This is not a bird related topic, but it does have to do with a natural
phenomenon. I have tried a Yahoo search under several different topics,
but have not gotten anywhere. Here is the question:

We all have heard that bath tub drain vortices rotate in opposite
directions depending on which hemisphere (north or south) they are located
in. Does anyone have a reliable reference that documents this idea? If
so, you can answer my querie directly to me and not clutter Tweeters with
non-bird information.
Thanks

Stan Ray