Water Flow from bathroom tap

[gumboil]

I've got a "waterfall" type mixer tap (faucet) fitted to my bathroom sink. The one shown in the link below is virtually identical to it.

http://www.ebay.co.uk...P&hash=item439c44ff6c

I've noticed recently that when the water stream falls off the edge of the glass skirt, the water stream physically twists in mid air. Does anyone know what might cause a stream of water to give a single twist like this. It looks very odd as you would expect the water to just fall off the edge of the skirt just like a waterfall rather than twist before falling.

thank you.

[jomifl]

If I understand your question properly the following may be the answer.
Because the water on the glass is in the form of a sheet (because of gravity) as it falls over the edge surface tension becomes dominant causing the water to coalesce into a solid stream. Because of conservation of momentum the water from the outside edges just keeps going and imparts its tangential motion to the mass of water( the spinning skater effect).