On 13 Apr 2005 14:39:27 -0400
Lewis Perin > wrote:

> "Alex Chaihorsky" > writes:
>
> > > I have found that among the many YiXing GungFu teapot "styles," those
> > > well made with a straight upward pointing spout work best in the drip
> > >
> > > department.
> > > The last drop is "pulled back" into the pot, as it ought to. This
> > > has to do with design much more than clay roughness and surface
> > > tension. Take it from Michael, the used-to-be potter.
> > >
> > > Michael
> >
> >
> > Its design plus material plus size and shape (that defines the
> > dynamics and geometry of how fast it is rotated around its
> > horizontal axis during pouring. Straight upward design works good
> > for smaller pots and yixing clay has very high surface tension
> > (watch drips of water sitting on its surface at different slope
> > angles and compare that with the behavior of water drops on glazed
> > porcelain) Same design does not work for large kettles at all also
> > because that design implies lifting the pot quite high and rotating
> > it at he higher angle, which is difficult with heavy pot. That is
> > why traditional kettle has a bent spout that allows for smaller
> > rotation angle and almost no lift.
> > Yixing pots are meant to be emptied into chahai by placing them
> > almost upside down with their spout inside chaihai opening. That is
> > not at all the dynamics of the usage of large teapot or kettle. Thus
> > the differences.
> >
> > With al due respect to a potter from a scientist.
>
> Neither potter nor scientist, I hesitate to raise a question I should
> have asked a bit earlier: Isn't surface tension a property of liquids,
> e.g. tea liquor, not solids, e.g. teapots?


Yeah, the property in question is often referred to as wetting. I have
no idea how much jargon surrounds that, suffice to say that a single
droplet of water (or oil, or acid, or etc) on a sterile plane of a given
material will take a different shape than on some other material. e.g. the
same amount of liquid will cover a given amount of surface area, and there
will also be differences in how it clings to it.