[math-fun] Bathtub drains
Long ago I read that water draining from a bathtub swirls one way in the N. hemisphere and the opposite way in the S. hemisphere. (Something about Coriolis forces.) But since then I've heard a number of times that this is just a myth. Does anyone know which is really true? (Perhaps it depends on the precision of your equipment?) --Dan _____________________________________________________________________ "It don't mean a thing if it ain't got that certain je ne sais quoi." --Peter Schickele
Yes, this is an urban legend, actualy some people tried it several times. Here is 1 explanation : http://planet-terre.ens-lyon.fr/planetterre/XML/db/planetterre/metadata/LOM-... (text in french). and a good one in english : http://www.straightdope.com/columns/read/149/do-bathtubs-drain-counterclockw... http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html but the effect of coriolis is the strongest, the strongest effect is the persistence of myths... Simon Plouffe
If I assume continuity, then the effect should be at a minimum at the equator? Then the effect would be at a maximum at the North & South poles? I understand that New York/Far East flights go over the North Pole every day. Perhaps someone has flushed while going over the North Pole? At 10:47 AM 9/15/2008, Simon Plouffe wrote:
Yes, this is an urban legend, actualy some people tried it several times.
Here is 1 explanation : http://planet-terre.ens-lyon.fr/planetterre/XML/db/planetterre/metadata/LOM-...
(text in french).
and a good one in english : http://www.straightdope.com/columns/read/149/do-bathtubs-drain-counterclockw... http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html
but the effect of coriolis is the strongest, the strongest effect is the persistence of myths...
Simon Plouffe
Quoting Dan Asimov <dasimov@earthlink.net>:
Long ago I read that water draining from a bathtub swirls one way in the N. hemisphere and the opposite way in the S. hemisphere. (Something about Coriolis forces.)
But since then I've heard a number of times that this is just a myth. Does anyone know which is really true? (Perhaps it depends on the precision of your equipment?)
Or of your bathtub ... Cyclones, tornadoes, whirlwinds work that way. But they have lots of space in which to work. Bathtubs probably depend more on the plumbing, given their relatively small size. - hvm ------------------------------------------------- www.correo.unam.mx UNAMonos Comunicándonos
participants (4)
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Dan Asimov -
Henry Baker -
mcintosh＠servidor.unam.mx -
Simon Plouffe