anand@utastro.UUCP (Anand Sivaramakrishnan) (12/16/85)
It's more a matter of plumbing and bath geometry. Drainpipe asymmetry causes any particular bath to prefer to swirl one way even if the drain is symmetrically placed in the bath. I have discovered that plumbing is often the root cause of many mysterious physical phenomena ( :-) ). Of course, there is the selection effect here that the places on the Earth where the whirlpool effect is most noticeable are exactly those places where baths freeze over before draining: i.e. the North and South Poles.