not everyone is cut out to tackle it.